@@ -1,1 +1,2 @@
-bin/+bin/
+dist/

@@ -1,6 +1,7 @@
 before:
   hooks:
     - go mod download
+    - make migration-pack
 
 builds:
   - main: ./cli/node/main.go
@@ -9,10 +10,8 @@ id: node
     goos:
       - linux
       - darwin
-      - windows
-    hooks:
-      pre: make migration-pack
-      post: make migration-clean
+    goarch:
+      - amd64
 
 archives:
   - replacements:

@@ -21,7 +21,7 @@ return
 	}
 	// API to common + verify signature
 	commonAuth := accountCreationAuthAPIToCommon(&apiAuth)
-	if !commonAuth.VerifySignature(a.chainID, a.hermezAddress) {
+	if !commonAuth.VerifySignature(a.cg.ChainID, a.hermezAddress) {
 		retBadReq(errors.New("invalid signature"), c)
 		return
 	}

@@ -1,3 +1,27 @@
+/*
+Package api implements the public interface of the hermez-node using a HTTP REST API.
+There are two subsets of endpoints:
+- coordinatorEndpoints: used to receive L2 transactions and account creation authorizations. Targeted for wallets.
+- explorerEndpoints: used to provide all sorts of information about the network. Targeted for explorers and similar services.
+
+About the configuration of the API:
+- The API is supposed to be launched using the cli found at the package cli/node, and configured through the configuration file.
+- The mentioned configuration file allows exposing any combination of the endpoint subsets.
+- Although the API can run in a "standalone" manner using the serveapi command, it won't work properly
+unless another process acting as a coord or sync is filling the HistoryDB.
+
+Design principles and considerations:
+- In order to decouple the API process from the rest of the node, all the communication between this package and the rest of
+the system is done through the SQL database. As a matter of fact, the only public function of the package is the constructor NewAPI.
+All the information needed for the API to work should be obtained through the configuration file of the cli or the database.
+- The format of the requests / responses doesn't match directly with the common types, and for this reason, the package api/apitypes is used
+to facilitate the format conversion. Most of the time, this is done directly at the db level.
+- The API endpoints are fully documented using OpenAPI aka Swagger. All the endpoints are tested against the spec to ensure consistency
+between implementation and specification. To get a sense of which endpoints exist and how they work, it's strongly recommended to check this specification.
+The specification can be found at api/swagger.yml.
+- In general, all the API endpoints produce queries to the SQL database in order to retrieve / insert the requested information. The most notable exceptions to this are
+the /config endpoint, which returns a static object generated at construction time, and the /state, which also is retrieved from the database, but it's generated by API/stateapiupdater package.
+*/
 package api
 
 import (
@@ -7,6 +31,7 @@ ethCommon "github.com/ethereum/go-ethereum/common"
 	"github.com/gin-gonic/gin"
 	"github.com/hermeznetwork/hermez-node/db/historydb"
 	"github.com/hermeznetwork/hermez-node/db/l2db"
+	"github.com/hermeznetwork/hermez-node/metric"
 	"github.com/hermeznetwork/tracerr"
 )
 
@@ -15,7 +40,6 @@ type API struct {
 	h             *historydb.HistoryDB
 	cg            *configAPI
 	l2            *l2db.L2DB
-	chainID       uint16
 	hermezAddress ethCommon.Address
 }
 
@@ -27,7 +51,6 @@ hdb *historydb.HistoryDB,
 	l2db *l2db.L2DB,
 ) (*API, error) {
 	// Check input
-	// TODO: is stateDB only needed for explorer endpoints or for both?
 	if coordinatorEndpoints && l2db == nil {
 		return nil, tracerr.Wrap(errors.New("cannot serve Coordinator endpoints without L2DB"))
 	}
@@ -44,19 +67,25 @@ cg: &configAPI{
 			RollupConstants:   *newRollupConstants(consts.Rollup),
 			AuctionConstants:  consts.Auction,
 			WDelayerConstants: consts.WDelayer,
+			ChainID:           consts.ChainID,
 		},
 		l2:            l2db,
-		chainID:       consts.ChainID,
 		hermezAddress: consts.HermezAddress,
 	}
 
+	middleware, err := metric.PrometheusMiddleware()
+	if err != nil {
+		return nil, err
+	}
+	server.Use(middleware)
+
 	server.NoRoute(a.noRoute)
 
 	v1 := server.Group("/v1")
 
 	// Add coordinator endpoints
 	if coordinatorEndpoints {
-		// Account
+		// Account creation authorization
 		v1.POST("/account-creation-authorization", a.postAccountCreationAuth)
 		v1.GET("/account-creation-authorization/:hezEthereumAddress", a.getAccountCreationAuth)
 		// Transaction
@@ -74,17 +103,23 @@ v1.GET("/exits/:batchNum/:accountIndex", a.getExit)
 		// Transaction
 		v1.GET("/transactions-history", a.getHistoryTxs)
 		v1.GET("/transactions-history/:id", a.getHistoryTx)
-		// Status
+		// Batches
 		v1.GET("/batches", a.getBatches)
 		v1.GET("/batches/:batchNum", a.getBatch)
 		v1.GET("/full-batches/:batchNum", a.getFullBatch)
+		// Slots
 		v1.GET("/slots", a.getSlots)
 		v1.GET("/slots/:slotNum", a.getSlot)
+		// Bids
 		v1.GET("/bids", a.getBids)
+		// State
 		v1.GET("/state", a.getState)
+		// Config
 		v1.GET("/config", a.getConfig)
+		// Tokens
 		v1.GET("/tokens", a.getTokens)
 		v1.GET("/tokens/:id", a.getToken)
+		// Coordinators
 		v1.GET("/coordinators", a.getCoordinators)
 	}
 

@@ -216,6 +216,7 @@ // Config (smart contract constants)
 	chainID := uint16(0)
 	_config := getConfigTest(chainID)
 	config = configAPI{
+		ChainID:           chainID,
 		RollupConstants:   *newRollupConstants(_config.RollupConstants),
 		AuctionConstants:  _config.AuctionConstants,
 		WDelayerConstants: _config.WDelayerConstants,
@@ -523,11 +524,16 @@ wdelayerVars := common.WDelayerVariables{
 		WithdrawalDelay: uint64(3000),
 	}
 
-	stateAPIUpdater = stateapiupdater.NewUpdater(hdb, nodeConfig, &common.SCVariables{
+	stateAPIUpdater, err = stateapiupdater.NewUpdater(hdb, nodeConfig, &common.SCVariables{
 		Rollup:   rollupVars,
 		Auction:  auctionVars,
 		WDelayer: wdelayerVars,
-	}, constants)
+	}, constants, &stateapiupdater.RecommendedFeePolicy{
+		PolicyType: stateapiupdater.RecommendedFeePolicyTypeAvgLastHour,
+	})
+	if err != nil {
+		panic(err)
+	}
 
 	// Generate test data, as expected to be received/sended from/to the API
 	testCoords := genTestCoordinators(commonCoords)

@@ -1,3 +1,11 @@
+/*
+Package apitypes is used to map the common types used across the node with the format expected by the API.
+
+This is done using different strategies:
+- Marshallers: they get triggered when the API marshals the response structs into JSONs
+- Scanners/Valuers: they get triggered when a struct is sent/received to/from the SQL database
+- Adhoc functions: when the already mentioned strategies are not suitable, functions are added to the structs to facilitate the conversions
+*/
 package apitypes
 
 import (

@@ -57,6 +57,7 @@ HermezAddress     ethCommon.Address
 }
 
 type configAPI struct {
+	ChainID           uint16                   `json:"chainId"`
 	RollupConstants   rollupConstants          `json:"hermez"`
 	AuctionConstants  common.AuctionConstants  `json:"auction"`
 	WDelayerConstants common.WDelayerConstants `json:"withdrawalDelayer"`

@@ -8,6 +8,7 @@
 	"github.com/gin-gonic/gin"
 	"github.com/hermeznetwork/hermez-node/db/historydb"
 	"github.com/hermeznetwork/hermez-node/log"
+	"github.com/hermeznetwork/hermez-node/metric"
 	"github.com/hermeznetwork/tracerr"
 	"github.com/lib/pq"
 	"github.com/russross/meddler"
@@ -46,7 +47,9 @@ )
 
 func retSQLErr(err error, c *gin.Context) {
 	log.Warnw("HTTP API SQL request error", "err", err)
-	errMsg := tracerr.Unwrap(err).Error()
+	unwrapErr := tracerr.Unwrap(err)
+	metric.CollectError(unwrapErr)
+	errMsg := unwrapErr.Error()
 	retDupKey := func(errCode pq.ErrorCode) {
 		// https://www.postgresql.org/docs/current/errcodes-appendix.html
 		if errCode == "23505" {
@@ -80,6 +83,7 @@ }
 
 func retBadReq(err error, c *gin.Context) {
 	log.Warnw("HTTP API Bad request error", "err", err)
+	metric.CollectError(err)
 	c.JSON(http.StatusBadRequest, errorMsg{
 		Message: err.Error(),
 	})

@@ -1,11 +1,20 @@
+/*
+Package stateapiupdater is responsible for generating and storing the object response of the GET /state endpoint exposed through the api package.
+This object is extensively defined at the OpenAPI spec located at api/swagger.yml.
+
+Deployment considerations: in a setup where multiple processes are used (dedicated api process, separated coord / sync, ...), only one process should care
+of using this package.
+*/
 package stateapiupdater
 
 import (
 	"database/sql"
+	"fmt"
 	"sync"
 
