Seed-Thinking-v1.5

ByteDance · 2025 · Reasoning LLM · China

A to Z

A · App: No
B · Built By: ByteDance
C · CEO & Politics: Liang Rubo — Not publicly documented (PRC-based; operates under Chinese regulatory environment)
D · Date: 2025
E · Expertise: Intermediate+
F · Free Tier: Yes
G · Generates: Text only
H · Deployment: Cloud only (proprietary)
I · Inputs: Text
J · Jurisdiction: China
K · Key Staffers: Liang Rubo (CEO)
L · Languages: Chinese-primary
M · Model Type: Reasoning LLM
N · Safety Issues: None reported
O · Open Source: Proprietary
P · Pricing: Volcengine API pricing
Q · AIDb Rating: 4/10 · AIDb v2.0 (rule-based): Capability 4/10 · Currency 4/10 · Access 5/10 · Significance 4/10 → 4.15
R · What Makes It Special: ByteDance Seed reasoning model that thinks before responding: a mixture-of-experts with 20B activated and 200B total parameters, scoring 86.7 on AIME 2024, 55.0 on Codeforces and 77.3 on GPQA.
S · Stock / Status: Private ($330B+ valuation, Aug 2025 employee buyback)
T · Training Cutoff: [UNKNOWN]
U · Users: [UNKNOWN]
V · Voice Chat: No
W · Weights: API only
X · X Handle: @ByteDanceTalk
Y · Year Founded: [UNKNOWN]
Z · Bottom Line: Proprietary Reasoning LLM from ByteDance, released 2025.

Data completeness 88% · Last verified 2026-06-11 · Primary source ↗

“Seed-Thinking-v1.5.” AIDb — The AI Database. Verified 2026-06-11. https://theaidatabase.com/m/bytedance-seed-thinking-v1-5.html