How to Reconnect a Failed Anthropic Credential in n8n

Open the failing workflow and look at the error message on the Anthropic or HTTP Request node. Common error messages include 401 Unauthorized (invalid API key), 403 Forbidden (key lacks permissions), 429 Too Many Requests (rate limit), and connection timeout errors. The error message tells you whether the problem is with your API key, your account, or your network. Click into the node's execution data to see the full error response from the Anthropic API.

Navigate to Settings in the left sidebar, then click Credentials. Find the Anthropic credential in the list — it may be named 'Anthropic API' or whatever you originally called it. Click to open it. You will see the API Key field (the value is hidden by default). If the key was rotated on the Anthropic console, the stored key in n8n is now invalid and needs to be replaced. If you are unsure whether the key is correct, generate a new one from console.anthropic.com under API Keys.

Clear the existing API Key field and paste your current valid API key from the Anthropic console. Make sure there are no leading or trailing spaces in the key. The key should start with sk-ant-. After pasting, click the Test button at the bottom of the credential form. n8n will make a test request to the Anthropic API to verify the key works. If the test succeeds, you will see a green success message. Click Save to store the updated credential.

Go back to the workflow that was failing and click Execute Workflow to run it manually. Check that the Anthropic node now receives a successful response from the Claude model. Look at the output data to confirm the response contains the expected content. If the workflow uses multiple Anthropic nodes, check each one. If you have multiple workflows using the same credential, they will all automatically use the updated key since credentials are shared references.

If the built-in Anthropic credential type does not work for your setup (for example, if you need to use a proxy endpoint or a custom API version), use an HTTP Request node instead. Configure it with a Header Auth credential type where the header name is x-api-key and the value is your Anthropic API key. Set the URL to https://api.anthropic.com/v1/messages, the method to POST, and add the required headers. This gives you full control over the request format.

1// HTTP Request node configuration
2// Method: POST
3// URL: https://api.anthropic.com/v1/messages
4// Headers:
5//   x-api-key: {{$credentials.httpHeaderAuth.value}}
6//   anthropic-version: 2023-06-01
7//   content-type: application/json
8// Body (JSON):
9{
10  "model": "claude-sonnet-4-20250514",
11  "max_tokens": 1024,
12  "messages": [
13    {
14      "role": "user",
15      "content": "{{ $json.prompt }}"
16    }
17  ]
18}