diff --git a/api/api_full.go b/api/api_full.go
index 8a23131af..4ae2ea531 100644
--- a/api/api_full.go
+++ b/api/api_full.go
@@ -823,9 +823,9 @@ type FullNode interface {
 	EthGasPrice(ctx context.Context) (ethtypes.EthBigInt, error)                                                                                                     //perm:read
 	EthFeeHistory(ctx context.Context, p jsonrpc.RawParams) (ethtypes.EthFeeHistory, error)                                                                          //perm:read
 
-	EthMaxPriorityFeePerGas(ctx context.Context) (ethtypes.EthBigInt, error)                                                     //perm:read
-	EthEstimateGas(ctx context.Context, tx ethtypes.EthCall, blkParam ethtypes.EthBlockNumberOrHash) (ethtypes.EthUint64, error) //perm:read
-	EthCall(ctx context.Context, tx ethtypes.EthCall, blkParam ethtypes.EthBlockNumberOrHash) (ethtypes.EthBytes, error)         //perm:read
+	EthMaxPriorityFeePerGas(ctx context.Context) (ethtypes.EthBigInt, error)                                             //perm:read
+	EthEstimateGas(ctx context.Context, p jsonrpc.RawParams) (ethtypes.EthUint64, error)                                 //perm:read
+	EthCall(ctx context.Context, tx ethtypes.EthCall, blkParam ethtypes.EthBlockNumberOrHash) (ethtypes.EthBytes, error) //perm:read
 
 	EthSendRawTransaction(ctx context.Context, rawTx ethtypes.EthBytes) (ethtypes.EthHash, error) //perm:read
 
diff --git a/api/api_gateway.go b/api/api_gateway.go
index 63489f31b..238bf43ab 100644
--- a/api/api_gateway.go
+++ b/api/api_gateway.go
@@ -114,7 +114,7 @@ type Gateway interface {
 	EthGasPrice(ctx context.Context) (ethtypes.EthBigInt, error)
 	EthFeeHistory(ctx context.Context, p jsonrpc.RawParams) (ethtypes.EthFeeHistory, error)
 	EthMaxPriorityFeePerGas(ctx context.Context) (ethtypes.EthBigInt, error)
-	EthEstimateGas(ctx context.Context, tx ethtypes.EthCall, blkParam ethtypes.EthBlockNumberOrHash) (ethtypes.EthUint64, error)
+	EthEstimateGas(ctx context.Context, p jsonrpc.RawParams) (ethtypes.EthUint64, error)
 	EthCall(ctx context.Context, tx ethtypes.EthCall, blkParam ethtypes.EthBlockNumberOrHash) (ethtypes.EthBytes, error)
 	EthSendRawTransaction(ctx context.Context, rawTx ethtypes.EthBytes) (ethtypes.EthHash, error)
 	EthGetLogs(ctx context.Context, filter *ethtypes.EthFilterSpec) (*ethtypes.EthFilterResult, error)
diff --git a/api/mocks/mock_full.go b/api/mocks/mock_full.go
index f27aa6f79..92b719550 100644
--- a/api/mocks/mock_full.go
+++ b/api/mocks/mock_full.go
@@ -1042,18 +1042,18 @@ func (mr *MockFullNodeMockRecorder) EthChainId(arg0 interface{}) *gomock.Call {
 }
 
 // EthEstimateGas mocks base method.
-func (m *MockFullNode) EthEstimateGas(arg0 context.Context, arg1 ethtypes.EthCall, arg2 ethtypes.EthBlockNumberOrHash) (ethtypes.EthUint64, error) {
+func (m *MockFullNode) EthEstimateGas(arg0 context.Context, arg1 jsonrpc.RawParams) (ethtypes.EthUint64, error) {
 	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "EthEstimateGas", arg0, arg1, arg2)
+	ret := m.ctrl.Call(m, "EthEstimateGas", arg0, arg1)
 	ret0, _ := ret[0].(ethtypes.EthUint64)
 	ret1, _ := ret[1].(error)
 	return ret0, ret1
 }
 