 	"github.com/hermeznetwork/hermez-node/common"
 	"github.com/hermeznetwork/hermez-node/db/historydb"
+	"github.com/hermeznetwork/hermez-node/log"
 	"github.com/hermeznetwork/tracerr"
 )
 
@@ -17,11 +26,45 @@ config historydb.NodeConfig
 	vars   common.SCVariablesPtr
 	consts historydb.Constants
 	rw     sync.RWMutex
+	rfp    *RecommendedFeePolicy
+}
+
+// RecommendedFeePolicy describes how the recommended fee is calculated
+type RecommendedFeePolicy struct {
+	PolicyType  RecommendedFeePolicyType `validate:"required"`
+	StaticValue float64
+}
+
+// RecommendedFeePolicyType describes the different available recommended fee strategies
+type RecommendedFeePolicyType string
+
+const (
+	// RecommendedFeePolicyTypeStatic always give the same StaticValue as recommended fee
+	RecommendedFeePolicyTypeStatic RecommendedFeePolicyType = "Static"
+	// RecommendedFeePolicyTypeAvgLastHour set the recommended fee using the average fee of the last hour
+	RecommendedFeePolicyTypeAvgLastHour RecommendedFeePolicyType = "AvgLastHour"
+)
+
+func (rfp *RecommendedFeePolicy) valid() bool {
+	switch rfp.PolicyType {
+	case RecommendedFeePolicyTypeStatic:
+		if rfp.StaticValue == 0 {
+			log.Warn("RcommendedFee is set to 0 USD, and the policy is static")
+		}
+		return true
+	case RecommendedFeePolicyTypeAvgLastHour:
+		return true
+	default:
+		return false
+	}
 }
 
 // NewUpdater creates a new Updater
 func NewUpdater(hdb *historydb.HistoryDB, config *historydb.NodeConfig, vars *common.SCVariables,
-	consts *historydb.Constants) *Updater {
+	consts *historydb.Constants, rfp *RecommendedFeePolicy) (*Updater, error) {
+	if ok := rfp.valid(); !ok {
+		return nil, tracerr.Wrap(fmt.Errorf("Invalid recommended fee policy: %v", rfp.PolicyType))
+	}
 	u := Updater{
 		hdb:    hdb,
 		config: *config,
@@ -31,9 +74,10 @@ NodePublicInfo: historydb.NodePublicInfo{
 				ForgeDelay: config.ForgeDelay,
 			},
 		},
+		rfp: rfp,
 	}
 	u.SetSCVars(vars.AsPtr())
-	return &u
+	return &u, nil
 }
 
 // Store the State in the HistoryDB
@@ -65,13 +109,27 @@ }
 
 // UpdateRecommendedFee update Status.RecommendedFee information
 func (u *Updater) UpdateRecommendedFee() error {
-	recommendedFee, err := u.hdb.GetRecommendedFee(u.config.MinFeeUSD, u.config.MaxFeeUSD)
-	if err != nil {
-		return tracerr.Wrap(err)
+	switch u.rfp.PolicyType {
+	case RecommendedFeePolicyTypeStatic:
+		u.rw.Lock()
+		u.state.RecommendedFee = common.RecommendedFee{
+			ExistingAccount:        u.rfp.StaticValue,
+			CreatesAccount:         u.rfp.StaticValue,
+			CreatesAccountInternal: u.rfp.StaticValue,
+		}
+		u.rw.Unlock()
+	case RecommendedFeePolicyTypeAvgLastHour:
+		recommendedFee, err := u.hdb.GetRecommendedFee(u.config.MinFeeUSD, u.config.MaxFeeUSD)
+		if err != nil {
+			return tracerr.Wrap(err)
+		}
+		u.rw.Lock()
+		u.state.RecommendedFee = *recommendedFee
+		u.rw.Unlock()
+	default:
+		return tracerr.New("Invalid recommende fee policy")
 	}
-	u.rw.Lock()
-	u.state.RecommendedFee = *recommendedFee
-	u.rw.Unlock()
+
 	return nil
 }
 

@@ -3040,10 +3040,15 @@ - maxWithdrawalDelay
             - maxEmergencyModeTime
             - hermezRollup
           additionalProperties: false
+        chainId:
+          type: integer
+          description: Id of the chain
+          example: 27
       required:
         - hermez
         - auction
         - withdrawalDelayer
+        - chainId
       additionalProperties: false
     Error:
       type: object

@@ -187,7 +187,7 @@ return tracerr.Wrap(fmt.Errorf("tx.TokenID (%v) != account.TokenID (%v)",
 			poolTx.TokenID, account.TokenID))
 	}
 	// Check signature
-	if !poolTx.VerifySignature(a.chainID, account.BJJ) {
+	if !poolTx.VerifySignature(a.cg.ChainID, account.BJJ) {
 		return tracerr.Wrap(errors.New("wrong signature"))
 	}
 	return nil

@@ -35,7 +35,7 @@ Symbol = "SUSHI"
 Addr = "0x6b3595068778dd592e39a122f4f5a5cf09c90fe2"
 
 [Debug]
-APIAddress = "localhost:12345"
+APIAddress = "0.0.0.0:12345"
 MeddlerLogs = true
 GinDebugMode = true
 
@@ -145,3 +145,11 @@ [Coordinator.Debug]
 BatchPath = "/tmp/iden3-test/hermez/batchesdebug"
 LightScrypt = true
 # RollupVerifierIndex = 0
+
+[RecommendedFeePolicy]
+# Strategy used to calculate the recommended fee that the API will expose.
+# Available options:
+# - Static: always return the same value (StaticValue) in USD
+# - AvgLastHour: calculate using the average fee of the forged transactions during the last hour
+PolicyType = "Static"
+StaticValue = 0.99

@@ -22,7 +22,7 @@ // where type:
 	// 	- L1UserTx: 0
 	// 	- L1CoordinatorTx: 1
 	TxID TxID `meddler:"id"`
-	// ToForgeL1TxsNum indicates in which the tx was forged / will be forged
+	// ToForgeL1TxsNum indicates in which L1UserTx queue the tx was forged / will be forged
 	ToForgeL1TxsNum *int64 `meddler:"to_forge_l1_txs_num"`
 	Position        int    `meddler:"position"`
 	// UserOrigin is set to true if the tx was originated by a user, false if it was

@@ -8,6 +8,7 @@ "time"
 
 	"github.com/BurntSushi/toml"
 	ethCommon "github.com/ethereum/go-ethereum/common"
+	"github.com/hermeznetwork/hermez-node/api/stateapiupdater"
 	"github.com/hermeznetwork/hermez-node/common"
 	"github.com/hermeznetwork/hermez-node/priceupdater"
 	"github.com/hermeznetwork/tracerr"
@@ -347,8 +348,9 @@ // SQLConnectionTimeout is the maximum amount of time that an API request
 		// can wait to stablish a SQL connection
 		SQLConnectionTimeout Duration
 	} `validate:"required"`
-	Debug       NodeDebug   `validate:"required"`
-	Coordinator Coordinator `validate:"-"`
+	RecommendedFeePolicy stateapiupdater.RecommendedFeePolicy `validate:"required"`
+	Debug                NodeDebug                            `validate:"required"`
+	Coordinator          Coordinator                          `validate:"-"`
 }
 
 // APIServer is the api server configuration parameters

@@ -80,6 +80,7 @@ type BatchInfo struct {
 	PipelineNum           int
 	BatchNum              common.BatchNum
 	ServerProof           prover.Client
+	ProofStart            time.Time
 	ZKInputs              *common.ZKInputs
 	Proof                 *prover.Proof
 	PublicInputs          []*big.Int

@@ -5,6 +5,7 @@ "context"
 	"database/sql"
 	"fmt"
 	"math/big"
+	"strconv"
 	"sync"
 	"time"
 
@@ -14,6 +15,7 @@ "github.com/hermeznetwork/hermez-node/db/historydb"
 	"github.com/hermeznetwork/hermez-node/db/l2db"
 	"github.com/hermeznetwork/hermez-node/eth"
 	"github.com/hermeznetwork/hermez-node/log"
+	"github.com/hermeznetwork/hermez-node/metric"
 	"github.com/hermeznetwork/hermez-node/prover"
 	"github.com/hermeznetwork/hermez-node/synchronizer"
 	"github.com/hermeznetwork/hermez-node/txselector"
@@ -246,6 +248,7 @@ }
 
 	// 3. Send the ZKInputs to the proof server
 	batchInfo.ServerProof = serverProof
+	batchInfo.ProofStart = time.Now()
 	if err := p.sendServerProof(ctx, batchInfo); ctx.Err() != nil {
 		return nil, ctx.Err()
 	} else if err != nil {
@@ -520,15 +523,30 @@ _l1UserTxs, err := p.historyDB.GetUnforgedL1UserTxs(p.state.lastForgeL1TxsNum + 1)
 		if err != nil {
 			return nil, nil, tracerr.Wrap(err)
 		}
+		// l1UserFutureTxs are the l1UserTxs that are not being forged
+		// in the next batch, but that are also in the queue for the
+		// future batches
+		l1UserFutureTxs, err := p.historyDB.GetUnforgedL1UserFutureTxs(p.state.lastForgeL1TxsNum + 1)
+		if err != nil {
+			return nil, nil, tracerr.Wrap(err)
+		}
+
 		coordIdxs, auths, l1UserTxs, l1CoordTxs, poolL2Txs, discardedL2Txs, err =
-			p.txSelector.GetL1L2TxSelection(p.cfg.TxProcessorConfig, _l1UserTxs)
+			p.txSelector.GetL1L2TxSelection(p.cfg.TxProcessorConfig, _l1UserTxs, l1UserFutureTxs)
 		if err != nil {
 			return nil, nil, tracerr.Wrap(err)
 		}
 	} else {
+		// get l1UserFutureTxs which are all the l1 pending in all the
+		// queues
+		l1UserFutureTxs, err := p.historyDB.GetUnforgedL1UserFutureTxs(p.state.lastForgeL1TxsNum) //nolint:gomnd
+		if err != nil {
+			return nil, nil, tracerr.Wrap(err)
+		}
+
 		// 2b: only L2 txs
 		coordIdxs, auths, l1CoordTxs, poolL2Txs, discardedL2Txs, err =
-			p.txSelector.GetL2TxSelection(p.cfg.TxProcessorConfig)
+			p.txSelector.GetL2TxSelection(p.cfg.TxProcessorConfig, l1UserFutureTxs)
 		if err != nil {
 			return nil, nil, tracerr.Wrap(err)
 		}
@@ -602,6 +620,9 @@ }
 
