diff --git a/ethers/provider.nim b/ethers/provider.nim
index dbad828..0a983c7 100644
--- a/ethers/provider.nim
+++ b/ethers/provider.nim
@@ -1,3 +1,4 @@
+import std/json
 import pkg/chronicles
 import ./basics
 import ./transaction
@@ -102,7 +103,7 @@ method getBlock*(provider: Provider, tag: BlockTag): Future[?Block] {.base, gcsa
   doAssert false, "not implemented"
 
 method call*(provider: Provider,
-             tx: PastTransaction,
+             tx: JsonNode,
              blockTag = BlockTag.latest): Future[seq[byte]] {.base, gcsafe.} =
   doAssert false, "not implemented"
 
diff --git a/ethers/providers/jsonrpc.nim b/ethers/providers/jsonrpc.nim
index eaa59ab..7068c1e 100644
--- a/ethers/providers/jsonrpc.nim
+++ b/ethers/providers/jsonrpc.nim
@@ -139,14 +139,14 @@ method getBlock*(provider: JsonRpcProvider,
     return await client.eth_getBlockByNumber(tag, false)
 
 method call*(provider: JsonRpcProvider,
-             tx: Transaction,
+             tx: JsonNode,
              blockTag = BlockTag.latest): Future[seq[byte]] {.async.} =
   convertError:
     let client = await provider.client
     return await client.eth_call(tx, blockTag)
 
 method call*(provider: JsonRpcProvider,
-             tx: PastTransaction,
+             tx: Transaction,
              blockTag = BlockTag.latest): Future[seq[byte]] {.async.} =
   convertError:
     let client = await provider.client
diff --git a/ethers/providers/jsonrpc/signatures.nim b/ethers/providers/jsonrpc/signatures.nim
index 916060a..688b632 100644
--- a/ethers/providers/jsonrpc/signatures.nim
+++ b/ethers/providers/jsonrpc/signatures.nim
@@ -3,6 +3,7 @@ proc eth_accounts: seq[Address]
 proc eth_blockNumber: UInt256
 proc eth_call(transaction: Transaction, blockTag: BlockTag): seq[byte]
 proc eth_call(transaction: PastTransaction, blockTag: BlockTag): seq[byte]
+proc eth_call(transaction: JsonNode, blockTag: BlockTag): seq[byte]
 proc eth_gasPrice(): UInt256
 proc eth_getBlockByNumber(blockTag: BlockTag, includeTransactions: bool): ?Block
 proc eth_getLogs(filter: EventFilter | Filter | FilterByBlockHash): JsonNode