Via API Key

Claude API Key can be used to control cost and usage for Claude Code. Useful for production-use-cases and automated systems.

The token is generated at https://platform.claude.com — "Create API key" (choose Workspace, name the key) → "Save your API key" (shown once, copy it) → can be selected during /login as method "2. Anthropic Console account".
Set it as an env var: ANTHROPIC_API_KEY=sk-ant-api03-...

To use the API you need to purchase credits:

"Credit balance" page (Organization → Billing) shows remaining balance, charged-to payment method, "Buy credits", auto-reload status; can also pay after-the-fact with monthly invoicing by contacting the Anthropic accounts team.
"Add credits" dialog: enter an amount ($5–$100 for Tier 1, limit increases with usage), optional auto-reload credits (reload amount + target balance), shows subtotal/taxes/total. Credits are consumed with API, Claude Code, and Workbench usage, and expire 1 year after purchase.