Compare Kimi K3 from Moonshot AI and Union Alpha (free) from Stealth on key metrics including benchmarks, price, context length, and other model features. Access both models and hundreds of others through the AIHubMix API.
Kimi K3
Union Alpha (free)Kimi K3 is Kimi’s flagship model for long-horizon coding and end-to-end knowledge work, with a 1M-token context window and industry-leading intelligence.
Developed by Stealth, Union Alpha is a multimodal model built for research, coding, and agentic workflows. It delivers frontier-level performance across a broad range of general-purpose tasks. Featuring a massive 262,144 token context window, this model is highly capable of handling extensive and complex tasks.
Prices are per million tokens. Time to First Token and throughput are rolling averages measured on AIHubMix.
Promotional prices show the discounted rate; see each model page for promotion windows.
Daily traffic served through AIHubMix — how demand for each model is trending.
Measured on real AIHubMix traffic, hourly buckets. Gaps mean no traffic in that hour.
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Monthly = daily × 30. Discounted rates applied where a promotion is active.
Kimi K3 accepts 1,048,576 and Union Alpha (free) accepts 262,144 input tokens.
Kimi K3 accepts text, image and video input and supports thinking, function calling and structured outputs; Union Alpha (free) accepts text and image input.
Yes. AIHubMix serves every model on this page behind one OpenAI-compatible endpoint, so switching between them is a one-line change to the model field — no second account, key or SDK.
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