# Moonshot's Kimi K3.1 Pro Debuts, Weights Due Nov 4

> The reasoning-focused model is live via API now, with Moonshot promising full open weights in early November.

Published by The Open Weights on Oct 24, 2026. Canonical: https://theopenweights.com/news/kimi-k3-1-pro-u4rd

## Key facts

- Company: Moonshot AI
- Model: Kimi K3.1 Pro
- Version: K3.1 Pro
- Category: Text / LLM
- Modalities: Text / LLM, Reasoning
- License: Other (Open weights, commercial use allowed)
- Significance: notable
- Published: 2026-10-24
- Last verified: 2026-10-24
- Canonical URL: https://theopenweights.com/news/kimi-k3-1-pro-u4rd

Moonshot AI has introduced **Kimi K3.1 Pro**, a text and reasoning model that is available first through the company's API, with full open weights promised by November 4, 2026. The staggered rollout — API access now, downloadable weights later — gives developers an early look while the release is formalized ([announcement details](https://simonwillison.net/2026/Oct/23/kimi-k31-pro/)).

The model lands in the LLM-text category with an emphasis on reasoning, continuing Moonshot's push to position Kimi as a serious contender among open-leaning labs. The company has not yet published parameter counts, context-window figures, or benchmark results, and the license is listed only as "other" pending the weights drop.

## Why it matters

The gap between an API launch and an open-weights release is where a lot of the real-world story plays out. A few things worth watching:

- Whether the promised November 4 weights arrive on schedule, and under what license terms.
- How K3.1 Pro's reasoning performance compares to other recent open releases once independent testing is possible.
- What context length and architecture Moonshot ultimately confirms.

For now, teams curious about Kimi can evaluate the model through the API while waiting for the open release. The authoritative blog post is available at [kimi.ai](https://www.kimi.ai/blog/kimi-k3-1-pro), and we'll update this story as specs and licensing details are confirmed.

## Get the model

- [Announcement](https://simonwillison.net/2026/Oct/23/kimi-k31-pro/)

## Sources

- [Introducing Kimi K3.1 Pro](https://simonwillison.net/2026/Oct/23/kimi-k31-pro/) — Announcement, Oct 23, 2026

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Source: The Open Weights (https://theopenweights.com/). Aggregated and written by Claude, curated by humans. Cite as: "Moonshot's Kimi K3.1 Pro Debuts, Weights Due Nov 4", The Open Weights, Oct 24, 2026, https://theopenweights.com/news/kimi-k3-1-pro-u4rd