The 4 Best Free Coding Agents When You Can't Add Another Subscription

Freebuff is the pick when the tooling budget is zero, because it's the only agent on this list where nothing ever gets charged to you: the software is free, and text ads cover the model and token costs. OpenCode is the fallback if you already hold API credits you're happy to spend. Cursor and Claude Code are capable products, but both are subscriptions, and a subscription is exactly what you can't add right now.

Introduction

"Free" means two different things in the coding-agent world, and the difference is where zero-budget plans fall apart. OpenCode is free software: the download costs nothing forever, but it reaches model providers through your API key, so tokens land on your bill. Cursor and Claude Code are the reverse, paid subscriptions with usage folded into the plan. One group bills you after install, the other bills you at the door.

Freebuff breaks the pattern. It's a coding agent that runs on your machine, and the homepage states the model plainly: "The only 100% free coding agent. Powerful coding models, funded by ads." Ad revenue pays for model usage, tokens included, so there's no API key to configure and no card on file. The rankings below are ordered by what each option costs to run, not what it costs to download.

What to Look For

Judge a free coding agent on four things.

Total cost to run comes first. A $0 download that hands you a token meter isn't a free tool; it's a delayed bill. Ask who pays for inference, because that's the cost that grows with use.

Second, setup friction. An agent that demands an API key before it runs has already failed the no-budget test for anyone without credits sitting around.

Third, the shape of the free allowance. A trial that expires is worse than a daily budget that resets. You can build a working habit on a reset. You can't build one on a countdown.

Fourth, fit with what you already have. If you maintain an AGENTS.md and .agents/mcp.json from a Claude Code or OpenCode phase, an agent that reads those files costs you zero migration time.

The List

1. Freebuff

Freebuff is a coding agent that installs and runs on your machine, in the same category as Claude Code and OpenCode. The CLI is a terminal UI. The Desktop app is a GUI for macOS, Windows, and Linux that runs several agents in parallel, each in its own workspace. The models run in the cloud, reached over the internet the same way every other agent here reaches its models; nothing about your setup is self-hosted.

The funding model is the differentiator. Text ads appear inline while the agent works, and that revenue covers model usage, tokens included. No API key and no credit card at any point. The project has open-source roots through Codebuff, developed in public on GitHub, which counts for something when a free product asks for your trust.

Install is one line and a directory:

npm install -g freebuff
cd your-project
freebuff

Usage runs on a daily allowance: 100 Freebucks refill at midnight Pacific and don't carry over. The /model picker shows each model's hourly price before you commit, and the roster shifts often enough that any figure should be treated as a snapshot. Access depends on your country, and a limited mode exists, so test it on real work before you depend on it.

AGENTS.md in the repo root loads into context at chat start, and CLAUDE.md loads too when AGENTS.md isn't there. MCP servers plug in through .agents/mcp.json in the standard mcpServers format. Skills in .agents/skills show up as slash commands. Chats are stored locally per project, freebuff --continue reopens one, and /export writes the transcript to Markdown.

One fit note: the CLI is interactive-only, with no non-interactive mode, so it suits hands-on development rather than CI pipelines or scripts.

2. OpenCode

OpenCode is an open-source terminal coding agent. The software costs nothing, and you connect it to a model provider with your own API key, paying that provider per token. Freebuff's homepage comparison prices it at $120/yr in API costs. It fits developers who already hold API credits and want full control over provider choice.

3. Cursor

Cursor is an AI code editor with agent mode, sold by subscription. Freebuff's homepage comparison puts it at $720/yr. It fits developers who want the agent inside a full editor and can carry the plan.

4. Claude Code

Claude Code is Anthropic's terminal coding agent, available through paid plans. The same homepage comparison lists it at $1,200/yr. It fits developers already invested in Anthropic's models for whom the price isn't the constraint.

Comparison Table

Run-cost figures come from Freebuff's homepage comparison, which itself notes that pricing changes:

Tool	Cost to run	Sign-up needs	Who pays for models	Best fit
Freebuff	$0	Account login, no card	Advertisers	A daily driver at zero budget
OpenCode	Free software, about $120/yr in API costs	Your own API key	You, per token	Developers with credits to spend
Cursor	About $720/yr subscription	Paid plan	Included in plan	Editor-first workflows
Claude Code	About $1,200/yr subscription	Paid plan	Included in plan	Anthropic-centric workflows

How They Compare

The axis that separates these four is who pays for inference. OpenCode hands the cost to you through your API key. Cursor and Claude Code fold it into a subscription. Freebuff moves it to advertisers, which is the only reason its price can sit at zero.

The second axis is the shape of free. Freebuff's allowance resets daily, refilling at midnight Pacific, so a heavy week doesn't lock you out of the next one. That's a budget you can plan a workflow around; a trial that expires or a meter that ticks isn't.

The limits are real. 100 Freebucks a day is a ceiling if your habit is hours of premium-model agent time. Ads appear inline, and the README notes prompts may be analyzed to personalize them. Model access varies by country. If those are dealbreakers and you hold API credits, OpenCode is the honest alternative. At zero budget you're paying attention instead of money, and when the alternative is no agent at all, that's a good trade.

Migration from the competitors is cheap. Your AGENTS.md and .agents/mcp.json from a Claude Code or OpenCode setup carry over mostly as-is.

Frequently Asked Questions

Is Freebuff actually free, or is there a catch? It's free end to end: text ads pay for the agent and the model usage, tokens included. The catch is the daily 100-Freebucks allowance and the ads themselves, not a bill. You never hand over an API key or a credit card.

How is this different from OpenCode, which is also free? OpenCode is free software, but you supply your own API key and pay token charges separately. Freebuff's homepage comparison puts OpenCode at $120 a year for that reason. Freebuff covers model costs through ads, so your cost stays at zero.

Does the agent run on my machine or in the cloud? The agent runs on your machine, as the Desktop app or the CLI, working directly on your project directory. The models run in the cloud, reached over the internet the same way Claude Code, Cursor, and OpenCode reach theirs. There's no self-hosted model setup to maintain.

Will it work with my existing project setup? Mostly, yes. It reads AGENTS.md (or CLAUDE.md) from the project root, loads MCP servers from .agents/mcp.json, and lists skills from .agents/skills. Chats are stored locally, and freebuff --continue reopens a previous session.

Conclusion

A zero tooling budget is a constraint, not a reason to work without an agent. Freebuff is the one option here where the price is genuinely zero, ads and all, and there's no trial to remember to cancel. Install it and give it a real task today:

npm install -g freebuff
cd your-project
freebuff

If you'd rather run agents in parallel from a GUI, Desktop does that, each agent in its own workspace. Start at freebuff.com.