 // EthEstimateGas indicates an expected call of EthEstimateGas.
-func (mr *MockFullNodeMockRecorder) EthEstimateGas(arg0, arg1, arg2 interface{}) *gomock.Call {
+func (mr *MockFullNodeMockRecorder) EthEstimateGas(arg0, arg1 interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "EthEstimateGas", reflect.TypeOf((*MockFullNode)(nil).EthEstimateGas), arg0, arg1, arg2)
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "EthEstimateGas", reflect.TypeOf((*MockFullNode)(nil).EthEstimateGas), arg0, arg1)
 }
 
 // EthFeeHistory mocks base method.
diff --git a/api/proxy_gen.go b/api/proxy_gen.go
index 3c53ba57b..8adcbc189 100644
--- a/api/proxy_gen.go
+++ b/api/proxy_gen.go
@@ -255,7 +255,7 @@ type FullNodeMethods struct {
 
 	EthChainId func(p0 context.Context) (ethtypes.EthUint64, error) `perm:"read"`
 
-	EthEstimateGas func(p0 context.Context, p1 ethtypes.EthCall, p2 ethtypes.EthBlockNumberOrHash) (ethtypes.EthUint64, error) `perm:"read"`
+	EthEstimateGas func(p0 context.Context, p1 jsonrpc.RawParams) (ethtypes.EthUint64, error) `perm:"read"`
 
 	EthFeeHistory func(p0 context.Context, p1 jsonrpc.RawParams) (ethtypes.EthFeeHistory, error) `perm:"read"`
 
@@ -679,7 +679,7 @@ type GatewayMethods struct {
 
 	EthChainId func(p0 context.Context) (ethtypes.EthUint64, error) ``
 
-	EthEstimateGas func(p0 context.Context, p1 ethtypes.EthCall, p2 ethtypes.EthBlockNumberOrHash) (ethtypes.EthUint64, error) ``
+	EthEstimateGas func(p0 context.Context, p1 jsonrpc.RawParams) (ethtypes.EthUint64, error) ``
 
 	EthFeeHistory func(p0 context.Context, p1 jsonrpc.RawParams) (ethtypes.EthFeeHistory, error) ``
 
@@ -2134,14 +2134,14 @@ func (s *FullNodeStub) EthChainId(p0 context.Context) (ethtypes.EthUint64, error
 	return *new(ethtypes.EthUint64), ErrNotSupported
 }
 
-func (s *FullNodeStruct) EthEstimateGas(p0 context.Context, p1 ethtypes.EthCall, p2 ethtypes.EthBlockNumberOrHash) (ethtypes.EthUint64, error) {
+func (s *FullNodeStruct) EthEstimateGas(p0 context.Context, p1 jsonrpc.RawParams) (ethtypes.EthUint64, error) {
 	if s.Internal.EthEstimateGas == nil {
 		return *new(ethtypes.EthUint64), ErrNotSupported
 	}
-	return s.Internal.EthEstimateGas(p0, p1, p2)
+	return s.Internal.EthEstimateGas(p0, p1)
 }
 
-func (s *FullNodeStub) EthEstimateGas(p0 context.Context, p1 ethtypes.EthCall, p2 ethtypes.EthBlockNumberOrHash) (ethtypes.EthUint64, error) {
+func (s *FullNodeStub) EthEstimateGas(p0 context.Context, p1 jsonrpc.RawParams) (ethtypes.EthUint64, error) {
 	return *new(ethtypes.EthUint64), ErrNotSupported
 }
 
@@ -4400,14 +4400,14 @@ func (s *GatewayStub) EthChainId(p0 context.Context) (ethtypes.EthUint64, error)
 	return *new(ethtypes.EthUint64), ErrNotSupported
 }
 
