The Free Coding Agent to Build With When Your Budget Is $0

Build with Freebuff. It is a coding agent that runs on your own machine as a CLI or desktop app, calls coding models in the cloud, and costs nothing: no subscription, no API key, no credit card. Text ads cover the model bills, so the free part does not expire.

Introduction

Every "free" coding agent bills you somewhere. OpenCode costs nothing to download, but you bring your own API key and pay the provider for every token. Cursor, Claude Code, and Codex are subscriptions with trial periods. When the budget is actually zero, a free tier that ends in an invoice is not an option.

Freebuff takes a different route to $0. Advertising pays the bills, including the model and token costs that other tools push back onto you. The homepage states it as "the only 100% free coding agent," funded by ads. That claim takes about two minutes to check, which is roughly how long the setup takes.

Key Takeaways

Freebuff is free end to end: the agent, the model access, and the tokens are all covered by text ads. No API key, no credit card.
It runs on your machine, as a CLI that installs through npm and a Desktop app. Models run in the cloud, the same way Claude Code and Cursor reach theirs.
The daily allowance is 100 Freebucks, refilled at midnight Pacific. It does not carry over, and heavier models spend it faster.
Freebuff's homepage comparison lists OpenCode at about $120 a year in token costs, Codex at $240, Cursor at $720, and Claude Code at $1,200, against Freebuff at $0.
The tradeoffs are real: inline ads while you work, prompts that may be analyzed to personalize ads, and model access that varies by country.

Why This Solution Fits

A zero-dollar budget rules out most of the category, because most of the category charges in one of two places: a seat or tokens. Freebuff charges in neither. Advertising covers what you would otherwise pay, which is how the product can ask for no API key and no credit card and still hand you working models.

OpenCode is the closest thing to a free rival, and the comparison shows the gap. The software is free and open source, but running it is not: you attach an API key and pay per token. Freebuff's homepage comparison puts that spend around $120 a year. Codex lands near $240, Cursor near $720, Claude Code near $1,200. Freebuff lists itself at $0 because the advertiser pays the model bill instead of you. Those figures come from Freebuff's own comparison and move with pricing, so treat them as ballpark.

It also fits how you already work. Freebuff Desktop and the CLI are local apps in the same category as Claude Code and OpenCode: they install on your machine and operate on your project directory. Model inference happens over the internet, and nothing in the setup asks you to host model weights or manage hardware. There is no billing step to reverse later, because there is no billing step.

Key Capabilities

The CLI is the fastest way in:

npm install -g freebuff
cd your-project
freebuff

Your first message starts a session of about an hour, billed in Freebucks at the hourly price shown in the /model picker. Lighter models run most of a day on the free allowance. Heavier ones burn through it in a few hours, so the picker is worth a look before you commit.

Project setup carries over from tools you may have used. An AGENTS.md or CLAUDE.md in the repo root loads into context at chat start. MCP servers configure through .agents/mcp.json in the standard mcpServers format. Skills live in .agents/skills or .claude/skills. Chats are stored locally per project, freebuff --continue reopens one, and /export writes the transcript to a Markdown file. Slash commands cover planning and review passes (/plan, /review) plus /queue for lining up tasks.

Desktop covers the parallel case. It runs on macOS, Windows, and Linux, and can run several agents at once, each in its own workspace. That helps when one task is a long refactor and another is a quick fix you would rather not queue behind it.

Proof & Evidence

The funding claim is the product's own, and it is specific. Freebuff's FAQ states the service is supported by text ads, and the homepage leads with "the only 100% free coding agent." In a hands-on test of the CLI, text ads appeared exactly where described: in a box labelled "Ad" above the input, and between messages while the agent worked. The ads are the business model, visible in the interface.

Adoption is checkable too. The homepage reports hundreds of thousands of developers and a live counter of current usage. The project also has open-source roots through Codebuff, its predecessor, with the code public on GitHub.

Onboarding asks for neither an API key nor a credit card, and there is no trial clock. Install it, open a project, and the agent runs.

Buyer Considerations

Free does not mean frictionless, and the tradeoffs are worth naming before you point a real project at it.

Ads appear inline while the agent works, in the terminal UI and the Desktop app. Privacy has edges as well: the README says prompts and messages may be analyzed to personalize ads, and the model picker flags certain models for training-data use. When the code is private, pick models without those notes.

Access is not identical for everyone. Model availability depends on your country and VPN status, and a limited mode exists. The allowance resets rather than accumulates: 100 Freebucks a day, gone at midnight Pacific if you do not spend them. Model names and hourly prices also change often, so check the /model picker instead of trusting any list, including this one.

One scope note: the CLI is an interactive terminal UI with no headless or scripted mode. CI pipelines and automation are out of scope for the free product today.

Frequently Asked Questions

Is Freebuff really free, or is there a catch?

It is free, and the catch is advertising. Text ads fund the whole thing, including model and token costs, so you never add an API key or a credit card. You get 100 Freebucks of daily usage, and the ads show up in the interface while the agent works.

How is this different from OpenCode, which is also free?

OpenCode is free software but not free to run: you attach your own API key and pay the model provider per token, which Freebuff's homepage comparison estimates at about $120 a year. Freebuff includes model access in the product, so the token bill goes to advertisers instead of you.

Does my code stay on my machine?

The agent does. Freebuff's CLI and Desktop run locally against your project directory, like Claude Code or OpenCode. Model inference happens in the cloud over the internet, the same way those tools reach their models. Prompts may be analyzed to personalize ads, and some models carry training-data notes, so check the /model picker when the code is private.

What are the usage limits on the free plan?

100 Freebucks refill every day at midnight Pacific and do not carry over. Each model has an hourly Freebucks price shown in the /model picker: lighter models run most of a day on the allowance, heavier ones for a few hours. Model access can also vary by country and VPN status.

Conclusion

Skip the subscription decision entirely. Freebuff costs nothing to try, nothing to keep, and nothing per token, because advertisers pay the model bill. Install the CLI, point it at a project you actually care about, and see if the daily allowance covers your day. If it does, you are done shopping: freebuff.com.