 // waitServerProof gets the generated zkProof & sends it to the SmartContract
 func (p *Pipeline) waitServerProof(ctx context.Context, batchInfo *BatchInfo) error {
+	defer metric.MeasureDuration(metric.WaitServerProof, batchInfo.ProofStart,
+		batchInfo.BatchNum.BigInt().String(), strconv.Itoa(batchInfo.PipelineNum))
+
 	proof, pubInputs, err := batchInfo.ServerProof.GetProof(ctx) // blocking call,
 	// until not resolved don't continue. Returns when the proof server has calculated the proof
 	if err != nil {

@@ -1,3 +1,24 @@
+/*
+Package historydb is responsible for storing and retrieving the historic data of the Hermez network.
+It's mostly but not exclusively used by the API and the synchronizer.
+
+Apart from the logic defined in this package, it's important to notice that there are some triggers defined in the
+migration files that have to be taken into consideration to understanding the results of some queries. This is especially true
+for reorgs: all the data is directly or indirectly related to a block, this makes handling reorgs as easy as deleting the
+reorged blocks from the block table, and all related items will be dropped in cascade. This is not the only case, in general
+functions defined in this package that get affected somehow by the SQL level defined logic has a special mention on the function description.
+
+Some of the database tooling used in this package such as meddler and migration tools is explained in the db package.
+
+This package is spitted in different files following these ideas:
+- historydb.go: constructor and functions used by packages other than the api.
+- apiqueries.go: functions used by the API, the queries implemented in this functions use a semaphore
+to restrict the maximum concurrent connections to the database.
+- views.go: structs used to retrieve/store data from/to the database. When possible, the common structs are used, however
+most of the time there is no 1:1 relation between the struct fields and the tables of the schema, especially when joining tables.
+In some cases, some of the structs defined in this file also include custom Marshallers to easily match the expected api formats.
+- nodeinfo.go: used to handle the interfaces and structs that allow communication across running in different machines/process but sharing the same database.
+*/
 package historydb
 
 import (
@@ -745,6 +766,24 @@ tx.amount, NULL AS effective_amount,
 		tx.deposit_amount, NULL AS effective_deposit_amount,
 		tx.eth_block_num, tx.type, tx.batch_num
 		FROM tx WHERE batch_num IS NULL AND to_forge_l1_txs_num = $1
+		ORDER BY position;`,
+		toForgeL1TxsNum,
+	)
+	return db.SlicePtrsToSlice(txs).([]common.L1Tx), tracerr.Wrap(err)
+}
+
+// GetUnforgedL1UserFutureTxs gets L1 User Txs to be forged after the L1Batch
+// with toForgeL1TxsNum (in one of the future batches, not in the next one).
+func (hdb *HistoryDB) GetUnforgedL1UserFutureTxs(toForgeL1TxsNum int64) ([]common.L1Tx, error) {
+	var txs []*common.L1Tx
+	err := meddler.QueryAll(
+		hdb.dbRead, &txs, // only L1 user txs can have batch_num set to null
+		`SELECT tx.id, tx.to_forge_l1_txs_num, tx.position, tx.user_origin,
+		tx.from_idx, tx.from_eth_addr, tx.from_bjj, tx.to_idx, tx.token_id,
+		tx.amount, NULL AS effective_amount,
+		tx.deposit_amount, NULL AS effective_deposit_amount,
+		tx.eth_block_num, tx.type, tx.batch_num
+		FROM tx WHERE batch_num IS NULL AND to_forge_l1_txs_num > $1
 		ORDER BY position;`,
 		toForgeL1TxsNum,
 	)

@@ -699,34 +699,55 @@ CreateAccountDeposit(2) A: 20
 		CreateAccountDeposit(1) B: 5
 		CreateAccountDeposit(1) C: 5
 		CreateAccountDeposit(1) D: 5
+		> block
 
+		> batchL1
 		> block
+
+		CreateAccountDeposit(1) E: 5
+		CreateAccountDeposit(1) F: 5
+		> block
+
 	`
 	tc := til.NewContext(uint16(0), 128)
 	blocks, err := tc.GenerateBlocks(set)
 	require.NoError(t, err)
 	// Sanity check
-	require.Equal(t, 1, len(blocks))
+	require.Equal(t, 3, len(blocks))
 	require.Equal(t, 5, len(blocks[0].Rollup.L1UserTxs))
 
-	toForgeL1TxsNum := int64(1)
-
 	for i := range blocks {
 		err = historyDB.AddBlockSCData(&blocks[i])
 		require.NoError(t, err)
 	}
 
-	l1UserTxs, err := historyDB.GetUnforgedL1UserTxs(toForgeL1TxsNum)
+	l1UserTxs, err := historyDB.GetUnforgedL1UserFutureTxs(0)
+	require.NoError(t, err)
+	assert.Equal(t, 7, len(l1UserTxs))
+
+	l1UserTxs, err = historyDB.GetUnforgedL1UserTxs(1)
 	require.NoError(t, err)
 	assert.Equal(t, 5, len(l1UserTxs))
 	assert.Equal(t, blocks[0].Rollup.L1UserTxs, l1UserTxs)
 
+	l1UserTxs, err = historyDB.GetUnforgedL1UserFutureTxs(1)
+	require.NoError(t, err)
+	assert.Equal(t, 2, len(l1UserTxs))
+
 	count, err := historyDB.GetUnforgedL1UserTxsCount()
 	require.NoError(t, err)
-	assert.Equal(t, 5, count)
+	assert.Equal(t, 7, count)
 
-	// No l1UserTxs for this toForgeL1TxsNum
 	l1UserTxs, err = historyDB.GetUnforgedL1UserTxs(2)
+	require.NoError(t, err)
+	assert.Equal(t, 2, len(l1UserTxs))
+
+	l1UserTxs, err = historyDB.GetUnforgedL1UserFutureTxs(2)
+	require.NoError(t, err)
+	assert.Equal(t, 0, len(l1UserTxs))
+
+	// No l1UserTxs for this toForgeL1TxsNum
+	l1UserTxs, err = historyDB.GetUnforgedL1UserTxs(3)
 	require.NoError(t, err)
 	assert.Equal(t, 0, len(l1UserTxs))
 }

@@ -1,3 +1,20 @@
+/*
+Package l2db is responsible for storing and retrieving the data received by the coordinator through the api.
+Note that this data will be different for each coordinator in the network, as this represents the L2 information.
+
+The data managed by this package is fundamentally PoolL2Tx and AccountCreationAuth. All this data come from
+the API sent by clients and is used by the txselector to decide which transactions are selected to forge a batch.
+
+Some of the database tooling used in this package such as meddler and migration tools is explained in the db package.
+
+This package is spitted in different files following these ideas:
+- l2db.go: constructor and functions used by packages other than the api.
+- apiqueries.go: functions used by the API, the queries implemented in this functions use a semaphore
+to restrict the maximum concurrent connections to the database.
+- views.go: structs used to retrieve/store data from/to the database. When possible, the common structs are used, however
+most of the time there is no 1:1 relation between the struct fields and the tables of the schema, especially when joining tables.
+In some cases, some of the structs defined in this file also include custom Marshallers to easily match the expected api formats.
+*/
 package l2db
 
 import (

@@ -1,3 +1,10 @@
+/*
+Package db have some common utilities shared by db/l2db and db/historydb, the most relevant ones are:
+- SQL connection utilities
+- Managing the SQL schema: this is done using migration files placed under db/migrations. The files are executed by
+order of the file name.
+- Custom meddlers: used to easily transform struct <==> table
+*/
 package db
 
 import (

@@ -245,15 +245,15 @@ blockNum := big.NewInt(number)
 	if number == -1 {
 		blockNum = nil
 	}
-	block, err := c.client.BlockByNumber(ctx, blockNum)
+	header, err := c.client.HeaderByNumber(ctx, blockNum)
 	if err != nil {
 		return nil, tracerr.Wrap(err)
 	}
 	b := &common.Block{
-		Num:        block.Number().Int64(),
-		Timestamp:  time.Unix(int64(block.Time()), 0),
-		ParentHash: block.ParentHash(),
-		Hash:       block.Hash(),
+		Num:        header.Number.Int64(),
+		Timestamp:  time.Unix(int64(header.Time), 0),
+		ParentHash: header.ParentHash,
+		Hash:       header.Hash(),
 	}
 	return b, nil
 }

