Building an AI feature no longer requires an OpenAI bill. In 2026, half a dozen providers hand developers genuinely free inference APIs — fast models, generous quotas, and OpenAI-compatible endpoints. Here is how the free tiers actually compare, so you can ship without paying for tokens.
Why free inference APIs matter
Inference is the cost center of every AI app. Paid APIs start cheap per token but scale brutally — free inference tiers exist so developers can prototype and run small apps at zero cost.
The landscape has one important shape to understand. There are two kinds of "free":
1. Recurring free tiers — a daily or monthly quota that resets. Groq, Google AI Studio, Cerebras, OpenRouter's free models, and Cloudflare Workers AI work this way. These are what you build on.
2. One-time signup credits — a small balance that expires. Together AI, Fireworks AI, NVIDIA NIM, and DeepInfra fall here. Great for prototyping, gone once spent.
OpenAI and Anthropic offer no free API credits anymore, so the free route runs on open-weight models and Google's Gemini free tier. Almost every provider below exposes an OpenAI-compatible endpoint, which means one codebase can switch providers by changing a base URL.
1. Groq — the fastest free lane
Groq is the default answer when you need tokens now. Its custom LPUs serve open-weight models like Llama 3.3 70B at interactive speed — hundreds of tokens per second — and the free tier requires no credit card.
The API is OpenAI-compatible at https://api.groq.com/openai/v1, so your existing openai client library works unchanged. Limits are set per model and are generous per day but tight per minute, so add simple backoff to your client. Groq also runs Whisper for speech-to-text, which makes it a strong free pick for transcription pipelines.
Best for: chatbots, agents, and anything where latency matters.
2. Google AI Studio (Gemini API) — the most generous quota
Google's AI Studio hands you a free API key with no billing account required, and the free quota on Gemini Flash-class models is among the largest of any provider. It is the best all-round free tier for most developers: strong reasoning, long context windows, multimodal input, and structured output.
Two caveats. First, Google no longer publishes one static free-tier table — your per-project rate limits live inside the AI Studio console. Second, prompts sent on the free tier may be used to improve Google products, so keep secrets and customer data out of free-tier calls.
Best for: prototypes that need vision, long context, or reliable structured output at no cost.
3. Cerebras — the ultra-fast alternative
Cerebras offers another speed-first inference lane with its wafer-scale chips. The free tier is self-serve: sign up at cloud.cerebras.ai, verify your email, and generate an API key from the console — no waitlist, no card needed.
The endpoint https://api.cerebras.ai/v1 is OpenAI-compatible, so swapping from Groq takes minutes. Keep Cerebras as your fallback when Groq throttles you mid-day.
Best for: a second speed lane for failover, and anywhere Groq's per-minute caps bite.
4. OpenRouter — many models, one key
OpenRouter is a unified API over hundreds of models, and it keeps a rotating pool of genuinely free models (tagged :free). The baseline free quota is 50 requests per day with no credit card — enough for testing and light personal use. If you add a one-time $10 credit, that rises to 1,000 requests per day on free models.
The real value is breadth. When a new open-weight model drops, OpenRouter usually lists a free endpoint within days, so one key and one base URL (https://openrouter.ai/api/v1) gives you access to models no other free tier hosts yet.
Best for: trying the newest models for free without signing up everywhere.
5. Hugging Face Inference Providers — the widest catalog
Hugging Face hosts over half a million public models, and its Inference Providers route your calls to serverless endpoints behind one API. Free accounts get a small monthly credit (around $0.10), and the API is OpenAI-compatible at router.huggingface.co/v1.
The free credit is tiny — this is a sampling tier, not a production tier. But when you need a model that no dedicated provider hosts, Hugging Face is often the only free door.
Best for: experimenting with niche and community models.
6. Cloudflare Workers AI — serverless on the edge
If your app already lives on Cloudflare, Workers AI gives you serverless inference on the same network: 10,000 neurons per day on the free plan. Neurons are compute units rather than a simple token grant, which takes some getting used to, but the quota is real and it resets daily.
Models are addressed by names like @cf/meta/llama-3.1-8b-instruct, and there is an OpenAI-compatible endpoint at api.cloudflare.com/client/v4/accounts/{ACCOUNT_ID}/ai/v1. The killer feature is colocation: no extra infrastructure, inference steps from your existing Workers code.
Best for: edge apps and Cloudflare-native projects.
7. NVIDIA NIM — free prototyping credits
NVIDIA's build.nvidia.com gives developers free credits to prototype against hosted NIM endpoints — a huge catalog including Llama, DeepSeek, Qwen, Kimi, and Nemotron variants behind one API key. These are trial and prototyping terms, not a production entitlement, and quotas are account-specific.
Treat NIM as a high-quality evaluation tier: test drive frontier open-weight models, benchmark them against your use case, then deploy your choice to a cheaper or free home.
Best for: benchmarking new models before committing to one.
8. Together AI, Fireworks AI, DeepInfra — the credit crew
Together AI, Fireworks AI, and DeepInfra each hand out a small free credit on signup. All are OpenAI-compatible and easy to wire up. The credit is one-time — once it is gone, you pay — so use them for load testing or as overflow during a traffic spike, not as your primary tier.
Cohere deserves a mention here too: its trial API keys allow around 1,000 calls per month on the Command R model family, and Mistral offers a free experiment tier for prototyping. Both are evaluation-grade, not production-grade.
One codebase, many providers
Because nearly every provider above speaks the OpenAI API dialect, you can write a tiny provider switch and stop worrying about lock-in:
PROVIDERS = {
"groq": "https://api.groq.com/openai/v1",
"cerebras": "https://api.cerebras.ai/v1",
"openrouter": "https://openrouter.ai/api/v1",
}
client = OpenAI(
base_url=PROVIDERS["groq"],
api_key=os.environ["GROQ_API_KEY"],
)Keep one key per provider in your .env, pick a primary, and add a fallback chain: if the primary returns a 429 rate-limit error, retry on the next provider. Free tiers are flaky by nature — a fallback ladder hides that from your users.
The 5 numbers that decide your pick
- Requests per day — the real ceiling for chatbots and agents. This varies by model, not just provider.
- Tokens per minute — the hidden bottleneck. Generous daily quotas mean nothing if per-minute caps throttle your bursts.
- Context window — long-context models matter for document work; not every free tier offers them.
- Speed (time to first token) — Groq and Cerebras win here by design.
- Data policy — free tiers sometimes train on your prompts. Check each provider's terms before sending anything sensitive.
A practical free-tier strategy
For a side project, run Groq as your primary (fast, generous daily quota) with Cerebras as the automatic fallback when per-minute limits hit. Use Google AI Studio's Gemini free tier for multimodal tasks and long-context work. Keep OpenRouter's free models in the drawer for evaluating new releases, and prototype on NVIDIA NIM before you commit. If you live on Cloudflare, Workers AI is the path of least resistance.
Free quotas change — providers adjust limits without announcement — so treat the numbers above as direction, not contract. Your provider dashboard and the rate-limit headers in API responses are the source of truth.