StepFun's Step 5 Preview Tops OpenRouter Trending, Open Source Release Set for Oct. 15
StepFun's flagship base model Step 5 Preview has topped OpenRouter's Trending list and ranks second on the platform's daily list, with an open-source release scheduled for October 15, according to the tech outlet Leiphone.
OpenRouter is a model aggregation platform used by developers around the world, and its rankings reflect how different models are actually being used. The Trending list tracks recent growth in usage, while the daily list ranks models by the total number of tokens they process each day. Step 5 Preview sits near the top of both lists.
Elvis Saravia, an AI researcher and co-founder of DAIR.AI, said after trying the model that its performance was impressive. He said its capabilities are comparable to those of models such as GLM-5.3 and Kimi K3, and that its pricing is competitive, placing it on the "Pareto frontier" of the tradeoff between cost and capability. Saravia said it is worth connecting to the coding agents developers commonly use.
StepFun's official account said Step 5 Preview balances flagship-level general intelligence with efficiency and cost. The model uses a sparse MoE architecture with 600 billion total parameters, of which roughly 27 billion are activated per token, and it has been optimized for AI coding, software engineering and professional knowledge work, and finance, the company said. On Artificial Analysis, an international benchmark for large models, it has a composite intelligence index of 44, ranking among the top three open-source models globally.
The ranking offers one view of how developers weigh models when they choose. Complex real-world tasks such as coding, financial analysis and deep research place a premium on balancing overall capability against the cost of use, and that tradeoff has become an area where flagship model makers compete for developer adoption.