Alternatives

# Best Open-Source the OpenAI API Alternatives in October 2026

> The strongest open-weight alternative to the OpenAI API as of October 2026 is Kimi K3 from Moonshot AI: 11.2 points behind GPT-6 Astra, 3.3× cheaper per token; open weights. Compared against GPT-6 Astra, the OpenAI API's current top model.
- Canonical page: https://noometry.com/alternatives/openai-api/open-source
- Last updated: 2026-10-11
- Title: Best Open-Source the OpenAI API Alternatives (October 2026)

The strongest open-weight alternative to the OpenAI API as of October 2026 is Kimi K3 from Moonshot AI: 11.2 points behind GPT-6 Astra, 3.3× cheaper per token; open weights. Compared against GPT-6 Astra, the OpenAI API's current top model.

Last verified October 11, 2026

1.  ## [Kimi K3](https://noometry.com/models/kimi-k3) Moonshot AI
    
    11.2 points behind GPT-6 Astra, 3.3× cheaper per token; open weights.
    
    Score 59.5, $6 per M tokens blended.[Compare with GPT-6 Astra](https://noometry.com/compare/gpt-6-astra-vs-kimi-k3)
    
2.  ## [GLM-5.3](https://noometry.com/models/glm-5-3) Z.ai (Zhipu)
    
    15.9 points behind GPT-6 Astra, 9.3× cheaper per token; open weights.
    
    Score 54.8, $2.15 per M tokens blended.[Compare with GPT-6 Astra](https://noometry.com/compare/glm-5-3-vs-gpt-6-astra)
    
3.  ## [DeepSeek V4 Pro](https://noometry.com/models/deepseek-v4-pro) DeepSeek
    
    16.4 points behind GPT-6 Astra, 20.2× cheaper per token; open weights.
    
    Score 54.3, $0.99 per M tokens blended.[Compare with GPT-6 Astra](https://noometry.com/compare/deepseek-v4-pro-vs-gpt-6-astra)
    
4.  ## [MiMo-V2.6-Pro](https://noometry.com/models/mimo-v2-6-pro) Xiaomi
    
    20.5 points behind GPT-6 Astra, 36.8× cheaper per token; open weights.
    
    Score 50.3, $0.54 per M tokens blended.[Compare with GPT-6 Astra](https://noometry.com/compare/gpt-6-astra-vs-mimo-v2-6-pro)
    
5.  ## [Inkling-Small](https://noometry.com/models/inkling-small) Thinking Machines Lab
    
    24.3 points behind GPT-6 Astra, 31.4× cheaper per token; open weights.
    
    Score 46.5, $0.64 per M tokens blended.[Compare with GPT-6 Astra](https://noometry.com/compare/gpt-6-astra-vs-inkling-small)
    
6.  ## [Qwen3.5 397B-A17B](https://noometry.com/models/qwen3-5-397b-a17b) Alibaba (Qwen)
    
    24.7 points behind GPT-6 Astra, 14.8× cheaper per token; open weights.
    
    Score 46.0, $1.35 per M tokens blended.[Compare with GPT-6 Astra](https://noometry.com/compare/gpt-6-astra-vs-qwen3-5-397b-a17b)
    
7.  ## [Hy4 preview](https://noometry.com/models/hy4-preview) Tencent
    
    25.5 points behind GPT-6 Astra, 16.0× cheaper per token; open weights.
    
    Score 45.3, $1.25 per M tokens blended.[Compare with GPT-6 Astra](https://noometry.com/compare/gpt-6-astra-vs-hy4-preview)
    
8.  ## [MiniMax-M3](https://noometry.com/models/minimax-m3) MiniMax
    
    27.0 points behind GPT-6 Astra, 38.1× cheaper per token; open weights.
    
    Score 43.8, $0.52 per M tokens blended.[Compare with GPT-6 Astra](https://noometry.com/compare/gpt-6-astra-vs-minimax-m3)
    

More: [All alternatives](https://noometry.com/alternatives/openai-api), [Cheaper](https://noometry.com/alternatives/openai-api/cheaper), [For coding](https://noometry.com/alternatives/openai-api/coding)

## Frequently asked questions

### What is the best alternative to the OpenAI API?

The strongest open-weight alternative to the OpenAI API as of October 2026 is Kimi K3 from Moonshot AI: 11.2 points behind GPT-6 Astra, 3.3× cheaper per token; open weights. Compared against GPT-6 Astra, the OpenAI API's current top model.

### How were these alternatives chosen?

Each is the highest-ranked model from a different provider with downloadable weights, compared on the Noometry Index against GPT-6 Astra.