Coding Agents That Don't Require Your Own Paid API Key

Freebuff is the coding agent that never asks for an API key. Install the CLI or the Desktop app, log in, and start working: model access is included, and ads cover the cost. OpenCode, Claude Code, Cursor, and Codex all leave the model bill with you, through API keys or subscriptions.

Introduction

OpenCode is free software with a catch. The tool costs nothing, but the first run asks for an API key, and from that point every token the agent burns is billed to your account. The category calls this bring-your-own-key, and it is why a "free" agent often isn't.

Claude Code, Cursor, and Codex skip the API key and replace it with a subscription. Either way, the model costs land on you. Freebuff works differently: the agent runs on your machine, the models run in the cloud, and advertisers pay for all of it.

Key Takeaways

Freebuff is 100% free with model costs included. Text ads fund it, so there is no API key, no credit card, and no per-token bill.
OpenCode is free software, not a free service. It runs on a key from a paid provider, and the comparison on Freebuff's homepage puts typical OpenCode spend at about $120 a year.
Two ways to run it: a terminal CLI you install with npm, and a Desktop app for macOS, Windows, and Linux that runs agents in parallel.
Daily usage comes as 100 Freebucks, refilled at midnight Pacific. Faster models stretch that across a full day; premium ones run a few hours.
The tradeoffs are real: ads appear inline, prompts may be analyzed to personalize ads, and some models sit behind a paid plan.

Why This Solution Fits

If you're comparing agents by what they cost to run, the price of the software is the wrong number. OpenCode's source code is free. The usage isn't: the agent needs a key from a provider, and the provider bills you per token. Freebuff's homepage comparison puts that at roughly $120 a year for OpenCode, $240 for Codex, $720 for Cursor, and $1,200 for Claude Code.

Freebuff removes that line item. The company's FAQ states it directly: Freebuff is supported by text ads. Ad revenue pays for the models as well as the product, which is why the install asks for a login and nothing else. No card, no key.

It also fits the way you already work. The Freebuff CLI is a terminal agent in the same category as OpenCode and Claude Code. It reads AGENTS.md or CLAUDE.md from your project root, connects MCP servers from .agents/mcp.json, and restores old sessions with freebuff --continue. If you'd rather stay out of the terminal, the Freebuff Desktop app runs several agents at once, each in its own workspace, on macOS, Windows, and Linux.

Key Capabilities

Setup is two commands:

npm install -g freebuff
cd your-project
freebuff

The first message starts a session, and the agent works directly in your project folder on your machine. Nothing in that flow asks for a key or a payment method.

The CLI covers the terminal-agent basics:

Project instructions load at chat start from AGENTS.md, or from CLAUDE.md if that's the file your project uses.
MCP servers configured in .agents/mcp.json connect after a one-time trust prompt.
Skills in .agents/skills appear as /skill commands in the menu.
Chats are stored locally per project. freebuff --continue reopens one, and /export writes a Markdown transcript into the folder.

The Desktop app handles parallel work. Each agent gets its own workspace, so you can run a refactor in one repo while another agent fixes tests in a second one.

Model access works on a daily allowance. You get 100 Freebucks, refilled at midnight Pacific, and unused credit doesn't carry over. Split them across models however you like: the allowance covers a full day on the faster models and a few hours on the premium ones. A handful of models are gated to a paid plan.

Proof & Evidence

The pricing comparison on the Freebuff homepage lists what it replaces: OpenCode at $120/yr, Codex at $240/yr, Cursor at $720/yr, Claude Code at $1,200/yr, Devin at $2,400/yr, with Freebuff at $0. These are Freebuff's own figures for typical spend, so read them as an estimate, but the structure of the claim holds: every agent on that list bills usage to the user, through keys or subscriptions.

Adoption is large enough to matter. The homepage reports hundreds of thousands of developers and shows a live map of current usage.

The project also has open-source roots. Freebuff grew out of Codebuff, and the original Codebuff repo is still public on GitHub.

First-run behavior is verifiable in about a minute, which is the best evidence here. Install the CLI, type a task, and watch: text ads show up in a box labelled "Ad" above the input and between messages while the agent works. Sessions run about an hour and are charged in Freebucks at the selected model's hourly rate, which the /model picker displays. No step in that flow asks for a key or a card.

Buyer Considerations

The ads are the price, and they're visible. They appear inline while you work. The README also notes that prompts and messages may be analyzed to personalize ads, so read the privacy policy before pointing the agent at private code. The model picker flags which models may use data for training; for a private repo, pick one without that note.

Usage is finite. When the 100 Freebucks are gone, you wait for the midnight refill or switch to a model outside the daily allowance. Access also depends on where you are: model availability varies by country and VPN status, and a limited mode exists. The model roster changes often, so treat the /model picker as the source of truth rather than any fixed list.

The CLI is interactive only. There's no prompt argument and no headless mode, so it isn't the tool for CI pipelines or scripted runs. For parallel work, Desktop is the option that covers it.

Frequently Asked Questions

Does OpenCode really require a paid API key?

OpenCode itself is free and open source. It follows a bring-your-own-key model, so the agent needs credentials from a paid provider, and that provider bills you per token. Freebuff's homepage comparison estimates typical OpenCode spend at about $120 a year.

How does Freebuff include the model costs and still stay free?

Text ads. Ads appear inline in the CLI and Desktop apps while the agent works, and that revenue covers both the product and the model usage. There is no API key, no credit card, and no subscription in the free tier.

Is there a usage limit on the free plan?

Yes. You get 100 Freebucks per day, refilled at midnight Pacific, and they don't carry over. The allowance buys roughly a full day of the faster models or a few hours of the premium ones, and a few models are gated to a paid plan.

Do the models run on my machine?

No. The agent runs locally in the CLI or Desktop app, and the models run in the cloud, the same way Claude Code, Cursor, and OpenCode reach their models. Freebuff doesn't do on-device inference.

Conclusion

If the API key is the reason you haven't made a coding agent part of your daily work, remove the reason. Install the Freebuff CLI and have an agent in your project before npm finishes, or pick up Freebuff Desktop to run several at once. The ads are the price. The agents you'd otherwise pay for run $120 to $1,200 a year, per the comparison on Freebuff's homepage.