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Step 3.5 Flash
stepfun/
Stepfun model · Served by DeepInfra · live on the gateway · :free available
Input / 1M
$0.090
Output / 1M
$0.300
Context
256K tokens
Max output
256K tokens
Input
Text
Released
8mo ago
Pricing
Input tokens$0.090 per 1M
Output tokens$0.300 per 1M
Provider list priceExactly what your balance is debited; our fee is charged when you buy credits
About Step 3.5 Flash
StepFun flash lane for quick multimodal reasoning and coding assistance
ReasoningTools
What it supports
- Tool calling (function calling)
- JSON mode and structured output
- Image input (vision)
- Audio input
- Extended reasoning
- Streaming responses
- OpenAI SDK, Anthropic SDK and any OpenAI-compatible client
Make a request
curl https://rapidrouter.ai/api/v1/chat/completions \
-H "Authorization: Bearer $RAPIDROUTER_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "stepfun/step-3.5-flash",
"messages": [{ "role": "user", "content": "Hello" }]
}'Frequently asked
How do I call Step 3.5 Flash through an OpenAI-compatible API?
Point any OpenAI-compatible client at https://rapidrouter.ai/api/v1 with a Rapid Router API key and set the model to stepfun/step-3.5-flash. The chat completions endpoint is https://rapidrouter.ai/api/v1/chat/completions.
What is the context window of Step 3.5 Flash?
Step 3.5 Flash has a context window of 256,000 tokens on Rapid Router, and returns up to 256,000 output tokens per reply.
Is there a free version of Step 3.5 Flash?
Yes. Call stepfun/step-3.5-flash:free and the request is paid for from Rapid Router's sponsored daily pool, within the free tier's daily request limit.
What can Step 3.5 Flash do?
On Rapid Router, Step 3.5 Flash supports tool calling, extended reasoning.