When was Kimi K2 released?

Kimi K2 was released by Moonshot AI on Friday, Jul 11 2025.

Kimi K2 was built by Moonshot AI. Chinese AI company building the Kimi family of models. Founded in 2023, known for long-context and efficient MoE architectures.

What benchmark scores did Kimi K2 get?

Kimi K2 reports 3 tracked benchmark scores — BullshitBench v2: 10%; SWE-Bench Verified: 65.8%; GPQA Diamond: 75.1%. Scores are the figures published at release by Moonshot AI.

What is the context window of Kimi K2?

Kimi K2 has a context window of 128k. That is the maximum amount of input plus output the model can hold in a single request.

How many parameters does Kimi K2 have?

Kimi K2 is reported at 1T parameters.

Is Kimi K2 open source?

Partly. Kimi K2 is an open-weight model: the trained weights are free to download and run locally or on your own infrastructure, but the training data and code are not fully released and the license may restrict some commercial uses. It is not open source in the strict sense.

What came before and after Kimi K2?

Moonshot AI's previous tracked release was Kimi-Dev on Jun 17 2025, 24 days earlier. It was followed by Kimi K2 (0905) on Sep 5 2025.

Kimi K2Open Weight

Released Jul 11 2025

Kimi K2 is an AI model released by Moonshot AI on Friday, Jul 11 2025, 24 days after Kimi-Dev. It is an open-weight model — the trained weights are available to download and run. It is a 1T parameter model with a 128k token context window. Benchmark results (shown below) cover BullshitBench v2, SWE-Bench Verified, and GPQA Diamond.

Available from


Novita	$0.57	$2.30	128K	fp8

USD per 1M tokens

Benchmarks

Coding

SWE-Bench Verified

65.8%

#41 of 57

Reasoning & science

GPQA Diamond

75.1%

#43 of 59

Robustness

BullshitBench v2

10%

#72 of 77

Compare Kimi K2 with

Kimi K2

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About

Kimi K2, released July 11, 2025, was Moonshot AI's open-weight breakout: a trillion-parameter mixture-of-experts model with about 32B active per token, trained with the novel MuonClip optimizer and tuned specifically for agentic tool use rather than chat. At release it was the largest open-weight model ever published.

It scored 65.8% on SWE-Bench Verified and 75.1% on GPQA Diamond — the strongest open-weight coding results of mid-2025 — and its low API pricing made it a popular Claude alternative in agent frameworks. The K2 (0905) refresh doubled the context window to 256K in September 2025, and K2 Thinking added reasoning that November.

Frequently asked questions

: Kimi K2 was released by Moonshot AI on Friday, Jul 11 2025.
: Kimi K2 was built by Moonshot AI. Chinese AI company building the Kimi family of models. Founded in 2023, known for long-context and efficient MoE architectures.
: Kimi K2 reports 3 tracked benchmark scores — BullshitBench v2: 10%; SWE-Bench Verified: 65.8%; GPQA Diamond: 75.1%. Scores are the figures published at release by Moonshot AI.
: Kimi K2 has a context window of 128k. That is the maximum amount of input plus output the model can hold in a single request.
: Kimi K2 is reported at 1T parameters.
: Partly. Kimi K2 is an open-weight model: the trained weights are free to download and run locally or on your own infrastructure, but the training data and code are not fully released and the license may restrict some commercial uses. It is not open source in the strict sense.
: Moonshot AI's previous tracked release was Kimi-Dev on Jun 17 2025, 24 days earlier. It was followed by Kimi K2 (0905) on Sep 5 2025.