Step 3.5 Flash 2603

step-3.5-flash-2603

CHAT Light tier Reasoning Open-weight

Step 3.5 Flash 2603 (step-3.5-flash-2603) is a chat model from stepfun with a 256K-token context window; open-weight; capabilities tools, reasoning; input text; output text.

256KContext

256KMax output

$0.10461$ / 1M in

Pricing

Input: $0.10461 / 1M tokens
Output: $0.31384 / 1M tokens
Currency: USD
Note: Indicative US list price — verify with the vendor.

Indicative US list price — a reference only, verify with the vendor. Source: models-dev. Last verified 2026-10-30.

Specifications

Context window: 256,000 tokens (256K)
Max output: 256,000 tokens
Weights: Open-weight
Input modalities: text
Output modalities: text
Knowledge cutoff: 2025-01
Release date: 2026-04-02

Capabilities

tools reasoning

Provenance

models-dev

Last verified: 2026-10-30

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