Last refreshed 2026-06-29. Next refresh: weekly.
Why use Step 3.5 Flash on OpenRouter?
OpenRouter offers Step 3.5 Flash with pay-as-you-go pricing at $0.10/1M input tokens. OpenRouter is a multi-provider LLM aggregator offering unified API access to 300+ models from all major labs and emerging providers, with automatic failover for reliability.
Input / 1M
$0.10
Output / 1M
$0.30
Cache
Not sourced
Batch
Not sourced
Setup recipe
Docs fallbackInstall
Use the provider REST API or SDKAuth
Create a provider API keyCall
model: stepfun/step-3.5-flashModel ID
stepfun/step-3.5-flashRequest example
Curated snippets for this provider are not sourced yet. Use OpenRouter documentation with model ID
stepfun/step-3.5-flash.Gotchas
- Use provider model ID "stepfun/step-3.5-flash", not the LLMReference slug "step-3.5-flash".
Pricing
| Type | Price (per 1M) |
|---|---|
| Input tokens | $0.10 |
| Output tokens | $0.30 |
Capabilities
Reasoning
About Step 3.5 Flash
Step 3.5 Flash is StepFun's most capable open-source foundation model. Its sparse Mixture of Experts architecture activates only 11B of 196B total parameters per token, making it highly efficient at long contexts. Achieves 60.47% on SWE-Bench Verified and 56.2% on SWE-Pro, competing with frontier closed models on agentic coding benchmarks. Supports 256K token context.
Get Started
Model Specs
Released2026-01-29
Parameters196B (11B active)
Context256k
ArchitectureMixture of Experts