caver-js ~v1.4.1

caver-js is a JavaScript API library that allows developers to interact with a Klaytn node using a HTTP or Websocket connection. It is available on npm.


  • Complete implementation of Klaytn’s JSON-RPC client API over HTTP and Websocket
  • Support of Klaytn transaction, account, and account key types
  • JavaScript smart contract package to deploy and execute a smart contract on the Klaytn network
  • In-memory wallet for managing Klaytn accounts
  • Support of fee-delegation
  • Support of the Klaytn wallet key format
  • Encoding/decoding of a transaction object in RLP
  • Signing of a transaction object
  • Easy to port web3-js application to caver-js

Packages in caver-js

Below are packages provided in caver-js.

Error Code Improvement

The error messages from Ethereum via web3.js are hardly figuring out where the error occurs. caver-js improves the interface to catch error messages from Klaytn.
More details can be found in the value of txError of the transaction receipt like the below:
Error: runtime error occurred in interpreter
"blockHash": "0xe7ec35c9fff1178d52cee1d46d40627d19f828c4b06ad1a5c3807698b99acb20",
"blockNumber": 7811,
"contractAddress": null,
"from": "0xa8a2d37727197cc0eb827f8c5a3a3aceb26cf59e",
"gasUsed": 9900000000,
"logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
"status": false,
"to": "0xf8425b0f65147969621f9390ca06139c7b439497",
"transactionHash": "0x85ce2b307899c90144442d9b3236827ac57375c522be2435093aebfd920b8c58",
"transactionIndex": 0,
"txError": "0x2",
"events": {}

Caution when Sending a Transaction to Klaytn

Klaytn은 고정된 가스 가격 (25 ston = 25 * 10^9)을 사용합니다. Klaytn 네트워크에 제출된 다른 가스 가격의 트랜잭션은 거절됩니다. 가스 가격에 대한 자세한 내용은 Gas and Unit Price Overview를 참조하세요. 네트워크에서 사용되는 가스 가격은 caver.klay.getGasPrice를 사용하여 얻을 수 있습니다.
만일 트랜잭션을 서명할 때나 제출할 때 gasPrice가 정의되지 않았을 경우, caver-js는 트랜잭션 가스 가격을 설정하기 위해 caver.klay.getGasPrice RPC 호출을 사용합니다.