> ## Documentation Index
> Fetch the complete documentation index at: https://docs.etherscan.io/llms.txt
> Use this file to discover all available pages before exploring further.

# V2 Migration

<Tip>
  [Contract verification](/contract-verification/verify-with-foundry) using Hardhat/Remix/Foundry also support using a single Etherscan API key for all chains
</Tip>

As of **August 15th, 2025**, the legacy **Etherscan API V1 endpoints have been deprecated** in favor of the new **Etherscan API V2**, which introduces a unified multichain experience across 60+ supported networks 🌈.

You’ll see a deprecation error message like this if you’re still using V1:

```json theme={null}
{
   "status":"0",
   "message":"NOTOK",
   "result":"You are using a deprecated V1 endpoint, switch to Etherscan API V2."
}
```

All existing endpoints remain compatible once you update them to the **V2 format**.

### How to Migrate

<Steps>
  <Step title="Create an Etherscan account">
    [**Sign up**](https://etherscan.io/register) if you don't have an account or if you're using other explorers like BaseScan, BscScan, Polygonscan, etc.
  </Step>

  <Step title="Create an Etherscan API Key">
    Under your Etherscan [**API dashboard**](https://etherscan.io/apidashboard), create a new key. This key can be used to access all [supported chains](/supported-chains) under API V2.
  </Step>

  <Step title="Migrating Endpoints from Etherscan API V1">
    Use `https://api.etherscan.io/v2/api` as your **base path**, and include a `chainid` for your target network (e.g., 1 for Ethereum).

    Before (V1):

    ```text theme={null}
    https://api.etherscan.io/api?&action=balance&apikey=YourEtherscanApiKey
    ```

    After (V2):

    ```text theme={null}
    https://api.etherscan.io/v2/api?chainid=1&action=balance&apikey=YourEtherscanApiKey
    ```
  </Step>

  <Step title="Migrating Endpoints from Other Explorers">
    Use the same base path (`https://api.etherscan.io/v2/api`) and include a `chainid` for the relevant chain from [this list](/supported-chains), in this case `137` for Polygon.

    Pass in your **Etherscan API key** instead of the old explorer-specific one.

    Before (PolygonScan V1):

    ```text theme={null}
    https://api.polygonscan.com/api?&action=balance&apikey=YourPolygonscanApiKey
    ```

    After (V2):

    ```text theme={null}
    https://api.etherscan.io/v2/api?chainid=137&action=balance&apikey=YourEtherscanApiKey
    ```
  </Step>
</Steps>