ChatGPT is OpenAI's general assistant. It writes, codes, researches, explains, and a great deal else. Hemmingway is narrower on purpose: it is built for writing to people, and for making that writing sound like you.
If you want one tool for everything, that is ChatGPT. If most of what you want help with is emails, messages and the things you keep putting off writing, this page is for you.
The short version
| Hemmingway | ChatGPT | |
|---|---|---|
| Built for | Writing that sounds like a person | Almost any task |
| Model | Hemmingway-1, 27B, open weights | OpenAI's GPT models |
| Everyday messages (our test) | 1026, first | GPT-6 Astra 976 |
| Sounds like a person (our test) | 1032, first | GPT-6 Astra 964 |
| EQ-Bench 4 (public) | 1330 | GPT-5.5 1316 |
| Long stories (our test) | Behind GPT-6 Astra | Stronger |
| Drafts replies from your inbox | Yes, in the apps | Not what it is built around |
| Trains on your chats | Never | See OpenAI's settings |
Writing emails and messages
We tested both on eighty real email and message requests in blind head-to-head matchups. Hemmingway-1 came first overall, fifty points ahead of GPT-6 Astra.
The widest gap was on hard asks: turning someone down, asking for money back, the message you keep rewriting. Judged on which reply sounded like a person wrote it, GPT-6 Astra's won 9% of the time and Hemmingway-1's 72%.
To be fair to GPT-6 Astra: its messages were short and it rarely buried them in commentary, which many models do. Where it fell behind was in sounding like a person rather than a well-behaved assistant. The full results are here.
Stories
For long fiction, GPT-6 Astra is the stronger writer in our tests. If you are drafting a novel, use a big model. For short pieces that have to sound like someone sat down and wrote them, Hemmingway is built for that. More on creative writing.
Writing as you, to the people you know
This is the main difference in how they work. In Hemmingway you tell it who people are: your boss, a client, your sister. It writes to each of them the way you would, in the language you use with them. It keeps a memory of what it should know, and you can read and change every line.
In the Hemmingway apps for Mac, Windows and Android, it can also read your mail and chats, including Gmail, Outlook, WhatsApp, Slack and Teams, and draft each reply for you to send. How that works.
Privacy
Hemmingway never trains its models on your chats, memory or People. On the web and on Android you can keep chats only on your device. Our privacy page lists everything we keep.
Which to use
- Code, research, maths, general questions: ChatGPT.
- Emails, texts, replies, anything that has to sound like you: Hemmingway.
- Both: plenty of people use a general assistant for thinking and Hemmingway for the words that go out under their name.