Nautilus vs Acumen³
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Nautilus
This app is a research-focused web browser and writing tool for iPad and iPhone. It allows users to read, annotate web pages and PDFs, and use AI for summarization and content generation. The app also supports document creation and organization, syncing across cloud services.
- Web browsing with research tools
- AI-powered page summarization and translation
- Direct annotation on web pages and PDFs
- Export markup as PDF, Word, or Markdown
- Integrated document drafting and organization
- Cloud syncing with Dropbox, Google Drive, and iCloud
- Lecture and interview recording with transcripts
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Nautilus is a web browser built for research. Read the web, mark it up, ask AI about what you find, and write up your work without leaving the app, on iPad and iPhone. Students, researchers, journalists, writers and professionals use it to go from first search to finished document in one place. Browse with research tools built in Open pages in tabs, pin the ones you come back to, and keep sites in bookmarks and history. Switch to Reader for a clean page without distractions, or let Reader turn on automatically. Request the desktop version of a site when you need it. Understand any page Ask AI about the page you're reading. Summarize a long article, or translate a page into your language or into English, then switch back to the original at any time. Circle it with Magic Lasso Circle a passage, chart or image on a page. Ask AI to explain it, ask your own question, highlight it, or save it as a clip on your Clippings board so your findings stay together. Mark up the web Draw and write directly on web pages. Export a page with your markup as a PDF in A4, Letter or Legal size, or as a Word document, Markdown, RTF, plain text or an image. Read and annotate your sources Open PDFs, papers and reports in tabs beside your web pages. Highlight, write in the margins, add comments, and compare two documents side by side. Fill and sign forms, scan paper pages into PDFs, measure scaled drawings, and hide sensitive text before you share. Write it up Draft in Word documents, RTF, Markdown or plain text. Plan a long paper or book section by section on a Corkboard, keep your sources open next to the draft, take snapshots of earlier versions, and compile everything into one document or ebook. Study Projects gather the readings for each subject in one place. AI help from first idea to final draft Chat through ideas, ask about your own documents, and get explanations. Rewrite, simplify, correct spelling and grammar, change the tone, or translate what you've written. Also in Nautilus Record lectures and interviews and create transcripts. Connect ideas on whiteboards with sticky notes, organize plans in outlines, and work through calculations and charts in Math Notebooks. Your library, safe and in sync Keep documents in folders and notebooks with covers, and find anything with search. Export to PDF, Word, HTML, EPUB and more. Sync with iCloud, Dropbox, Box, Google Drive or WebDAV. Automatic saving, recovery and backups protect your work, and passcodes lock the app or private folders. Formerly Notes Writer Pro Nautilus is the new name of Notes Writer Pro. Your existing PDF notes and outlines open here. Privacy Policy http://www.noteswriter.com/Kairoos_Privacy_Policy.html Terms of Use https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Acumen³
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The Acumen³ mobile application allows registered corporations and users of the Acumen³ system (https://acumen3.com.au) to view and monitor their people counting data from their mobile device. A registered user account with Acumen³ (https://acumen3.com.au) is required to use this application.
Screenshots
Verdict
The clearest difference is in-app purchases: Acumen³ at none against Nautilus's 3. Acumen³ also leads on iOS requirement (15.1 vs 26.0). Nautilus's advantage is update cadence (fortnightly vs every 15 months). On price, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Nautilus sells 3 in-app purchases, starting at $3.99 per month. Acumen³ asks for nothing beyond the download.
Nautilus ships an update fortnightly, Acumen³ every 15 months. The most recent releases landed on November 6, 2026 and October 30, 2026 respectively.
| Parameter | Nautilus | Acumen³ |
|---|---|---|
| Price | Free | Free |
| Rating | 4.6 (3.2K ratings) — better | — |
| Positive reviews | 48.3% of reviews | — |
| Number of ratings | 3.2K — better | — |
| Update frequency | Fortnightly — better | Every 15 months |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Freemium | — |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 26.0 | 15.1 — better |
| Further details — not scored | ||
| Size | 502 MB | 30 MB |
| Age rating | 17+ | 4+ |
| Developer | Kairoos Solutions SL | Micromax |
Bugs and requests
Nautilus
Reported bugs
5 issues- Notes randomly disappearing
- Formatting issues with text and images
- Unreliable audio recording and playback
- Compatibility problems with newer iOS versions
- Inability to transfer files between free and pro versions
Requested features
5 requests- Handwriting recognition
- Improved eraser and shape tools
- Customizable keyboard and toolbar
- Better integration with cloud storage
- Ability to rotate and resize images
Acumen³
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Nautilus
- Nautilus Unlock All and AI3 Days trial$3.991 Month
- Nautilus Unlock All and AI3 Days trial$14.991 Year
- Nautilus Pro Lifetime$14.99
Acumen³
No in-app purchases