@@ -0,0 +1,192 @@
+package metric
+
+import (
+	"time"
+
+	"github.com/hermeznetwork/hermez-node/log"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+type (
+	// Metric represents the metric type
+	Metric string
+)
+
+const (
+	namespaceError      = "error"
+	namespaceSync       = "synchronizer"
+	namespaceTxSelector = "txselector"
+	namespaceAPI        = "api"
+)
+
+var (
+	// Errors errors count metric.
+	Errors = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: namespaceError,
+			Name:      "errors",
+			Help:      "",
+		}, []string{"error"})
+
+	// WaitServerProof duration time to get the calculated
+	// proof from the server.
+	WaitServerProof = prometheus.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: namespaceSync,
+			Name:      "wait_server_proof",
+			Help:      "",
+		}, []string{"batch_number", "pipeline_number"})
+
+	// Reorgs block reorg count
+	Reorgs = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: namespaceSync,
+			Name:      "reorgs",
+			Help:      "",
+		})
+
+	// LastBlockNum last block synced
+	LastBlockNum = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: namespaceSync,
+			Name:      "synced_last_block_num",
+			Help:      "",
+		})
+
+	// EthLastBlockNum last eth block synced
+	EthLastBlockNum = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: namespaceSync,
+			Name:      "eth_last_block_num",
+			Help:      "",
+		})
+
+	// LastBatchNum last batch synced
+	LastBatchNum = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: namespaceSync,
+			Name:      "synced_last_batch_num",
+			Help:      "",
+		})
+
+	// EthLastBatchNum last eth batch synced
+	EthLastBatchNum = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: namespaceSync,
+			Name:      "eth_last_batch_num",
+			Help:      "",
+		})
+
+	// GetL2TxSelection L2 tx selection count
+	GetL2TxSelection = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: namespaceTxSelector,
+			Name:      "get_l2_txselection_total",
+			Help:      "",
+		})
+
+	// GetL1L2TxSelection L1L2 tx selection count
+	GetL1L2TxSelection = prometheus.NewCounter(
+		prometheus.CounterOpts{
+			Namespace: namespaceTxSelector,
+			Name:      "get_l1_l2_txselection_total",
+			Help:      "",
+		})
+
+	// SelectedL1CoordinatorTxs selected L1 coordinator tx count
+	SelectedL1CoordinatorTxs = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: namespaceTxSelector,
+			Name:      "selected_l1_coordinator_txs",
+			Help:      "",
+		})
+
+	// SelectedL1UserTxs selected L1 user tx count
+	SelectedL1UserTxs = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: namespaceTxSelector,
+			Name:      "selected_l1_user_txs",
+			Help:      "",
+		})
+
+	// SelectedL2Txs selected L2 tx count
+	SelectedL2Txs = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: namespaceTxSelector,
+			Name:      "selected_l2_txs",
+			Help:      "",
+		})
+
+	// DiscardedL2Txs discarded L2 tx count
+	DiscardedL2Txs = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: namespaceTxSelector,
+			Name:      "discarded_l2_txs",
+			Help:      "",
+		})
+)
+
+func init() {
+	if err := registerCollectors(); err != nil {
+		log.Error(err)
+	}
+}
+func registerCollectors() error {
+	if err := registerCollector(Errors); err != nil {
+		return err
+	}
+	if err := registerCollector(WaitServerProof); err != nil {
+		return err
+	}
+	if err := registerCollector(Reorgs); err != nil {
+		return err
+	}
+	if err := registerCollector(LastBlockNum); err != nil {
+		return err
+	}
+	if err := registerCollector(LastBatchNum); err != nil {
+		return err
+	}
+	if err := registerCollector(EthLastBlockNum); err != nil {
+		return err
+	}
+	if err := registerCollector(EthLastBatchNum); err != nil {
+		return err
+	}
+	if err := registerCollector(GetL2TxSelection); err != nil {
+		return err
+	}
+	if err := registerCollector(GetL1L2TxSelection); err != nil {
+		return err
+	}
+	if err := registerCollector(SelectedL1CoordinatorTxs); err != nil {
+		return err
+	}
+	if err := registerCollector(SelectedL1UserTxs); err != nil {
+		return err
+	}
+	return registerCollector(DiscardedL2Txs)
+}
+
+func registerCollector(collector prometheus.Collector) error {
+	err := prometheus.Register(collector)
+	if err != nil {
+		if _, ok := err.(prometheus.AlreadyRegisteredError); !ok {
+			return err
+		}
+	}
+	return nil
+}
+
+// MeasureDuration measure the method execution duration
+// and save it into a histogram metric
+func MeasureDuration(histogram *prometheus.HistogramVec, start time.Time, lvs ...string) {
+	duration := time.Since(start)
+	histogram.WithLabelValues(lvs...).Observe(float64(duration.Milliseconds()))
+}
+
+// CollectError collect the error message and increment
+// the error count
+func CollectError(err error) {
+	Errors.With(map[string]string{"error": err.Error()}).Inc()
+}

@@ -0,0 +1,78 @@
+package metric
+
+import (
+	"strconv"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const (
+	favicon = "/favicon.ico"
+)
+
+// Prometheus contains the metrics gathered by the instance and its path
+type Prometheus struct {
+	reqCnt *prometheus.CounterVec
+	reqDur *prometheus.HistogramVec
+}
+
+// NewPrometheus generates a new set of metrics with a certain subsystem name
+func NewPrometheus() (*Prometheus, error) {
+	reqCnt := prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: namespaceAPI,
+			Name:      "requests_total",
+			Help:      "How many HTTP requests processed, partitioned by status code and HTTP method",
+		},
+		[]string{"code", "method", "path"},
+	)
+	if err := registerCollector(reqCnt); err != nil {
+		return nil, err
+	}
+	reqDur := prometheus.NewHistogramVec(
+		prometheus.HistogramOpts{
+			Namespace: namespaceAPI,
+			Name:      "request_duration_seconds",
+			Help:      "The HTTP request latencies in seconds",
+		},
+		[]string{"code", "method", "path"},
+	)
+	if err := registerCollector(reqDur); err != nil {
+		return nil, err
+	}
+	return &Prometheus{
+		reqCnt: reqCnt,
+		reqDur: reqDur,
+	}, nil
+}
+
+// PrometheusMiddleware creates the prometheus collector and
+// defines status handler function for the middleware
+func PrometheusMiddleware() (gin.HandlerFunc, error) {
+	p, err := NewPrometheus()
+	if err != nil {
+		return nil, err
+	}
+	return p.Middleware(), nil
+}
+
+// Middleware defines status handler function for middleware
+func (p *Prometheus) Middleware() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		if c.Request.URL.Path == favicon {
+			c.Next()
+			return
+		}
+		start := time.Now()
+		c.Next()
+
+		status := strconv.Itoa(c.Writer.Status())
+		elapsed := float64(time.Since(start)) / float64(time.Second)
+		fullPath := c.FullPath()
+
+		p.reqDur.WithLabelValues(status, c.Request.Method, fullPath).Observe(elapsed)
+		p.reqCnt.WithLabelValues(status, c.Request.Method, fullPath).Inc()
+	}
+}

@@ -288,7 +288,16 @@ if err := historyDB.SetConstants(&hdbConsts); err != nil {
 		return nil, tracerr.Wrap(err)
 	}
 
-	stateAPIUpdater := stateapiupdater.NewUpdater(historyDB, &hdbNodeCfg, initSCVars, &hdbConsts)
+	stateAPIUpdater, err := stateapiupdater.NewUpdater(
+		historyDB,
+		&hdbNodeCfg,
+		initSCVars,
+		&hdbConsts,
+		&cfg.RecommendedFeePolicy,
+	)
+	if err != nil {
+		return nil, tracerr.Wrap(err)
+	}
 
 	var coord *coordinator.Coordinator
 	if mode == ModeCoordinator {

@@ -173,6 +173,10 @@ case UpdateMethodTypeCoingeckoV3:
 			tokenPrice, err = p.getTokenPriceCoingecko(ctx, token.Addr)
 		case UpdateMethodTypeStatic:
 			tokenPrice = token.StaticValue
+			if tokenPrice == float64(0) {
+				log.Warn("token price is set to 0. Probably StaticValue is not put in the configuration file,",
+					"token", token.Symbol)
+			}
 		case UpdateMethodTypeIgnore:
 			continue
 		}

@@ -1,44 +0,0 @@
-package synchronizer
-
-import "github.com/prometheus/client_golang/prometheus"
-
-var (
-	metricReorgsCount = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Name: "sync_reorgs",
-			Help: "",
-		},
-	)
-	metricSyncedLastBlockNum = prometheus.NewGauge(
-		prometheus.GaugeOpts{
-			Name: "sync_synced_last_block_num",
-			Help: "",
-		},
-	)
-	metricEthLastBlockNum = prometheus.NewGauge(
-		prometheus.GaugeOpts{
-			Name: "sync_eth_last_block_num",
-			Help: "",
-		},
-	)
-	metricSyncedLastBatchNum = prometheus.NewGauge(
-		prometheus.GaugeOpts{
-			Name: "sync_synced_last_batch_num",
-			Help: "",
-		},
-	)
-	metricEthLastBatchNum = prometheus.NewGauge(
-		prometheus.GaugeOpts{
-			Name: "sync_eth_last_batch_num",
-			Help: "",
-		},
-	)
-)
-
-func init() {
-	prometheus.MustRegister(metricReorgsCount)
-	prometheus.MustRegister(metricSyncedLastBlockNum)
-	prometheus.MustRegister(metricEthLastBlockNum)
-	prometheus.MustRegister(metricSyncedLastBatchNum)
-	prometheus.MustRegister(metricEthLastBatchNum)
-}

