StepFun logo

StepFun: Step 3.5 Flash 2603

StepFun flash model for efficient multimodal reasoning, coding, and tool use

Source-linked Open weights Released 2026-04-02
API record Report
InputT
OutputT
Input price$0.1/M
Output price$0.3/M
Context256K
Max output256K
Providers6
Inference availability

Providers

Provider-specific identifiers, limits, and listed prices per million tokens. Every row links back to the provider's own documentation.

Report a price
Providers offering Step 3.5 Flash 2603
ProviderProvider model IDContextMax outputInputOutputCache readCapabilitiesDocs
StepFun Step Plan (Global) step-3.5-flash-2603 256K 256K ReasoningTools Docs ↗
StepFun Step Plan (China) step-3.5-flash-2603 256K 256K ReasoningTools Docs ↗
NanoGPT stepfun-ai/step-3.5-flash-2603 262.144K 65.536K $0.1 $0.3 $0.05 Reasoning Docs ↗
EmpirioLabs AI step-3-5-flash-2603 256K 131.072K $0.1 $0.3 $0.02 ReasoningToolsJSON Docs ↗
StepFun (Global) step-3.5-flash-2603 256K 256K $0.1 $0.3 $0.02 ReasoningTools Docs ↗
StepFun (China) step-3.5-flash-2603 256K 256K $0.1 $0.3 $0.02 ReasoningTools Docs ↗

Capability badges appear only where the provider catalog explicitly lists support. A blank cell means the source is silent, not that the feature is absent.

Listed rates

Price across providers

Input price per million tokens as published by each provider. Bars are drawn from listed rates only — no traffic weighting, since the catalog observes no requests.

Lowest input $0.1/M

Across 4 priced providers

Median input $0.1/M

Midpoint of listed rates

Highest input $0.1/M

Same as the lowest listed rate

Output range $0.3 – $0.3

Per million output tokens

NanoGPT $0.1/M
EmpirioLabs AI $0.1/M
StepFun (Global) $0.1/M
StepFun (China) $0.1/M
Cost calculator

Estimate a workload

$0.00
Excludes taxes, non-token charges, and tiered discounts.

4 providers list the identical $0.1 input rate, so price alone will not separate them — compare context limits, max output, and capabilities above.

Context limits also differ by provider, from 256K to 262.144K tokens. Compare the provider table above before choosing on price alone.

Specification

Capabilities

Recorded from the source catalog and provider listings.

Reasoning Yes
× Tool calling No
× Structured output No
× Attachments No
× Vision input No
Open weights Yes
Creator
StepFun
Model family
Not documented
Knowledge cutoff
2025-01
License
Not documented
Release date
2026-04-02
Model ID
stepfun/step-3.5-flash-2603

Weights: Hugging Face ↗

Published evaluations

Benchmarks

Every result stays attached to its source, version, metric and harness. Scores from different versions are never merged, and the profile below plots each benchmark against its own population rather than on a shared scale.

Benchmark registry
Benchmark profile
SciCodeSciCode AA Coding IndexArtificial Analysis Coding Index Terminal-Bench…Terminal-Bench Hard This model — SciCode: 38.5 percent correct (79.6th percentile) This model — Artificial Analysis Coding Index: 34.6 index (90.4th percentile) This model — Terminal-Bench Hard: 32.6 success rate (88.6th percentile)

Each axis is this model's percentile among the 3 benchmarks it has published results for, measured against every other model with a score on that same benchmark. Percentiles are used because benchmarks do not share a scale — a 60 on one is not a 60 on another. Hover any point for the raw score.

SciCode percent correct · 2026-06-02 Source ↗
SciCode #6 of 27
Artificial Analysis Coding Index index · 2026-06-02 Source ↗
Artificial Analysis Coding Index #3 of 26
Terminal-Bench Hard success rate · 2026-06-02 Source ↗
Terminal-Bench Hard #3 of 22

Each strip shows every published score for that benchmark, with this model marked. The lighter shape behind the ticks is the density of results, and the dashed line is the median.

