A free AI model is winning over developers. And nobody knows whose servers it runs on

An anonymous model called Ox Alpha appeared on OpenRouter last week, free to use with a million-token context window, and developers have been impressed. OpenRouter’s own listing says prompts and completions are retained by the unidentified provider.

A model that nobody will take credit for is being tested across the industry. Ox Alpha appeared on OpenRouter last Thursday as a stealth release from an anonymous third-party provider, free to use, with a context window of just over a million tokens.

The scale on offer is not modest. The open-source agent OpenCode said the model would be free for a week with near unlimited usage, and that its provider had capacity for 100 trillion tokens a day.

Developers rate it. Stripe’s chief executive Patrick Collison tried it and called it “very impressive,” and it is positioned for coding, long-horizon agent work and production use.

The guessing game has been inconclusive. The leading theory points to Z.ai, which previously tested GLM-5 anonymously under another name, while a competing analysis of its tokenizer suggests Microsoft’s MAI family instead, in a market already reshaped by free Chinese models.

By the weekend the confidence had drained out of every theory. The AI analyst Andrew Curran wrote that people seemed “less sure of anything” than they had been the night before.