This is the preferred option for contract verification via API. However, you can also use RPC endpoints, more info is available here.

​
License type

You can specify license type of the smart contract as string or number. For example for GNU General Public License v2.0 (GNU GPLv2) you could pass either 4 or "gnu_gpl_v2" We are supporting such types of license as: 
1. No License (None)
2. The Unlicense (Unlicense)
3. MIT License (MIT)
4. GNU General Public License v2.0 (GNU GPLv2)
5. GNU General Public License v3.0 (GNU GPLv3)
6. GNU Lesser General Public License v2.1 (GNU LGPLv2.1)
7. GNU Lesser General Public License v3.0 (GNU LGPLv3)
8. BSD 2-clause "Simplified" license (BSD-2-Clause)
9. BSD 3-clause "New" Or "Revised" license* (BSD-3-Clause)
10. Mozilla Public License 2.0 (MPL-2.0)
11. Open Software License 3.0 (OSL-3.0)
12. Apache 2.0 (Apache-2.0)
13. GNU Affero General Public License (GNU AGPLv3)
14. Business Source License (BSL 1.1)
API license types: 
none
unlicense
mit
gnu_gpl_v2
gnu_gpl_v3
gnu_lgpl_v2_1
gnu_lgpl_v3
bsd_2_clause
bsd_3_clause
mpl_2_0
osl_3_0
apache_2_0
gnu_agpl_v3
bsl_1_1

​
Verify smart contract

Use the appropriate Blockscout instance endpoint to verify if the smart contract microservice is enabled. In the following examples we use https://eth.blockscout.com to query Ethereum.

​
verification service running

GET https://eth.blockscout.com/api/v2/smart-contracts/verification/config Responses 
GET /api/v2/smart-contracts/verification/config HTTP/1.1
Host: eth.blockscout.com
Accept: */*
200 Successful Response
No content
0x contract addresses in POST example urls below should be replaced with your contract hash supplied on contract creation. Variables in the body are examples and should be replaced with your contract details.

​
Flattened contract

For more information on parameters to pass, see the flattened source code information on the Verifying a smart contract page.

​
verification flattened contract

POST https://eth.blockscout.com/api/v2/smart-contracts/0xb12cad649a56e67188bbaa56583c18dc7d2812ed/verification/via/flattened-code Body
​
object
Example: {"compiler_version":"v0.8.17+commit.8df45f5f","license_type":"mit","source_code":"// SPDX-License-Identifier: GPL-3.0\n\npragma solidity >=0.7.0 <0.9.0;\n\n/**\n * @title Owner\n * @dev Set & change owner\n */\ncontract Owner {\n\n address private owner;\n \n // event for EVM logging 2345678ewqwertyui54567890987654345678\n event OwnerSet(address indexed oldOwner, address indexed newOwner);\n \n // modifier to check if caller is owner\n modifier isOwner() {\n // If the first argument of 'require' evaluates to 'false', execution terminates and all\n // changes to the state and to Ether balances are reverted.\n // This used to consume all gas in old EVM versions, but not anymore.\n // It is often a good idea to use 'require' to check if functions are called correctly.\n // As a second argument, you can also provide an explanation about what went wrong.\n require(msg.sender == owner, \"Caller is not owner\");\n _;\n }\n \n /**\n * @dev Set contract deployer as owner\n */\n constructor(uint112 abc, address abb, bytes32 ghnc) {\n // console.log(\"Owner contract deployed by:\", msg.sender);\n owner = msg.sender; // 'msg.sender' is sender of current call, contract deployer for a constructor\n emit OwnerSet(address(0), owner);\n }\n\n /**\n * @dev Change owner\n * @param newOwner address of new owner\n */\n function changeOwner(address newOwner) public isOwner {\n emit OwnerSet(owner, newOwner);\n owner = newOwner;\n }\n\n /**\n * @dev Return owner address \n * @return address of owner\n */\n function getOwner() external view returns (address) {\n return owner;\n }\n}","is_optimization_enabled":true,"optimization_runs":199,"contract_name":"Owner","libraries":{"Libcheck":"0x030f7c7dbd472864220bcf9e37ede1b8a3125970","Libcheck_1":"0x030f7c7dbd472864220bcf9e37ede1b8a3125970"},"evm_version":"berlin","autodetect_constructor_args":true}
Responses 
POST /api/v2/smart-contracts/0xb12cad649a56e67188bbaa56583c18dc7d2812ed/verification/via/flattened-code HTTP/1.1
Host: eth.blockscout.com
Content-Type: application/json
Accept: */*
Content-Length: 2029

