Kimi K3.1 Pro

Kimi K3.1 Pro is a large language model from the Beijing company Moonshot AI, the first in its K3.1 series, released on 23 October 2026 on Kimi.ai, Kimi Work, Kimi Code and the Kimi API. Moonshot describes it as a post-trained version of Kimi K3 with much more reinforcement-learning compute, in the 3-trillion-parameter class, with a context window of 1,048,576 tokens. A second version, Kimi K3.1 Pro Highspeed, runs two to three times faster at twice the price.

## What it does

Moonshot pitches K3.1 Pro at coding agents, financial research, 3D creation and other multi-step agentic work. It reports 65.7% on Terminal-Bench 4.0, a test of coding agents working on constrained terminal tasks, and 61.2% on its own long-horizon coding benchmark against 55.95% for K3; those are Moonshot's evaluations, so no score is stored here. Artificial Analysis places it fourth of 215 models on its Intelligence Index, with a score of 55, and measured about 80.7 output tokens per second.

The API price is $2.00 per million input tokens and $10.00 per million output tokens, with cached input at $0.20; Highspeed costs $4.00 and $20.00. Writing to the cache costs $2.00 per million tokens for five minutes and $4.00 for an hour on the standard model. On the same pricing page Moonshot says the K2 series closes to new users on 31 October 2026 and will be retired by the end of December, so teams still building on K2 have a migration to plan.

## Who it is for

The model suits teams that want a long-context coding and agent model at a lower list price than the largest proprietary models, and that may later want to run the weights themselves. Moonshot says the full weights will be released by 4 November; until then it is an API and app model, and Artificial Analysis still labels it proprietary. Enterprise administrators must switch it on for their workspace, as it is off by default.

## Key facts

**Maker:** Moonshot AI **Released:** 23 October 2026 **Context:** 1,048,576 tokens **Price:** $2.00 input, $10.00 output, $0.20 cached input per 1M tokens (Highspeed $4.00 and $20.00) **Weights:** promised by 4 November 2026, licence not named **Predecessor:** Kimi K3; K2 series retired by end of December 2026

Not yet independently verified: Moonshot's blog says the model is available today but prints no date, so the 23 October release rests on its pricing page banner and Artificial Analysis, which lists it as released in October 2026. The weights are promised by 4 November under a licence not yet named, and the benchmark results are Moonshot's own. We will update this when it can be confirmed, and remove this note.