Steps to Verify contracts on Etherscan

Set etherscan API Key

export API_KEY=<etherscan_api_key>

Install node modules

npm install

Build your contract

You can build your contract with truffle command if not done already.

truffle compile

Build output file will be .json

Update variables in build file

• Add/Update compiler information section like below:

"compiler": {
    "name": "solc",
    "version": "0.5.0+commit.1d4f565a"
  },

• Update correct source path of the contract. Example:

    "sourcePath": "./mosaic-contracts/contracts/gateway/OSTComposer.sol",
  

• Add/Update build file with network section.

"networks": {
    "3": {
      "address": "0xe322ed07e235a6501bd017ae9ea059b12723c55c",
      "transactionHash": "0xaaae864d3b5b5a81ea7f54d877fc65ddde856577a8646f9a0f011fbb610f463a",
      "links": {}
    }

- address: deployed contract address.
- transactionHash: Transaction hash when the contract was deployed.
- links: Library contract addresses.
  Example: {
    "MerklePatriciaProof": "0x168803ca6d5d466ea7005627bfd6eaf0b5b164b0",
    "MessageBus": "0x9c50ad270a2ca1d897326b0880b3f639c3b0acef"
  }
  
- For verification of library linked contracts, make sure library contract addresses are verified     

Verify contract

npx verify-on-etherscan --network goerli <contract build path> --optimize-runs 200 --output <flattenedFilePath>

Example

npx verify-on-etherscan --network goerli ./build/contracts/eip20Token.json --optimize-runs 200 --output 200

Checkout more options.