Step 5 Preview is StepFun's flagship model for agentic work, built on a sparse Mixture-of-Experts architecture (27B active / 600B total parameters). It performs strongly in software engineering and professional...
With CoreAI, you can start chatting with StepFun: Step 5 Preview instantly — no separate subscription needed. CoreAI lets you chat with StepFun: Step 5 Preview alongside 300+ other AI models from Stepfun and other providers like OpenAI, Anthropic, Google, Meta, and more.
Among the 449 chat models on CoreAI, StepFun: Step 5 Preview ranks #119 by context window — 1M tokens, roughly 750,000 words or 1,500 pages of text in a single conversation. On price, it is the #129 cheapest of 213 standard-tier models by input cost. Released 2026-10-08, it is one of the 1 newest additions to the catalog. It supports step-by-step reasoning (thinking mode) and accepts image input.
Every model in this table is available on CoreAI — open the web app and run the same prompt through StepFun: Step 5 Preview and StepFun: Step 3.7 Flash side by side to judge with your own eyes.
A typical question (about 1,000 tokens in, 500 out) runs $0.00235 on StepFun: Step 5 Preview's raw per-token rates; a heavy session with a 50K-token document costs about $0.064. On CoreAI you don't juggle these numbers — one subscription covers StepFun: Step 5 Preview and 300+ other models under a plan usage limit, with no API keys. See plans.
StepFun: Step 5 Preview handles 1M tokens of context — roughly 750,000 words, or about 1,500 pages of text in one conversation.
StepFun: Step 5 Preview's underlying rates are $1 per 1M input tokens and $2.7 per 1M output tokens. On CoreAI it is included in one subscription alongside 300+ models, so there is no per-token billing to manage.
Yes — StepFun: Step 5 Preview accepts image input, so you can attach screenshots, photos or diagrams and ask questions about them.
Yes. StepFun: Step 5 Preview can work through problems step by step before answering; on CoreAI you can toggle thinking mode per message.
Open the CoreAI web app or the iOS/Android app, pick StepFun: Step 5 Preview in the model selector, and chat — no API key, no per-token billing. One subscription covers StepFun: Step 5 Preview and 300+ other models.
The closest alternatives on CoreAI are StepFun: Step 3.7 Flash, Anthropic: Claude Sonnet 5.5, DeepSeek: DeepSeek V4 Flash Latest — similar tier and capability. The fastest way to choose is running one prompt through them side by side in CoreAI's Compare view.
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