@@ -47,6 +47,7 @@ "github.com/hermeznetwork/hermez-node/db/l2db"
 	"github.com/hermeznetwork/hermez-node/db/statedb"
 	"github.com/hermeznetwork/hermez-node/eth"
 	"github.com/hermeznetwork/hermez-node/log"
+	"github.com/hermeznetwork/hermez-node/metric"
 	"github.com/hermeznetwork/hermez-node/txprocessor"
 	"github.com/hermeznetwork/tracerr"
 )
@@ -581,6 +582,7 @@ if err != nil {
 				return nil, nil, tracerr.Wrap(err)
 			}
 			discarded := lastSavedBlock.Num - lastDBBlockNum
+			metric.Reorgs.Inc()
 			return nil, &discarded, nil
 		}
 	}
@@ -673,16 +675,16 @@ return nil, nil, tracerr.Wrap(err)
 	}
 
 	for _, batchData := range rollupData.Batches {
-		metricSyncedLastBatchNum.Set(float64(batchData.Batch.BatchNum))
-		metricEthLastBatchNum.Set(float64(s.stats.Eth.LastBatchNum))
+		metric.LastBatchNum.Set(float64(batchData.Batch.BatchNum))
+		metric.EthLastBatchNum.Set(float64(s.stats.Eth.LastBatchNum))
 		log.Debugw("Synced batch",
 			"syncLastBatch", batchData.Batch.BatchNum,
 			"syncBatchesPerc", s.stats.batchesPerc(batchData.Batch.BatchNum),
 			"ethLastBatch", s.stats.Eth.LastBatchNum,
 		)
 	}
-	metricSyncedLastBlockNum.Set(float64(s.stats.Sync.LastBlock.Num))
-	metricEthLastBlockNum.Set(float64(s.stats.Eth.LastBlock.Num))
+	metric.LastBlockNum.Set(float64(s.stats.Sync.LastBlock.Num))
+	metric.EthLastBlockNum.Set(float64(s.stats.Eth.LastBlock.Num))
 	log.Debugw("Synced block",
 		"syncLastBlockNum", s.stats.Sync.LastBlock.Num,
 		"syncBlocksPerc", s.stats.blocksPerc(),

@@ -156,7 +156,7 @@ l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[i].Batch.ForgeL1TxsNum])
 		}
 		// TxSelector select the transactions for the next Batch
 		coordIdxs, _, oL1UserTxs, oL1CoordTxs, oL2Txs, _, err :=
-			txsel.GetL1L2TxSelection(txprocConfig, l1UserTxs)
+			txsel.GetL1L2TxSelection(txprocConfig, l1UserTxs, nil)
 		require.NoError(t, err)
 		// BatchBuilder build Batch
 		zki, err := bb.BuildBatch(coordIdxs, configBatch, oL1UserTxs, oL1CoordTxs, oL2Txs)
@@ -180,7 +180,7 @@ addL2Txs(t, l2DBTxSel, l2Txs) // Add L2s to TxSelector.L2DB
 	l1UserTxs := til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[6].Batch.ForgeL1TxsNum])
 	// TxSelector select the transactions for the next Batch
 	coordIdxs, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err :=
-		txsel.GetL1L2TxSelection(txprocConfig, l1UserTxs)
+		txsel.GetL1L2TxSelection(txprocConfig, l1UserTxs, nil)
 	require.NoError(t, err)
 	// BatchBuilder build Batch
 	zki, err := bb.BuildBatch(coordIdxs, configBatch, oL1UserTxs, oL1CoordTxs, oL2Txs)
@@ -209,7 +209,7 @@ addL2Txs(t, l2DBTxSel, l2Txs) // Add L2s to TxSelector.L2DB
 	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[7].Batch.ForgeL1TxsNum])
 	// TxSelector select the transactions for the next Batch
 	coordIdxs, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err =
-		txsel.GetL1L2TxSelection(txprocConfig, l1UserTxs)
+		txsel.GetL1L2TxSelection(txprocConfig, l1UserTxs, nil)
 	require.NoError(t, err)
 	// BatchBuilder build Batch
 	zki, err = bb.BuildBatch(coordIdxs, configBatch, oL1UserTxs, oL1CoordTxs, oL2Txs)
@@ -236,7 +236,7 @@ addL2Txs(t, l2DBTxSel, l2Txs) // Add L2s to TxSelector.L2DB
 	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[1].Rollup.Batches[0].Batch.ForgeL1TxsNum])
 	// TxSelector select the transactions for the next Batch
 	coordIdxs, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err =
-		txsel.GetL1L2TxSelection(txprocConfig, l1UserTxs)
+		txsel.GetL1L2TxSelection(txprocConfig, l1UserTxs, nil)
 	require.NoError(t, err)
 	// BatchBuilder build Batch
 	zki, err = bb.BuildBatch(coordIdxs, configBatch, oL1UserTxs, oL1CoordTxs, oL2Txs)
@@ -256,7 +256,7 @@ l2Txs = []common.PoolL2Tx{}
 	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[1].Rollup.Batches[1].Batch.ForgeL1TxsNum])
 	// TxSelector select the transactions for the next Batch
 	coordIdxs, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err =
-		txsel.GetL1L2TxSelection(txprocConfig, l1UserTxs)
+		txsel.GetL1L2TxSelection(txprocConfig, l1UserTxs, nil)
 	require.NoError(t, err)
 	// BatchBuilder build Batch
 	zki, err = bb.BuildBatch(coordIdxs, configBatch, oL1UserTxs, oL1CoordTxs, oL2Txs)
@@ -319,7 +319,7 @@ // batch2
 	// TxSelector select the transactions for the next Batch
 	l1UserTxs := til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[1].Batch.ForgeL1TxsNum])
 	coordIdxs, _, oL1UserTxs, oL1CoordTxs, oL2Txs, _, err :=
-		txsel.GetL1L2TxSelection(txprocConfig, l1UserTxs)
+		txsel.GetL1L2TxSelection(txprocConfig, l1UserTxs, nil)
 	require.NoError(t, err)
 	// BatchBuilder build Batch
 	zki, err := bb.BuildBatch(coordIdxs, configBatch, oL1UserTxs, oL1CoordTxs, oL2Txs)
@@ -342,7 +342,7 @@ l2Txs, err := tc.GeneratePoolL2Txs(batchPoolL2)
 	require.NoError(t, err)
 	addL2Txs(t, l2DBTxSel, l2Txs) // Add L2s to TxSelector.L2DB
 	coordIdxs, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err :=
-		txsel.GetL1L2TxSelection(txprocConfig, nil)
+		txsel.GetL1L2TxSelection(txprocConfig, nil, nil)
 	require.NoError(t, err)
 	assert.Equal(t, 1, len(coordIdxs))
 	assert.Equal(t, 0, len(oL1UserTxs))

@@ -1,53 +0,0 @@
-package txselector
-
-import "github.com/prometheus/client_golang/prometheus"
-
-var (
-	metricGetL2TxSelection = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Name: "txsel_get_l2_txselecton_total",
-			Help: "",
-		},
-	)
-	metricGetL1L2TxSelection = prometheus.NewCounter(
-		prometheus.CounterOpts{
-			Name: "txsel_get_l1_l2_txselecton_total",
-			Help: "",
-		},
-	)
-
-	metricSelectedL1CoordinatorTxs = prometheus.NewGauge(
-		prometheus.GaugeOpts{
-			Name: "txsel_selected_l1_coordinator_txs",
-			Help: "",
-		},
-	)
-	metricSelectedL1UserTxs = prometheus.NewGauge(
-		prometheus.GaugeOpts{
-			Name: "txsel_selected_l1_user_txs",
-			Help: "",
-		},
-	)
-	metricSelectedL2Txs = prometheus.NewGauge(
-		prometheus.GaugeOpts{
-			Name: "txsel_selected_l2_txs",
-			Help: "",
-		},
-	)
-	metricDiscardedL2Txs = prometheus.NewGauge(
-		prometheus.GaugeOpts{
-			Name: "txsel_discarded_l2_txs",
-			Help: "",
-		},
-	)
-)
-
-func init() {
-	prometheus.MustRegister(metricGetL2TxSelection)
-	prometheus.MustRegister(metricGetL1L2TxSelection)
-
-	prometheus.MustRegister(metricSelectedL1CoordinatorTxs)
-	prometheus.MustRegister(metricSelectedL1UserTxs)
-	prometheus.MustRegister(metricSelectedL2Txs)
-	prometheus.MustRegister(metricDiscardedL2Txs)
-}

