Verify a smart contract on Monad using Foundry

Once your contract is deployed to a live network, the next step is to verify its source code on the block explorer. Verifying a contract means uploading its source code, along with the settings used to compile the code, to a repository (typically maintained by a block explorer). This allows anyone to compile it and compare the generated bytecode with what is deployed on chain. Doing this is extremely important in an open platform like Monad. In this guide we’ll explain how to do this using Foundry v1.8 or later with the Monad execution environment enabled.

This guide assumes you have Foundry v1.8.0 or later installed and network = "monad" configured in foundry.toml. See the installation and configuration instructions if you haven’t set it up yet.

Mainnet
Testnet

Foundry Monad template (Recommended)
Default Foundry Project

The foundry-monad template is configured for testnet by default. To use mainnet, update your foundry.toml file:

Change eth-rpc-url="https://testnet-rpc.monad.xyz" to your mainnet RPC URL
Change chain_id = 10143 to 143

If you are using foundry-monad template, you can use the commands below based on your preferred block explorer:

MonadVision
Monadscan

forge verify-contract \
    <contract_address> \
    <contract_name> \
    --chain 143 \
    --verifier sourcify \
    --verifier-url https://sourcify-api-monad.blockvision.org/

Example:

forge verify-contract \
    0x8fEc29BdEd7A618ab6E3CD945456A79163995769 \
    Counter \
    --chain 143 \
    --verifier sourcify \
    --verifier-url https://sourcify-api-monad.blockvision.org/

On successful verification of smart contract, you should get a similar output in your terminal:

Start verifying contract `0x8fEc29BdEd7A618ab6E3CD945456A79163995769` deployed on monad-mainnet
Attempting to verify on Sourcify. Pass the --etherscan-api-key <API_KEY> to verify on Etherscan, or use the --verifier flag to verify on another provider.

Submitting verification for [Counter] "0x8fEc29BdEd7A618ab6E3CD945456A79163995769".
Contract successfully verified

Now check the contract on MonadVision.

forge verify-contract \
    <contract_address> \
    <contract_name> \
    --chain 143 \
    --verifier etherscan \
    --etherscan-api-key YourApiKeyToken \
    --watch

Example:

forge verify-contract \
    0x8fEc29BdEd7A618ab6E3CD945456A79163995769 \
    Counter \
    --chain 143 \
    --verifier etherscan \
    --etherscan-api-key YourApiKeyToken \
    --watch

On successful verification of smart contract, you should get a similar output in your terminal:

Start verifying contract `0x8fEc29BdEd7A618ab6E3CD945456A79163995769` deployed on monad-mainnet

Submitting verification for [src/Counter.sol:Counter] 0x8fEc29BdEd7A618ab6E3CD945456A79163995769.
Submitted contract for verification:
        Response: `OK`
        GUID: `fhxxx4wsub68jce24ejvhe68fqabgtpmpzheqpdqvencgph1za`
        URL: https://monadscan.com/address/0x8fec29bded7a618ab6e3cd945456a79163995769
Contract verification status:
Response: `NOTOK`
Details: `Pending in queue`
Warning: Verification is still pending...; waiting 15 seconds before trying again (7 tries remaining)
Contract verification status:
Response: `OK`
Details: `Pass - Verified`
Contract successfully verified

Now check the contract on Monadscan.

1. Update `foundry.toml` with Monad Configuration

foundry.toml

[profile.default]
src = "src"
out = "out"
libs = ["lib"]
metadata = true
metadata_hash = "none"  # disable ipfs
use_literal_content = true # use source code

# Monad Configuration
eth-rpc-url="https://rpc.monad.xyz"
chain_id = 143

2. Verify the contract using one of the following block explorers:

MonadVision
Monadscan

If you are using MonadVision, you can use this guide. In particular, the Verify Contract page provides a convenient way to verify your contract.

forge verify-contract \
    <contract_address> \
    <contract_name> \
    --chain 143 \
    --verifier sourcify \
    --verifier-url https://sourcify-api-monad.blockvision.org/

Example:

forge verify-contract \
    0x8fEc29BdEd7A618ab6E3CD945456A79163995769 \
    Counter \
    --chain 143 \
    --verifier sourcify \
    --verifier-url https://sourcify-api-monad.blockvision.org/

On successful verification of smart contract, you should get a similar output in your terminal:

Start verifying contract `0x8fEc29BdEd7A618ab6E3CD945456A79163995769` deployed on monad-mainnet
Attempting to verify on Sourcify. Pass the --etherscan-api-key <API_KEY> to verify on Etherscan, or use the --verifier flag to verify on another provider.

