MDL
Step 3.5 Flash 2603
StepFun
Verified against Artificial Analysis · Jul 13, 2026
Capability
79
percentile index
Price /M
$0.1 / $0.3
in / out
Context
—
Avg score
54.9
7 benchmarks
AA Intelligence
26.0
index
Speed
201 tok/s
TTFT 0.8s
Released
Apr 2, 2026
About
Step 3.5 Flash 2603 is a proprietary model in the Step family from StepFun. Benchmarked on 7 evals, averaging 54.9.
Benchmark scores · 7
avg 54.9 — higher is betterThe research behind this model
all papers mentioning it →OPD-Evolver: Cultivating Holistic Agent Evolver via On-Policy Distillation▲ 27 on HF · Jun 16, 2026Step 3.5 Flash: Open Frontier-Level Intelligence with 11B Active ParametersFeb 11, 2026
Mentions matched by name in title/abstract — from the arXiv + HF daily corpus.
Performance & price
Output speed201 tok/s
Latency (TTFT)0.8s
First answer11s
Price in / out$0.1 / $0.3 per 1M
Blended price$0.15 / 1M
Median across API providers, via Artificial Analysis. Blended = 3:1 input:output. For reasoning models, latency includes thinking time. Methodology →
History
full ledger →Capability over time
Append-only ledger — every observed change to this model's numbers.
API providers
Artificial Analysis$0.3/M