If you want a writing model you can run yourself and fine-tune, you need open weights and a licence that lets you use them. Hemmingway-1 has both: it is free for non-commercial use, and commercial use is by agreement with us, and it was built for one job: writing that sounds like a person wrote it.
What it is
| Parameters | 27B |
|---|---|
| Built on | Qwen3.8-27B |
| Context | 262,144 tokens |
| Licence | CC BY-NC 4.0; commercial use by agreement |
| Weights | huggingface.co/Altworld/Hemmingway-1 |
| Code | github.com/lukeckprobierts/Hemmingway-1 |
How it scores against open and closed models
The most telling comparison for an open model is against the model it started from. Hemmingway-1 is Qwen3.8-27B trained further for writing, so the base model's scores show what the training did.
| Test | Hemmingway-1 | Qwen3.8 27B (base) |
|---|---|---|
| CommunicationBench (everyday writing) | 1026 | 954 |
| Human-Likeness | 1032 | 952 |
| StoryBench (creative writing) | 1197 | 693 |
Against much larger models, on everyday writing it came first of all we tested, level with Fable 5.1 and ahead of Fable 5, GLM-5.3, Kimi K3, GPT-6 Astra, Grok 4.6 and DeepSeek V4 Pro. On the public EQ-Bench 4 it placed third. On long stories it sits level with Kimi K3, ahead of Qwen3.8 Max and DeepSeek V4 Pro, and behind Fable 5 Max and GLM-5.3. All of the scores are on the model card.
CommunicationBench, Human-Likeness and StoryBench are our own benchmarks. Every matchup was blind, run in both orders, and judged by a model that was not one of those being judged. EQ-Bench 4 is not ours.
Running it
With vLLM:
vllm serve Altworld/Hemmingway-1 --max-model-len 262144
Or with Transformers, as a normal chat model: load Altworld/Hemmingway-1 with AutoModelForCausalLM and AutoTokenizer, and build the prompt with the tokenizer's chat template. The README on GitHub has a full example.
Or skip the hardware
If you would rather not run a 27B model yourself, the same model is behind an OpenAI-compatible API as hemmingway-27b. Most code that already talks to a model needs two lines changed. The API docs are here, and keys are on the API platform.
What it is not good at
It is English-first. It can be wrong and still sound certain, so do not use it to decide anything medical, legal or financial. And for very long fiction, the largest story models are better.
Common questions
What is the best open-source LLM for writing?
Hemmingway-1 is an open-weights model built for writing that sounds like a person. On our CommunicationBench it came first of all the models we tested, open and closed, level with Fable 5.1. CommunicationBench is our own benchmark; all the scores are on the model card.
Can I use Hemmingway-1 commercially?
Yes, with an agreement. Hemmingway-1 is released under CC BY-NC 4.0, which is free for personal, research and other non-commercial use. For commercial use, write to luka@hemmingway.io; we are glad to work with anyone who asks. The weights are on Hugging Face at Altworld/Hemmingway-1 and the code on GitHub.
How do I run Hemmingway-1 locally?
With vLLM, run vllm serve Altworld/Hemmingway-1 --max-model-len 262144. Or load it with Transformers as a normal chat model, using AutoModelForCausalLM, AutoTokenizer and the tokenizer's chat template. The README on GitHub has a full example.
What is Hemmingway-1's context length?
262,144 tokens. It is a 27B model built on Qwen3.8-27B.
Is there an API for Hemmingway-1?
Yes. The same model is behind an OpenAI-compatible API as hemmingway-27b, so most existing code needs two lines changed. The API docs are here, keys are on the API platform, and cost is on the pricing page.