I Run Claude Code on $0/Month: A Practical Guide to Free LLM APIs

A developer has documented a method for running AI coding assistants such as Claude Code, Cursor, and Codex CLI entirely on free LLM API tiers by overriding backend environment variables like ANTHROPIC_BASE_URL and ANTHROPIC_AUTH_TOKEN to route requests through providers including Google AI Studio, Groq, NVIDIA NIM, OpenRouter, Cerebras, and Mistral. The setup relies on a directory at freellm.net that tracks 489 free models across 30 providers, with Google AI Studio's Gemini 2.5 Flash (500 requests/day, 1M context) and Groq's Llama 3.3 70B cited as the best free options for coding.

AI coding assistants are incredible — until the API bill arrives. If you've ever watched your Claude Code or Cursor usage tick upward and wondered whether there's a cheaper way, this guide is for you. The good news: in 2026, the free tier landscape for LLM APIs is genuinely good. Not "free trial for 7 days" good — permanently free, no credit card required, production-usable models. The bad news: the information is scattered across dozens of provider docs, and free tiers change constantly. Here's the practical setup I actually use. Not all free tiers are equal. These are the ones with permanent free tiers, no credit card required: | Provider | Standout model | Why it's good | |---|---|---| | Google AI Studio | Gemini 2.5 Flash 1M context, multimodal | Most capable free tier, 500 req/day | | Groq | Llama 3.3 70B, gpt-oss-120b | Fastest inference, ultra-low latency | | NVIDIA NIM | 100+ open models DeepSeek R1/V3, Llama | Huge selection, one API key | | OpenRouter | 35+ free models | Single key, single endpoint for everything | | Cerebras | Llama 3.3 70B | Extremely fast | | Mistral | Mistral Small/Medium | ~1B tokens/month free | The full comparison — rate limits, context windows, credit card requirements — is maintained at freellm.net https://freellm.net , a directory of 489 free models across 30 providers. I use it as my reference because free tiers change often and static lists go stale fast. Pick one provider to start. My recommendation for coding: Google AI Studio best model quality or Groq best speed . That's it. You now have a working LLM API key that costs $0. Claude Code reads two environment variables to override its backend: export ANTHROPIC BASE URL="https://generativelanguage.googleapis.com/v1beta/openai" export ANTHROPIC AUTH TOKEN="your-google-ai-studio-key" For Groq: ANTHROPIC BASE URL="https://api.groq.com/openai/v1" . Then just run claude as normal. It will route through the free provider instead of Anthropic's API. For Cursor : Settings → Models → Add Model, paste the base URL and key. For Codex CLI : set OPENAI BASE URL + OPENAI API KEY . Ready-to-copy snippets for every provider/model combination are at freellm.net/config https://freellm.net/config/ — pick your tool, pick your model, paste. Before wiring a key into your daily workflow, test it. The freellm.net playground https://freellm.net/playground/ lets you paste a key and chat with any model right in the browser — no install, and your key goes directly to the provider, never stored on their servers. Free tiers have limits, and you should know them upfront: $0/month. I do the bulk of my AI-assisted coding on Gemini 2.5 Flash via Google AI Studio's free tier, and fall back to Groq when I need speed. When I hit a rate limit rare , I switch providers — which takes 30 seconds since it's just env vars. If you're a student, indie hacker, or just cost-conscious, there's no reason to pay for API access while these tiers exist. The setup takes less time than reading this article did. Reference: freellm.net https://freellm.net — 489 free LLM APIs from 30 providers, with rate limits, context windows, and one-click configs for Claude Code, Cursor, and Codex.