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Comparison

Sidenote vs HARPA AI

Both live in your browser. HARPA AI is a multi-model automation agent that summarises pages, searches the live web, drives web tasks and monitors sites. Sidenote is a focused reader that answers questions about the document you already have open and pins every claim to the exact source passage.

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Sidenote

A citation-first reader that grounds every answer in the document you already have open.

HARPA AI

A multi-model AI agent that summarises pages and automates tasks across the whole web.

The short answer

Should you use Sidenote or HARPA AI?

Choose Sidenote if…

You are reading documents you need to trust — PDFs, wikis, articles — and you want every answer cited to a passage you can click through to and verify.

Choose HARPA AI if…

You want one extension to automate the web — fill forms, scrape and monitor pages, track prices, draft emails — and to pick between many AI models while you do it.

Plenty of people run both: HARPA AI to automate and act across the web, Sidenote when they need a cited, trustworthy read of a specific document.

Compared honestly

Sidenote vs HARPA AI: feature by feature.

CapabilitySidenoteHARPA AI
Reads the page or document you already have open Yes Yes
Citations scroll & highlight the exact passage Yes No
Server-side citation check drops unsupported claims Yes No
Works on private Confluence, Notion & SharePoint pages Yes Partial
Ask across many documents at once Yes No
One-click glossary of jargon & acronyms Yes No
Reads scanned PDFs with built-in OCR Yes Partial
Per-document Store / Discard retention control Yes No
Summarise a document Yes Yes
Searches the public web No Yes
Automates web tasks, scraping & site monitoring No Yes
Choice of multiple AI models No Yes

HARPA AI wins on reach and action — it searches the live web, automates and monitors pages, and lets you pick between models. Sidenote wins on trust: retrieval across the documents you open, a citation on every claim, and a click that scrolls the live page to the source. The cross-document row is powered by Sidenote Collections.

The core difference

An agent that acts across the web, or a reader that grounds every answer.

HARPA AI is a browser-automation Swiss-army knife: it combines ChatGPT, Claude, Gemini, Perplexity, DeepSeek and Llama (via web sessions, your own API keys, or its CloudGPT service) with web search, form-filling, scraping, price and site monitoring, email drafting and Zapier, Make and n8n hooks. If you want one extension to do things across the whole web, it is a genuinely broad pick.

Sidenote does one thing and goes deep: it turns the documents you read into something you can question and trust. Every answer is checked server-side against the source, unsupported claims are dropped, and each citation scrolls the live page to the exact sentence.

The difference in one example

Ask \"what does this contract say about termination?\" — HARPA AI gives a capable summary from the page and can search the web around it. Sidenote retrieves the clause, validates the answer against it, drops anything it cannot ground, and scrolls you to the exact sentence to confirm.

Giving credit

Where HARPA AI is the better tool.

HARPA AI is a strong tool that does far more than read. Where these are what you need, it is built for it in ways Sidenote deliberately is not:

Real browser automation

Fill forms, scrape and extract data, monitor sites and track prices, then push results to Zapier, Make or n8n. Sidenote reads and cites; it does not act on the web for you.

Many models, plus the live web

Switch between ChatGPT, Claude, Gemini, Perplexity, DeepSeek and Llama, or connect your own API keys, with web-search-grounded answers. Sidenote picks one model for the job rather than offering a marketplace.

A developer API and custom agents

HARPA exposes a CloudAI API and lets you build reusable custom agents and prompt commands — an automation surface Sidenote does not offer.

FAQ

Sidenote vs HARPA AI — common questions

It depends what you need. HARPA AI is a broad, multi-model automation agent for the whole web. Sidenote is the focused choice when your job is reading documents you need to trust: it retrieves across the docs you open and pins every answer to a source passage you can jump to and verify.
Depth and trust. Sidenote answers across many documents at once, checks every answer server-side against the source and drops unsupported claims, scrolls the live page to the exact cited sentence, and builds a one-click glossary of jargon. It is built specifically for reading you need to rely on, not general web tasks.
No — that is HARPA AI's strength, not Sidenote's. HARPA AI can fill forms, scrape data, monitor sites and track prices, and connect to Zapier, Make and n8n. Sidenote deliberately stays a reader: it explains and cites documents rather than acting on the web for you.
No, and that is deliberate. Sidenote picks the model for the job — a fast one for everyday chat, a stronger one on higher tiers for dense documents. HARPA AI's strength is the opposite: a choice across ChatGPT, Claude, Gemini, Perplexity, DeepSeek and Llama, or your own API keys, that you pick from.
Neither has a native mobile app. Both are desktop browser extensions; HARPA AI can run on Android via Kiwi Browser with reduced functionality, and Sidenote also offers a companion web app. For reading on a phone, neither is a full mobile solution today.
Both have a free tier. Sidenote is free to install with a 7-day Pro trial that needs no card, and paid plans start at £10/month. HARPA AI's free Demo tier needs no card, and its cheapest paid plan starts around $12/month billed annually, unlocking its CloudGPT and automation features.
Try it on a document

Read anything. With citations.

Add Sidenote to Chrome, open a document, and ask. Every answer comes with the passage that proves it.

Add to Chrome — freeSee pricing

7-day Pro trial · No card required · Free tier forever