diff --git a/jsonrpc/codec.go b/jsonrpc/codec.go
index 1129ff1cf7..b0c3128941 100644
--- a/jsonrpc/codec.go
+++ b/jsonrpc/codec.go
@@ -169,6 +169,21 @@ func (bnh *BlockNumberOrHash) UnmarshalJSON(data []byte) error {
 	return nil
 }
 
+// stringToBlockNumberSafe parses string and returns Block Number
+// works similar to stringToBlockNumber
+// but treats empty string or pending block number as a latest
+func stringToBlockNumberSafe(str string) (BlockNumber, error) {
+	switch str {
+	case "", pending:
+		return LatestBlockNumber, nil
+	default:
+		return stringToBlockNumber(str)
+	}
+}
+
+// stringToBlockNumber parses string and returns Block Number
+// empty string is treated as an error
+// pending blocks are allowed
 func stringToBlockNumber(str string) (BlockNumber, error) {
 	if str == "" {
 		return 0, fmt.Errorf("value is empty")
@@ -176,7 +191,9 @@ func stringToBlockNumber(str string) (BlockNumber, error) {
 
 	str = strings.Trim(str, "\"")
 	switch str {
-	case pending, latest:
+	case pending:
+		return PendingBlockNumber, nil
+	case latest:
 		return LatestBlockNumber, nil
 	case earliest:
 		return EarliestBlockNumber, nil
diff --git a/jsonrpc/codec_test.go b/jsonrpc/codec_test.go
index 2b1c221929..38f41e7219 100644
--- a/jsonrpc/codec_test.go
+++ b/jsonrpc/codec_test.go
@@ -16,6 +16,7 @@ func TestBlockNumberOrHash_UnmarshalJSON(t *testing.T) {
 
 	blockNumberZero := BlockNumber(0x0)
 	blockNumberLatest := LatestBlockNumber
+	blockNumberPending := PendingBlockNumber
 
 	tests := []struct {
 		name        string
@@ -58,6 +59,14 @@ func TestBlockNumberOrHash_UnmarshalJSON(t *testing.T) {
 				BlockNumber: &blockNumberLatest,
 			},
 		},
+		{
+			"should unmarshal pending block number properly",
+			`"pending"`,
+			false,
+			BlockNumberOrHash{
+				BlockNumber: &blockNumberPending,
+			},
+		},
 		{
 			"should unmarshal block number 0 properly #1",
 			`{"blockNumber": "0x0"}`,
diff --git a/jsonrpc/dispatcher_test.go b/jsonrpc/dispatcher_test.go
index e3d1cb780f..ae0331b228 100644
--- a/jsonrpc/dispatcher_test.go
+++ b/jsonrpc/dispatcher_test.go
@@ -304,7 +304,7 @@ func TestDispatcherFuncDecode(t *testing.T) {
 		{
 			"filter",
 			`[{"fromBlock": "pending", "toBlock": "earliest"}]`,
-			LogQuery{fromBlock: LatestBlockNumber, toBlock: EarliestBlockNumber}, // pending = latest
+			LogQuery{fromBlock: LatestBlockNumber, toBlock: EarliestBlockNumber}, // pending == latest
 		},
 	}
 
diff --git a/jsonrpc/eth_endpoint.go b/jsonrpc/eth_endpoint.go
index e7d7d4d7ec..e517bbb06f 100644
--- a/jsonrpc/eth_endpoint.go
+++ b/jsonrpc/eth_endpoint.go
@@ -498,7 +498,7 @@ func (e *Eth) EstimateGas(arg *txnArgs, rawNum *BlockNumber) (interface{}, error
 		return nil, err
 	}
 
-	forksInTime := e.store.GetForksInTime(uint64(number))
+	forksInTime := e.store.GetForksInTime(header.Number)
 
 	var standardGas uint64
 	if transaction.IsContractCreation() && forksInTime.Homestead {
@@ -717,7 +717,7 @@ func (e *Eth) GetTransactionCount(address types.Address, filter BlockNumberOrHas
 
 	// The filter is empty, use the latest block by default
 	if filter.BlockNumber == nil && filter.BlockHash == nil {
-		filter.BlockNumber, _ = createBlockNumberPointer("latest")
+		filter.BlockNumber, _ = createBlockNumberPointer(latest)
 	}
 
 	if filter.BlockNumber == nil {
diff --git a/jsonrpc/helper.go b/jsonrpc/helper.go
index a1ac53a4e1..bd0d72b531 100644
--- a/jsonrpc/helper.go
+++ b/jsonrpc/helper.go
@@ -138,12 +138,9 @@ type nonceGetter interface {
 func GetNextNonce(address types.Address, number BlockNumber, store nonceGetter) (uint64, error) {
 	if number == PendingBlockNumber {
 		// Grab the latest pending nonce from the TxPool
-		//
 		// If the account is not initialized in the local TxPool,
 		// return the latest nonce from the world state
-		res := store.GetNonce(address)
-
-		return res, nil
+		return store.GetNonce(address), nil
 	}
 
