Ptero
Free AI Chat For Developers
About Ptero
Ptero is a free AI chat platform that puts fifteen language models behind a single interface, with no account required to start a conversation. It is aimed at developers, students and creators who want to test a prompt, debug a function or compare how different models answer the same question without signing up for anything or paying per token. The whole thing is open source under Apache 2.0, and the source link sits in the interface itself rather than buried in a footer.
What separates it from the usual free chat wrapper is that the free position is written into the terms rather than offered as a trial. The Terms of Service state that Ptero is completely free and will always be free, with no premium plans, subscriptions, paywalls or paid tier of any kind. The model list reflects the trade being made: these are small and fast models rather than frontier ones. Chat history is stored in your own browser rather than on their servers, with one documented exception covered below.
You open the site and clear three gates before the chat appears: a notice offering you the source code, a Terms of Service checkbox, and a Cloudflare human verification step. There is no email, password or payment detail at any point, but it is not quite the zero-click experience the marketing suggests.
Once through, you pick a model from the dropdown and type. Four starter prompts (write an email, explain a topic, debug code, analyse a file) seed the box if you would rather edit than compose from nothing. Response shape is controlled by two toggles rather than settings buried in a menu: Fast Task against Complex, and Quick Answer against Full Output.
Switching models mid-conversation is the workflow the tool is built around. You send the same prompt to a second model from the same picker and compare the answers, which is the practical way to find out which of the free models handles your particular kind of question best.
- •Fifteen models in one picker - the list spans Qwen, DeepSeek, GPT-OSS, Nemotron, MiMo and others, all selectable without leaving the conversation.
- •No account for chat - guest access is the default state, not a limited preview of a signed-in product.
- •500,000 tokens an hour - the free allowance is metered hourly rather than daily or monthly, tied to a guest identity and device, and it resets on the hour. Starring their GitHub repository doubles the quota.
- •Local history by default - conversations are kept in your browser rather than on their servers. Clearing browser data or switching device loses them, so export a backup first.
- •Projects - a folder layer for grouping related chats. This is the exception to local storage: Project chats are synced to their servers so they follow you across devices, and that part does require signing in.
- •Built-in code editor - a panel for working with generated code directly, with file download and preview, rather than copying out into an editor elsewhere.
- •File analysis - attach a file and ask questions against it, one of the four first-class starter actions.
- •Apache 2.0 source - the full PHP application is on GitHub, so it can be read, forked or self-hosted.
Developers who want a scratchpad for debugging and prompt testing without burning API credits or opening another paid seat. Students and learners who need a capable assistant with no card on file. Anyone comparing model behaviour, since switching between fifteen options in one window is faster than holding accounts with five separate providers.
It is a poor fit if you need frontier-model quality, because the catalogue is deliberately small and fast rather than state of the art. It is also the wrong tool for confidential work: a free service with no account gives you no contractual protection, and anything you put into a Project leaves your machine.
