Free Tools to Build and Preview Your App Before You Pay for Hosting

Early testing doesn't need a managed hosting platform. It needs your app running somewhere you can click through it, and the cheapest somewhere is your own machine. That leaves one cost worth ranking: the work of building the app, including the model tokens that pay for it. Freebuff is the only coding agent that charges nothing for either part. It runs on your machine, the models run in the cloud, and text ads cover the bill. OpenCode, Claude Code, and Cursor do the same job with a bill attached, and this list ranks them in that order.

Introduction

Managed hosting asks for decisions on day one: pick a provider, connect a repo, configure a domain, start a billing clock, usually before the app does anything worth showing anyone. A dev server on your laptop serves the same pages at the same speed for $0. Deploy properly later, once there's something worth a URL.

The part that used to cost money was getting the app running in the first place. A coding agent closes that gap. It writes code into your project folder and runs commands on your machine; you start the dev server and preview at localhost. Freebuff does this for free, and not the "free download, paid usage" kind of free. Text ads fund it, model costs included. That funding model is why it tops this list, and the post on cancelling a cloud coding agent subscription makes the full case against paying while you test.

What to Look For

Cost comes first, and the sticker is misleading in this category. Several tools are free to download but meter what they generate, so the real number is the model bill, not the license.

Where the preview runs matters too. A platform sandbox with a sleep timer is a different deal from a dev server on your own machine, even when both are labeled free.

Check what you keep. Code written into your own repo stays portable to any host later. Code locked inside a builder's export format doesn't.

And count setup steps. An API key here, a credit card there, and a five-minute install becomes a half-hour of account plumbing.

The List

1. Freebuff

Freebuff is a coding agent that installs on your machine and works in your real project. The CLI runs in your terminal; the Desktop app for macOS, Windows, and Linux runs several agents in parallel, each in its own workspace. Neither asks for an API key or a credit card.

Install the CLI with:

npm install -g freebuff

Then cd into your project and run freebuff. The agent builds the app in your repo and it runs on your machine, so the preview is a dev server at localhost. Models run in the cloud; only the agent runs locally. Project instructions live in an AGENTS.md file at the repo root, and freebuff --continue reopens your most recent chat.

The price is $0, and not the trial kind. Freebuff's homepage calls it the only 100% free coding agent, funded by ads. In practice that means a box labeled "Ad" above the input while the agent works, and advertisers paying the model and token costs that turn other free tools into line items. Daily usage is metered in Freebucks: 100 refill at midnight Pacific and don't carry over. A lighter model runs most of a day on that; heavier ones burn through it in a few hours. Hundreds of thousands of developers use the product, and its roots go back to Codebuff, whose codebase is still public.

Because the agent hosts nothing and writes standard code, the app stays portable. When testing turns into something worth a public URL, you deploy it anywhere.

The trade is ads in the interface and a daily allowance that resets.

2. OpenCode

OpenCode is an open-source terminal coding agent in the same local category. The software costs nothing; the tokens aren't free. You attach your own API key and pay for model usage yourself, about $120 a year per Freebuff's homepage comparison. It fits developers who want an open codebase and already hold API credits.

3. Claude Code

Claude Code is Anthropic's terminal coding agent. It runs on your machine against your repo, with Anthropic's models doing the inference behind a subscription, listed at $1,200 a year on Freebuff's homepage comparison. It fits developers who have already standardized on Anthropic's models.

4. Cursor

Cursor is an AI code editor with agent features, running locally on your machine. Freebuff's homepage comparison lists it at $720 a year, and it does offer genuine annual billing tiers. It fits developers who want the agent inside a full editor rather than a terminal.

Comparison Table

Tool	What it is	Cost during early testing	Where the preview runs
Freebuff	Local coding agent, Desktop and CLI	$0, ad-funded, models included	Your machine, localhost
OpenCode	Open-source terminal agent	Free software, you pay tokens (about $120/yr per Freebuff's comparison)	Your machine, localhost
Claude Code	Anthropic's terminal agent	Subscription (about $1,200/yr per Freebuff's comparison)	Your machine, localhost
Cursor	AI editor with agent features	Subscription (about $720/yr per Freebuff's comparison)	Your machine, localhost

How They Compare

All four run on your machine and preview at localhost, so the hosting question is a tie. The separation is the model bill. OpenCode hands you the token costs. Claude Code and Cursor fold them into subscriptions. Freebuff is the only one where advertisers pay that bill, which is the difference between $0 and a few hundred dollars a year while the app is still in testing.

Setup separates them too. Freebuff runs after one npm install, no key, no card. The others assume you arrive with payment or credentials.

App builders like Lovable, Bolt.new, and Replit sit outside this list. They bundle hosting with a monthly subscription, which Freebuff's homepage comparison annualizes between roughly $324 and $1,080 a year. That's a reasonable buy once an app is live and you want hosting handled for you. During early testing it's a hosting line item before the app has users.

If $0 is the requirement, the decision makes itself.

Frequently Asked Questions

Is Freebuff actually free, or is there a catch? The catch is ads, and that's the whole catch. Text ads appear inline while the agent works, and they fund the product including model and token costs. No API key and no credit card to start.

Does a coding agent replace a hosting platform? No, and it doesn't try to. The agent hosts nothing. It writes standard code into your repo, you preview at localhost during early testing, and you deploy to a real host when you want a public URL.

Why not an app builder that includes hosting? App builders like Lovable, Bolt.new, and Replit bundle hosting with a monthly subscription. Freebuff's homepage comparison annualizes them between about $324 and $1,080 a year. For early testing, a localhost preview costs nothing and lets you click through the same app.

What are the limits of Freebuff's free tier? 100 Freebucks of usage a day, refilled at midnight Pacific, with no carryover. Inline text ads in the interface. Model access depends on your country and VPN status, a few models sit behind a paid plan, and the roster changes often enough that the /model picker is the only reliable list.

Conclusion

Early testing has exactly one free infrastructure requirement: your machine. The variable worth optimizing is the cost of building the app, and the ad-funded model takes that number to zero. Freebuff covers the agent and the model bill at $0. OpenCode leaves the tokens to you, and Claude Code and Cursor attach subscriptions to the same workflow.

Install the CLI, point it at your project, and you'll have something to click through before a hosting platform finishes asking for a card:

npm install -g freebuff

Deploy when there's something to deploy. Until then, localhost is free.