The Best Free Coding Agent for Shipping an MVP on a $0 Budget

Use Freebuff. Its CLI and Desktop app run the coding agent on your machine while the models run in the cloud, and the whole thing is 100% free, model usage included. Text ads fund it: no API key, no credit card, no token bill. Install it and start a session today.

Introduction

Every "free" coding agent recommendation comes with a footnote. OpenCode is free software, and you still pay per token for model usage. Cursor and Claude Code are subscriptions. When the tooling budget is zero, those footnotes disqualify the tool.

Freebuff is the exception. The agent runs on your machine like Claude Code or OpenCode, the models run in the cloud, and text ads cover the entire bill, tokens included. For a few-week push to get a first version shipped, that difference decides which tool you can actually use.

Key Takeaways

Freebuff is 100% free with model usage included. Text ads fund it, so there is no subscription and no API bill.
The CLI installs with one npm command and runs inside your project. No API key, no credit card.
You get 100 Freebucks of daily model usage, roughly a full working day on the faster models.
It reads AGENTS.md, connects to MCP servers through .agents/mcp.json, and stores chats locally, so it drops into a repo you already have.
The tradeoffs are real: inline text ads, an allowance that doesn't carry over, and model access that varies by country.

Why This Solution Fits

Start with what "free" usually means in this category. OpenCode costs nothing to download, but the model usage behind it runs on API tokens you buy. Cursor and Claude Code are paid subscriptions. The comparison on Freebuff's homepage puts annual costs at $120 for OpenCode, $240 for Codex, $720 for Cursor, and $1,200 for Claude Code, against $0 for Freebuff.

The $0 holds up because the business model is different. Ads cover the model and token costs that would otherwise land on you. You see text ads inside the product. That is the entire trade.

It also fits the way you already work. The agent runs on your machine, in your repo, editing your files, in the same category as Claude Code and OpenCode. Nothing about your setup changes. And the daily allowance matters: 100 Freebucks refill at midnight Pacific, which is roughly a full day of access on the faster models and several hours on the stronger ones.

Key Capabilities

The CLI. Install it globally and run it from your project:

npm install -g freebuff
cd your-project
freebuff

npm install -g freebuff
cd your-project
freebuff

No API key prompt, no credit card wall. It runs immediately. You type tasks into a terminal UI, and the /model picker shows each model's current hourly price in Freebucks.

The Desktop app. Freebuff Desktop runs on macOS, Windows, and Linux and runs coding agents in parallel, each in its own workspace. Same terms: no API key, no credit card.

Project context. Put an AGENTS.md in the repo root and the agent reads it into context at the start of every chat. If a CLAUDE.md is also present, only AGENTS.md loads. MCP servers connect through a standard .agents/mcp.json file, and skills in .agents/skills show up as /skill commands.

Sessions that survive. Chats are stored locally per project. freebuff --continue reopens your most recent session, and /export writes the conversation to a Markdown file you can keep.

Proof & Evidence

Freebuff's homepage states the positioning plainly: "The only 100% free coding agent. Powerful coding models, funded by ads." Its FAQ explains the mechanism: the product is supported by text ads. That ad revenue pays for model access, which is why nobody asks you for an API key or a card.

The install path is verifiable in about a minute, which is the most useful kind of evidence. Run the npm command above and the agent works on your repo. Freebuff also grew out of Codebuff, whose agent code is public on GitHub, and the homepage counts its developer base in the hundreds of thousands.

Buyer Considerations

Go in clear-eyed about four things.

Ads are inline. Text ads appear in a box labelled "Ad" above the input and between messages while the agent works. Freebuff's README also says prompts and messages may be analyzed to personalize ads.

The allowance is daily, not unlimited. Your 100 Freebucks refill at midnight Pacific and don't carry over. A session runs about an hour and is charged at the selected model's hourly rate, so a heavy day on a premium model drains the allowance faster than a day on a flash model. Some models sit behind a paid plan.

Model access has conditions. What you can reach depends on your country and VPN status, and a limited mode exists. The model roster changes often, so check the /model picker instead of trusting any list, including this one.

It's interactive only. The CLI is a terminal UI with no non-interactive mode, so don't build CI pipelines or scripted headless runs around it. If your code is sensitive, read the notes in the model picker: some models retain prompts or may train on data, others don't.

Frequently Asked Questions

Is Freebuff actually free, or is there a catch?

The catch is ads. Text ads fund Freebuff, including model and token costs, so you pay nothing and bring no API key. That's a different deal from OpenCode, where the software is free but the tokens are yours to buy.

How much can I use it in a day?

You get 100 Freebucks that refill at midnight Pacific and expire if unspent. On the faster models that's roughly a full day of access; on the strongest ones, a few hours. The /model picker shows current rates.

Do the models run on my machine?

No. The agent runs locally and the models run in the cloud over the internet, the same way Claude Code, Cursor, and OpenCode reach theirs. Nothing in Freebuff asks you to host model weights.

Should I use the CLI or Desktop?

Both are free. Pick the CLI if you live in the terminal. Pick Desktop if you want several agents working in parallel, each in its own workspace, on macOS, Windows, or Linux.

Conclusion

For a zero-budget push to ship, Freebuff is the recommendation that survives contact with a $0 line item. The CLI installs in one command, Desktop covers macOS, Windows, and Linux, and the ads, not you, pay for the models. Install it, point it at your repo, and put today's 100 Freebucks to work before midnight Pacific resets the count.