Cost against capability

Price and performance

Listed input price plotted against SciCode, the benchmark with the widest published coverage that this model appears in.

0 23 45 $0.1 $1 $10 Qwen3-Coder 30B-A3B Instruct — $0.45/M, score 27.8 Qwen3 Max — $1.2/M, score 38.3 DeepSeek-R1 — $0.7/M, score 35.7 Gemini 2.5 Flash — $0.3/M, score 39.4 Gemini 2.5 Flash-Lite — $0.1/M, score 19.3 Gemini 2.5 Pro — $1.25/M, score 42.8 Llama-3.3-70B-Instruct — $0.1/M, score 26.0 Devstral 2 — $0.4/M, score 33.1 Mistral Large 2.1 — $2/M, score 29.2 Mistral Large 3 — $0.5/M, score 36.2 Mistral Medium 3 — $0.4/M, score 33.1 Mistral Small 4 — $0.15/M, score 38.0 GPT-4 Turbo — $10/M, score 31.9 GPT-4o (2024-05-13) — $5/M, score 30.9 GPT-4o (2024-08-06) — $2.5/M, score 33.1 GPT-4o (2024-11-20) — $2.5/M, score 33.3 GPT-4o mini — $0.15/M, score 22.9 GPT-5-Codex — $1.1/M, score 40.9 Sonar — $1/M, score 22.9 Sonar Pro — $3/M, score 22.6 Step 3.5 Flash — $0.1/M, score 40.4 Step 3.5 Flash 2603 — $0.1/M, score 38.5 Step 3.7 Flash — $0.185/M, score 40.0 GLM-4.5 — $0.6/M, score 34.8 GLM-4.5-Air — $0.2/M, score 30.6 GLM-4.5V — $0.6/M, score 22.1 GLM-4.6 — $0.6/M, score 38.4 Step 3.5 Flash 2603 Input price per million tokens (log scale) Percent correct

The stepped line is the efficient frontier: at each price, the best score available for that money or less. A model sitting on it is not being beaten by anything cheaper. Price is log-scaled because listed rates span four orders of magnitude. Only models with both a listed price and a score on this benchmark can appear.

Catalog activity

Change log

Field-level changes detected between successful source imports.

Full change log
No changes recorded

This record has not changed within the retained import history.

Provenance

Sources & verification

Every figure on this page traces back to one of these records.

Methodology
Public API

Use this record

Fetch the complete source-linked model record. No key, no account, no rate-limited tier.

API documentation
Endpoint
GET https://model.kyssta.lol/api/v1/models/stepfun/step-3.5-flash-2603
curl
curl "https://model.kyssta.lol/api/v1/models/stepfun/step-3.5-flash-2603"
Common questions

Frequently asked questions

Answered directly from the stored record — nothing here is generated beyond the catalog's own fields.

What is Step 3.5 Flash 2603?

StepFun flash model for efficient multimodal reasoning, coding, and tool use. It is published by StepFun and catalogued here from Models.dev.

How much does Step 3.5 Flash 2603 cost?

Listed input pricing starts at $0.1 per million tokens from NanoGPT.

What is the context length of Step 3.5 Flash 2603?

Step 3.5 Flash 2603 accepts up to 256K tokens of context and returns up to 256K output tokens.

Does Step 3.5 Flash 2603 support tool calling and structured output?

Provider catalogs list support for reasoning.

Which providers serve Step 3.5 Flash 2603?

6 providers list this model: StepFun Step Plan (Global), StepFun Step Plan (China), NanoGPT, EmpirioLabs AI, StepFun (Global), StepFun (China).

Are the weights for Step 3.5 Flash 2603 open?

Yes. The weights are published and downloadable from Hugging Face.

When was Step 3.5 Flash 2603 released?

The catalog records a release date of 2026-04-02, last verified Sep 11, 2026.

More models from StepFun

View all →