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Step 3.5 FlashOPEN
Step 3.5 Flash is StepFun's most capable open-source foundation model.
Prices update automatically — checked daily against provider list prices.
- $0.15 per 1M tokens, assuming 3 input for 1 output the convention used by Artificial Analysis
- cheaper than 67% of the 191 open-weight models tracked here
Benchmarks & performance
Independent benchmark scores for Step 3.5 Flash, measured by Artificial Analysis. Higher is better.
For the same budget, Step 3.5 Flash delivers 28 times more capability. Open weights also mean you can self-host it and pay nothing per token.
Models at this level cost $0.96 per 1M tokens (median of 14) — this one costs $0.15.
Cheaper and better on this index: GLM 5.3 Flash · DeepSeek V4 Flash 0731 · DeepSeek V4 Flash 0423 and 3 more
About this model
Step 3.5 Flash is an open-weight AI model by Stepfun. You can download and self-host it for free; the prices below are hosted-API list prices, tracked daily, for when you prefer convenience over self-hosting.
Frequently asked questions
What is Step 3.5 Flash?
Step 3.5 Flash is an AI language model from Stepfun. It is open-weight: you can download it and run it on your own hardware, for free. It scores 26.5 on the Artificial Analysis intelligence index.
Is Step 3.5 Flash free?
The weights are free and open — you can self-host Step 3.5 Flash and pay nothing per token. If you prefer a hosted API, list prices are $0.1 per million input tokens and $0.3 per million output tokens.
What is Step 3.5 Flash good at?
Independent benchmarks from Artificial Analysis give it GPQA 82.6%, Humanity's Last Exam 24.5%, Long Context Reasoning 60.3%, SciCode 38.5%, IFBench 66.5%, τ²-Bench 87.4%, Terminal-Bench Hard 32.6%.
Can I self-host Step 3.5 Flash?
Yes. Step 3.5 Flash has open weights, so you can download it and run it on your own GPU or server with tools like Ollama, vLLM or llama.cpp — with no per-token cost.