Open-Source Alternatives to 
o3 Pro
The best open-weight, self-hostable alternatives to o3 Pro in 2026 — compared on price, context window and capabilities. Run them locally and cut API costs.
Refreshed from live data · olud.ai
The best open-weight alternatives to o3 Pro
o3 Pro is a proprietary, API-only model. These open-weight models can be self-hosted, run offline and used at a fraction of the cost — here's how the top ones stack up.
Step 3.7 Flash Open
Within 2.2 pts of o3 Pro on the Artificial Analysis intelligence index · 69.6× cheaper per million output tokens
Step 3.7 Flash is StepFun's latest high-efficiency multimodal Mixture-of-Experts model. It pairs a 196B-parameter language backbone with a vision encoder for native image and video understanding, activating roughly 11B parameters...
Step 3.7 Flash vs o3 Pro →Mistral Medium 3.5 Open
Within 2.6 pts of o3 Pro on the Artificial Analysis intelligence index · 10.7× cheaper per million output tokens
Mistral Medium 3.5 is a dense 128B instruction-following model from Mistral AI. It supports text and image inputs with text output, and is designed for agentic workflows, coding, and complex...
Mistral Medium 3.5 vs o3 Pro →See the full open-source leaderboard
Live ranking of open-weight models with pricing, context windows and capabilities.
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