Flash — fastest and cheapest, lighter reasoningOpen Weights

Step 3.5 Flash Pricing

StepFun · stepfun-step-3-5-flash

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Input / 1M tokens

$0.100

Output / 1M tokens

$0.300

Context window

262,144 tokens

≈ 350 pages of text

Max output

65,536 tokens

What it costs in practice

Typical request (1,200 in + 400 out tokens)$0.0002

1,000 requests / month$0.24/mo 10,000 requests / month$2.40/mo 100,000 requests / month$24.00/mo

Estimate your own workloadOpens the calculator with Step 3.5 Flash preloaded — adjust volume and token counts there.

Price history

List price per 1M tokens since we started tracking in Jun 2026. Each step marks a price change — hover a point for the exact date and rate.

What it excels at

Low-cost open-weights model with 256k context suited for high-volume text processing and local or self-hosted deployments.

The business tradeoff

Limited ecosystem, documentation, and third-party tooling; reasoning depth and output consistency lag behind established closed models of similar size.

Same tier from other providers

GPT-5.4 NanoOpenAI$0.0007/ typical request Claude Haiku 4.5Anthropic$0.0032/ typical request Gemini 3.5 FlashGoogle$0.0054/ typical request

Head-to-head

Step 3.5 Flash vs GPT-5.4 Nano →Step 3.5 Flash vs Claude Haiku 4.5 →Step 3.5 Flash vs Gemini 3.5 Flash →

Vendor list rates, as of Jun 29, 2026 · source: openrouter · per-request examples assume 1,200 input + 400 output tokens.