Contracts

Get Contract ABI for Verified Contract Source Codes

Returns the Contract Application Binary Interface ( ABI ) of a verified smart contract.

Find verified contracts ✅on our Verified Contracts Source Code page.

https://api.basescan.org/api
   ?module=contract
   &action=getabi
   &address=0xe1621db14277d66c356e14888c57ef1c0c0dc195
   &apikey=YourApiKeyToken

Try this endpoint in your browser 🔗

Request

Query Parameters

Parameter	Description
address	the contract address that has a verified source code

Response

Sample Response

{
   "status":"1",
   "message":"OK",
   "result":"[{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"owner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"spender\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"value\",\"type\":\"uint256\"}],\"name\":\"Approval\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"from\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"to\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"value\",\"type\":\"uint256\"}],\"name\":\"Transfer\",\"type\":\"event\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"name\":\"allowance\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"spender\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"amount\",\"type\":\"uint256\"}],\"name\":\"approve\",\"outputs\":[{\"internalType\":\"bool\",\"name\":\"\",\"type\":\"bool\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"name\":\"balanceOf\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"amount\",\"type\":\"uint256\"}],\"name\":\"burn\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"decimals\",\"outputs\":[{\"internalType\":\"uint8\",\"name\":\"\",\"type\":\"uint8\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"amount\",\"type\":\"uint256\"}],\"name\":\"mint\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"name\",\"outputs\":[{\"internalType\":\"string\",\"name\":\"\",\"type\":\"string\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"symbol\",\"outputs\":[{\"internalType\":\"string\",\"name\":\"\",\"type\":\"string\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"totalSupply\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"amount\",\"type\":\"uint256\"}],\"name\":\"transfer\",\"outputs\":[{\"internalType\":\"bool\",\"name\":\"\",\"type\":\"bool\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"amount\",\"type\":\"uint256\"}],\"name\":\"transferFrom\",\"outputs\":[{\"internalType\":\"bool\",\"name\":\"\",\"type\":\"bool\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"}]"
}

Get Contract Source Code for Verified Contract Source Codes

Returns the Solidity source code of a verified smart contract.

📩 Tip : You can also download a CSV list of verified contracts addresses of which the code publishers have provided a corresponding Open Source license for redistribution.

https://api.basescan.org/api
   ?module=contract
   &action=getsourcecode
   &address=0xe1621db14277d66c356e14888c57ef1c0c0dc195
   &apikey=YourApiKeyToken 

Try this endpoint in your browser 🔗

Request

Query Parameters

Parameter	Description
address	the contract address that has a verified source code

