> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.0x.org/api-reference/evm-ap-is/gasless/chains/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.0x.org/_mcp/server.

# getChains

GET https://api.0x.org/gasless/chains

Get list of supported chains for gasless

Reference: https://docs.0x.org/api-reference/evm-ap-is/gasless/chains

## Request

### Headers

- `0x-api-key` (string, required) — Visit dashboard.0x.org to get your API Key
- `0x-version` (string, required) — API version

## Response

### 200

Successful response

- `chains` (list of GaslessChainsGetResponsesContentApplicationJsonSchemaChainsItems, required)
- `zid` (string, required) — The unique ZeroEx identifier of the request

## Errors

### 500 Internal Server Error

500 error response

- `Gasless::chainsRequestInternalServerError`

## Types

### GaslessChainsGetResponsesContentApplicationJsonSchemaChainsItems

- `chainId` (double, required)
- `chainName` (string, required)

### INTERNAL_SERVER_ERROR

- `name` (enum, required)
  - Allowed values: `INTERNAL_SERVER_ERROR`
- `message` (string, required)
- `data` (InternalServerErrorData, required)

### UNCATEGORIZED

- `name` (enum, required)
  - Allowed values: `UNCATEGORIZED`
- `message` (string, required)
- `data` (UncategorizedData, required)

### InternalServerErrorData

- `zid` (string, required) — The unique ZeroEx identifier of the request

### UncategorizedData

- `zid` (string, required) — The unique ZeroEx identifier of the request

## Examples

**Response**

```json
{
  "chains": [
    {
      "chainId": 1.1,
      "chainName": "string"
    }
  ],
  "zid": "string"
}
```

**SDK Code**

```python Gasless_chains_example
import requests

url = "https://api.0x.org/gasless/chains"

headers = {
    "0x-api-key": "0x-api-key",
    "0x-version": "v2"
}

response = requests.get(url, headers=headers)

print(response.json())
```

```javascript Gasless_chains_example
const url = 'https://api.0x.org/gasless/chains';
const options = {method: 'GET', headers: {'0x-api-key': '0x-api-key', '0x-version': 'v2'}};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```

```go Gasless_chains_example
package main

import (
	"fmt"
	"net/http"
	"io"
)

func main() {

	url := "https://api.0x.org/gasless/chains"

	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("0x-api-key", "0x-api-key")
	req.Header.Add("0x-version", "v2")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(res)
	fmt.Println(string(body))

}
```

```ruby Gasless_chains_example
require 'uri'
require 'net/http'

url = URI("https://api.0x.org/gasless/chains")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Get.new(url)
request["0x-api-key"] = '0x-api-key'
request["0x-version"] = 'v2'

response = http.request(request)
puts response.read_body
```

```java Gasless_chains_example
import com.mashape.unirest.http.HttpResponse;
import com.mashape.unirest.http.Unirest;

HttpResponse<String> response = Unirest.get("https://api.0x.org/gasless/chains")
  .header("0x-api-key", "0x-api-key")
  .header("0x-version", "v2")
  .asString();
```

```php Gasless_chains_example
<?php
require_once('vendor/autoload.php');

$client = new \GuzzleHttp\Client();

$response = $client->request('GET', 'https://api.0x.org/gasless/chains', [
  'headers' => [
    '0x-api-key' => '0x-api-key',
    '0x-version' => 'v2',
  ],
]);

echo $response->getBody();
```

```csharp Gasless_chains_example
using RestSharp;

var client = new RestClient("https://api.0x.org/gasless/chains");
var request = new RestRequest(Method.GET);
request.AddHeader("0x-api-key", "0x-api-key");
request.AddHeader("0x-version", "v2");
IRestResponse response = client.Execute(request);
```

```swift Gasless_chains_example
import Foundation

let headers = [
  "0x-api-key": "0x-api-key",
  "0x-version": "v2"
]

let request = NSMutableURLRequest(url: NSURL(string: "https://api.0x.org/gasless/chains")! as URL,
                                        cachePolicy: .useProtocolCachePolicy,
                                    timeoutInterval: 10.0)
request.httpMethod = "GET"
request.allHTTPHeaderFields = headers

let session = URLSession.shared
let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in
  if (error != nil) {
    print(error as Any)
  } else {
    let httpResponse = response as? HTTPURLResponse
    print(httpResponse)
  }
})

dataTask.resume()
```

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