Nous Research
5 models built
Nous Research is a US-based open-source lab founded in 2023, best known for the Hermes model series and the Psyche decentralized-training network. Instead of building foundation models from scratch, Nous fine-tunes and releases open weights on top of existing base models — Llama 3.1 for Hermes 3, and a newer base for Hermes 4 — optimizing for steerability and instruction-following rather than chasing a proprietary frontier model. Through OpenKey you get 5 Hermes models, all text-to-text, all with a 131,072-token context window, ranging from a 70B parameter model up to 405B. One variant is free.
Lineup
For most work, Hermes 4 70B is the value pick: $0.13/M input and $0.40/M output (OpenKey: $0.1339/M in, $0.412/M out after the 3% fee), with the same 131K context as the larger models. If you need the extra scale of a 405B model, Hermes 4 405B runs $1.00/M input and $3.00/M output ($1.03/M and $3.09/M on OpenKey) and is the newest release (Aug 26, 2025). To test the lineup at zero cost, use Hermes 3 405B Instruct (free) — same 405B/131K spec as the paid Hermes 3 405B, just capped or rate-limited as a free tier.
- Hermes 4 405BAug 26, 2025 131K $1.03 $3.09 ctx 131K · in $1.03 · out $3.09
- Hermes 4 70BAug 26, 2025 131K $0.134 $0.412 ctx 131K · in $0.134 · out $0.412
- Hermes 3 70B InstructAug 18, 2024 131K $0.721 $0.721 ctx 131K · in $0.721 · out $0.721
- Hermes 3 405B InstructAug 16, 2024 131K $1.03 $1.03 ctx 131K · in $1.03 · out $1.03
- Hermes 3 405B Instruct (free)FreeAug 16, 2024 131K Free Free ctx 131K · in Free · out Free
Prices per 1M tokens, flat 3% fee included.
Questions
- What does Nous Research charge for its models?
- Prices range from $0.13/M input tokens (Hermes 4 70B) up to $1.00/M input on the 405B models, with output pricing from $0.40/M to $3.00/M (Hermes 4 405B). On OpenKey, add the flat 3% fee: provider price x 1.03 — e.g., Hermes 4 70B becomes $0.1339/M input and $0.412/M output. One model, Hermes 3 405B Instruct, is also offered free.
- Which Nous Research model should I start with?
- Hermes 4 70B is the cheapest paid option at $0.13/M input / $0.40/M output and still gets the full 131,072-token context. If you want to try Nous's approach before paying anything, Hermes 3 405B Instruct (free) gives you the 405B model at $0 input/output.
- How do I access Nous Research models through OpenKey?
- All 5 Hermes models — including the free Hermes 3 405B variant — are available through OpenKey's single API key, alongside 324 other models from 51 other labs. Pricing is provider list price plus a flat 3% fee, so there's no separate account or contract needed with Nous Research directly.