How to Create a Claude API Key in 5 Minutes

How to Create a Claude API Key

There are two ways to create a Claude API key, and which one you need depends on whether you already have a Claude Pro/Max subscription or you're starting fresh with a pay-as-you-go Anthropic Console account.

If you don't have Claude yet: sign up at the Anthropic Console, add billing details, and generate a key from the API Keys page. If you already pay for Claude Pro or Max but don't want a second, separate billing account, you can turn that subscription into an API key through a service like SubToAPI instead of opening a new console account. Both paths get you a working key — the rest of this guide walks through both.

Method 1: Create a Key in the Anthropic Console

This is the standard route if you're building a new project and don't mind a separate usage-based bill.

1. Go to the Anthropic Console and create an account (or sign in).
2. Add a payment method under Billing — API access is prepaid/usage-based and won't work without one.
3. Navigate to API Keys in the left sidebar.
4. Click Create Key, give it a descriptive name (e.g. prod-backend, local-dev), and save it somewhere secure — it's only shown once.
5. Set an optional spending limit if you want a hard cap on usage.

Once you have the key, a basic request looks like this:

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-sonnet-4-5",
    "max_tokens": 1024,
    "messages": [{"role": "user", "content": "Hello, Claude"}]
  }'

This works well if you're comfortable managing a separate billing relationship, tracking token-based costs, and rotating keys manually across a team.

Method 2: Create a Key From Your Claude Subscription

Many developers already pay for Claude Pro or Max and would rather not open a second account just to get programmatic access. This is where SubToAPI fits in — it turns your existing Claude subscription into an HTTPS API with its own key, without asking you to manage a separate Anthropic billing account.

The setup looks like this:

1. Create a SubToAPI account and start the free trial at /signup.
2. Connect your existing Claude access.
3. Generate an application key from your dashboard — it will look like sub_live_....
4. Send requests to https://api.subtoapi.app/v1/messages using that key.

curl https://api.subtoapi.app/v1/messages \
  -H "Authorization: Bearer $SUBTOAPI_KEY" \
  -H "content-type: application/json" \
  -d '{
    "model": "claude-sonnet-4-5",
    "max_tokens": 1024,
    "messages": [{"role": "user", "content": "Hello, Claude"}]
  }'

The request/response shape matches what you'd expect from a Claude Messages API, including streaming and tool use, so you're not learning a new interface — just a different way of authenticating and billing. See /docs/quickstart and /docs/messages for the full request format.

This route makes sense if you want:

• A single key per application instead of sharing one raw account credential across services
• Team seats and shared usage visibility without giving every developer console access
• To avoid setting up a second, usage-metered billing account just to prototype

Plans start at €9/month for Solo use, with Team (€19/seat) and Scale (€49/seat) tiers for shared projects — see /pricing for details.

Which Method Should You Use?

| Situation | Recommended path | |---|---| | No Claude subscription yet, want pay-per-token pricing | Anthropic Console | | Already have Claude Pro/Max, want an API key without new billing | SubToAPI | | Need multiple app-specific keys under one account | Either — both support key management | | Building a team product with shared usage tracking | SubToAPI (seat-based plans, team dashboard) | | Need enterprise contracts, custom rate limits, SLAs | Anthropic Console (direct relationship) |

Securing Your Key After Creation

Regardless of where you generate it, treat the key like a password:

• Store it in environment variables or a secrets manager, never hardcoded in source
• Add .env files to .gitignore before your first commit
• Use separate keys for development, staging, and production so you can revoke one without breaking the others
• Rotate keys periodically, especially after a team member leaves or a key is accidentally exposed in logs

A leaked key is the most common way API costs spiral unexpectedly — a few minutes of key hygiene up front saves debugging a surprise bill later.

Testing Your New Key

Once you've created a key, run a minimal request before wiring it into your application:

const response = await fetch("https://api.subtoapi.app/v1/messages", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.SUBTOAPI_KEY}`,
    "content-type": "application/json"
  },
  body: JSON.stringify({
    model: "claude-sonnet-4-5",
    max_tokens": 256,
    messages: [{ role: "user", content: "Say hi in one sentence." }]
  })
});

const data = await response.json();
console.log(data);

If you get a valid JSON response with a content array, your key is active and correctly scoped. If not, double-check the header name, that the key hasn't expired, and that billing is set up on the account behind it.

Questions

Do I need a credit card to create a Claude API key? For the Anthropic Console, yes — API access is usage-based and requires a payment method before keys become active. If you go through SubToAPI, you sign up and start a free trial first, then choose a plan.

Can I create more than one API key per account? Yes, in both the Anthropic Console and SubToAPI you can generate multiple keys — useful for separating dev, staging, and production, or giving each application its own key so you can revoke access individually.

What's the difference between an API key and a Claude subscription login? A subscription login (Claude Pro/Max) is for using Claude's chat interface. An API key is a separate credential for programmatic access from your own code, with its own authentication headers, usage tracking, and — in the Console's case — separate billing.