{
  "compiler_version": "v0.8.17+commit.8df45f5f",
  "license_type": "mit",
  "source_code": "// SPDX-License-Identifier: GPL-3.0\n\npragma solidity >=0.7.0 <0.9.0;\n\n/**\n * @title Owner\n * @dev Set & change owner\n */\ncontract Owner {\n\n    address private owner;\n    \n    // event for EVM logging 2345678ewqwertyui54567890987654345678\n    event OwnerSet(address indexed oldOwner, address indexed newOwner);\n    \n    // modifier to check if caller is owner\n    modifier isOwner() {\n        // If the first argument of 'require' evaluates to 'false', execution terminates and all\n        // changes to the state and to Ether balances are reverted.\n        // This used to consume all gas in old EVM versions, but not anymore.\n        // It is often a good idea to use 'require' to check if functions are called correctly.\n        // As a second argument, you can also provide an explanation about what went wrong.\n        require(msg.sender == owner, \"Caller is not owner\");\n        _;\n    }\n    \n    /**\n     * @dev Set contract deployer as owner\n     */\n    constructor(uint112 abc, address abb, bytes32 ghnc) {\n        // console.log(\"Owner contract deployed by:\", msg.sender);\n        owner = msg.sender; // 'msg.sender' is sender of current call, contract deployer for a constructor\n        emit OwnerSet(address(0), owner);\n    }\n\n    /**\n     * @dev Change owner\n     * @param newOwner address of new owner\n     */\n    function changeOwner(address newOwner) public isOwner {\n        emit OwnerSet(owner, newOwner);\n        owner = newOwner;\n    }\n\n    /**\n     * @dev Return owner address \n     * @return address of owner\n     */\n    function getOwner() external view returns (address) {\n        return owner;\n    }\n}",
  "is_optimization_enabled": true,
  "optimization_runs": 199,
  "contract_name": "Owner",
  "libraries": {
    "Libcheck": "0x030f7c7dbd472864220bcf9e37ede1b8a3125970",
    "Libcheck_1": "0x030f7c7dbd472864220bcf9e37ede1b8a3125970"
  },
  "evm_version": "berlin",
  "autodetect_constructor_args": true
}
200 Successful Response
No content

​
Via Standard JSON input

For more information on parameters to pass, see the flattened source code information on the Verifying a smart contract page. 0x contract in POST example should be replaced with your contract hash.

​
verification standard json

POST https://eth.blockscout.com/api/v2/smart-contracts/0x9c1c619176b4f8521a0ab166945d785b92aef453/verification/via/standard-input Body
​
compiler_version
number
Example: v0.8.17+commit.8df45f5f
​
contract_name
string
Example: Owner
​
files[0]
string . binary
 
​
autodetect_constructor_args
boolean
Example: false
​
constructor_args
string
Example: 00000000000000000000000000000000000000000000000000000002d2982db3000000000000000000000000bb36c792b9b45aaf8b848a1392b0d6559202729e666f6f0000000000000000000000000000000000000000000000000000000000
​
license_type
string
Example: gnu_gpl_v2
Responses 
POST /api/v2/smart-contracts/0x9c1c619176b4f8521a0ab166945d785b92aef453/verification/via/standard-input HTTP/1.1
Host: eth.blockscout.com
Content-Type: multipart/form-data
Accept: */*
Content-Length: 370

{
  "compiler_version": "v0.8.17+commit.8df45f5f",
  "contract_name": "Owner",
  "files[0]": "binary",
  "autodetect_constructor_args": "false",
  "constructor_args": "00000000000000000000000000000000000000000000000000000002d2982db3000000000000000000000000bb36c792b9b45aaf8b848a1392b0d6559202729e666f6f0000000000000000000000000000000000000000000000000000000000",
  "license_type": "gnu_gpl_v2"
}
200 Successful Response
No content

​
Via Sourcify Files

For more information on parameters to pass, see the Contract Verification via Sourcify. 0x contract in POST example url should be replaced with your contract hash, as should your relevant variables.

