Contract Verification with Filfox
The following guide walks you through the process of contract verification using the Filfox Contract Verification page.
Prerequisites
- A deployed smart contract on Filecoin mainnet or Calibration testnet
- Your contract source code, either as a flattened
.solfile or the source files requested by the Filfox form - The deployed contract address
- The Solidity compiler version used for deployment
- The license, optimization settings, optimizer runs, EVM version, and
viaIRsetting used for deployment - Constructor arguments, if the contract was deployed with any and the form prompts for them
Step-by-Step Verification Process
Step 1: Prepare Your Contract Source Code
- Open Remix IDE if you are preparing a flattened source file for upload:

Flatten your contract:
- In the File Explorer sidebar, under contracts, right-click on your contract
- Select Flatten from the menu
- This creates a
<contract-name>_flattened.solfile with all dependencies included
Verify contract details:
- Ensure the license and Solidity version match your original contract
- Click Save to save the flattened contract
Download the flattened contract:
- Right-click on
<contract-name>_flattened.sol - Select Download to save the file locally
- Right-click on
Gather required information:
- Contract deployment address
- Contract license type (if any)
- Solidity compiler version used for deployment
- Optimization settings, optimizer runs, EVM version, and
viaIRsetting - Constructor arguments, if your contract constructor used arguments
Step 2: Submit for Verification
- Access Filfox verification page:
- For Filecoin mainnet, navigate to the Filfox Contract Verification page. Mainnet uses chain ID
314. - For Calibration testnet, navigate to the Calibration Filfox Contract Verification page. Calibration uses chain ID
314159.
- For Filecoin mainnet, navigate to the Filfox Contract Verification page. Mainnet uses chain ID
- Fill in contract information:
- Enter your contract's deployment address
- Select the appropriate license type
- Choose the compiler version used for deployment
- Match any prompted compiler and constructor settings to the original deployment

- Upload source code:
- Click Continue to proceed
- Click Select .sol files
- Choose your flattened
.solfile - Click Verify and Publish to submit
Step 3: Verification Complete
Once submitted, Filfox will process your verification request. Upon successful verification, you'll see a success message confirming your contract is now verified.

Viewing Your Verified Contract
- Navigate to your contract:
- Enter your contract address in the Filfox search bar
- This will take you to your contract's page

View verification status:
- Scroll down and select the Contract tab
- Look for the Contract Source Code Verified banner
- Your contract's source code and ABI will now be publicly visible
Explore verified contracts:
- Browse other verified contracts on Filfox
- Learn from verified contract examples in the ecosystem
