Step 3.5 Flash is free on 1 provider today. Permanent free tiers come first, then one-time trials.
| Provider | API model ID | Context | Free limits | Sign-up |
|---|---|---|---|---|
| ModelScope | stepfun-ai/Step-3.5-Flash |
— | 500 requests/day per model | Phone |
Free lists change often. Each provider page shows its full limits and code examples, and every change is logged in the changelog. Want to call it from Claude Code or Cursor? Use the setup generator.