What Free Tiers Can You Actually Build a Real Agent On?

Every week someone asks whether free tiers are just demo bait or whether you can ship something real on them. The honest answer is: it depends on what "real" means. A real agent that handles ten users a day is different from one handling ten thousand. This post is a ledger of what actually works, what the hard limits are, and where the walls will hit you.

Why does the free tier question matter so much for agent builders?

It matters because the agent build cycle is iterative and expensive if you are paying for every experiment. Agents fail in unexpected ways: the retrieval step hallucates a tool call, the memory store returns stale context, the orchestration loop runs 40 times instead of 4. You need room to break things without a billing alarm going off every afternoon.

The platforms below are evaluated on three criteria: does the free plan allow outbound HTTP calls (agents need to call tools), does it allow persistent storage (agents need memory), and does it impose a rate limit or sleep delay that would break a real user session.

Which LLM API free tiers are usable for agent loops?

OpenAI gives new accounts a small credit window. It is time-limited, not volume-limited, which means you can burn through it fast if you run multi-step chains. Use it to validate your prompt structure, then move to a pay-as-you-go key before you start load testing.

Google's Gemini API via Google AI Studio has a free tier with no time expiry as of mid-2024, documented on the Google AI Studio pricing page. The free tier allows up to 15 requests per minute on Gemini 1.5 Flash. That is enough for a single-user agent running sequential tool calls. It is not enough for concurrent sessions.

Groq offers a free tier with high token throughput on open models including Llama 3. Rate limits are published on Groq's documentation. For agents that need fast inference on structured outputs, Groq free is the strongest option in the no-cost tier right now.

Anthropic's Claude does not have a public free tier beyond the consumer app. If you want to build on Claude, budget for API costs from day one.

Which hosting platforms run agent code without charging for idle time?

This is where most builders get surprised. An agent is not a static site. It needs to receive a webhook, run a loop that may take 30 seconds, call external APIs, and write back to a store. Most free hosting tiers that spin down after inactivity will timeout in the middle of that loop.

Cloudflare Workers is the cleanest solution here. The free plan allows 100,000 requests per day and has no cold start spin-down problem because Workers run on an edge runtime that stays warm. The constraint is a 10ms CPU time limit per request, which matters if your agent does heavy in-process computation. For agents that delegate work to external APIs and wait on responses, the Workers model fits well. See Cloudflare Workers pricing for the current free tier details.

Render's free web service tier does spin down after 15 minutes of inactivity. That is a real problem for agent endpoints. The workaround is a free uptime ping service, but that is a workaround, not a solution. Use Render free for background worker processes that you trigger manually during testing, not for production-facing agent endpoints.

Railway gives new users a small monthly credit. It does not spin down. For a simple agent server running continuously, Railway's starter credit usually covers a full month of light workloads before you need to add a card.

Which database and memory tiers survive a real agent's read/write pattern?

Agents write more than typical web apps. Every tool call result, every retrieved chunk, every turn of the conversation loop is a write. Free database tiers with low write limits will hit a wall fast.

Supabase's free tier includes a Postgres database with 500MB storage and their pg_vector extension for embeddings. The free tier pauses after one week of inactivity, but an active agent project will not hit that. For builders who want a single free tier that covers structured data, vector search, and auth, Supabase is the strongest option. Documentation is at supabase.com/pricing.

Pinecone's free Starter plan includes one index with limited dimension and record count. It is enough to store a few thousand document chunks for a retrieval-augmented agent. It is not enough for a multi-tenant agent that stores per-user memory at scale.

Upstash Redis free tier gives 10,000 commands per day. For an agent that uses Redis to store short-term session state between tool calls, 10,000 commands goes fast in a multi-step loop. Know your command count before you depend on it.

What does a practical free-tier agent stack actually look like?

Here is a stack that has been validated on real agent projects, not a theoretical combination:

• LLM: Groq free tier for fast inference, or Gemini 1.5 Flash for longer context
• Orchestration: Python with LangChain or a plain async loop, no paid service needed
• Hosting: Cloudflare Workers for the agent endpoint, no spin-down risk
• Memory and retrieval: Supabase free for Postgres plus pg_vector
• Short-term state: Upstash Redis free, with careful command budgeting
• Secrets management: Cloudflare Workers environment variables, no extra cost

This stack handles a single-user agent at low volume with no monthly cost. The first limit you will hit is Groq's rate limit if you run concurrent sessions. The second is Supabase's row limits if you store verbose conversation history without pruning.

What are the real walls you will hit?

Being honest about limits is more useful than a feature checklist:

• Concurrent users: Free LLM tiers are rate-limited per minute, not per day. Three users hitting your agent simultaneously will likely exceed Groq or Gemini free RPM limits.
• Long-running loops: Cloudflare Workers' CPU time limit means you cannot run a 30-second synchronous agent loop on the free plan. You need to break work into async steps or use a queue.
• Storage growth: Supabase's 500MB fills up if you store raw document chunks without chunking strategy or cleanup jobs.
• No SLA: Free tiers have no uptime guarantees. That is fine for prototypes, not fine for a client-facing product.

For more on structuring an agent that scales past the free tier, see our breakdown of 10-agent architectures and the agent memory patterns guide. The free tier stack above is the same foundation those architectures start from.

The builder move here is not to avoid costs forever. It is to avoid costs during the phase when you are still finding out whether the agent does what you need it to do. That phase is where free tiers earn their place.