Response

Sample Response

{
   "status":"1",
   "message":"OK",
   "result":[
      {
         "SourceCode":"// SPDX-License-Identifier: MIT\r\npragma solidity ^0.8.17;\r\n \r\n// https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v3.0.0/contracts/token/ERC20/IERC20.sol\r\ninterface IERC20 {\r\n   function totalSupply() external view returns (uint);\r\n \r\n   function balanceOf(address account) external view returns (uint);\r\n \r\n   function transfer(address recipient, uint amount) external returns (bool);\r\n \r\n   function allowance(address owner, address spender) external view returns (uint);\r\n \r\n   function approve(address spender, uint amount) external returns (bool);\r\n \r\n   function transferFrom(\r\n       address sender,\r\n       address recipient,\r\n       uint amount\r\n   ) external returns (bool);\r\n \r\n   event Transfer(address indexed from, address indexed to, uint value);\r\n   event Approval(address indexed owner, address indexed spender, uint value);\r\n}\r\n \r\n \r\n \r\ncontract ERC20 is IERC20 {\r\n   uint public totalSupply;\r\n   mapping(address => uint) public balanceOf;\r\n   mapping(address => mapping(address => uint)) public allowance;\r\n   string public name = \"base2\";\r\n   string public symbol = \"9889\";\r\n   uint8 public decimals = 18;\r\n \r\n   function transfer(address recipient, uint amount) external returns (bool) {\r\n       balanceOf[msg.sender] -= amount;\r\n       balanceOf[recipient] += amount;\r\n       emit Transfer(msg.sender, recipient, amount);\r\n       return true;\r\n   }\r\n \r\n   function approve(address spender, uint amount) external returns (bool) {\r\n       allowance[msg.sender][spender] = amount;\r\n       emit Approval(msg.sender, spender, amount);\r\n       return true;\r\n   }\r\n \r\n   function transferFrom(\r\n       address sender,\r\n       address recipient,\r\n       uint amount\r\n   ) external returns (bool) {\r\n       allowance[sender][msg.sender] -= amount;\r\n       balanceOf[sender] -= amount;\r\n       balanceOf[recipient] += amount;\r\n       emit Transfer(sender, recipient, amount);\r\n       return true;\r\n   }\r\n \r\n   function mint(uint amount) external {\r\n       balanceOf[msg.sender] += amount;\r\n       totalSupply += amount;\r\n       emit Transfer(address(0), msg.sender, amount);\r\n   }\r\n \r\n   function burn(uint amount) external {\r\n       balanceOf[msg.sender] -= amount;\r\n       totalSupply -= amount;\r\n       emit Transfer(msg.sender, address(0), amount);\r\n   }\r\n}",
         "ABI":"[{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"owner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"spender\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"value\",\"type\":\"uint256\"}],\"name\":\"Approval\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"from\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"to\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"value\",\"type\":\"uint256\"}],\"name\":\"Transfer\",\"type\":\"event\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"name\":\"allowance\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"spender\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"amount\",\"type\":\"uint256\"}],\"name\":\"approve\",\"outputs\":[{\"internalType\":\"bool\",\"name\":\"\",\"type\":\"bool\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"name\":\"balanceOf\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"amount\",\"type\":\"uint256\"}],\"name\":\"burn\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"decimals\",\"outputs\":[{\"internalType\":\"uint8\",\"name\":\"\",\"type\":\"uint8\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"amount\",\"type\":\"uint256\"}],\"name\":\"mint\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"name\",\"outputs\":[{\"internalType\":\"string\",\"name\":\"\",\"type\":\"string\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"symbol\",\"outputs\":[{\"internalType\":\"string\",\"name\":\"\",\"type\":\"string\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"totalSupply\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"amount\",\"type\":\"uint256\"}],\"name\":\"transfer\",\"outputs\":[{\"internalType\":\"bool\",\"name\":\"\",\"type\":\"bool\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"amount\",\"type\":\"uint256\"}],\"name\":\"transferFrom\",\"outputs\":[{\"internalType\":\"bool\",\"name\":\"\",\"type\":\"bool\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"}]",
         "ContractName":"ERC20",
         "CompilerVersion":"v0.8.17+commit.8df45f5f",
         "OptimizationUsed":"0",
         "Runs":"200",
         "ConstructorArguments":"",
         "EVMVersion":"Default",
         "Library":"",
         "LicenseType":"MIT",
         "Proxy":"0",
         "Implementation":"",
         "SwarmSource":"ipfs://35412f2550150e8cfe24159e1f44963debe0ce5919b2df53cb352cfa1d0e8ddd"
      }
   ]
}

Get Contract Creator and Creation Tx Hash

Returns a contract's deployer address and transaction hash it was created, up to 5 at a time.

https://api.basescan.org/api
   ?module=contract
   &action=getcontractcreation
   &contractaddresses=0xB83c27805aAcA5C7082eB45C868d955Cf04C337F,0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45,0xe4462eb568E2DFbb5b0cA2D3DbB1A35C9Aa98aad,0xdAC17F958D2ee523a2206206994597C13D831ec7,0xf5b969064b91869fBF676ecAbcCd1c5563F591d0
   &apikey=YourApiKeyToken 

Try this endpoint in your browser 🔗

Request

Query Parameters

Parameter	Description
contractaddresses	the contract address , up to 5 at a time

Response

Sample Response

{
   "status":"1",
   "message":"OK",
   "result":[
      {
         "contractAddress":"0x68b3465833fb72a70ecdf485e0e4c7bd8665fc45",
         "contractCreator":"0x6c9fc64a53c1b71fb3f9af64d1ae3a4931a5f4e9",
         "txHash":"0x7299cca7203f60a831756e043f4c2ccb0ee6cb7cf8aed8420f0ae99a16883a2b"
      },
      {
         "contractAddress":"0xb83c27805aaca5c7082eb45c868d955cf04c337f",
         "contractCreator":"0x390dcfddebeff949b9862ec91d7be337b8995553",
         "txHash":"0x0dbad4991b6727df606650635c9e632dad8a92c6363c91652307680efd336c6e"
      },
      {
         "contractAddress":"0xdac17f958d2ee523a2206206994597c13d831ec7",
         "contractCreator":"0x36928500bc1dcd7af6a2b4008875cc336b927d57",
         "txHash":"0x2f1c5c2b44f771e942a8506148e256f94f1a464babc938ae0690c6e34cd79190"
      },
      {
         "contractAddress":"0xe4462eb568e2dfbb5b0ca2d3dbb1a35c9aa98aad",
         "contractCreator":"0xa6d3a33a1c66083859765b9d6e407d095a908193",
         "txHash":"0x785bcd378c8168b63c9fdef64219f8ff69eec1f785f081a74513f21b18072f93"
      },
      {
         "contractAddress":"0xf5b969064b91869fbf676ecabccd1c5563f591d0",
         "contractCreator":"0x435a5760aa360cae8c246039abab7754e80a1af1",
         "txHash":"0x779cceffd0a5b4df6718674f7d88dda3edde9ff0a6fec271eb584f65a56997c6"
      }
   ]
}

Verify Source Code

Submits a contract source code to BaseScan for verification.