@@ -13,6 +13,7 @@ "github.com/hermeznetwork/hermez-node/db/kvdb"
 	"github.com/hermeznetwork/hermez-node/db/l2db"
 	"github.com/hermeznetwork/hermez-node/db/statedb"
 	"github.com/hermeznetwork/hermez-node/log"
+	"github.com/hermeznetwork/hermez-node/metric"
 	"github.com/hermeznetwork/hermez-node/txprocessor"
 	"github.com/hermeznetwork/tracerr"
 	"github.com/iden3/go-iden3-crypto/babyjub"
@@ -84,7 +85,7 @@ // selection, positionL1 must be increased 1.
 func (txsel *TxSelector) coordAccountForTokenID(l1CoordinatorTxs []common.L1Tx,
 	tokenID common.TokenID, positionL1 int) (*common.L1Tx, int, error) {
 	// check if CoordinatorAccount for TokenID is already pending to create
-	if checkAlreadyPendingToCreate(l1CoordinatorTxs, tokenID,
+	if checkPendingToCreateL1CoordTx(l1CoordinatorTxs, tokenID,
 		txsel.coordAccount.Addr, txsel.coordAccount.BJJ) {
 		return nil, positionL1, nil
 	}
@@ -121,11 +122,12 @@ // Coordinator with L1CoordinatorTxs of those accounts that does not exist yet
 // but there is a transactions to them and the authorization of account
 // creation exists. The L1UserTxs, L1CoordinatorTxs, PoolL2Txs that will be
 // included in the next batch.
-func (txsel *TxSelector) GetL2TxSelection(selectionConfig txprocessor.Config) ([]common.Idx,
+func (txsel *TxSelector) GetL2TxSelection(selectionConfig txprocessor.Config, l1UserFutureTxs []common.L1Tx) ([]common.Idx,
 	[][]byte, []common.L1Tx, []common.PoolL2Tx, []common.PoolL2Tx, error) {
-	metricGetL2TxSelection.Inc()
+	metric.GetL2TxSelection.Inc()
 	coordIdxs, accCreationAuths, _, l1CoordinatorTxs, l2Txs,
-		discardedL2Txs, err := txsel.getL1L2TxSelection(selectionConfig, []common.L1Tx{})
+		discardedL2Txs, err := txsel.getL1L2TxSelection(selectionConfig,
+		[]common.L1Tx{}, l1UserFutureTxs)
 	return coordIdxs, accCreationAuths, l1CoordinatorTxs, l2Txs,
 		discardedL2Txs, tracerr.Wrap(err)
 }
@@ -139,11 +141,11 @@ // but there is a transactions to them and the authorization of account
 // creation exists. The L1UserTxs, L1CoordinatorTxs, PoolL2Txs that will be
 // included in the next batch.
 func (txsel *TxSelector) GetL1L2TxSelection(selectionConfig txprocessor.Config,
-	l1UserTxs []common.L1Tx) ([]common.Idx, [][]byte, []common.L1Tx,
+	l1UserTxs, l1UserFutureTxs []common.L1Tx) ([]common.Idx, [][]byte, []common.L1Tx,
 	[]common.L1Tx, []common.PoolL2Tx, []common.PoolL2Tx, error) {
-	metricGetL1L2TxSelection.Inc()
+	metric.GetL1L2TxSelection.Inc()
 	coordIdxs, accCreationAuths, l1UserTxs, l1CoordinatorTxs, l2Txs,
-		discardedL2Txs, err := txsel.getL1L2TxSelection(selectionConfig, l1UserTxs)
+		discardedL2Txs, err := txsel.getL1L2TxSelection(selectionConfig, l1UserTxs, l1UserFutureTxs)
 	return coordIdxs, accCreationAuths, l1UserTxs, l1CoordinatorTxs, l2Txs,
 		discardedL2Txs, tracerr.Wrap(err)
 }
@@ -157,7 +159,7 @@ // but there is a transactions to them and the authorization of account
 // creation exists. The L1UserTxs, L1CoordinatorTxs, PoolL2Txs that will be
 // included in the next batch.
 func (txsel *TxSelector) getL1L2TxSelection(selectionConfig txprocessor.Config,
-	l1UserTxs []common.L1Tx) ([]common.Idx, [][]byte, []common.L1Tx,
+	l1UserTxs, l1UserFutureTxs []common.L1Tx) ([]common.Idx, [][]byte, []common.L1Tx,
 	[]common.L1Tx, []common.PoolL2Tx, []common.PoolL2Tx, error) {
 	// WIP.0: the TxSelector is not optimized and will need a redesign. The
 	// current version is implemented in order to have a functional
@@ -221,10 +223,11 @@ if err != nil {
 			return nil, nil, nil, nil, nil, nil, tracerr.Wrap(err)
 		}
 
-		metricSelectedL1UserTxs.Set(float64(len(l1UserTxs)))
-		metricSelectedL1CoordinatorTxs.Set(0)
-		metricSelectedL2Txs.Set(0)
-		metricDiscardedL2Txs.Set(float64(len(discardedL2Txs)))
+		metric.SelectedL1UserTxs.Set(float64(len(l1UserTxs)))
+		metric.SelectedL1CoordinatorTxs.Set(0)
+		metric.SelectedL2Txs.Set(0)
+		metric.DiscardedL2Txs.Set(float64(len(discardedL2Txs)))
+
 		return nil, nil, l1UserTxs, nil, nil, discardedL2Txs, nil
 	}
 
@@ -233,7 +236,7 @@ var l1CoordinatorTxs []common.L1Tx
 	var validTxs, discardedL2Txs []common.PoolL2Tx
 	l2TxsForgable = sortL2Txs(l2TxsForgable)
 	accAuths, l1CoordinatorTxs, validTxs, discardedL2Txs, err =
-		txsel.processL2Txs(tp, selectionConfig, len(l1UserTxs),
+		txsel.processL2Txs(tp, selectionConfig, len(l1UserTxs), l1UserFutureTxs,
 			l2TxsForgable, validTxs, discardedL2Txs)
 	if err != nil {
 		return nil, nil, nil, nil, nil, nil, tracerr.Wrap(err)
@@ -247,8 +250,8 @@ var accAuths2 [][]byte
 		var l1CoordinatorTxs2 []common.L1Tx
 		accAuths2, l1CoordinatorTxs2, validTxs, discardedL2Txs, err =
 			txsel.processL2Txs(tp, selectionConfig,
-				len(l1UserTxs)+len(l1CoordinatorTxs), l2TxsNonForgable,
-				validTxs, discardedL2Txs)
+				len(l1UserTxs)+len(l1CoordinatorTxs), l1UserFutureTxs,
+				l2TxsNonForgable, validTxs, discardedL2Txs)
 		if err != nil {
 			return nil, nil, nil, nil, nil, nil, tracerr.Wrap(err)
 		}
@@ -320,17 +323,18 @@ if err != nil {
 		return nil, nil, nil, nil, nil, nil, tracerr.Wrap(err)
 	}
 
-	metricSelectedL1UserTxs.Set(float64(len(l1UserTxs)))
-	metricSelectedL1CoordinatorTxs.Set(float64(len(l1CoordinatorTxs)))
-	metricSelectedL2Txs.Set(float64(len(validTxs)))
-	metricDiscardedL2Txs.Set(float64(len(discardedL2Txs)))
+	metric.SelectedL1CoordinatorTxs.Set(float64(len(l1CoordinatorTxs)))
+	metric.SelectedL1UserTxs.Set(float64(len(l1UserTxs)))
+	metric.SelectedL2Txs.Set(float64(len(validTxs)))
+	metric.DiscardedL2Txs.Set(float64(len(discardedL2Txs)))
 
 	return coordIdxs, accAuths, l1UserTxs, l1CoordinatorTxs, validTxs, discardedL2Txs, nil
 }
 
 func (txsel *TxSelector) processL2Txs(tp *txprocessor.TxProcessor,
-	selectionConfig txprocessor.Config, nL1Txs int, l2Txs, validTxs, discardedL2Txs []common.PoolL2Tx) (
-	[][]byte, []common.L1Tx, []common.PoolL2Tx, []common.PoolL2Tx, error) {
+	selectionConfig txprocessor.Config, nL1Txs int, l1UserFutureTxs []common.L1Tx,
+	l2Txs, validTxs, discardedL2Txs []common.PoolL2Tx) ([][]byte, []common.L1Tx,
+	[]common.PoolL2Tx, []common.PoolL2Tx, error) {
 	var l1CoordinatorTxs []common.L1Tx
 	positionL1 := nL1Txs
 	var accAuths [][]byte
@@ -432,7 +436,8 @@ // Exit type and is used.
 		if l2Txs[i].ToIdx == 0 { // ToEthAddr/ToBJJ case
 			validL2Tx, l1CoordinatorTx, accAuth, err :=
 				txsel.processTxToEthAddrBJJ(validTxs, selectionConfig,
-					nL1Txs, l1CoordinatorTxs, positionL1, l2Txs[i])
+					nL1Txs, l1UserFutureTxs, l1CoordinatorTxs,
+					positionL1, l2Txs[i])
 			if err != nil {
 				log.Debugw("txsel.processTxToEthAddrBJJ", "err", err)
 				// Discard L2Tx, and update Info parameter of
@@ -572,18 +577,35 @@ // CreateAccountDeposit (with 0 as DepositAmount) is created and added to the
 // l1CoordinatorTxs array, and then the PoolL2Tx is added into the validTxs
 // array.
 func (txsel *TxSelector) processTxToEthAddrBJJ(validTxs []common.PoolL2Tx,
-	selectionConfig txprocessor.Config, nL1UserTxs int, l1CoordinatorTxs []common.L1Tx,
-	positionL1 int, l2Tx common.PoolL2Tx) (*common.PoolL2Tx, *common.L1Tx,
-	*common.AccountCreationAuth, error) {
+	selectionConfig txprocessor.Config, nL1UserTxs int, l1UserFutureTxs,
+	l1CoordinatorTxs []common.L1Tx, positionL1 int, l2Tx common.PoolL2Tx) (
+	*common.PoolL2Tx, *common.L1Tx, *common.AccountCreationAuth, error) {
 	// if L2Tx needs a new L1CoordinatorTx of CreateAccount type, and a
 	// previous L2Tx in the current process already created a
 	// L1CoordinatorTx of this type, in the DB there still seem that needs
 	// to create a new L1CoordinatorTx, but as is already created, the tx
 	// is valid
-	if checkAlreadyPendingToCreate(l1CoordinatorTxs, l2Tx.TokenID, l2Tx.ToEthAddr, l2Tx.ToBJJ) {
+	if checkPendingToCreateL1CoordTx(l1CoordinatorTxs, l2Tx.TokenID, l2Tx.ToEthAddr, l2Tx.ToBJJ) {
 		return &l2Tx, nil, nil, nil
 	}
 