-func (s *GatewayStruct) EthEstimateGas(p0 context.Context, p1 ethtypes.EthCall, p2 ethtypes.EthBlockNumberOrHash) (ethtypes.EthUint64, error) {
+func (s *GatewayStruct) EthEstimateGas(p0 context.Context, p1 jsonrpc.RawParams) (ethtypes.EthUint64, error) {
 	if s.Internal.EthEstimateGas == nil {
 		return *new(ethtypes.EthUint64), ErrNotSupported
 	}
-	return s.Internal.EthEstimateGas(p0, p1, p2)
+	return s.Internal.EthEstimateGas(p0, p1)
 }
 
-func (s *GatewayStub) EthEstimateGas(p0 context.Context, p1 ethtypes.EthCall, p2 ethtypes.EthBlockNumberOrHash) (ethtypes.EthUint64, error) {
+func (s *GatewayStub) EthEstimateGas(p0 context.Context, p1 jsonrpc.RawParams) (ethtypes.EthUint64, error) {
 	return *new(ethtypes.EthUint64), ErrNotSupported
 }
 
diff --git a/build/openrpc/full.json.gz b/build/openrpc/full.json.gz
index cbe2471bb..994266492 100644
Binary files a/build/openrpc/full.json.gz and b/build/openrpc/full.json.gz differ
diff --git a/build/openrpc/gateway.json.gz b/build/openrpc/gateway.json.gz
index e9c3d096c..2a3e5c939 100644
Binary files a/build/openrpc/gateway.json.gz and b/build/openrpc/gateway.json.gz differ
diff --git a/chain/types/ethtypes/eth_types.go b/chain/types/ethtypes/eth_types.go
index b796e6f56..b933329f4 100644
--- a/chain/types/ethtypes/eth_types.go
+++ b/chain/types/ethtypes/eth_types.go
@@ -799,6 +799,45 @@ func GetContractEthAddressFromCode(sender EthAddress, salt [32]byte, initcode []
 	return ethAddr, nil
 }
 
+// EthEstimateGasParams handles raw jsonrpc params for eth_estimateGas
+type EthEstimateGasParams struct {
+	Tx       EthCall
+	BlkParam *EthBlockNumberOrHash
+}
+
+func (e *EthEstimateGasParams) UnmarshalJSON(b []byte) error {
+	var params []json.RawMessage
+	err := json.Unmarshal(b, &params)
+	if err != nil {
+		return err
+	}
+
+	switch len(params) {
+	case 2:
+		err = json.Unmarshal(params[1], &e.BlkParam)
+		if err != nil {
+			return err
+		}
+		fallthrough
+	case 1:
+		err = json.Unmarshal(params[0], &e.Tx)
+		if err != nil {
+			return err
+		}
+	default:
+		return xerrors.Errorf("expected 1 or 2 params, got %d", len(params))
+	}
+
+	return nil
+}
+
+func (e EthEstimateGasParams) MarshalJSON() ([]byte, error) {
+	if e.BlkParam != nil {
+		return json.Marshal([]interface{}{e.Tx, e.BlkParam})
+	}
+	return json.Marshal([]interface{}{e.Tx})
+}
+
 // EthFeeHistoryParams handles raw jsonrpc params for eth_feeHistory
 type EthFeeHistoryParams struct {
 	BlkCount          EthUint64
diff --git a/documentation/en/api-v1-unstable-methods.md b/documentation/en/api-v1-unstable-methods.md
index 377f8b4e6..c2929f0f5 100644
--- a/documentation/en/api-v1-unstable-methods.md
+++ b/documentation/en/api-v1-unstable-methods.md
@@ -2402,15 +2402,7 @@ Perms: read
 Inputs:
 ```json
 [
-  {
-    "from": "0x5cbeecf99d3fdb3f25e309cc264f240bb0664031",
-    "to": "0x5cbeecf99d3fdb3f25e309cc264f240bb0664031",
-    "gas": "0x5",
-    "gasPrice": "0x0",
-    "value": "0x0",
-    "data": "0x07"
-  },
-  "string value"
+  "Bw=="
 ]
 ```
 
