Step 3.7 Flash

Step 3.7 Flash is StepFun's open-weight, high-speed multimodal reasoning model, a sparse mixture-of-experts with 198B total and 11B active parameters.

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input · usd / 1m tok

$0.20

output · usd / 1m tok

$1.15

context window

262.14ktokens

modalities · in → out

pricing

base api ratesusd per 1m tokens

input: $0.20
output: $1.15
cache read: $0.04

providers

StepFun hosts Step 3.7 Flash. Impossibl routes your request intelligently and handles failover automatically when a provider is down.

StepFun

specifications

takes text and image in, gives text outstepfun/step-3.7-flash

creatorStepFun
model typeText generation
context window262,144 tokens
maximum outputnot published
input
takes text and image in, gives text out
outputtext
tool callingnot verified
releasedmay 29, 2026
endpoint/v1/chat/completions

unknown means the public catalog does not establish that fact. a model's documented capabilities can differ from what a particular api supports. see the model documentation for integration details.

try it · your prompt, this model, live

# responses API
import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["IMPOSSIBL_API_KEY"],
    base_url="https://api.impossibl.com/v1",
)

resp = client.responses.create(
    model="stepfun/step-3.7-flash",
    input="▌",
)
print(resp.output_text)

edit the prompt, then run

# responses API
import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["IMPOSSIBL_API_KEY"],
    base_url="https://api.impossibl.com/v1",
)

resp = client.responses.create(
    model="stepfun/step-3.7-flash",
    input="▌",
)
print(resp.output_text)

edit the prompt, then run

benchmarks

benchmark results are not available for this model yet.

compare Step 3.7 Flash with other models

frontier labs and open weights, best-ranked firstusd / 1m tok · in / out

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frequently asked questions

What is Step 3.7 Flash?

Step 3.7 Flash is StepFun's open-weight, high-speed multimodal reasoning model, a sparse mixture-of-experts with 198B total and 11B active parameters. It takes text and image input over a 256K context, reasons at a selectable effort level before answering, and is tuned for agent, coding and tool-calling workloads.

How much does Step 3.7 Flash cost?

Step 3.7 Flash costs $0.20 per million input tokens and $1.15 per million output tokens through the Impossibl API. Cache reads cost $0.04 per million tokens. All rates are in USD.

view the pricing table ↑

What is the context length of Step 3.7 Flash?

Step 3.7 Flash has a 262,144-token context window through the Impossibl API.

What inputs and outputs does Step 3.7 Flash support?

Step 3.7 Flash accepts text and image as input. Step 3.7 Flash returns text.

How do I use Step 3.7 Flash through an API?

Step 3.7 Flash is available through the Impossibl API. Use stepfun/step-3.7-flash as the model identifier with /v1/chat/completions. The quickstart explains how to create an API key and send your first request.

follow the api quickstart →

When was Step 3.7 Flash released?

StepFun released Step 3.7 Flash on May 29, 2026.

Creator release announcement ↗

this page describes Step 3.7 Flash as listed by the impossibl public api. prices and availability come from that catalog, refreshed here every five minutes. this is an impossibl offering, not a comparison of independent hosting-provider quotes. model descriptions and release dates, where available, use the creator sources linked under the answers above.

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