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Models/StepFun

Step 3.5 Flash

StepFun flash lane for quick multimodal reasoning and coding assistance

Source-linked Open weights Released 2026-01-29
API data Report
Input modalitiesT
Output modalitiesT
Input price$0.1/1M tokens
Output price$0.3/1M tokens
Context window256K
Max output256K
Overview

Capabilities and specifications

✓ Reasoning Yes
✓ Tool calling Yes
? Structured output Unknown
× Attachments No
× Vision input No
✓ Open weights Yes
Creator
StepFun
Model family
Not documented
Knowledge cutoff
2025-01
License
Not documented
Release date
2026-01-29
Model ID
stepfun/step-3.5-flash
Inference availability

Provider pricing and availability

Provider-specific identifiers, limits, and prices per million tokens.

Report a price
Providers offering Step 3.5 Flash
ProviderProvider model IDContextInputOutputCache readCapabilitiesSource
Qiniu stepfun/step-3.5-flash 64K Not listed Not listed - Not listed Docs
StepFun Step Plan (Global) step-3.5-flash 256K Not listed Not listed - ReasoningTools Docs
Nvidia stepfun-ai/step-3.5-flash 256K Not listed Not listed - ReasoningTools Docs
StepFun Step Plan (China) step-3.5-flash 256K Not listed Not listed - ReasoningTools Docs
Vercel AI Gateway stepfun/step-3.5-flash 262.114K $0.09 $0.3 $0.02 ReasoningTools Docs
Hugging Face stepfun-ai/Step-3.5-Flash 262.144K $0.1 $0.3 - ReasoningTools Docs
StepFun (Global) step-3.5-flash 256K $0.1 $0.3 $0.02 ReasoningTools Docs
ZenMux stepfun/step-3.5-flash 256K $0.1 $0.3 - Tools Docs
StepFun (China) step-3.5-flash 256K $0.1 $0.3 $0.02 ReasoningTools Docs
EmpirioLabs AI step-3-5-flash 256K $0.1 $0.3 $0.02 ReasoningToolsJSON Docs
Kilo Gateway stepfun/step-3.5-flash 256K $0.1 $0.3 $0.02 ReasoningTools Docs
OpenRouter stepfun/step-3.5-flash 262.144K $0.1 $0.3 - ReasoningTools Docs

Capability badges appear only when the provider catalog explicitly lists support.

Serving quality

Performance and reliability

Observed serving measurements stay separate from model specifications and are never estimated from price or model size.

Throughput Not reported

Generation speed; higher is faster.

Latency / TTFT Not reported

Time until the first output token arrives.

Uptime Not reported

Successful requests over a measured period.

Performance varies by inference provider, region, and load. Provider-level measurements appear only when a source reports them.

Published evaluations

Benchmarks

Raw results remain attached to their original source and version.

Benchmark registry
Artificial Analysis Coding Index - Unversioned - indexTop 7 reported models
GPT-5-Codex
38.9
Step 3.7 Flash
37.1
Step 3.5 Flash 2603
34.6
Gemini 2.5 Pro
32.0
Step 3.5 Flash
31.6
GLM-4.6
29.5
Qwen3 Max
26.4
SWE-Bench Verified - Unversioned - resolvedTop 8 reported models
Claude Fable 5
95.0
Claude Opus 4.8
88.6
Claude Sonnet 5
85.2
DeepSeek V4 Pro
80.6
Qwen3.7 Max
80.4
Kimi K2.6
80.2
DeepSeek V4 Flash
79.0
Step 3.5 Flash
74.4
SciCode - Unversioned - percent correctTop 7 reported models
Gemini 2.5 Pro
42.8
GPT-5-Codex
40.9
Step 3.5 Flash
40.4
Step 3.7 Flash
40.0
Gemini 2.5 Flash
39.4
Step 3.5 Flash 2603
38.5
GLM-4.6
38.4
Terminal-Bench Hard - Unversioned - success rateTop 7 reported models
GPT-5-Codex
37.9
Step 3.7 Flash
35.6
Step 3.5 Flash 2603
32.6
Step 3.5 Flash
27.3
Gemini 2.5 Pro
26.5
GLM-4.6
25.0
GLM-4.5
22.0
Catalog activity

Recent record changes

Detected changes from successful source imports.

Full change log
Max Output Tokens65536 → 256000
Context Length262144 → 256000
Price Prompt0.09999999999999999 → 0.1
Max Output Tokens256000 → 65536
Context Length256000 → 262144
Price Prompt0.1 → 0.09999999999999999
Context Length262144 → 256000
Max Output Tokens65536 → 256000
Public API

Use this record

Fetch the complete source-linked model record without an API key.

API documentation
Endpoint
GET https://www.modelbench.lol/api/v1/models/stepfun/step-3.5-flash
curl
curl "https://www.modelbench.lol/api/v1/models/stepfun/step-3.5-flash"