HARPA AI vs AI Reply Writer: automation agent or reply writer?
HARPA AI and AI Reply Writer compared: a browser automation agent with AI commands, versus a focused AI reply button in Gmail, LinkedIn, WhatsApp Web and more.
HARPA AI is a browser AI agent: page-aware commands, custom automations, web monitoring and an AI chat that can also draft emails. AI Reply Writer does one job — writing replies — from a button built into the reply box on 23 sites, and never acts on a page by itself. Choose HARPA if you want to automate browser tasks and are comfortable configuring it; choose AI Reply Writer if you want fast, in-place replies with nothing to set up.
At a glance
| HARPA AI | AI Reply Writer | |
|---|---|---|
| What it is | An AI agent and automation tool for the browser | An AI reply writer: a ✦ AI Reply button inside the reply box |
| Where it works | Any page, with commands for email services such as Gmail and Outlook | 23 sites, including Gmail, Outlook, LinkedIn, WhatsApp Web, Instagram, Facebook, Slack and Teams |
| Reads the conversation | Yes — its commands are page-aware | Yes — the thread you have open, plus photos and PDFs in Gmail, Outlook and WhatsApp Web |
| Review replies | Not a focus of the product | Yes — Google Business Profile and Trustpilot, reading the star rating |
| Free plan | Yes, with a usage allowance | 20 replies a month |
| Paid plans | Paid plans — see their pricing page | Starter $7, Elite $14, Ultra $29 a month |
| Browsers and phone | A Chromium browser extension | Chrome, Edge, Brave, Opera, Vivaldi and Firefox; a web app on phones |
| Sends anything for you? | It can run automations you set up | Never — it fills the box, you press Send |
What HARPA AI is
HARPA AI is one of the most capable AI extensions for power users. It combines an AI chat with page-aware commands — summarise this page, reply to this email, extract this data — and lets you build your own automations without code. It can monitor pages for changes and alert you, and it connects to several AI providers, including your own accounts and API keys.
That flexibility is the point: HARPA is a toolkit you shape to your own workflow.
What AI Reply Writer is
AI Reply Writer has no automations by design. It adds one button — ✦ AI Reply — to the reply box of each supported app, reads the conversation in front of you, and writes a draft you edit and send. It does nothing until you press it, and it never posts, sends or clicks anything for you.
- Nothing to configure: install, open Gmail or WhatsApp Web, press the button.
- Built per app across 23 sites, including social apps and review sites.
- Safe for platforms with automation rules, such as LinkedIn, because it only fills a box you send yourself.
The main differences
Toolkit vs single purpose
HARPA can do far more, and asks more of you to set it up. AI Reply Writer does less, and is ready the moment it is installed. For most people who just want replies, the simpler tool is faster day to day.
Automation and platform rules
Automating actions on sites like LinkedIn can break their user agreements. AI Reply Writer avoids the question entirely: it only writes drafts. If you use automation tools, check each platform's rules — see our note in the best LinkedIn Chrome extensions.
Reading each app
AI Reply Writer's per-app reading — the right message in a group chat, the post a comment belongs to, the stars on a review — is built into the product rather than written as a prompt.
Pricing
HARPA has a free tier and paid plans; its current prices are on its website.
AI Reply Writer has a free plan with 20 replies a month, no card needed. Paid plans are Starter ($7 a month), Elite ($14) and Ultra ($29); higher plans unlock more advanced AI models and larger allowances, and teams can buy the same plans per member. See pricing.
Which should you choose?
- Choose HARPA AI if you want a configurable AI agent for research, monitoring and browser automation.
- Choose AI Reply Writer if you want replies written in place, across many apps, with nothing to configure and nothing automated.
About this comparison: it is based on each product's public information as of October 2026, and both products change often — check the other product's own website for its current features and prices before you decide. Product names are trademarks of their owners; AI Reply Writer is not affiliated with them.
Frequently asked questions
What is the difference between HARPA AI and AI Reply Writer?
HARPA is a configurable AI agent with page commands and automations. AI Reply Writer is a focused reply tool that drafts answers inside the reply box and never acts on its own.
Is there a simpler alternative to HARPA AI for email replies?
AI Reply Writer adds a reply button to Gmail, Outlook and many other apps, with no setup, and has a free plan.
Does AI Reply Writer automate anything?
No. It writes a draft when you press the button. Sending, posting and clicking are always up to you.
Is AI Reply Writer safe to use on LinkedIn?
It does not automate anything on LinkedIn: no connection requests, no messages sent for you, no scraping. It reads the page you have open and writes a draft you send yourself.