diff --git a/gateway/node.go b/gateway/node.go
index 5c686e774..f2464d274 100644
--- a/gateway/node.go
+++ b/gateway/node.go
@@ -131,7 +131,7 @@ type TargetAPI interface {
 	EthGasPrice(ctx context.Context) (ethtypes.EthBigInt, error)
 	EthFeeHistory(ctx context.Context, p jsonrpc.RawParams) (ethtypes.EthFeeHistory, error)
 	EthMaxPriorityFeePerGas(ctx context.Context) (ethtypes.EthBigInt, error)
-	EthEstimateGas(ctx context.Context, tx ethtypes.EthCall, blkParam ethtypes.EthBlockNumberOrHash) (ethtypes.EthUint64, error)
+	EthEstimateGas(ctx context.Context, p jsonrpc.RawParams) (ethtypes.EthUint64, error)
 	EthCall(ctx context.Context, tx ethtypes.EthCall, blkParam ethtypes.EthBlockNumberOrHash) (ethtypes.EthBytes, error)
 	EthSendRawTransaction(ctx context.Context, rawTx ethtypes.EthBytes) (ethtypes.EthHash, error)
 	EthGetLogs(ctx context.Context, filter *ethtypes.EthFilterSpec) (*ethtypes.EthFilterResult, error)
diff --git a/gateway/proxy_eth.go b/gateway/proxy_eth.go
index 4fc3b2fd6..13a12acfa 100644
--- a/gateway/proxy_eth.go
+++ b/gateway/proxy_eth.go
@@ -353,13 +353,19 @@ func (gw *Node) EthMaxPriorityFeePerGas(ctx context.Context) (ethtypes.EthBigInt
 	return gw.target.EthMaxPriorityFeePerGas(ctx)
 }
 
-func (gw *Node) EthEstimateGas(ctx context.Context, tx ethtypes.EthCall, blkParam ethtypes.EthBlockNumberOrHash) (ethtypes.EthUint64, error) {
+func (gw *Node) EthEstimateGas(ctx context.Context, p jsonrpc.RawParams) (ethtypes.EthUint64, error) {
+	// validate params
+	_, err := jsonrpc.DecodeParams[ethtypes.EthEstimateGasParams](p)
+	if err != nil {
+		return ethtypes.EthUint64(0), xerrors.Errorf("decoding params: %w", err)
+	}
+
 	if err := gw.limit(ctx, stateRateLimitTokens); err != nil {
 		return 0, err
 	}
 
 	// todo limit gas? to what?
-	return gw.target.EthEstimateGas(ctx, tx, blkParam)
+	return gw.target.EthEstimateGas(ctx, p)
 }
 
 func (gw *Node) EthCall(ctx context.Context, tx ethtypes.EthCall, blkParam ethtypes.EthBlockNumberOrHash) (ethtypes.EthBytes, error) {
diff --git a/itests/eth_account_abstraction_test.go b/itests/eth_account_abstraction_test.go
index 62c0083a7..5ca672674 100644
--- a/itests/eth_account_abstraction_test.go
+++ b/itests/eth_account_abstraction_test.go
@@ -3,6 +3,7 @@ package itests
 import (
 	"context"
 	"encoding/hex"
+	"encoding/json"
 	"os"
 	"testing"
 	"time"
@@ -272,10 +273,13 @@ func TestEthAccountAbstractionFailsFromEvmActor(t *testing.T) {
 	contract, err := hex.DecodeString(string(contractHex))
 	require.NoError(t, err)
 
-	gaslimit, err := client.EthEstimateGas(ctx, ethtypes.EthCall{
+	gasParams, err := json.Marshal(ethtypes.EthEstimateGasParams{Tx: ethtypes.EthCall{
 		From: &ethAddr,
 		Data: contract,
-	}, ethtypes.NewEthBlockNumberOrHashFromPredefined("latest"))
+	}})
+	require.NoError(t, err)
+
+	gaslimit, err := client.EthEstimateGas(ctx, gasParams)
 	require.NoError(t, err)
 
