Step 5 Preview

Name: StepFun: Step 5 Preview
Brand: stepfun
SKU: stepfun/step-5-preview
Price: 1.1 USD
Availability: InStock

stepfun/step-5-preview

about 0.2¢ a message

A typical message: about 500 tokens you send and 500 it writes.

$1.10 per 1M tokens you send$2.97 per 1M tokens it writesreads 1M tokens at once

Published capabilitiesreads imagestool callingjson schema

Chat with Step 5 Preview Call it from code Lock this price

About

Step 5 Preview is StepFun's flagship model for agentic work, built on a sparse Mixture-of-Experts architecture (27B active / 600B total parameters). It performs strongly in software engineering and professional...

In StepFun's words.

Try it here

Cmd+Enter sends

Whatever it says appears here.

Published facts

What the upstream's catalog says about this world, with its price as billed here.

Context window: 1,048,576 tokens
Longest answer: 64,000 tokens
Input, per 1M tokens: $1.10upstream $1.00
Output, per 1M tokens: $2.97upstream $2.70
Cached input, per 1M: $0.11upstream $0.10
Margin: +10%
Reads: text and images
First listed: 2026-10-08

Price and latency history as JSON: GET /api/planet/history?id=stepfun/step-5-preview.

Measured here

Price

it writes $2.97 you send $1.10max $2.97

2026-10-08now

The price per 1M tokens as billed here: each rate the upstream published, as this deployment observed it, with today's markup applied where the operator set one. First seen 2026-10-08, 1 change since. Nothing before the first observation is shown, because nothing before it was seen.

Call it

One OpenAI compatible endpoint, this model's id, and an am_live_ key from the dashboard. Or try it in chat first, no key needed.

curl https://useantimatter.com/v1/chat/completions \
  -H "Authorization: Bearer $ANTIMATTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "stepfun/step-5-preview", "messages": [{"role": "user", "content": "Hello"}]}'

Everything else is in the docs.

Embed this

A badge with this world's live price per million tokens, as billed here, for a README or a site. It links back to this page.

<a href="https://useantimatter.com/planet/stepfun/step-5-preview"><img src="https://useantimatter.com/api/badge/price?id=stepfun%2Fstep-5-preview" alt="Step 5 Preview price on Antimatter" height="28"></a>

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Observed	You send	It writes	Cache read	Cache write
2026-10-08	$1.10	$2.97	$0.055	unpublished
2026-10-15	$1.10	$2.97	$0.11	unpublished