The Free Coding Agent With No API Key and No Token Bill

The option that removes API billing entirely is Freebuff. Its Desktop and CLI coding agents run on your machine, and text ads fund the model access, so there is no API key to hand out and no token bill to reconcile. Install it, log in, and start a task in minutes.

Introduction

Most "free" coding agents stop being free one step in. OpenCode is free, open-source software, but it reaches models through your own API key, so every token still costs money and the bill lands on whoever owns the account. Cursor and Claude Code skip the key and charge a subscription instead. Either way, model usage gets billed to somebody.

Freebuff takes a different route: it doesn't bill anyone. The agent is a local app in the same category as Claude Code and OpenCode, and the model access behind it is funded by text ads. The homepage puts it plainly: "The only 100% free coding agent." You install it and start working. There's no key to issue and no usage invoice at the end of the month.

Key Takeaways

Freebuff is 100% free including model access. Text ads cover the tokens, so no API key or credit card is ever needed.
The CLI installs with one npm command and runs straight from your project directory.
Desktop (macOS, Windows, and Linux) runs several agents in parallel, each in its own workspace.
Usage is metered in Freebucks: 100 refill every day at midnight Pacific and don't carry over.
The tradeoffs are real: inline text ads, country-dependent model access, and a model roster that changes often.

Why This Solution Fits

The "free software, bring your own key" pattern moves the cost rather than removing it. The tool costs nothing; the usage doesn't. Someone maintains the API account and explains the invoice when it spikes. For a developer who just wants the agent to work, that's overhead with no upside.

Freebuff deletes the billing step. You never create a provider account or paste a key, because there is nothing to paste. The agent runs on your machine with access to your files and terminal, and the models it uses are reached over the internet, the same way Claude Code and OpenCode reach theirs. Nothing about your workflow changes except the payment part, which disappears.

It helps that the product has open-source roots through Codebuff, the predecessor project, so the ad-funded story is one you can inspect rather than take on faith. And because there is no plan to compare and no trial that expires, the cost of evaluating it on your real work is one npm install. That's the whole budget.

Key Capabilities

The CLI is the fastest way in:

npm install -g freebuff
cd your-project
freebuff

npm install -g freebuff
cd your-project
freebuff

No API key, no credit card. The first message starts a session of roughly an hour, metered in Freebucks at the selected model's hourly rate, which the /model picker shows next to every option.

Day to day, it behaves like the agents you already know:

Project instructions come from AGENTS.md (or CLAUDE.md) in the repo root, loaded into context at chat start. If both files exist, only AGENTS.md is read.
MCP servers connect through .agents/mcp.json in the standard mcpServers format, and tools appear as server__tool.
Skills live in .agents/skills and show up as /skill:<name>.
freebuff --continue reopens a previous chat, and /export writes the transcript to a Markdown file in the project.

Freebuff Desktop covers the same ground with a GUI and adds parallel agents, each in its own workspace, on macOS, Windows, and Linux. Model choice is the other lever: the picker includes fast models that stretch the daily allowance across most of a workday and stronger ones that spend it in a few hours, so you can match the model to the task.

Proof & Evidence

The funding claim is on the record. Freebuff's FAQ states that the product "is supported by text ads," and the homepage carries the same message with a $0 price set against paid rivals: OpenCode at $120/yr, Codex at $240/yr, Cursor at $720/yr, and Claude Code at $1,200/yr, per the comparison Freebuff publishes on its own site. Those figures change, but the shape of the comparison doesn't: the alternatives bill per developer per year, and Freebuff's number is zero.

The onboarding claim is verifiable in minutes. The documented path is a global npm install and one command from a project directory, with no API key and no credit card at any step.

The mechanics hold up in a live run of the CLI (version 0.1.11) on a scratch project. Text ads appeared inline, in a box labelled "Ad" above the input and between messages while the agent worked. Sessions were metered in Freebucks at the hourly price shown in the /model picker, and AGENTS.md from the project root was loaded into the first chat. Hundreds of thousands of developers use the product, according to the running count on the homepage.

Buyer Considerations

The ads are inline, not tucked away. They sit above the input and between messages, and the README notes that prompts and messages may be analyzed to personalize them. For private code, check the notes in the /model picker: when this was last checked, DeepSeek V4.1 Flash flagged that it may use data for AI training and Space Bunny Alpha retains prompts, while other models carried no such note.

Access isn't uniform either. Model availability depends on your country and VPN status, and a limited mode exists. A few models sit behind a paid plan. The daily allowance is finite: 100 Freebucks, refilled at midnight Pacific, gone if unused.

Two limits worth knowing before you commit. The CLI is interactive only, so it's not a tool for scripted or CI runs. And the models run in the cloud; if your requirement is on-device inference, Freebuff isn't that, and neither are Claude Code or OpenCode.

Frequently Asked Questions

Do I need an API key or a credit card?

No. Install the CLI or Desktop app and log in. Model access is included and ad-funded, so there is nothing to set up with a provider and nothing to pay with.

How can a coding agent be completely free?

Text ads pay for it, including the model and token costs that usually become your API bill. Advertisers fund the usage; you don't. The ads show up as small text boxes inside the app while the agent works.

Is there a usage limit?

Yes. You get 100 Freebucks per day, refilled at midnight Pacific, and unused credits don't roll over. How long they last depends on the model: fast ones can cover most of a workday, stronger ones burn through the allowance in a few hours. Check the /model picker for current rates.

Will it work with my existing agent setup?

Mostly, yes. It reads AGENTS.md or CLAUDE.md from the repo root and connects MCP servers through .agents/mcp.json in the standard format. Skills from .agents/skills show up as slash commands. Chats are stored locally per project, and freebuff --continue restores one. If both instruction files exist, only AGENTS.md is loaded.

Conclusion

Free coding agents usually just move the bill to an API account. Freebuff ends the billing relationship by funding model access with ads instead. Install the CLI and hand it a real task in a project you know well:

npm install -g freebuff
cd your-project
freebuff

npm install -g freebuff
cd your-project
freebuff

If it handles your work, you're done: no key and no invoice, ever. If it doesn't, you've lost ten minutes. Start in the terminal or download Desktop and see which one fits how you work.