 	maxPriorityFeePerGas, err := client.EthMaxPriorityFeePerGas(ctx)
diff --git a/itests/eth_conformance_test.go b/itests/eth_conformance_test.go
index c43dd7dfa..9c1b2ae34 100644
--- a/itests/eth_conformance_test.go
+++ b/itests/eth_conformance_test.go
@@ -35,7 +35,7 @@ type ethAPIRaw struct {
 	EthBlockNumber                         func(context.Context) (json.RawMessage, error)
 	EthCall                                func(context.Context, ethtypes.EthCall, ethtypes.EthBlockNumberOrHash) (json.RawMessage, error)
 	EthChainId                             func(context.Context) (json.RawMessage, error)
-	EthEstimateGas                         func(context.Context, ethtypes.EthCall, ethtypes.EthBlockNumberOrHash) (json.RawMessage, error)
+	EthEstimateGas                         func(context.Context, jsonrpc.RawParams) (json.RawMessage, error)
 	EthFeeHistory                          func(context.Context, ethtypes.EthUint64, string, []float64) (json.RawMessage, error)
 	EthGasPrice                            func(context.Context) (json.RawMessage, error)
 	EthGetBalance                          func(context.Context, ethtypes.EthAddress, ethtypes.EthBlockNumberOrHash) (json.RawMessage, error)
@@ -182,10 +182,13 @@ func TestEthOpenRPCConformance(t *testing.T) {
 		{
 			method: "eth_estimateGas",
 			call: func(a *ethAPIRaw) (json.RawMessage, error) {
-				return ethapi.EthEstimateGas(context.Background(), ethtypes.EthCall{
+				gasParams, err := json.Marshal(ethtypes.EthEstimateGasParams{Tx: ethtypes.EthCall{
 					From: &senderEthAddr,
 					Data: contractBin,
-				}, ethtypes.NewEthBlockNumberOrHashFromPredefined("latest"))
+				}})
+				require.NoError(t, err)
+
+				return ethapi.EthEstimateGas(ctx, gasParams)
 			},
 		},
 
@@ -448,10 +451,13 @@ func TestEthOpenRPCConformance(t *testing.T) {
 }
 
 func createRawSignedEthTx(ctx context.Context, t *testing.T, client *kit.TestFullNode, senderEthAddr ethtypes.EthAddress, receiverEthAddr ethtypes.EthAddress, senderKey *key.Key, contractBin []byte) []byte {
-	gaslimit, err := client.EthEstimateGas(ctx, ethtypes.EthCall{
+	gasParams, err := json.Marshal(ethtypes.EthEstimateGasParams{Tx: ethtypes.EthCall{
 		From: &senderEthAddr,
 		Data: contractBin,
-	}, ethtypes.NewEthBlockNumberOrHashFromPredefined("latest"))
+	}})
+	require.NoError(t, err)
+
+	gaslimit, err := client.EthEstimateGas(ctx, gasParams)
 	require.NoError(t, err)
 
 	maxPriorityFeePerGas, err := client.EthMaxPriorityFeePerGas(ctx)
diff --git a/itests/eth_deploy_test.go b/itests/eth_deploy_test.go
index 422bc3449..68861f98f 100644
--- a/itests/eth_deploy_test.go
+++ b/itests/eth_deploy_test.go
@@ -60,10 +60,13 @@ func TestDeployment(t *testing.T) {
 	// verify the deployer address is an Placeholder.
 	client.AssertActorType(ctx, deployer, manifest.PlaceholderKey)
 
-	gaslimit, err := client.EthEstimateGas(ctx, ethtypes.EthCall{
+	gasParams, err := json.Marshal(ethtypes.EthEstimateGasParams{Tx: ethtypes.EthCall{
 		From: &ethAddr,
 		Data: contract,
-	}, ethtypes.NewEthBlockNumberOrHashFromPredefined("latest"))
+	}})
+	require.NoError(t, err)
+
+	gaslimit, err := client.EthEstimateGas(ctx, gasParams)
 	require.NoError(t, err)
 
 	maxPriorityFeePerGas, err := client.EthMaxPriorityFeePerGas(ctx)
diff --git a/itests/eth_hash_lookup_test.go b/itests/eth_hash_lookup_test.go
index dd3980867..0a2c11d3c 100644
--- a/itests/eth_hash_lookup_test.go
+++ b/itests/eth_hash_lookup_test.go
@@ -3,6 +3,7 @@ package itests
 import (
 	"context"
 	"encoding/hex"
+	"encoding/json"
 	"os"
 	"testing"
 	"time"
@@ -47,10 +48,13 @@ func TestTransactionHashLookup(t *testing.T) {
 	// send some funds to the f410 address
 	kit.SendFunds(ctx, t, client, deployer, types.FromFil(10))
 
