> 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/blockscout.md).

# Verify using Blockscout

The following guide walks you through the process of contract verification using the [Blockscout](https://filecoin.blockscout.com/) explorer.

## Prerequisites

* A deployed smart contract on Filecoin mainnet or Calibration testnet
* Your contract source code, either as a flattened `.sol` file or the same source files and metadata used at compile time
* 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

## Step-by-Step Verification Process

### Step 1: Prepare Your Contract Source Code

1. **Open Remix IDE** if you are using Blockscout's single-file Solidity verification method:

![](/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 (optional)
   * Solidity compiler version used for deployment
   * Optimization settings, including enabled/disabled and runs count
   * EVM version and `viaIR` setting, if your deployment used non-default values
   * ABI-encoded constructor arguments, if your contract constructor used arguments

### Step 2: Submit for Verification

6. **Access Blockscout verification page:**
   * For Filecoin mainnet, navigate to [Filecoin Blockscout Contract Verification](https://filecoin.blockscout.com/contract-verification). Mainnet uses chain ID `314`.
   * For Calibration testnet, navigate to [Calibration Blockscout Contract Verification](https://filecoin-testnet.blockscout.com/contract-verification). Calibration uses chain ID `314159`.
7. **Fill in contract information:**
   * Enter your contract's deployment address
   * Select the appropriate license type (optional)
   * Choose verification method: `Solidity (Single file)`
   * Select the compiler version used for deployment
   * Paste the source code from your `<contract-name>_flattened.sol` file
   * Configure the `Optimization enabled` checkbox to match your deployment settings
   * Enter optimizer runs, constructor arguments, and any advanced compiler settings if the form prompts for them

![](/files/EI1igs8O7UTgc4ONywue)

8. **Submit for verification:**
   * Click **Verify & Publish** to submit your contract

### Step 3: Verification Complete

Upon successful verification, Blockscout will display a success message and redirect you to your verified contract dashboard where you can view the source code and interact with your contract.

![](/files/pzA6L3HZ9ItpkgvndCL4)