Submitting verification for [Counter] "0x8fEc29BdEd7A618ab6E3CD945456A79163995769".
Contract successfully verified

Now check the contract on MonadVision.

forge verify-contract \
    <contract_address> \
    <contract_name> \
    --chain 143 \
    --verifier etherscan \
    --etherscan-api-key YourApiKeyToken \
    --watch

Example:

forge verify-contract \
    0x8fEc29BdEd7A618ab6E3CD945456A79163995769 \
    Counter \
    --chain 143 \
    --verifier etherscan \
    --etherscan-api-key YourApiKeyToken \
    --watch

On successful verification of smart contract, you should get a similar output in your terminal:

Start verifying contract `0x8fEc29BdEd7A618ab6E3CD945456A79163995769` deployed on monad-mainnet

Submitting verification for [src/Counter.sol:Counter] 0x8fEc29BdEd7A618ab6E3CD945456A79163995769.
Submitted contract for verification:
        Response: `OK`
        GUID: `fhxxx4wsub68jce24ejvhe68fqabgtpmpzheqpdqvencgph1za`
        URL: https://monadscan.com/address/0x8fec29bded7a618ab6e3cd945456a79163995769
Contract verification status:
Response: `NOTOK`
Details: `Pending in queue`
Warning: Verification is still pending...; waiting 15 seconds before trying again (7 tries remaining)
Contract verification status:
Response: `OK`
Details: `Pass - Verified`
Contract successfully verified

Now check the contract on Monadscan.

Foundry Monad template (Recommended)
Default Foundry Project

If you are using foundry-monad template, you can use the commands below based on your preferred block explorer:

MonadVision
Monadscan

forge verify-contract \
    <contract_address> \
    <contract_name> \
    --chain 10143 \
    --verifier sourcify \
    --verifier-url https://sourcify-api-monad.blockvision.org/

Example:

forge verify-contract \
    0x8fEc29BdEd7A618ab6E3CD945456A79163995769 \
    Counter \
    --chain 10143 \
    --verifier sourcify \
    --verifier-url https://sourcify-api-monad.blockvision.org/

On successful verification of smart contract, you should get a similar output in your terminal:

Start verifying contract `0x8fEc29BdEd7A618ab6E3CD945456A79163995769` deployed on monad-testnet
Attempting to verify on Sourcify. Pass the --etherscan-api-key <API_KEY> to verify on Etherscan, or use the --verifier flag to verify on another provider.

Submitting verification for [Counter] "0x8fEc29BdEd7A618ab6E3CD945456A79163995769".
Contract successfully verified

Now check the contract on MonadVision.

forge verify-contract \
    <contract_address> \
    <contract_name> \
    --chain 10143 \
    --verifier etherscan \
    --etherscan-api-key YourApiKeyToken \
    --watch

Example:

forge verify-contract \
    0x8fEc29BdEd7A618ab6E3CD945456A79163995769 \
    Counter \
    --chain 10143 \
    --verifier etherscan \
    --etherscan-api-key YourApiKeyToken \
    --watch

On successful verification of smart contract, you should get a similar output in your terminal:

Start verifying contract `0x8fEc29BdEd7A618ab6E3CD945456A79163995769` deployed on monad-testnet

Submitting verification for [src/Counter.sol:Counter] 0x8fEc29BdEd7A618ab6E3CD945456A79163995769.
Submitted contract for verification:
        Response: `OK`
        GUID: `fhxxx4wsub68jce24ejvhe68fqabgtpmpzheqpdqvencgph1za`
        URL: https://testnet.monadscan.com/address/0x8fec29bded7a618ab6e3cd945456a79163995769
Contract verification status:
Response: `NOTOK`
Details: `Pending in queue`
Warning: Verification is still pending...; waiting 15 seconds before trying again (7 tries remaining)
Contract verification status:
Response: `OK`
Details: `Pass - Verified`
Contract successfully verified

Now check the contract on Monadscan.

