Contract Verification

Sourcify is the preferred service for the verification of smart contracts deployed on Sapphire. Make sure you have the address of each deployed contract available (your deployment scripts should report those) and the contracts JSON metadata file generated when compiling contracts (Hardhat stores it inside the artifacts/build-info folder and names it as a 32-digit hex number). If your project contains multiple contracts, you will need to verify each contract separately.

Contract deployment encryption

Do not deploy your contract with an encrypted contract deployment transaction, if you want to verify it. For example, if your hardhat.config.ts or deployment script contains import '@oasisprotocol/sapphire-hardhat' or import '@oasisprotocol/sapphire-paratime' lines at the beginning, you should comment those out for the deployment.

Verification services will try to match the contract deployment transaction code with the one in the provided contract's metadata. Because the transaction was encrypted with an ephemeral ParaTime key, the verification service will not be able to decrypt it. Some services may extract the contract's bytecode from the chain directly by calling eth_getCode RPC, but this will not work correctly for contracts with immutable variables.

Verification with Hardhat

If you use Hardhat to deploy your contracts, consider using the hardhat-verify plugin.

To configure it, add the following to your hardhat.config.ts file:

hardhat.config.ts

	etherscan: {
		//  Enabled by default (not supported on Sapphire)
		enabled: false
	},
	sourcify: {
		// Disabled by default
		// Doesn't need an API key
		enabled: true
	}

Now you can use the verify task:

pnpm hardhat verify --network sapphire-testnet DEPLOYED_CONTRACT_ADDRESS "Constructor argument 1"

Verification with Foundry

Foundry natively supports Sourcify verification. To use Sourcify as a provider, specify it with the --verifier option.

Example:

forge verify-contract <address> src/MyToken.sol:MyToken --verifier sourcify

info

To see all available options and more examples visit the verify-contract page of foundry or the sourcify docs

Verification on Sourcify

To verify maunally a contract deployed on Sapphire Mainnet or Testnet on Sourcify:

1. Visit the Sourcify website and hit the "VERIFY CONTRACT" button.

   

2. Upload the contracts JSON metadata file. (Sourcify can parse the Hardhat .json output file under artifacts/build-info)

   

   Store your metadata files

   For production deployments, it is generally a good idea to archive your contract metadata JSON file since it is not only useful for the verification, but contains a copy of all the source files, produced bytecode, an ABI, compiler and other relevant contract-related settings that may be useful in the future. Sourcify will store the metadata file for you and will even make it available via IPFS, but it is still a good idea to store it yourself.

3. Sourcify will decode the metadata and prepare a list of included contracts on the right. Enter the address of the specific contract and select the "Oasis Sapphire" or "Oasis Sapphire Testnet" chain for Mainnet or Testnet accordingly. If your contract assigns any immutable variables in the constructor, you will also need to correctly fill those out under the "More Inputs (optional)" panel. Finally, click on the "Verify" button.

   

4. If everything goes well, you will get a Perfect match notice. Your contract is now verified. Congratulations!

In case of a Partial match, the contracts metadata JSON differs from the one used for deployment although the compiled contract bytecode matched. Make sure the source code .sol file of the contract is the same as the one used during the deployment (including the comments, variable names and source code file names) and use the same version of Hardhat and solc compiler.

info

You can also explore all verification methods on Sourcify by reading the official Sourcify contract verification instructions.

Troubleshooting

Etherscan error with hardhat-verify

• Cause: hardhat-verify tries to verify a contract on Etherscan for an unsupported network.
• Solution: Disable Etherscan verification with

  etherscan: {
      //  Enabled by default (not supported on Sapphire)
      enabled: false
  },