How to Get a Claude API Key: Step by Step

An API key lets your own code use Claude — in an app, a script, or tools that ask for one. Here's how to get one, and the few things to set up before you use it.

API key vs Claude subscription

These are separate:

A Claude subscription (Free, Pro, Max) is for using Claude yourself — in the Claude apps and in Claude Code.
An API key is for software calling Claude, billed per token from prepaid credits. (Claude API pricing explained)

A Pro or Max subscription doesn't include API credits, and API credits don't give you a subscription. If you only want to use Claude Code, you usually don't need an API key — logging in with your subscription is simpler and often cheaper. (Claude Pro vs Max vs API key for Claude Code)

Step 1: create a developer account

Go to the Claude Developer Platform at platform.claude.com (the old console.anthropic.com address redirects there) and sign up.

Step 2: add credits

API usage is prepaid. Open Billing, add a payment method, and buy credits. Start small — a few dollars goes a long way while you're testing with a small model.

Step 3: set a spend limit

Before creating a key, set a monthly spend limit in your organisation's limits settings. If the key ever leaks or your code loops by mistake, this caps the damage. Do this now, not later.

Step 4: create the key

Open API Keys, click Create Key, give it a descriptive name ("recipe-app-production"), and copy it. It starts with sk-ant-.

You only see the full key once. Store it immediately (below). If you lose it, delete it and create a new one.

Step 5: store it as an environment variable

Never paste the key into your code. Put it in an environment variable:

# .env (and add .env to .gitignore!)
ANTHROPIC_API_KEY=sk-ant-...

Anthropic's official SDKs read ANTHROPIC_API_KEY automatically. (Environment variables explained, .gitignore explained)

Step 6: make a test request

curl https://api.anthropic.com/v1/messages \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "content-type: application/json" \
  -d '{
    "model": "claude-haiku-4-5",
    "max_tokens": 200,
    "messages": [{"role": "user", "content": "Say hello in five words."}]
  }'

If you get a JSON reply with Claude's answer, it works. (What is curl?)

Keeping it safe

Never put it in frontend code. Anything shipped to the browser — including variables starting with VITE_ or NEXT_PUBLIC_ — can be read by anyone. Call Claude from your backend. (Keep API keys out of an AI-built app)
Never commit it to Git. Even in a private repo. (GitHub secret scanning)
One key per app or environment, so you can revoke one without breaking the rest.
Don't paste it into chats, screenshots or support tickets.
Rate-limit your own users, so a single user can't burn through your credits. (Stop bots running up your AI bill)

If it leaks

Delete the key in the console immediately, create a new one, update your app, and check your usage for anything unexpected. (I leaked an API key. What now?)

Using the key with Claude Code

Claude Code can use an API key instead of a subscription — useful in CI or for pay-as-you-go billing. Set ANTHROPIC_API_KEY in the environment and Claude Code will use it. Note that it then bills the API, not your subscription. (Claude Code GitHub Actions)

EasySpawn gives your app a server-side backend with environment variables kept out of your code, so your Claude key stays on the server where it belongs. See how it works or join the waitlist.

How to Get a Claude API Key (and Keep It Safe)