If you use foundry-monad you can skip the configuration step

1. Update `foundry.toml` with Monad Configuration

foundry.toml

[profile.default]
src = "src"
out = "out"
libs = ["lib"]  
metadata = true
metadata_hash = "none"  # disable ipfs
use_literal_content = true # use source code

# Monad Configuration
eth-rpc-url="https://testnet-rpc.monad.xyz"
chain_id = 10143

2. Verify the contract using one of the following block explorers:

MonadVision
Monadscan

forge verify-contract \
    <contract_address> \
    <contract_name> \
    --chain 10143 \
    --verifier sourcify \
    --verifier-url https://sourcify-api-monad.blockvision.org/

Example:

forge verify-contract \
    0x8fEc29BdEd7A618ab6E3CD945456A79163995769 \
    Counter \
    --chain 10143 \
    --verifier sourcify \
    --verifier-url https://sourcify-api-monad.blockvision.org/

On successful verification of smart contract, you should get a similar output in your terminal:

Start verifying contract `0x8fEc29BdEd7A618ab6E3CD945456A79163995769` deployed on monad-testnet
Attempting to verify on Sourcify. Pass the --etherscan-api-key <API_KEY> to verify on Etherscan, or use the --verifier flag to verify on another provider.

Submitting verification for [Counter] "0x8fEc29BdEd7A618ab6E3CD945456A79163995769".
Contract successfully verified

Now check the contract on MonadVision.

forge verify-contract \
    <contract_address> \
    <contract_name> \
    --chain 10143 \
    --verifier etherscan \
    --etherscan-api-key YourApiKeyToken \
    --watch

Example:

forge verify-contract \
    0x8fEc29BdEd7A618ab6E3CD945456A79163995769 \
    Counter \
    --chain 10143 \
    --verifier etherscan \
    --etherscan-api-key YourApiKeyToken \
    --watch

On successful verification of smart contract, you should get a similar output in your terminal:

Start verifying contract `0x8fEc29BdEd7A618ab6E3CD945456A79163995769` deployed on monad-testnet

Submitting verification for [src/Counter.sol:Counter] 0x8fEc29BdEd7A618ab6E3CD945456A79163995769.
Submitted contract for verification:
        Response: `OK`
        GUID: `fhxxx4wsub68jce24ejvhe68fqabgtpmpzheqpdqvencgph1za`
        URL: https://testnet.monadvision.com/address/0x8fec29bded7a618ab6e3cd945456a79163995769
Contract verification status:
Response: `NOTOK`
Details: `Pending in queue`
Warning: Verification is still pending...; waiting 15 seconds before trying again (7 tries remaining)
Contract verification status:
Response: `OK`
Details: `Pass - Verified`
Contract successfully verified

Now check the contract on Monadscan.

Introduction

Developer Essentials

Tooling and Infrastructure

Reference

Guides

Resources

Verify a smart contract on Monad using Foundry

1. Update `foundry.toml` with Monad Configuration

2. Verify the contract using one of the following block explorers:

1. Update `foundry.toml` with Monad Configuration

2. Verify the contract using one of the following block explorers:

​1. Update foundry.toml with Monad Configuration

​2. Verify the contract using one of the following block explorers:

​1. Update foundry.toml with Monad Configuration

​2. Verify the contract using one of the following block explorers:

1. Update `foundry.toml` with Monad Configuration

2. Verify the contract using one of the following block explorers:

1. Update `foundry.toml` with Monad Configuration

2. Verify the contract using one of the following block explorers: