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.