​
verification sourcify

POST https://eth.blockscout.com/api/v2/smart-contracts/0x030f7c7dbd472864220bcf9e37ede1b8a3125970/verification/via/sourcify Body
​
files[0]
string
 
​
chosen_contract_index
integer
Example: 4
Responses 
POST /api/v2/smart-contracts/0x030f7c7dbd472864220bcf9e37ede1b8a3125970/verification/via/sourcify HTTP/1.1
Host: eth.blockscout.com
Content-Type: multipart/form-data
Accept: */*
Content-Length: 47

{
  "files[0]": "text",
  "chosen_contract_index": "4"
}
200 Successful Response
No content

​
Multi-part Solidity files

​
verification multipart Copy

POST https\://eth.blockscout.com/api/v2/smart-contracts/0x030f7c7dbd472864220bcf9e37ede1b8a3125970/verification/via/multi-part Body
​
compiler_version
number
Example: v0.8.17+commit.8df45f5f
​
license_type
string
Example: gnu_gpl_v3
​
is_optimization_enabled
boolean
Example: true
​
libraries
string
Example: {"Libcheck": "0x030f7c7dbd472864220bcf9e37ede1b8a3125970"}
​
evm_version
string
Example: london
​
optimization_runs
integer
Example: 199
​
files[0]
string
 
​
files[1]
string . binary
 
Responses 
POST /api/v2/smart-contracts/0x030f7c7dbd472864220bcf9e37ede1b8a3125970/verification/via/multi-part HTTP/1.1
Host: eth.blockscout.com
Content-Type: multipart/form-data
Accept: */*
Content-Length: 271

{
  "compiler_version": "v0.8.17+commit.8df45f5f",
  "license_type": "gnu_gpl_v3",
  "is_optimization_enabled": "true",
  "libraries": "{\"Libcheck\": \"0x030f7c7dbd472864220bcf9e37ede1b8a3125970\"}",
  "evm_version": "london",
  "optimization_runs": "199",
  "files[0]": "text",
  "files[1]": "binary"
}
200 Successful Response
No content