+	// check if L2Tx receiver account will be created by a L1UserFutureTxs
+	// (in the next batch, the current frozen queue). In that case, the L2Tx
+	// will be discarded at the current batch, even if there is an
+	// AccountCreationAuth for the account, as there is a L1UserTx in the
+	// frozen queue that will create the receiver Account.  The L2Tx is
+	// discarded to avoid the Coordinator creating a new L1CoordinatorTx to
+	// create the receiver account, which will be also created in the next
+	// batch from the L1UserFutureTx, ending with the user having 2
+	// different accounts for the same TokenID. The double account creation
+	// is supported by the Hermez zkRollup specification, but it was decided
+	// to mitigate it at the TxSelector level for the explained cases.
+	if checkPendingToCreateFutureTxs(l1UserFutureTxs, l2Tx.TokenID, l2Tx.ToEthAddr, l2Tx.ToBJJ) {
+		return nil, nil, nil, fmt.Errorf("L2Tx discarded at the current batch, as the" +
+			" receiver account does not exist yet, and there is a L1UserTx that" +
+			" will create that account in a future batch.")
+	}
+
 	var l1CoordinatorTx *common.L1Tx
 	var accAuth *common.AccountCreationAuth
 	if l2Tx.ToEthAddr != common.EmptyAddr && l2Tx.ToEthAddr != common.FFAddr {
@@ -686,12 +708,29 @@
 	return &l2Tx, l1CoordinatorTx, accAuth, nil
 }
 
-func checkAlreadyPendingToCreate(l1CoordinatorTxs []common.L1Tx, tokenID common.TokenID,
+func checkPendingToCreateL1CoordTx(l1CoordinatorTxs []common.L1Tx, tokenID common.TokenID,
 	addr ethCommon.Address, bjj babyjub.PublicKeyComp) bool {
 	for i := 0; i < len(l1CoordinatorTxs); i++ {
 		if l1CoordinatorTxs[i].FromEthAddr == addr &&
 			l1CoordinatorTxs[i].TokenID == tokenID &&
 			l1CoordinatorTxs[i].FromBJJ == bjj {
+			return true
+		}
+	}
+	return false
+}
+
+func checkPendingToCreateFutureTxs(l1UserFutureTxs []common.L1Tx, tokenID common.TokenID,
+	addr ethCommon.Address, bjj babyjub.PublicKeyComp) bool {
+	for i := 0; i < len(l1UserFutureTxs); i++ {
+		if l1UserFutureTxs[i].FromEthAddr == addr &&
+			l1UserFutureTxs[i].TokenID == tokenID &&
+			l1UserFutureTxs[i].FromBJJ == bjj {
+			return true
+		}
+		if l1UserFutureTxs[i].FromEthAddr == addr &&
+			l1UserFutureTxs[i].TokenID == tokenID &&
+			common.EmptyBJJComp == bjj {
 			return true
 		}
 	}

@@ -182,7 +182,7 @@
 	log.Debug("block:0 batch:1")
 	l1UserTxs := []common.L1Tx{}
 	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, _, err :=
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, 0, len(oL1UserTxs))
 	assert.Equal(t, 0, len(oL1CoordTxs))
@@ -193,7 +193,7 @@
 	log.Debug("block:0 batch:2")
 	l1UserTxs = []common.L1Tx{}
 	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, _, err =
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, 0, len(oL1UserTxs))
 	assert.Equal(t, 0, len(oL1CoordTxs))
@@ -204,7 +204,7 @@
 	log.Debug("block:0 batch:3")
 	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[2].Batch.ForgeL1TxsNum])
 	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, _, err =
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, 2, len(oL1UserTxs))
 	assert.Equal(t, 0, len(oL1CoordTxs))
@@ -217,7 +217,7 @@
 	log.Debug("block:0 batch:4")
 	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[3].Batch.ForgeL1TxsNum])
 	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, _, err =
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, 1, len(oL1UserTxs))
 	assert.Equal(t, 0, len(oL1CoordTxs))
@@ -231,7 +231,7 @@
 	log.Debug("block:0 batch:5")
 	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[4].Batch.ForgeL1TxsNum])
 	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, _, err =
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, 0, len(oL1UserTxs))
 	assert.Equal(t, 0, len(oL1CoordTxs))
@@ -245,7 +245,7 @@
 	log.Debug("block:0 batch:6")
 	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[5].Batch.ForgeL1TxsNum])
 	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, _, err =
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, 1, len(oL1UserTxs))
 	assert.Equal(t, 0, len(oL1CoordTxs))
@@ -279,7 +279,7 @@ assert.True(t, l2TxsFromDB[0].VerifySignature(chainID, tc.Users["A"].BJJ.Public().Compress()))
 	assert.True(t, l2TxsFromDB[1].VerifySignature(chainID, tc.Users["B"].BJJ.Public().Compress()))
 	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[6].Batch.ForgeL1TxsNum])
 	coordIdxs, accAuths, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err :=
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, []common.Idx{261, 263}, coordIdxs)
 	assert.Equal(t, txsel.coordAccount.AccountCreationAuth, accAuths[0])
@@ -328,7 +328,7 @@ assert.True(t, l2TxsFromDB[2].VerifySignature(chainID, tc.Users["B"].BJJ.Public().Compress()))
 	assert.True(t, l2TxsFromDB[3].VerifySignature(chainID, tc.Users["A"].BJJ.Public().Compress()))
 	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[7].Batch.ForgeL1TxsNum])
 	coordIdxs, accAuths, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err =
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, []common.Idx{261, 263}, coordIdxs)
 	assert.Equal(t, 0, len(accAuths))
@@ -372,7 +372,7 @@ assert.True(t, l2TxsFromDB[0].VerifySignature(chainID, tc.Users["D"].BJJ.Public().Compress()))
 	assert.True(t, l2TxsFromDB[1].VerifySignature(chainID, tc.Users["B"].BJJ.Public().Compress()))
 	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[1].Rollup.Batches[0].Batch.ForgeL1TxsNum])
 	coordIdxs, accAuths, oL1UserTxs, oL1CoordTxs, oL2Txs, _, err =
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, []common.Idx{263}, coordIdxs)
 	assert.Equal(t, 0, len(accAuths))
@@ -434,7 +434,7 @@ ChainID:  chainID,
 	}
 	// batch1
 	l1UserTxs := []common.L1Tx{}
-	_, _, _, _, _, _, err = txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+	_, _, _, _, _, _, err = txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	// 1st TransferToEthAddr
 	expectedTxID0 := "0x028847b86613c0b70be18c8622119ed045b42e4e47d7938fa90bb3d1dc14928965"
@@ -456,7 +456,7 @@ addL2Txs(t, txsel, poolL2Txs)
 
 	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[1].Batch.ForgeL1TxsNum])
 	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err :=
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, 3, len(oL1UserTxs))
 	assert.Equal(t, 0, len(oL1CoordTxs))
@@ -481,7 +481,7 @@ addL2Txs(t, txsel, poolL2Txs)
 
 	l1UserTxs = []common.L1Tx{}
 	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err =
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, 0, len(oL1UserTxs))
 	assert.Equal(t, 0, len(oL1CoordTxs))
@@ -500,7 +500,7 @@ // make the selection of another batch, which should include the
 	// initial PoolExit, which now is valid as B has enough Balance
 	l1UserTxs = []common.L1Tx{}
 	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err =
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, 0, len(oL1UserTxs))
 	assert.Equal(t, 0, len(oL1CoordTxs))
@@ -550,7 +550,7 @@ }
 	// batch1 to freeze L1UserTxs that will create some accounts with
 	// positive balance
 	l1UserTxs := []common.L1Tx{}
-	_, _, _, _, _, _, err = txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+	_, _, _, _, _, _, err = txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 
 	// Transfer is ToBJJ to a BJJ-only account that doesn't exist
@@ -568,7 +568,7 @@ addL2Txs(t, txsel, poolL2Txs)
 
 	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[1].Batch.ForgeL1TxsNum])
 	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err :=
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, 4, len(oL1UserTxs))
 	// We expect the coordinator to add an L1CoordTx to create an account for the recipient of the l2tx
@@ -595,7 +595,7 @@ addL2Txs(t, txsel, poolL2Txs)
 
 	l1UserTxs = []common.L1Tx{}
 	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err =
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, 0, len(oL1UserTxs))
 	// Since the BJJ-only account B already exists, the coordinator doesn't add any L1CoordTxs
@@ -623,7 +623,7 @@ addL2Txs(t, txsel, poolL2Txs)
 
 	l1UserTxs = []common.L1Tx{}
 	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err =
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, 0, len(oL1UserTxs))
 	// We expect the coordinator to add an L1CoordTx to create an account
@@ -678,7 +678,7 @@ ChainID:  chainID,
 	}
 	// batch1 to freeze L1UserTxs
 	l1UserTxs := []common.L1Tx{}
-	_, _, _, _, _, _, err = txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+	_, _, _, _, _, _, err = txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 
 	// 8 transfers from the same account
@@ -710,7 +710,7 @@ // batch 2 to crate some accounts with positive balance, and do 8 L2Tx
 	// transfers from account A
 	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[1].Batch.ForgeL1TxsNum])
 	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err :=
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, 3, len(oL1UserTxs))
 	require.Equal(t, 0, len(oL1CoordTxs))
@@ -760,7 +760,7 @@ ChainID:  chainID,
 	}
 	// batch1 to freeze L1UserTxs
 	l1UserTxs := []common.L1Tx{}
-	_, _, _, _, _, _, err = txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+	_, _, _, _, _, _, err = txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 
 	batchPoolL2 := `
@@ -794,7 +794,7 @@ l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[1].Batch.ForgeL1TxsNum])
 
