I Run Claude Code on $0/Month: Free LLM API Setup

こんにちは！Claude Code を無料で使い倒したいエンジニアの皆さんへ。

Claude Code is one of the most productive AI coding assistants available today — but heavy use can make API costs add up quickly. In this tutorial, I'll show you how I run Claude Code on $0/month using free LLM API tiers, keeping the same terminal workflow you already know.

Why $0/Month?

• Zero-risk experimenting: try prompts, agents, and hooks without watching your wallet
• Perfect for side projects: nights-and-weekends coding shouldn't cost money
• Learn the ecosystem: free tiers are ideal for learning how LLM APIs work

Step 1: Choose a Free LLM API Provider

Many providers offer generous free tiers. Solid options (limits change often, so check their docs):

• Google AI Studio — free Gemini API tier with generous limits
• Groq — free tier with extremely fast inference
• Cerebras — free tier with very high throughput
• Mistral AI — free tier on La Plateforme
• OpenRouter — models tagged :free cost nothing

Tip: I maintain a curated, regularly updated directory of free LLM APIs — providers, limits, and setup notes — at freellm.net. Start there instead of digging through docs.

Step 2: Get Your Free API Key

1. Sign up at your chosen provider (most need only an email address)
2. Create an API key in the dashboard
3. Note the base URL if the provider uses an OpenAI-style endpoint

Step 3: Point Claude Code at the Free Endpoint

Claude Code reads standard environment variables. Set the base URL and key before launching:

export ANTHROPIC_BASE_URL="https://your-free-provider.example/v1"
export ANTHROPIC_API_KEY="sk-your-free-key"
claude

If your provider only speaks the OpenAI API format, run a tiny local proxy (e.g. LiteLLM) that translates between the two, and point ANTHROPIC_BASE_URL at the proxy:

# terminal 1: start the translator proxy on localhost:4000
litellm --port 4000

# terminal 2: use Claude Code through the proxy
export ANTHROPIC_BASE_URL="http://localhost:4000"
export ANTHROPIC_API_KEY="sk-anything"
claude

Step 4: Verify It's Working (and Free)

Inside Claude Code, ask it something simple:

> What model are you running on?

Then check the provider's dashboard — you should see requests counted against the free tier, with $0 billed.

Practical Tips for Staying Free

• Respect rate limits: free tiers usually cap requests per minute, so keep parallel agents modest
• Pick smaller models for small jobs: a fast free model for summaries, a stronger one for hard reasoning
• Rotate providers: if you hit a limit on one, switch the env vars to another free provider
• Cache aggressively: reuse context instead of re-sending huge files

Wrapping Up

You don't need a paid API plan to get real work done with Claude Code. With a free-tier key and two environment variables, the full agentic coding loop — plan, edit, run, iterate — works at $0/month.

For the latest list of free providers and their limits, bookmark freellm.net.

Happy (free) coding!

— MyToolster