-	gaslimit, err := client.EthEstimateGas(ctx, ethtypes.EthCall{
+	gasParams, err := json.Marshal(ethtypes.EthEstimateGasParams{Tx: ethtypes.EthCall{
 		From: &ethAddr,
 		Data: contract,
-	}, ethtypes.NewEthBlockNumberOrHashFromPredefined("latest"))
+	}})
+	require.NoError(t, err)
+
+	gaslimit, err := client.EthEstimateGas(ctx, gasParams)
 	require.NoError(t, err)
 
 	maxPriorityFeePerGas, err := client.EthMaxPriorityFeePerGas(ctx)
@@ -350,10 +354,13 @@ func TestEthGetMessageCidByTransactionHashEthTx(t *testing.T) {
 	// send some funds to the f410 address
 	kit.SendFunds(ctx, t, client, deployer, types.FromFil(10))
 
-	gaslimit, err := client.EthEstimateGas(ctx, ethtypes.EthCall{
+	gasParams, err := json.Marshal(ethtypes.EthEstimateGasParams{Tx: ethtypes.EthCall{
 		From: &ethAddr,
 		Data: contract,
-	}, ethtypes.NewEthBlockNumberOrHashFromPredefined("latest"))
+	}})
+	require.NoError(t, err)
+
+	gaslimit, err := client.EthEstimateGas(ctx, gasParams)
 	require.NoError(t, err)
 
 	maxPriorityFeePerGas, err := client.EthMaxPriorityFeePerGas(ctx)
diff --git a/itests/eth_transactions_test.go b/itests/eth_transactions_test.go
index 0039ebde0..59e5852c9 100644
--- a/itests/eth_transactions_test.go
+++ b/itests/eth_transactions_test.go
@@ -3,6 +3,7 @@ package itests
 import (
 	"context"
 	"encoding/hex"
+	"encoding/json"
 	"os"
 	"testing"
 	"time"
@@ -44,10 +45,13 @@ func TestValueTransferValidSignature(t *testing.T) {
 
 	kit.SendFunds(ctx, t, client, deployer, types.FromFil(1000))
 
-	gaslimit, err := client.EthEstimateGas(ctx, ethtypes.EthCall{
+	gasParams, err := json.Marshal(ethtypes.EthEstimateGasParams{Tx: ethtypes.EthCall{
 		From: &ethAddr,
 		Data: contract,
-	}, ethtypes.NewEthBlockNumberOrHashFromPredefined("latest"))
+	}})
+	require.NoError(t, err)
+
+	gaslimit, err := client.EthEstimateGas(ctx, gasParams)
 	require.NoError(t, err)
 
 	maxPriorityFeePerGas, err := client.EthMaxPriorityFeePerGas(ctx)
@@ -231,11 +235,14 @@ func TestContractInvocation(t *testing.T) {
 	params, err := hex.DecodeString("f8b2cb4f000000000000000000000000ff00000000000000000000000000000000000064")
 	require.NoError(t, err)
 