 	// select L1 & L2 txs
 	_, accAuths, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err :=
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	require.Equal(t, 3, len(oL1UserTxs))
 	require.Equal(t, 0, len(oL1CoordTxs))
@@ -809,7 +809,7 @@
 	// batch 3
 	l1UserTxs = []common.L1Tx{}
 	_, accAuths, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err =
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 
 	require.Equal(t, 0, len(oL1UserTxs))
@@ -825,7 +825,7 @@
 	// batch 4
 	l1UserTxs = []common.L1Tx{}
 	_, accAuths, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err =
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 
 	require.Equal(t, 0, len(oL1UserTxs))
@@ -873,10 +873,10 @@ ChainID:  chainID,
 	}
 	// batch1 to freeze L1UserTxs
 	l1UserTxs := []common.L1Tx{}
-	_, _, _, _, _, _, err = txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+	_, _, _, _, _, _, err = txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 
-	// 8 transfers from the same account
+	// 3 transfers from the same account
 	batchPoolL2 := `
 	Type: PoolL2
 	PoolTransfer(0) A-B: 10 (126)
@@ -889,10 +889,10 @@ require.Equal(t, 3, len(poolL2Txs))
 
 	// add the PoolL2Txs to the l2DB
 	addL2Txs(t, txsel, poolL2Txs)
-	// batch 2 to crate some accounts with positive balance, and do 8 L2Tx transfers from account A
+	// batch 2 to crate some accounts with positive balance, and do 3 L2Tx transfers from account A
 	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[1].Batch.ForgeL1TxsNum])
 	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err :=
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	assert.Equal(t, 3, len(oL1UserTxs))
 	require.Equal(t, 0, len(oL1CoordTxs))
@@ -968,7 +968,7 @@ ChainID:  chainID,
 	}
 	// batch1 to freeze L1UserTxs
 	l1UserTxs := []common.L1Tx{}
-	_, _, _, _, _, _, err = txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+	_, _, _, _, _, _, err = txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 
 	// batch 2 to crate the accounts (from L1UserTxs)
@@ -976,7 +976,7 @@ l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[1].Batch.ForgeL1TxsNum])
 
 	// select L1 & L2 txs
 	_, accAuths, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err :=
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 	require.Equal(t, 3, len(oL1UserTxs))
 	require.Equal(t, 0, len(oL1CoordTxs))
@@ -1014,7 +1014,7 @@ // add the PoolL2Txs to the l2DB
 	addL2Txs(t, txsel, poolL2Txs)
 	l1UserTxs = []common.L1Tx{}
 	_, accAuths, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err =
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 
 	require.Equal(t, 0, len(oL1UserTxs))
@@ -1029,7 +1029,7 @@ require.NoError(t, err)
 
 	// batch 4. In this Batch, account B has enough balance to send the txs
 	_, accAuths, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err =
-		txsel.GetL1L2TxSelection(tpc, l1UserTxs)
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, nil)
 	require.NoError(t, err)
 
 	require.Equal(t, 0, len(oL1UserTxs))
@@ -1038,3 +1038,112 @@ require.Equal(t, 5, len(oL2Txs))
 	require.Equal(t, 3, len(discardedL2Txs))
 	require.Equal(t, 0, len(accAuths))
 }
+
+func TestL1UserFutureTxs(t *testing.T) {
+	set := `
+		Type: Blockchain
+
+		CreateAccountDeposit(0) Coord: 0
+		CreateAccountDeposit(0) A: 100
+
+		> batchL1 // freeze L1User{2}
+		CreateAccountDeposit(0) B: 18
+		> batchL1 // forge L1User{2}, freeze L1User{1}
+		> batchL1 // forge L1User{1}
+		> block
+	`
+
+	chainID := uint16(0)
+	tc := til.NewContext(chainID, common.RollupConstMaxL1UserTx)
+	blocks, err := tc.GenerateBlocks(set)
+	assert.NoError(t, err)
+
+	hermezContractAddr := ethCommon.HexToAddress("0xc344E203a046Da13b0B4467EB7B3629D0C99F6E6")
+	txsel, _ := initTest(t, chainID, hermezContractAddr, tc.Users["Coord"])
+
+	// restart nonces of TilContext, as will be set by generating directly
+	// the PoolL2Txs for each specific batch with tc.GeneratePoolL2Txs
+	tc.RestartNonces()
+
+	tpc := txprocessor.Config{
+		NLevels:  16,
+		MaxFeeTx: 10,
+		MaxTx:    10,
+		MaxL1Tx:  10,
+		ChainID:  chainID,
+	}
+	// batch1 to freeze L1UserTxs
+	l1UserTxs := []common.L1Tx{}
+	l1UserFutureTxs := []common.L1Tx{}
+	_, _, _, _, _, _, err = txsel.GetL1L2TxSelection(tpc, l1UserTxs, l1UserFutureTxs)
+	require.NoError(t, err)
+
+	batchPoolL2 := `
+	Type: PoolL2
+	PoolTransferToEthAddr(0) A-B: 10 (126)
+	`
+	poolL2Txs, err := tc.GeneratePoolL2Txs(batchPoolL2)
+	require.NoError(t, err)
+	require.Equal(t, 1, len(poolL2Txs))
+
+	// add AccountCreationAuth for B
+	_ = addAccCreationAuth(t, tc, txsel, chainID, hermezContractAddr, "B")
+	// add the PoolL2Txs to the l2DB
+	addL2Txs(t, txsel, poolL2Txs)
+	// batch 2 to crate some accounts with positive balance, and do 1 L2Tx transfer from account A
+	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[1].Batch.ForgeL1TxsNum])
+	l1UserFutureTxs =
+		til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[2].Batch.ForgeL1TxsNum])
+	require.Equal(t, 2, len(l1UserTxs))
+	require.Equal(t, 1, len(l1UserFutureTxs))
+	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err :=
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, l1UserFutureTxs)
+	require.NoError(t, err)
+	assert.Equal(t, 2, len(oL1UserTxs))
+	require.Equal(t, 0, len(oL1CoordTxs))
+	// no L2Tx selected due the L1UserFutureTx, the L2Tx will be processed
+	// at the next batch once the L1UserTx of CreateAccount B is processed,
+	// despite that there is an AccountCreationAuth for Account B.
+	assert.Equal(t, 0, len(oL2Txs))
+	assert.Equal(t, 1, len(discardedL2Txs))
+	assert.Equal(t, "Tx not selected (in processTxToEthAddrBJJ) due to L2Tx"+
+		" discarded at the current batch, as the receiver account does"+
+		" not exist yet, and there is a L1UserTx that will create that"+
+		" account in a future batch.",
+		discardedL2Txs[0].Info)
+
+	err = txsel.l2db.StartForging(common.TxIDsFromPoolL2Txs(oL2Txs),
+		txsel.localAccountsDB.CurrentBatch())
+	require.NoError(t, err)
+
+	l1UserTxs = til.L1TxsToCommonL1Txs(tc.Queues[*blocks[0].Rollup.Batches[2].Batch.ForgeL1TxsNum])
+	l1UserFutureTxs = []common.L1Tx{}
+	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err =
+		txsel.GetL1L2TxSelection(tpc, l1UserTxs, l1UserFutureTxs)
+	require.NoError(t, err)
+	assert.Equal(t, 1, len(oL1UserTxs))
+	require.Equal(t, 0, len(oL1CoordTxs))
+	// L2Tx selected as now the L1UserTx of CreateAccount B is processed
+	assert.Equal(t, 1, len(oL2Txs))
+	assert.Equal(t, 0, len(discardedL2Txs))
+	err = txsel.l2db.StartForging(common.TxIDsFromPoolL2Txs(oL2Txs),
+		txsel.localAccountsDB.CurrentBatch())
+	require.NoError(t, err)
+
+	// generate a new L2Tx A-B and check that is processed
+	poolL2Txs, err = tc.GeneratePoolL2Txs(batchPoolL2)
+	require.NoError(t, err)
+	require.Equal(t, 1, len(poolL2Txs))
+	// add the PoolL2Txs to the l2DB
+	addL2Txs(t, txsel, poolL2Txs)
+	_, _, oL1UserTxs, oL1CoordTxs, oL2Txs, discardedL2Txs, err =
+		txsel.GetL1L2TxSelection(tpc, nil, nil)
+	require.NoError(t, err)
+	assert.Equal(t, 0, len(oL1UserTxs))
+	require.Equal(t, 0, len(oL1CoordTxs))
+	assert.Equal(t, 1, len(oL2Txs))
+	assert.Equal(t, 0, len(discardedL2Txs))
+	err = txsel.l2db.StartForging(common.TxIDsFromPoolL2Txs(oL2Txs),
+		txsel.localAccountsDB.CurrentBatch())
+	require.NoError(t, err)
+}