 	header, err := GetBlockHeader(number, store)
diff --git a/jsonrpc/query.go b/jsonrpc/query.go
index 765bc423c2..34521160af 100644
--- a/jsonrpc/query.go
+++ b/jsonrpc/query.go
@@ -90,20 +90,13 @@ func (q *LogQuery) UnmarshalJSON(data []byte) error {
 
 	q.BlockHash = obj.BlockHash
 
-	if obj.FromBlock == "" {
-		q.fromBlock = LatestBlockNumber
-	} else {
-		if q.fromBlock, err = stringToBlockNumber(obj.FromBlock); err != nil {
-			return err
-		}
+	// pending from/to blocks or "" is treated as a latest block
+	if q.fromBlock, err = stringToBlockNumberSafe(obj.FromBlock); err != nil {
+		return err
 	}
 
-	if obj.ToBlock == "" {
-		q.toBlock = LatestBlockNumber
-	} else {
-		if q.toBlock, err = stringToBlockNumber(obj.ToBlock); err != nil {
-			return err
-		}
+	if q.toBlock, err = stringToBlockNumberSafe(obj.ToBlock); err != nil {
+		return err
 	}
 
 	if obj.Address != nil {
diff --git a/jsonrpc/query_test.go b/jsonrpc/query_test.go
index 34a168d1af..c0b0cfe278 100644
--- a/jsonrpc/query_test.go
+++ b/jsonrpc/query_test.go
@@ -1,10 +1,11 @@
 package jsonrpc
 
 import (
-	"reflect"
 	"testing"
 
 	"github.com/0xPolygon/polygon-edge/types"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 var (
@@ -99,13 +100,23 @@ func TestFilterDecode(t *testing.T) {
 				},
 			},
 		},
+		{
+			`{
+				"fromBlock": "earliest",
+				"toBlock": ""
+			}`,
+			&LogQuery{
+				fromBlock: EarliestBlockNumber,
+				toBlock:   LatestBlockNumber, // empty is converted to the latest
+			},
+		},
 		{
 			`{
 				"fromBlock": "pending",
 				"toBlock": "earliest"
 			}`,
 			&LogQuery{
-				fromBlock: LatestBlockNumber, // pending = latest
+				fromBlock: LatestBlockNumber, // pending is converted to the latest
 				toBlock:   EarliestBlockNumber,
 			},
 		},
@@ -121,22 +132,15 @@ func TestFilterDecode(t *testing.T) {
 		},
 	}
 
-	for indx, c := range cases {
+	for _, c := range cases {
 		res := &LogQuery{}
 		err := res.UnmarshalJSON([]byte(c.str))
 
-		if err != nil && c.res != nil {
-			t.Fatal(err)
-		}
-
-		if err == nil && c.res == nil {
-			t.Fatal("it should fail")
-		}
-
 		if c.res != nil {
-			if !reflect.DeepEqual(res, c.res) {
-				t.Fatalf("bad %d", indx)
-			}
+			require.NoError(t, err)
+			require.Equal(t, c.res, res)
+		} else {
+			require.Error(t, err)
 		}
 	}
 }
@@ -223,9 +227,7 @@ func TestFilterMatch(t *testing.T) {
 		},
 	}
 
-	for indx, c := range cases {
-		if c.filter.Match(c.log) != c.match {
-			t.Fatalf("bad %d", indx)
-		}
+	for _, c := range cases {
+		assert.Equal(t, c.match, c.filter.Match(c.log))
 	}
 }
diff --git a/txpool/txpool.go b/txpool/txpool.go
index aa4707a9a8..7def50a235 100644
--- a/txpool/txpool.go
+++ b/txpool/txpool.go
@@ -811,6 +811,8 @@ func (p *TxPool) addTx(origin txOrigin, tx *types.Transaction) error {
 		} else if oldTxWithSameNonce.GetGasPrice(p.baseFee).Cmp(
 			tx.GetGasPrice(p.baseFee)) >= 0 {
 			// if tx with same nonce does exist and has same or better gas price -> return error
+			metrics.IncrCounter([]string{txPoolMetrics, "underpriced_tx"}, 1)
+
 			return ErrUnderpriced
 		}
 
@@ -822,6 +824,8 @@ func (p *TxPool) addTx(origin txOrigin, tx *types.Transaction) error {
 
 		// reject low nonce tx
 		if tx.Nonce < accountNonce {
+			metrics.IncrCounter([]string{txPoolMetrics, "nonce_too_low_tx"}, 1)
+
 			return ErrNonceTooLow
 		}
 	}