OpenHermes 2.5

Nous Research · 2023 · LLM · USA

A to Z

A · App: No
B · Built By: Nous Research
C · CEO & Politics: Jeffrey Quesnelle
D · Date: 2023
E · Expertise: Intermediate+
F · Free Tier: Yes
G · Generates: Text only
H · Deployment: Cloud + Local (open weights)
I · Inputs: Text
J · Jurisdiction: USA
K · Key Staffers: Jeffrey Quesnelle (CEO), Karan Malhotra (Head of Behavior), Teknium (Head of Post-Training), Shivani Mitra (Co-founder)
L · Languages: English-primary
M · Model Type: LLM
N · Safety Issues: None reported
O · Open Source: Yes — open weights
P · Pricing: Free (open weights, Apache 2.0)
Q · AIDb Rating: [UNKNOWN]
R · What Makes It Special: OpenHermes 2.5, a Mistral 7B fine-tune trained on 1,000,000 entries of mainly GPT-4-generated data plus filtered open datasets; added code instructions (an estimated 7% to 14% of the data) raised its HumanEval pass@1 from 43% (OpenHermes 2) to 50.7% and boosted several non-code benchmarks. Uses the ChatML prompt format.
S · Stock / Status: Private
T · Training Cutoff: [UNKNOWN]
U · Users: [UNKNOWN]
V · Voice Chat: No
W · Weights: Downloadable
X · X Handle: @NousResearch
Y · Year Founded: [UNKNOWN]
Z · Bottom Line: Open-weights LLM from Nous Research, released 2023.

Data completeness 85% · Last verified 2026-05-12 · Primary source ↗

“OpenHermes 2.5.” AIDb — The AI Database. Verified 2026-05-12. https://theaidatabase.com/m/openhermes-25.html