How to get a Claude API key

Create a Claude API key in 5 steps

1. Sign in to the Claude Console at platform.claude.com, or sign up for a new account if you don't have one yet.
2. Open the keys page at platform.claude.com/settings/keys.
3. Click Create key and enter a name for your new Anthropic Console API key.
4. Pick an expiration (3 hours, 1 day, 7 days, 30 days, a custom duration, or Never), set the linked account to yourself for a personal key or to a service account, and optionally scope the key to a workspace.
5. Copy the sk-ant- key secret right away and store it somewhere safe, because the Console only shows it once at creation and you can't view it again later.

Add credits before your first call

Most organizations pay for API usage with prepaid credits bought on the Console Billing page at platform.claude.com/settings/billing with Buy credits, where you can also turn on auto-reload to top up your balance automatically. Organizations with an invoicing arrangement through Anthropic's sales team are billed monthly instead. The table below outlines how billing and spend tiers work, and you can check per-model token rates for individual model costs.

New organizations, or those with limited history, may start in an Evaluation tier with limits below the standard tiers.

Does a Claude subscription include API access?

A Claude subscription and Console API usage are paid separately, but Max and Team plans include monthly API credits. The table below shows what each plan includes.

• You can claim subscriber API credits 7 days after subscribing by linking a Claude Console organization under Settings > Billing on Max (Organization settings > Billing on Team), and they will appear as Promotional credits in the Console.
• Any claimed subscriber credits expire at the end of each billing cycle (monthly on annual plans), and on Team plans all seat credits are pooled into one monthly balance capped at $500.
• These promotional credits don't pay for Claude Code, which Pro and Max users run without a key by signing in with /login (see Claude Code pricing and plan details).

Make your first API call

Export your key in your shell as ANTHROPIC_API_KEY, and pass it in the x-api-key header (or Authorization: Bearer) when calling POST https://api.anthropic.com/v1/messages. Every request also needs the anthropic-version header, such as anthropic-version: 2023-06-01, alongside content-type: application/json. If your key isn't scoped to a single workspace, also send an anthropic-workspace-id header with the workspace ID from platform.claude.com/settings/workspaces.

Official SDKs exist for Python, TypeScript, C#, Go, Java, PHP and Ruby.

curl https://api.anthropic.com/v1/messages \
  -H "content-type: application/json" \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -d '{
    "model": "claude-opus-5-5",
    "max_tokens": 1000,
    "messages": [{"role": "user", "content": "Hello, Claude"}]
  }'

Keep your API key safe

• Store your key in a secrets manager or an environment variable, and never put it in client-side code or commit it to a git repository.
• Set an expiration date when you create a key and rotate your keys on a regular schedule; Anthropic emails the key's creator 7 days before expiry for keys that last at least 14 days, and 1 day before for keys that last at least 7 days.
• Use service account keys for CI, production and agents instead of personal keys, since a personal key acts as you and stops working if you leave the organization.
• Disable a key right away if you suspect it leaked (which sets its status to inactive and is reversible), or delete it permanently (archived).
• Remember that an expired key returns 401 authentication_error and cannot be reactivated.
• In Claude Code, having ANTHROPIC_API_KEY set in your environment overrides a Pro or Max login and bills your Console credits at standard API rates.

Alternative: a key backed by your Claude plan

If you already pay for a Claude Pro or Max subscription and want an API key without separate per-token billing, Plan2API's Claude subscription proxy gives you a p2a_ key backed directly by your plan. Your subscription's own usage limits apply, and you keep paying Anthropic for your plan while Plan2API never bills per token. You can link your account at the Plan2API connect page on the Free plan, which costs $0 with no card required and includes 1 connected subscription, 2 API keys, and 50 chat requests a day.

Requests go to https://api.plan2api.com/v1 using POST /v1/chat/completions in the OpenAI Chat Completions format with an Authorization: Bearer header, and you select a Claude model by using the claude/ or anthropic/ model id prefix. A key sent in an x-api-key header gets 401 invalid_api_key, and there is no Anthropic /v1/messages endpoint, so use the OpenAI SDK as shown below.

from openai import OpenAI

client = OpenAI(
    base_url="https://api.plan2api.com/v1",
    api_key="p2a_...",
)

reply = client.chat.completions.create(
    model="claude/claude-opus-5-5",
    messages=[{"role": "user", "content": "Hello, Claude"}],
)
print(reply.choices[0].message.content)