​
Vyper Contracts

​
verification vyper contract

POST https://eth.blockscout.com/api/v2/smart-contracts/0xd73249995040f04cb891bdf0f997579ee3a6676c/verification/via/vyper-code Body
​
object
Example: {"compiler_version":"v0.2.12+commit.2c6842c","license_type":"gnu_agpl_v3","source_code":"from vyper.interfaces import ERC20\n\nimplements: ERC20\n\nevent Transfer:\n sender: indexed(address)\n receiver: indexed(address)\n value: uint256\n\nevent Approval:\n owner: indexed(address)\n spender: indexed(address)\n value: uint256\n\nname: public(String[64])\nsymbol: public(String[32])\ndecimals: public(uint256)\n\nbalanceOf: public(HashMap[address, uint256])\nallowance: public(HashMap[address, HashMap[address, uint256]])\ntotalSupply: public(uint256)\nminter: address\n_supply: uint256\n_check: uint256 #1% of the total supply check\n\n\n@external\ndef __init__():\n self._supply = 10_000_000_000 \n self._check = 100_000_000\n self.decimals = 18\n self.name = 'Kooopa'\n self.symbol = 'KOO'\n \n init_supply: uint256 = self._supply * 10 ** self.decimals\n \n self.balanceOf[msg.sender] = init_supply\n self.totalSupply = init_supply\n self.minter = msg.sender\n\n log Transfer(ZERO_ADDRESS, msg.sender, init_supply)\n\n\n@internal\ndef _transfer(_from : address, _to : address, _value : uint256) -> bool:\n assert _value <= self._check, 'Transfer limit of 1%(100 Million) Tokens'\n\n TargetBalance: uint256 = self.balanceOf[_to] + _value\n assert TargetBalance <= self._check, 'Single wallet cannot hold more than 1%(100 Million) Tokens'\n\n self.balanceOf[_from] -= _value\n self.balanceOf[_to] += _value\n log Transfer(_from, _to, _value)\n return True\n\n\n@external\ndef transfer(_to : address, _value : uint256) -> bool:\n self._transfer(msg.sender, _to, _value)\n return True\n\n\n@external\ndef transferFrom(_from : address, _to : address, _value : uint256) -> bool:\n self._transfer(_from, _to, _value)\n self.allowance[_from][msg.sender] -= _value\n return True\n\n\n@external\ndef approve(_spender : address, _value : uint256) -> bool:\n assert _value <= self._check, 'Cant Approve more than 1%(100 Million) Tokens for transfer'\n\n self.allowance[msg.sender][_spender] = _value\n log Approval(msg.sender, _spender, _value)\n return True\n\n\n@external\ndef mint(_to: address, _value: uint256):\n assert msg.sender == self.minter\n assert _to != ZERO_ADDRESS\n self.totalSupply += _value\n self.balanceOf[_to] += _value\n log Transfer(ZERO_ADDRESS, _to, _value)\n\n\n@internal\ndef _burn(_to: address, _value: uint256):\n \n assert _to != ZERO_ADDRESS\n self.totalSupply -= _value\n self.balanceOf[_to] -= _value\n log Transfer(_to, ZERO_ADDRESS, _value)\n\n\n@external\ndef burn(_value: uint256):\n self._burn(msg.sender, _value)\n\n\n@external\ndef burnFrom(_to: address, _value: uint256):\n self.allowance[_to][msg.sender] -= _value\n self._burn(_to, _value)","constructor_args":null,"contract_name":"Storage","evm_version":"istanbul"}
Responses 
POST /api/v2/smart-contracts/0xd73249995040f04cb891bdf0f997579ee3a6676c/verification/via/vyper-code HTTP/1.1
Host: eth.blockscout.com
Content-Type: application/json
Accept: */*
Content-Length: 2891

{
  "compiler_version": "v0.2.12+commit.2c6842c",
  "license_type": "gnu_agpl_v3",
  "source_code": "from vyper.interfaces import ERC20\n\nimplements: ERC20\n\nevent Transfer:\n    sender: indexed(address)\n    receiver: indexed(address)\n    value: uint256\n\nevent Approval:\n    owner: indexed(address)\n    spender: indexed(address)\n    value: uint256\n\nname: public(String[64])\nsymbol: public(String[32])\ndecimals: public(uint256)\n\nbalanceOf: public(HashMap[address, uint256])\nallowance: public(HashMap[address, HashMap[address, uint256]])\ntotalSupply: public(uint256)\nminter: address\n_supply: uint256\n_check: uint256 #1% of the total supply check\n\n\n@external\ndef __init__():\n    self._supply = 10_000_000_000 \n    self._check = 100_000_000\n    self.decimals = 18\n    self.name = 'Kooopa'\n    self.symbol = 'KOO'\n    \n    init_supply: uint256 = self._supply * 10 ** self.decimals\n    \n    self.balanceOf[msg.sender] = init_supply\n    self.totalSupply = init_supply\n    self.minter = msg.sender\n\n    log Transfer(ZERO_ADDRESS, msg.sender, init_supply)\n\n\n@internal\ndef _transfer(_from : address, _to : address, _value : uint256) -> bool:\n    assert _value <= self._check, 'Transfer limit of 1%(100 Million) Tokens'\n\n    TargetBalance: uint256 = self.balanceOf[_to] + _value\n    assert TargetBalance <= self._check, 'Single wallet cannot hold more than 1%(100 Million) Tokens'\n\n    self.balanceOf[_from] -= _value\n    self.balanceOf[_to] += _value\n    log Transfer(_from, _to, _value)\n    return True\n\n\n@external\ndef transfer(_to : address, _value : uint256) -> bool:\n    self._transfer(msg.sender, _to, _value)\n    return True\n\n\n@external\ndef transferFrom(_from : address, _to : address, _value : uint256) -> bool:\n    self._transfer(_from, _to, _value)\n    self.allowance[_from][msg.sender] -= _value\n    return True\n\n\n@external\ndef approve(_spender : address, _value : uint256) -> bool:\n    assert _value <= self._check, 'Cant Approve more than 1%(100 Million) Tokens for transfer'\n\n    self.allowance[msg.sender][_spender] = _value\n    log Approval(msg.sender, _spender, _value)\n    return True\n\n\n@external\ndef mint(_to: address, _value: uint256):\n    assert msg.sender == self.minter\n    assert _to != ZERO_ADDRESS\n    self.totalSupply += _value\n    self.balanceOf[_to] += _value\n    log Transfer(ZERO_ADDRESS, _to, _value)\n\n\n@internal\ndef _burn(_to: address, _value: uint256):\n    \n    assert _to != ZERO_ADDRESS\n    self.totalSupply -= _value\n    self.balanceOf[_to] -= _value\n    log Transfer(_to, ZERO_ADDRESS, _value)\n\n\n@external\ndef burn(_value: uint256):\n    self._burn(msg.sender, _value)\n\n\n@external\ndef burnFrom(_to: address, _value: uint256):\n    self.allowance[_to][msg.sender] -= _value\n    self._burn(_to, _value)",
  "constructor_args": null,
  "contract_name": "Storage",
  "evm_version": "istanbul"
}
200 Successful Response
No content

