Step 3.5 Flash (Stepfun): live API pricing, context window and the best open-source alternatives, tracked daily by olud.ai.
Prices update automatically — checked hourly against provider list prices.
Independent benchmark scores for Step 3.5 Flash, measured by Artificial Analysis. Higher is better.
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 hourly, for when you prefer convenience over self-hosting.
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 on the Artificial Analysis intelligence index.
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.
Independent benchmarks from Artificial Analysis give it GPQA 82.6%, Humanity's Last Exam 22.6%, Long Context Reasoning 54.3%, SciCode 38.5%, IFBench 66.5%, τ²-Bench 87.4%, Terminal-Bench Hard 32.6%.
It generates about 289.4 tokens per second, with a median 0.75s delay before the first token. Measured independently by Artificial Analysis.
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.