Type
Spec
Rate
Input
per 1M prompt tokens
$0.20
Output
per 1M generated tokens
$1.15
Implicit cache read
per 1M cached input tokens
$0.04
Web Search (Linkup)
per call when invoked
$0.013
Step 3.7 Flash and Step 3.5 Flash 2603 side by side: specs, capabilities, parameters, and live pricing from the EmpirioLabs catalog.
StepFun Text GenerationStep 3.7 Flash and Step 3.5 Flash 2603 are both StepFun models in the Text Generation category, available through the EmpirioLabs API.
| Spec | Step 3.7 Flash | Step 3.5 Flash 2603 |
|---|---|---|
| Model ID | step-3-7-flash | step-3-5-flash-2603 |
| Author | StepFun | StepFun |
| Released | May 28, 2026 | Apr 2, 2026 |
| Context window | 256K tokens | 256K tokens |
| Max output | 131,072 tokens | 131,072 tokens |
| Input | Text Image Video | Text |
| Output | Text | Text |
| Structured output | JSON Mode | Not supported |
| Region | International | International |
| Endpoints | POST /v1/chat/completions POST /v1/responses POST /v1/messages POST /v1beta/models/step-3-7-flash:generateContent | POST /v1/chat/completions POST /v1/responses POST /v1/messages POST /v1beta/models/step-3-5-flash-2603:generateContent |
| Capabilities |
Live rates from the EmpirioLabs catalog for both models. Each rate card always matches what the API charges.
Request parameters each model lists on EmpirioLabs, with the allowed values or range where one applies. A dash marks a parameter the model does not list.
| Parameter | Step 3.7 Flash | Step 3.5 Flash 2603 |
|---|---|---|
| temperature | 0 to 2 Default: 0.5 | 0 to 2 Default: 0.5 |
| top_p | 0.01 to 1 Default: 0.9 | 0.01 to 1 Default: 0.9 |
| max_tokens | 1 to 131072 Default: 4096 | 1 to 131072 Default: 4096 |
| stop | array | array |
| frequency_penalty | -2 to 2 Default: 0 | -2 to 2 Default: 0 |
| reasoning_effort | low, medium, high Default: low | low, high Default: low |
| response_format | object | - |
| reasoning_format | general, deepseek-style Default: general | general, deepseek-style Default: general |
| tools | array | array |
| tool_choice | string | string |
| web_search_linkup | boolean Default: false | boolean Default: false |
| disable_formatting | boolean Default: false | boolean Default: false |
Supports text, image, and video input with 256K context, function tools, JSON object mode, reasoning_effort low, medium, or high, and optional Linkup web search. Video input supports MP4 under 128 MB, with clips under 5 minutes recommended.
Text-only agent model with 256K context, function tools, prompt-cache billing, reasoning_effort low or high, and optional Linkup web search.
Step 3.7 Flash serves the OpenAI-compatible Chat Completions API. Point any OpenAI SDK at https://api.empiriolabs.ai/v1 with your EmpirioLabs API key and use the model id step-3-7-flash. Both models are called through the same endpoint. Set model to step-3-7-flash or step-3-5-flash-2603. Get an API key from the EmpirioLabs dashboard.
curl https://api.empiriolabs.ai/v1/chat/completions \
-H "Authorization: Bearer $EMPIRIOLABS_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "step-3-7-flash",
"messages": [
{"role": "user", "content": "Write a haiku about the ocean."}
]
}'Step 3.7 Flash is the newer release (May 28, 2026); Step 3.5 Flash 2603 was released on Apr 2, 2026. Both models have a context window of 256K tokens. Input types only Step 3.7 Flash accepts: Image, Video. The specs, rate cards, and parameters on this page come from the live EmpirioLabs catalog.
Step 3.7 Flash is the newer release (May 28, 2026); Step 3.5 Flash 2603 was released on Apr 2, 2026.
Step 3.5 Flash 2603 lists the lower rate for Input (per 1M prompt tokens) and Output (per 1M generated tokens). Both live rate cards are on this page and always match what the API charges.
Yes. Both models use POST /v1/chat/completions with the same EmpirioLabs API key, so most integrations switch by changing the model value. Check the parameters table on this page first if you rely on a model-specific parameter.
Yes. Open each model in the EmpirioLabs playground and run the same prompt on both, with the parameters the API exposes.
Check out our pricing or reach out if you want your own model deployed on our stack.