🌐 Tutorial : Etherscan now supports submitting multichain contract verification.

📝 Note : This endpoint is limited to 100 verifications/day, regardless of API PRO tier.

https://api.basescan.org/api
   ?module=contract
   &action=verifysourcecode
   &apikey=YourApiKeyToken 

Request

Query Parameters

Requests must be sent using HTTP POST

Parameter	Description
codeformat	single file, use solidity-single-file JSON file ( recommended ), use solidity-standard-json-input
sourceCode	the Solidity source code
constructorArguements	optional, include if your contract uses constructor arguments
contractaddress	the address your contract is deployed at
contractname	the name of your contract, such as contracts/Verified.sol:Verified
compilerversion	compiler version used, such as v0.8.24+commit.e11b9ed9
optimizationUsed	0 - no optimization 1 - optimization used
runs	no. of optimization runs used, eg 200
evmversion	leave blank for compiler default available options homestead, tangerineWhistle, spuriousDragon, byzantium, constantinople, petersburg, istanbul, paris

Response

Sample Response

{
    "status": "1",
    "message": "OK",
    "result": "a7lpxkm9kpcpicx7daftmjifrfhiuhf5vqqnawhkfhzfrcpnxj"
}

Check Source Code Verification Status

Returns the success or error status of a contract verification request.

https://api.basescan.org/api
   ?module=contract
   &action=checkverifystatus
   &guid=x3ryqcqr1zdknhfhkimqmizlcqpxncqc6nrvp3pgrcpfsqedqi
   &apikey=YourApiKeyToken 

Try this endpoint in your browser 🔗

Request

Query Parameters

Parameter	Description
guid	the unique guid received from the verification request

Response

Sample Response

If your encounter an error, reference our error list

{
    "status": "1",
    "message": "OK",
    "result": "Pass - Verified"
}

Verify Proxy Contract

Submits a proxy contract source code to BaseScan for verification.

1. Requires a valid BaseScan API key, it will be rejected otherwise

2. Current daily limit of 100 submissions per day per user (subject to change)

3. Only supports HTTP post

4. Upon successful submission you will receive a GUID (50 characters) as a receipt

5. You may use this GUID to track the status of your submission

6. Verified proxy contracts will display the "Read/Write as Proxy" of the implementation contract under the contract address's contract tab

Verifying Proxy Contract using cURL

Request

// example with only the mandatory contract address parameter
curl -d "address=0xcbdcd3815b5f975e1a2c944a9b2cd1c985a1cb7f" "https://api.basescan.org/api?module=contract&action=verifyproxycontract&apikey=YourApiKeyToken"

// example using the expectedimplementation optional parameter
// the expectedimplementation enforces a check to ensure the returned implementation contract address == address picked up by the verifier
curl -d "address=0xbc46363a7669f6e12353fa95bb067aead3675c29&expectedimplementation=0xe45a5176bc0f2c1198e2451c4e4501d4ed9b65a6" "https://api.basescan.org/api?module=contract&action=verifyproxycontract&apikey=YourApiKeyToken"

Response

// OK
{"status":"1","message":"OK","result":"gwgrrnfy56zf6vc1fljuejwg6pelnc5yns6fg6y2i6zfpgzquz"}

// NOTOK
{"status":"0","message":"NOTOK","result":"Invalid API Key"}

Checking Proxy Contract Verification Submission Status using cURL

Request

curl "https://api.basescan.org/api?module=contract&action=checkproxyverification&guid=gwgrrnfy56zf6vc1fljuejwg6pelnc5yns6fg6y2i6zfpgzquz&apikey=YourApiKeyToken"

Response

// OK
{"status":"1","message":"OK","result":"The proxy's (0xbc46363a7669f6e12353fa95bb067aead3675c29) implementation contract is found at 0xe45a5176bc0f2c1198e2451c4e4501d4ed9b65a6 and is successfully updated."}
                                    
// NOTOK
{"status":"0","message":"NOTOK","result":"A corresponding implementation contract was unfortunately not detected for the proxy address."}