> For the complete documentation index, see [llms.txt](https://docs.filecoin.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.filecoin.io/build-on-filecoin/verification/filfox.md).

# Verify using Filfox

The following guide walks you through the process of contract verification using the [Filfox Contract Verification](https://filfox.info/en/contract) page.

## Prerequisites

* A deployed smart contract on Filecoin mainnet or Calibration testnet
* Your contract source code, either as a flattened `.sol` file 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 `viaIR` setting 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

1. **Open Remix IDE** if you are preparing a flattened source file for upload:

![](/files/gQpJs9fpMwciG8BGjsMF)

2. **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.sol` file with all dependencies included
3. **Verify contract details:**
   * Ensure the license and Solidity version match your original contract
   * Click **Save** to save the flattened contract
4. **Download the flattened contract:**
   * Right-click on `<contract-name>_flattened.sol`
   * Select **Download** to save the file locally
5. **Gather required information:**
   * Contract deployment address
   * Contract license type (if any)
   * Solidity compiler version used for deployment
   * Optimization settings, optimizer runs, EVM version, and `viaIR` setting
   * Constructor arguments, if your contract constructor used arguments

### Step 2: Submit for Verification

6. **Access Filfox verification page:**
   * For Filecoin mainnet, navigate to the [Filfox Contract Verification](https://filfox.info/en/contract) page. Mainnet uses chain ID `314`.
   * For Calibration testnet, navigate to the [Calibration Filfox Contract Verification](https://calibration.filfox.info/en/contract) page. Calibration uses chain ID `314159`.
7. **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

![](/files/bQqD0UmBITds39wG1fbu)

8. **Upload source code:**
   * Click **Continue** to proceed
   * Click **Select .sol files**
   * Choose your flattened `.sol` file
   * 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.

![](/files/Atd8Coc1avhS2p27EVpn)

## Viewing Your Verified Contract

1. **Navigate to your contract:**
   * Enter your contract address in the [Filfox search bar](https://filfox.info/)
   * This will take you to your contract's page

![](/files/1CEFWNn5NBFTPBJbUkiJ)

2. **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
3. **Explore verified contracts:**
   * Browse [other verified contracts on Filfox](https://filfox.info/en/fevm/verified-contracts)
   * Learn from verified contract examples in the ecosystem

![](/files/OGaxWEMJIFz2md3ubpHm)