-	gaslimit, err := client.EthEstimateGas(ctx, ethtypes.EthCall{
+	gasParams, err := json.Marshal(ethtypes.EthEstimateGasParams{Tx: ethtypes.EthCall{
 		From: &ethAddr,
 		To:   &contractAddr,
 		Data: params,
-	}, ethtypes.NewEthBlockNumberOrHashFromPredefined("latest"))
+	}})
+	require.NoError(t, err)
+
+	gaslimit, err := client.EthEstimateGas(ctx, gasParams)
 	require.NoError(t, err)
 
 	maxPriorityFeePerGas, err := client.EthMaxPriorityFeePerGas(ctx)
@@ -350,10 +357,15 @@ func TestGetBlockByNumber(t *testing.T) {
 }
 
 func deployContractTx(ctx context.Context, client *kit.TestFullNode, ethAddr ethtypes.EthAddress, contract []byte) (*ethtypes.EthTxArgs, error) {
-	gaslimit, err := client.EthEstimateGas(ctx, ethtypes.EthCall{
+	gasParams, err := json.Marshal(ethtypes.EthEstimateGasParams{Tx: ethtypes.EthCall{
 		From: &ethAddr,
 		Data: contract,
-	}, ethtypes.NewEthBlockNumberOrHashFromPredefined("latest"))
+	}})
+	if err != nil {
+		return nil, err
+	}
+
+	gaslimit, err := client.EthEstimateGas(ctx, gasParams)
 	if err != nil {
 		return nil, err
 	}
diff --git a/itests/fevm_test.go b/itests/fevm_test.go
index 7b09ac7f9..2dcb8ef1d 100644
--- a/itests/fevm_test.go
+++ b/itests/fevm_test.go
@@ -6,6 +6,7 @@ import (
 	"crypto/rand"
 	"encoding/binary"
 	"encoding/hex"
+	"encoding/json"
 	"fmt"
 	"testing"
 	"time"
@@ -657,11 +658,15 @@ func TestFEVMRecursiveActorCallEstimate(t *testing.T) {
 			t.Logf("running with %d recursive calls", r)
 
 			params := makeParams(r)
-			gaslimit, err := client.EthEstimateGas(ctx, ethtypes.EthCall{
+
+			gasParams, err := json.Marshal(ethtypes.EthEstimateGasParams{Tx: ethtypes.EthCall{
 				From: &ethAddr,
 				To:   &contractAddr,
 				Data: params,
-			}, ethtypes.NewEthBlockNumberOrHashFromPredefined("latest"))
+			}})
+			require.NoError(t, err)
+
+			gaslimit, err := client.EthEstimateGas(ctx, gasParams)
 			require.NoError(t, err)
 			require.LessOrEqual(t, int64(gaslimit), build.BlockGasLimit)
 
@@ -816,11 +821,14 @@ func TestFEVMBareTransferTriggersSmartContractLogic(t *testing.T) {
 	contractEth, err := ethtypes.EthAddressFromFilecoinAddress(contractAddr)
 	require.NoError(t, err)
 
-	gaslimit, err := client.EthEstimateGas(ctx, ethtypes.EthCall{
+	gasParams, err := json.Marshal(ethtypes.EthEstimateGasParams{Tx: ethtypes.EthCall{
 		From:  &accntEth,
 		To:    &contractEth,
 		Value: ethtypes.EthBigInt(big.NewInt(100)),
-	}, ethtypes.NewEthBlockNumberOrHashFromPredefined("latest"))
+	}})
+	require.NoError(t, err)
+
+	gaslimit, err := client.EthEstimateGas(ctx, gasParams)
 	require.NoError(t, err)
 
 	maxPriorityFeePerGas, err := client.EthMaxPriorityFeePerGas(ctx)
@@ -1034,10 +1042,13 @@ func TestFEVMErrorParsing(t *testing.T) {
 				require.ErrorContains(t, err, expected)
 			})
 			t.Run("EthEstimateGas", func(t *testing.T) {
-				_, err := e.EthEstimateGas(ctx, ethtypes.EthCall{
+				gasParams, err := json.Marshal(ethtypes.EthEstimateGasParams{Tx: ethtypes.EthCall{
 					To:   &contractAddrEth,
 					Data: entryPoint,
-				}, ethtypes.NewEthBlockNumberOrHashFromPredefined("latest"))
+				}})
+				require.NoError(t, err)
+
+				_, err = e.EthEstimateGas(ctx, gasParams)
 				require.ErrorContains(t, err, expected)
 			})
 		})
diff --git a/node/impl/full/dummy.go b/node/impl/full/dummy.go
index 857b4c57f..11ff95a63 100644
--- a/node/impl/full/dummy.go
+++ b/node/impl/full/dummy.go
@@ -122,7 +122,7 @@ func (e *EthModuleDummy) EthGasPrice(ctx context.Context) (ethtypes.EthBigInt, e
 	return ethtypes.EthBigIntZero, ErrModuleDisabled
 }
 
