# Kimi K2 Kimi K2 is an AI model released by Moonshot AI on Jul 11 2025. It has 1T parameters, a 128k context window and open weight. At release it scored 10% on BullshitBench v2, 75.1% on GPQA Diamond and 65.8% on SWE-Bench Verified. ## Facts | Field | Value | | --- | --- | | Model | Kimi K2 | | Developer | Moonshot AI | | Release date | Friday, Jul 11 2025 | | Licensing | Open Weight | | Parameters | 1T | | Context window | 128k | ## Benchmark scores published at release | Benchmark | Score | What it measures | | --- | --- | --- | | BullshitBench v2 | 10% | Given a confidently-worded but nonsensical prompt, does the AI spot that it makes no sense and push back — instead of playing along and inventing an answer? The score is how often it clearly called out the nonsense. Higher is better. | | SWE-Bench Verified | 65.8% | Real coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | | GPQA Diamond | 75.1% | Graduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | ## About Kimi K2 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. ## Questions and answers ### When was Kimi K2 released? Kimi K2 was released by Moonshot AI on Friday, Jul 11 2025. ### Who made Kimi K2? 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. --- Canonical page: https://aireleasetracker.com/model/moonshot/kimi-k2 Full dataset: https://aireleasetracker.com/llms-full.txt · JSON: https://aireleasetracker.com/models.json Source: AI Release Tracker (https://aireleasetracker.com). Benchmark scores are the figures published by the releasing lab at launch.