A mysterious model appeared on OpenRouter and OpenCode Zen with no announcement, no named developer, and specs that made the coding community stop scrolling: a 1.05M-token context window, 131K output, multimodal input, and agentic coding good enough that early testers rate it favorably against frontier models. It's called 0x Alpha, it's free while in preview, and nobody's officially said who built it. This is the native desktop client for it — so instead of poking at it through a raw API, you get a real coding workspace around the stealth model of the moment, one click to install.
No hype beyond the facts — because half the fun of a stealth model is that nobody's confirmed the rest:
- 1.05M-token context, up to 131K tokens of output — enormous even by frontier standards
- Multimodal — takes text, images, and video
- Built for long-horizon software engineering — sustained, multi-step agentic coding and terminal workflows, not one-shot answers
- Strong early reviews — the OpenCode community jumped on it fast; early testers report it handling multi-step refactoring and bug-fixing favorably against frontier models
- Preview privacy terms — requests are retained for the trial period but, per the stated terms, not used to train the model
- Free while in preview — available across OpenRouter and OpenCode Zen at no cost during the trial Who made it? Officially unknown. The community has theories; we're not going to pretend to settle it. What we can do is give you the best way to actually use it while it's here.
Reaching a stealth model on OpenRouter means API keys, config, and no real workspace — you're testing a frontier-class coder through a chat box or a curl command. This wraps it in an actual environment:
- One-click install — signed installer for Windows and Mac, no API wrangling to start
- Real coding workspace — a proper interface for multi-step, long-horizon tasks, which is exactly what 0x Alpha is built for
- Use that 1M context for real — load a whole codebase, not snippets, and keep it all in view
- Local project library — your prompts, chats, and generated code stay organized on your machine
- Multimodal in — drop screenshots, diagrams, or video frames straight into the workflow
Long-horizon coding is the whole point of this model, and the app is built around it:
- Whole-codebase work — the 1.05M context holds an entire real project; refactor across files without losing the thread
- Agentic, multi-step tasks — the kind of sustained "work through this repo" jobs 0x Alpha was tuned for
- Big outputs — with up to 131K output tokens, it can generate large files or whole modules in one pass
- Vision-assisted dev — hand it a UI screenshot or an architecture diagram and build from it
0x Alpha is a stealth preview, and we're being straight about what that means. It's free right now because it's in an open trial across OpenRouter and OpenCode Zen — that trial can change or end at any time, and the model may later relaunch under an official name with different terms. This client is built to keep working through that: if and when the model surfaces officially, the app moves with it. For now, you get an easy, free way to use one of the most talked-about models in the coding community while it's out in the open.
- Windows →
0x-Alpha-x64.exe, double-click. Signed. - Mac →
0x-Alpha.dmg, drag to Applications. Notarized, Apple Silicon + Intel. Connect it to the preview on first launch and start building.
Is it really free? Yes, while it's in preview. 0x Alpha is available at no cost across OpenRouter and OpenCode Zen during its stealth trial, and this client uses that access. Previews don't last forever — terms can change or the trial can end — but for now it's genuinely free to use.
Who made 0x Alpha? Officially, nobody's said. It launched with no developer attribution, which is exactly why the coding community is fascinated by it. There are theories, but nothing confirmed, and we're not going to fabricate an answer. What's known are the specs and the strong early reviews.
Is it safe to install? The client is signed on Windows, notarized on Mac, with SHA-256 checksums published, and the source is on GitHub. It's a workspace around the model's preview access — download only from the Releases page here.
What happens when the preview ends or it gets an official name? This client is designed to follow the model. If 0x Alpha relaunches officially, the app updates to keep working with it, so you're not left stranded. Your local project library stays on your machine regardless.
What's it actually good at? Long-horizon, agentic coding — multi-step refactors, whole-repo work, big generations — which is what the model was built for. The 1.05M context and 131K output are the standout specs, and early testers rate its agentic coding favorably against frontier models.
Independent third-party desktop client for 0x Alpha, a stealth preview model available on OpenRouter and OpenCode Zen. The model's developer is not publicly known; this project makes no claim about its origin and is not affiliated with or endorsed by whoever built it, OpenRouter, or OpenCode Zen. "0x Alpha" is used solely to identify the model this client connects to (nominative fair use). Access is via the model's public preview, which is free during the trial and subject to change or termination at any time under the preview's own terms; requests are handled under those terms. MIT-licensed client — see LICENSE.
Using the stealth model before everyone else figures out what it is? A ⭐ helps other developers find it while it's still a mystery.