-func (e *EthModuleDummy) EthEstimateGas(ctx context.Context, tx ethtypes.EthCall, blkParam ethtypes.EthBlockNumberOrHash) (ethtypes.EthUint64, error) {
+func (e *EthModuleDummy) EthEstimateGas(ctx context.Context, p jsonrpc.RawParams) (ethtypes.EthUint64, error) {
 	return 0, ErrModuleDisabled
 }
 
diff --git a/node/impl/full/eth.go b/node/impl/full/eth.go
index 12a9d56ea..d4298492f 100644
--- a/node/impl/full/eth.go
+++ b/node/impl/full/eth.go
@@ -66,7 +66,7 @@ type EthModuleAPI interface {
 	NetListening(ctx context.Context) (bool, error)
 	EthProtocolVersion(ctx context.Context) (ethtypes.EthUint64, error)
 	EthGasPrice(ctx context.Context) (ethtypes.EthBigInt, error)
-	EthEstimateGas(ctx context.Context, tx ethtypes.EthCall, blkParam ethtypes.EthBlockNumberOrHash) (ethtypes.EthUint64, error)
+	EthEstimateGas(ctx context.Context, p jsonrpc.RawParams) (ethtypes.EthUint64, error)
 	EthCall(ctx context.Context, tx ethtypes.EthCall, blkParam ethtypes.EthBlockNumberOrHash) (ethtypes.EthBytes, error)
 	EthMaxPriorityFeePerGas(ctx context.Context) (ethtypes.EthBigInt, error)
 	EthSendRawTransaction(ctx context.Context, rawTx ethtypes.EthBytes) (ethtypes.EthHash, error)
@@ -1007,8 +1007,13 @@ func (a *EthModule) applyMessage(ctx context.Context, msg *types.Message, tsk ty
 	return res, nil
 }
 
-func (a *EthModule) EthEstimateGas(ctx context.Context, tx ethtypes.EthCall, blkParam ethtypes.EthBlockNumberOrHash) (ethtypes.EthUint64, error) {
-	msg, err := ethCallToFilecoinMessage(ctx, tx)
+func (a *EthModule) EthEstimateGas(ctx context.Context, p jsonrpc.RawParams) (ethtypes.EthUint64, error) {
+	params, err := jsonrpc.DecodeParams[ethtypes.EthEstimateGasParams](p)
+	if err != nil {
+		return ethtypes.EthUint64(0), xerrors.Errorf("decoding params: %w", err)
+	}
+
+	msg, err := ethCallToFilecoinMessage(ctx, params.Tx)
 	if err != nil {
 		return ethtypes.EthUint64(0), err
 	}
@@ -1017,9 +1022,14 @@ func (a *EthModule) EthEstimateGas(ctx context.Context, tx ethtypes.EthCall, blk
 	// gas estimation actually run.
 	msg.GasLimit = 0
 
-	ts, err := getTipsetByEthBlockNumberOrHash(ctx, a.Chain, blkParam)
-	if err != nil {
-		return ethtypes.EthUint64(0), xerrors.Errorf("failed to process block param: %v; %w", blkParam, err)
+	var ts *types.TipSet
+	if params.BlkParam == nil {
+		ts = a.Chain.GetHeaviestTipSet()
+	} else {
+		ts, err = getTipsetByEthBlockNumberOrHash(ctx, a.Chain, *params.BlkParam)
+		if err != nil {
+			return ethtypes.EthUint64(0), xerrors.Errorf("failed to process block param: %v; %w", params.BlkParam, err)
+		}
 	}
 
 	gassedMsg, err := a.GasAPI.GasEstimateMessageGas(ctx, msg, nil, ts.Key())