# Step 5 Preview: AI model fact sheet

- **Provider:** stepfun
- **Released:** 2026-10-08
- **Context window:** 1,000,000 tokens
- **Max output:** 64,000 tokens
- **Parameters:** 600B (27B active)
- **API pricing:** $1.00 / 1M input, $2.70 / 1M output
- **OpenRouter ID:** stepfun/step-5-preview
- **Capabilities:** conversation, reasoning, code-generation, analysis, function-calling

StepFun’s reasoning model for coding and long-running agent tasks. Its mixture-of-experts architecture activates 27B of 600B parameters and accepts text, images and video across a one-million-token context.

Source: real side-by-side outputs, pricing and specs at https://rival.tips/models/step-5-preview