An AI reply assistant reads the messages you get and writes the answers for you. Some only draft, and you send. Some send on their own. They differ in three ways that matter: which messages they can read, whether they send without you, and who they are built for.
Here are five. Hemmingway is ours. Everything about the other four comes from their own websites, as we read them on 27 October 2026; check their pages for anything that has changed since.
The short version
| Hemmingway | Carly | Tera Chat | NOX (once RPLY) | folk | |
|---|---|---|---|---|---|
| Built for | Your own messages and email, in your voice | An AI agent for email, scheduling and business workflows | Dating chats | One inbox for all your chats | A sales CRM |
| Reads | Gmail, Outlook, WhatsApp, Slack, Teams; iMessage on Mac; texts and chat notifications on Android | Gmail and Outlook; texts to your agent; WhatsApp through the Business API | iMessage, WhatsApp, Telegram, Instagram, Tinder | iMessage, WhatsApp, Slack, Telegram, Signal, Instagram, X, LinkedIn, Discord, email | Email and WhatsApp threads |
| Sends on its own | Only with Autopilot, which is off until you turn it on | Its workflows can | Only in chats you let send; off by default | Never: it drafts | Follow-ups: no, you send them |
| Runs on | Mac, Windows, Android, web | Web, email, text and Slack | Mac | Mac | Web, Chrome, iPhone and Android |
| Price, from its own page | Free to try; Autopilot on Plus, Pro and Max | Free plan; Personal $35 a month | Free with your own AI key; AI Plus $9.99 a month | 10 free drafts; Pro $50 a month, billed yearly | From $24 a member a month, billed yearly |
Hemmingway
Hemmingway is an AI writing app with its own model, Hemmingway-1.5. In the apps for Mac, Windows and Android, its Inbox puts your mail and chats in one list and drafts each reply for you to read and send. It works with Gmail and Outlook, WhatsApp, Slack and Teams, and iMessage on the Mac. On Android it also drafts replies to texts and to the chat apps that show up in your notifications.
What sets it apart is whose voice the reply is in. In People you say who someone is, and it writes to them the way you would, in the language you use with them. Memory holds what it should know, and you can read, change and delete every line. The model behind it was built for writing that sounds like a person: 90% of Hemmingway-1.5's writing passes GPTZero and the top AI detectors on the first try. How that was tested.
Autopilot, in the Mac and Android apps on the paid plans, answers the easy messages that match your rules. It is off until you turn it on. A message from someone not in your contacts is kept as a draft, and every reply it sends is listed in Activity with the reason. We never train on your chats, Memory or People. More on how it answers texts.
Carly
Carly, at usecarly.com, calls itself an AI agent platform that connects to thousands of apps. You email, copy in, text or Slack Carly, and its agents handle email, scheduling and other work.
- Replies: in Gmail and Outlook it suggests replies; you review them, ask for changes or tell it to send, and it sends from your address.
- Sending on its own: its workflows can. Its own tutorial builds an instant reply to customer support emails that runs by itself.
- Texts and WhatsApp: you text your agent; a higher plan adds business texting. WhatsApp goes through the WhatsApp Business API, from a business number.
- Where: a web dashboard, plus email, text and Slack. There is a Chrome extension for scheduling.
- Price: a free plan, and Personal at $35 a month.
- Privacy: its privacy page says your data is never used for AI model training.
Tera Chat
Tera Chat, at terachat.co, is an AI dating assistant for Tinder and Instagram on the Mac. It writes openers and replies in your own texting style, and remembers birthdays and what people tell you.
- Replies: a button writes a reply that you send yourself.
- Sending on its own: Autopilot is off by default. Its replies wait in Drafts unless you let that chat send on its own. It can also send good-morning and good-night messages to a person you turn that on for. It has quiet hours, rate limits and an emergency stop.
- Channels: iMessage, WhatsApp, Telegram, Instagram and Tinder. Its page says Hinge is in beta and cannot send yet, and Bumble is coming.
- Where: Mac only, Apple silicon, macOS 15 or later. Its page says there is no Windows, iPhone or web version right now.
- Price: free if you bring your own ChatGPT, Claude or Grok account; AI Plus $9.99 a month with Autopilot in 5 chats; AI Pro $19.99 a month with Autopilot in every chat.
- Privacy: it says your inbox is stored on your Mac.
NOX, once called RPLY
RPLY's old address, heynox.com/rply, now shows NOX, and NOX's own changelog called the app RPLY until March 2026. NOX describes itself as an AI-native messaging assistant for macOS: one inbox for your conversations, with replies drafted in your voice.
- Replies: drafts only. Its page answers "Does NOX send messages automatically?" with "Never."
- Channels: iMessage, WhatsApp, Slack, Telegram, Signal, Instagram, X, LinkedIn, Discord and email.
- Where: Mac only, M1 or newer, macOS 14 or later.
- Price: a free tier with 10 drafted replies; Pro at $50 a month, billed yearly.
- Privacy: messages are stored on your Mac, drafting uses cloud models unless you switch on its on-device option, and it says it does not collect, store or train on your conversations.
folk
folk, at folk.app, is a CRM for sales teams. Its Follow-up Assistant watches email and WhatsApp threads that went quiet and suggests a follow-up written in your tone of voice.
- Replies: for email, the suggestion opens as a draft you send. For WhatsApp, it takes you to WhatsApp Web to send the message there.
- Sending on its own: follow-ups, no. Its separate workflows can send outreach emails when a trigger fires.
- Where: the web app, a Chrome extension, and phone apps for iPhone and Android.
- Price: from $24 a member a month billed yearly, with a two-week free trial.
- Privacy: its help page says your data is not used to train any large language models.
Which to pick
- Your own messages and email, in your voice, on Windows or Android as well as the Mac: Hemmingway. It is the only one of the five with apps for all three, and it writes with its own model, built to sound like a person.
- Dating apps on a Mac: Tera Chat is built for exactly that.
- One Mac inbox for many chat apps, drafts only: NOX.
- An agent you email to run business email and scheduling: Carly.
- Sales follow-ups that live in a CRM: folk.
Try HemmingwayDownload the app
Common questions
What is an AI reply assistant?
An app that reads the messages and emails you get and writes the replies for you. Most draft a reply for you to send; some, like Hemmingway's Autopilot, can also send the easy ones on their own by rules you set.
Which AI reply assistant can send replies on its own?
Hemmingway, with Autopilot in its Mac and Android apps, off until you turn it on. Tera Chat, in chats you let send, also off by default. Carly's workflows can too. NOX says it never sends on its own, and folk's follow-ups are sent by you.
Which AI reply assistant works on Android and Windows?
Of these five, Hemmingway has apps for Mac, Windows and Android, plus the web. Tera Chat and NOX are Mac only. Carly runs on the web and through email, text and Slack, and folk has a web app and phone apps.
Is there a free AI reply assistant?
Hemmingway is free to try, and Carly has a free plan. Tera Chat is free if you bring your own AI account, and NOX gives 10 free drafted replies. Autopilot, Hemmingway's auto-reply, is on its paid plans.
What happened to RPLY?
RPLY's old address, heynox.com/rply, now shows an app called NOX, and NOX's changelog called the app RPLY until March 2026. NOX drafts replies for you on the Mac and never sends them on its own.