Step 3.5 Flash is StepFun's most capable open-source foundation model. Built on a sparse Mixture of Experts (MoE) architecture, it selectively activates only 11B of its 196B parameters per token....
With CoreAI, you can start chatting with StepFun: Step 3.5 Flash instantly — no separate subscription needed. CoreAI lets you chat with StepFun: Step 3.5 Flash alongside 300+ other AI models from Stepfun and other providers like OpenAI, Anthropic, Google, Meta, and more.
StepFun: Step 3.5 Flash holds the #157 spot for context size out of 392 chat models in the CoreAI catalog — 262K tokens, roughly 196,608 words or 393 pages of text in a single conversation. On price, it is the #48 cheapest of 128 budget-tier models by input cost. It joined the catalog on 2026-01-29. It supports step-by-step reasoning (thinking mode).
Every model in this table is available on CoreAI — open the web app and run the same prompt through StepFun: Step 3.5 Flash 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 $0.00025 on StepFun: Step 3.5 Flash's raw per-token rates; a heavy session with a 50K-token document costs about $0.007. On CoreAI you don't juggle these numbers — one subscription covers StepFun: Step 3.5 Flash and 300+ other models under a plan usage limit, with no API keys. See plans.
StepFun: Step 3.5 Flash handles 262K tokens of context — roughly 196,608 words, or about 393 pages of text in one conversation.
StepFun: Step 3.5 Flash's underlying rates are $0.1 per 1M input tokens and $0.3 per 1M output tokens. On CoreAI it is included in one subscription alongside 300+ models, so there is no per-token billing to manage.
No — StepFun: Step 3.5 Flash is text-only. If you need image understanding, its budget-tier peers with vision are listed in the comparison table above.
Yes. StepFun: Step 3.5 Flash 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 3.5 Flash in the model selector, and chat — no API key, no per-token billing. One subscription covers StepFun: Step 3.5 Flash and 300+ other models.
The closest alternatives on CoreAI are StepFun: Step 3.7 Flash, NVIDIA: Nemotron 3.5 Lightning, inclusionAI: Ling-2.6-flash — similar capability. The fastest way to choose is running one prompt through them side by side in CoreAI's Compare view.
Chat with StepFun: Step 3.5 Flash and 300+ other AI models — all in one app.