Step-5-Preview vs Ling 3.1 Flash

API pricing, benchmark indices and specs — updated 19 October 2026.

stepfun-ai · A · Open weights
Params
604.3 B
Context
—
30d
2 K
inclusionai · B · API-only
Input / 1M
$0.075
Output / 1M
$0.23
AA index
41.1
proprietary · 262.1K context

Specification comparison

Differences are highlighted; identical values are muted.

Specification Step-5-Preview Ling 3.1 Flash
Deployment Open weights · also via API API-only (closed weights)
Parameters 604.3 B n/a — API-only
Architecture Step5ForConditionalGeneration n/a — API-only
Context length 1,000,000 262,144
Licence other Proprietary
Commercial use Unknown Per API terms
Languages — n/a — API-only
Downloads 30d 2,467 n/a — API-only
Downloads all time 2 K n/a — API-only
Quantizations on the Hub SAFETENSORS n/a — API-only
Gated No n/a — API-only
First seen on the Hub 2026-09-20 n/a — API-only
API input price / 1M tokens $1.00 $0.075
API output price / 1M tokens $2.70 $0.23
Est. cost per 1M input + 1M output tokens $3.70 $0.30
Cached input / 1M tokens $0.10 $0.015
AA Intelligence Index 43.7 41.1
AA Coding Index — —
AA Agentic Index — —
Max output tokens 64,000 235,929
API providers 4 2
Tool calling Yes Yes
Reasoning mode Yes Yes

API cost

Estimated cost of 1M input + 1M output tokens via OpenRouter

Step-5-Preview $3.70
Ling 3.1 Flash $0.30

Ling 3.1 Flash is 12.3× cheaper at list price.

VRAM side by side

On RTX 4090 · 24 GB · 8K context unless noted

Step-5-Preview · fp16 806.5 GB / 24 GB
❌ Won’t fit

Adjacent comparisons