How to get an Anthropic (Claude) API key for Claude Code and n8n

If you're using Claude (by Anthropic) for the AI steps, whether in a coding setup like Claude Code or an n8n automation we built, you need your own Anthropic API key. This walkthrough gets you from zero to a working key, then shows both ways to use it: pasted into a local .env file or connected in n8n.

One thing to know up front: the Anthropic API is separate from a Claude.ai chat subscription. A Claude Pro plan does not include API access. You set up API billing separately, and it's pay-as-you-go (you only pay for what your automation actually uses).

1. Create your Anthropic Console account

Go to console.anthropic.com and sign up (or log in). This is the developer console, a different place from the Claude.ai chat app. If you already chat with Claude, you'll still need to register here for API access.

2. Add credits (set up billing)

The API runs on prepaid credits. In the Console, open Billing (sometimes under Settings) and buy an initial batch of credits. A small amount like $5 is plenty to test an automation. Without credits, every request fails with a "credit balance too low" error.

Cost is per token (input + output) and depends on which model you use. For current rates, check Anthropic's pricing page. Most lead-gen and admin automations cost cents per run.

3. Create the API key

In the Console, go to API Keys (under Settings) and click Create Key. Give it a recognizable name (e.g. claude-code or n8n-production) so you know what it's for later.

Anthropic shows you the full key exactly once. It starts with sk-ant-. Copy it immediately and paste it somewhere safe (a password manager). If you close the dialog without copying, you'll have to revoke it and create a new one. You can't view it again.

4. Add the key to your local environment (Claude Code / coding)

If you're working in a coding environment like Claude Code, the key lives in your project's environment, not in a UI. The standard place is a .env file:

1. In your project folder, create a file named .env (or open the one already there).
2. Add a line with your key:

   ANTHROPIC_API_KEY=sk-ant-...

3. Add .env to your .gitignore so the key is never committed to git.
4. The Anthropic SDK reads ANTHROPIC_API_KEY from the environment automatically, so the key stays out of your code.

5. Or connect the key in n8n

Prefer n8n? The same key goes on an Anthropic credential, which the AI nodes then reuse:

1. Open your workflow and click the Anthropic Chat Model node (it sits under an AI Agent node), or add an Anthropic node.
2. In the node's Credential dropdown, choose Create New Credential.
3. Paste your key (sk-ant-…) into the API Key field and save.
4. Back on the node, pick a model from the dropdown (the model is set here, not on the credential).
5. Click Execute / Test step. If it returns a response, you're connected.

That's it. Whether in your code or in n8n, every AI step now runs on your key and your credits.

Fix the "credit balance is too low" error

If a request fails with "Your credit balance is too low to access the Anthropic API," the key works fine. The account is simply out of prepaid credit. Anthropic's API is prepaid and has no card-on-file auto-billing by default:

• Add prepaid credits under Billing in the Anthropic Console. Even $5 is enough to test an automation.
• Turn on auto-reload if you want credits to top up automatically when the balance runs low, so live automations don't stall.
• Confirm the key belongs to the workspace you funded. A key from a different workspace won't see those credits.
• Remember API credits are separate from a Claude Pro or Max subscription. A chat plan adds no API balance.

Official reference

Anthropic's dashboards change from time to time. If a screen looks different from this guide, their own docs are the source of truth: the Anthropic Console and Anthropic API docs. For Claude Code, see the Claude Code authentication docs. For the n8n side, see n8n's Anthropic credential docs.

FAQ

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