When was Kimi K3.1 Pro released?

It launched in Moonshot AI's API on 23 October 2026. The open weights followed on Hugging Face on 4 November 2026.

How large is Kimi K3.1 Pro?

It has 2.8 trillion total parameters with about 104 billion active per token. The published weight files total about 1.56 TB.

Kimi K3.1 Pro news

Open-weight large language model1 story

Kimi K3.1 Pro is a mixture-of-experts language model from Moonshot AI with 2.8 trillion total and about 104 billion active parameters and a context window of about 1 million tokens.

Image Moonshot AI on Hugging Face published with the announcement covered in this story — Moonshot AI publishes Kimi K3.1 Pro open weights: 2.8T parameters, cyber data removed

Open Source AI5 Nov 2026, 16:41 UTC

Moonshot AI put the weights of Kimi K3.1 Pro on Hugging Face on 4 November 2026: 2.8T parameters, about 104B active, a 1M context and a custom license.

Summary

Moonshot AI published the weights of Kimi K3.1 Pro on Hugging Face on 4 November 2026, meeting the date it set when the model launched in its API on 23 October. The mixture-of-experts model has 2.8 trillion total and about 104 billion active parameters and a context window of about 1 million tokens. Moonshot says it removed cyber-related training data before the open release. The weights ship under a custom Kimi license.

About Kimi K3.1 Pro

Kimi K3.1 Pro is a mixture-of-experts language model from Moonshot AI with 2.8 trillion total and about 104 billion active parameters and a context window of about 1 million tokens. It launched in the Kimi API on 23 October 2026 and its weights were published on Hugging Face on 4 November 2026.

Reviewed 5 Nov 2026 · by Moonshot AI

Facts at a glance

Developer: Moonshot AI
API launch: 23 October 2026 source
Open weights published: 4 November 2026, about 1.56 TB source
Parameters: 2.8T total, about 104B active (mixture of experts) source
Context window: About 1M tokens source
API price: $2 per 1M input tokens, $0.20 per 1M cached input tokens, $10 per 1M output tokens source
Variant: K3.1 Pro Highspeed, 2 to 3 times faster output at $4 input and $20 output per 1M tokens (API only) source
License: Kimi K3.1-Pro License (custom; extra conditions for very large commercial users) source

More about Kimi K3.1 Pro (show)

Cyber-related training data removed

Moonshot AI says it removed cyber-related data from the mid-training and reinforcement learning stages of the open release, while keeping general coding work. On its internal exploit development test, the released model solved 81.0% of tasks against 90.5% for a checkpoint trained without the filtering. Moonshot has not published that benchmark.

Questions people ask

When was Kimi K3.1 Pro released?: It launched in Moonshot AI's API on 23 October 2026. The open weights followed on Hugging Face on 4 November 2026.
How large is Kimi K3.1 Pro?: It has 2.8 trillion total parameters with about 104 billion active per token. The published weight files total about 1.56 TB.

Kimi K3.1 Pro news

Every story about Kimi K3.1 Pro

Moonshot AI publishes Kimi K3.1 Pro open weights: 2.8T parameters, cyber data removed