Step 3.5 Flash pricing
Step 3.5 Flash API cost from StepFun — $0.090 per 1M input tokens and $0.300 per 1M output tokens. Cheapest Step tier. Estimate your real monthly bill below, then compare it against every other model.
Fast / cheap 256K context · all prices USD per 1M tokens, list price last verified 2026-06-27.
Step 3.5 Flash capabilities & limits
Representative specs for this tier — confirm exact limits in the StepFun docs.
Call Step 3.5 Flash from your code
The exact model string and endpoint to use. Works with the OpenAI SDK — just point base_url at the URL below.
step-3.5-flashhttps://api.stepfun.com/v1STEP_API_KEYcurl https://api.stepfun.com/v1/chat/completions \
-H "Authorization: Bearer $STEP_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "step-3.5-flash",
"messages": [{"role": "user", "content": "Hello"}]
}'Model strings follow each provider's naming convention; confirm the current id in the StepFun docs before relying on it.
What a Step 3.5 Flash API call actually costs
Blended input + output cost at Step 3.5 Flash's list rates — useful yardsticks before you commit to volume.
Step 3.5 Flash cost calculator
Enter your monthly volume to estimate the Step 3.5 Flash bill. Runs entirely in your browser.
StepFun models — Step 3.5 Flash in context
How Step 3.5 Flash prices against its siblings. Cheapest reference cost first.
| Model | Input /1M | Output /1M | Cost / call* | Context | Type |
|---|---|---|---|---|---|
| Step 3.5 Flash Cheapest Step tier | $0.090 | $0.300 | $0.0004 | 256K | Fast / cheap |
| Step 3.7 Flash Fast tier | $0.200 | $1.15 | $0.0014 | 256K | Fast / cheap |
*Reference cost of one call with 1,000 input + 1,000 output tokens — a neutral yardstick. Use the calculator for your real usage. Cheapest row highlighted.
How Step 3.5 Flash pricing works
Step 3.5 Flash is billed per token: a lower input price of $0.090 per million tokens for everything you send, and a higher output price of $0.300 per million for everything the model generates. To turn that into a real Step 3.5 Flash bill, multiply by your monthly request volume and average prompt/response length — the calculator above does exactly that.
Step 3.5 Flash does not list a separate cached-input rate, so every input token bills at $0.090 per million. If repeated context is a big part of your prompts, a model with prompt caching may end up cheaper in practice.
List prices move fast — always confirm the current numbers on the official StepFun pricing page before relying on them for budgeting.
Step 3.5 Flash pricing FAQ
How much does the Step 3.5 Flash API cost?
Step 3.5 Flash costs $0.090 per 1M input tokens and $0.300 per 1M output tokens. A typical 3K-input / 500-output call works out to about $0.0004.
What is Step 3.5 Flash's context window?
Step 3.5 Flash has a 256K-token context window. Tokens you put in the prompt are billed at the $0.090 per 1M input rate.
Does Step 3.5 Flash charge extra for output tokens?
Yes. Output (generated) tokens cost $0.300 per 1M, versus $0.090 per 1M for input — about 3.3× more, which is normal for LLM APIs.
Is there a cheaper alternative to Step 3.5 Flash?
In the same fast / cheap tier, Gemini 1.5 Flash-8B (Google) is cheaper at $0.037 in / $0.150 out. The overall cheapest model on the market is Gemini 1.5 Flash-8B.