​
Vyper Multi-part files

​
verification multipart vyper

POST https://eth.blockscout.com/api/v2/smart-contracts/0xc3fd3c09d5481f4d6c85e70775804de4c93fe630/verification/via/vyper-multi-part Body
​
compiler_version
number
Example: v0.3.7+commit.6020b8bb
​
license_type
string
Example: gnu_lgpl_v2_1
​
evm_version
string
Example: istanbul
​
files[0]
string . binary
 
​
files[1]
string . binary
 
​
interfaces[0]
string . binary
 
​
interfaces[1]
string . binary
 
​
interfaces[2]
string . binary
 
Responses 
POST /api/v2/smart-contracts/0xc3fd3c09d5481f4d6c85e70775804de4c93fe630/verification/via/vyper-multi-part HTTP/1.1
Host: eth.blockscout.com
Content-Type: multipart/form-data
Accept: */*
Content-Length: 216

{
  "compiler_version": "v0.3.7+commit.6020b8bb",
  "license_type": "gnu_lgpl_v2_1",
  "evm_version": "istanbul",
  "files[0]": "binary",
  "files[1]": "binary",
  "interfaces[0]": "binary",
  "interfaces[1]": "binary",
  "interfaces[2]": "binary"
}
200 Successful Response
No content

​
Vyper Standard JSON input

​
verification standard json vyper

POST https://eth.blockscout.com/api/v2/smart-contracts/0xc3fd3c09d5481f4d6c85e70775804de4c93fe630/verification/via/vyper-standard-input Body
​
compiler_version
number
Example: v0.2.7+commit.0b3f3b3
​
license_type
string
Example: gnu_lgpl_v3
​
evm_version
string
Example: istanbul
​
files[0]
string . binary
 
​
files[1]
string . binary
 
Responses 
POST /api/v2/smart-contracts/0xc3fd3c09d5481f4d6c85e70775804de4c93fe630/verification/via/vyper-standard-input HTTP/1.1
Host: eth.blockscout.com
Content-Type: multipart/form-data
Accept: */*
Content-Length: 138

{
  "compiler_version": "v0.2.7+commit.0b3f3b3",
  "license_type": "gnu_lgpl_v3",
  "evm_version": "istanbul",
  "files[0]": "binary",
  "files[1]": "binary"
}
200 Successful Response
No content