Comparison

Scollr vs Rex

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Scollr

Features
Read full description

Scollr is a personalized feed for discovering research papers from journals, preprint servers, and academic repositories. Follow the topics, authors, and journals that matter to you. Scollr learns from the signals you give it - what you follow, save, and read - to build a research feed that fits your interests. PERSONALIZED RESEARCH FEED See papers shaped by your topics, authors, journals, bookmarks, and reading signals. Two researchers in the same field can get meaningfully different feeds based on what they care about. FOLLOW TOPICS, AUTHORS, AND JOURNALS Track broad fields, niche topics, specific researchers, journals, and preprint sources. Refine your follows anytime as your projects change. PLAIN-LANGUAGE PAPER SUMMARIES Many papers include short TLDR summaries so you can quickly decide what deserves a deeper read. SAVE PAPERS TO COLLECTIONS Organize papers by project, theme, class, lab meeting, or read-later list. Keep collections private or share them publicly. DISCUSS RESEARCH Comment on papers, ask questions, and point other readers to related work. FOLLOWING, DISCOVER, AND LATEST Use Following for personalized papers, Discover for broader recommendations, and Latest for new arrivals in your fields. BUILT FOR SCHOLARS AND CURIOUS READERS Scollr is for PhD students, researchers, clinicians, engineers, students, and anyone who wants a better way to keep up with academic papers. Scollr indexes millions of papers from OpenAlex across disciplines, journals, preprints, and repositories. New papers are added daily. Free to use. No paywall. No ads.

About

Rex

This app offers an interactive learning experience by explaining concepts aloud and allowing users to manipulate 3D models and live charts. It consolidates notes, PDFs, and web research onto a single canvas and supports collaborative study sessions.

Highlights
  • Voice explanations of questions
  • Interactive 3D scenes and live charts
  • Consolidated study canvas
  • Lecture transcription and note-taking
  • Read-aloud functionality for notes and PDFs
  • Language practice with real scenes
  • Live collaborative study boards
Read full description

Rex is a study companion that teaches out loud. Ask a question and hear it explained on a board you can draw on, pull apart, and keep. Most study apps hand you more text to read. Rex shows you the thing itself: a heart mid-beat, a cell you can fly into, a physics problem you can grab and change while it runs. ASK, AND ACTUALLY UNDERSTAND Type or speak a question and get a clear explanation built onto the board in front of you, not buried in a chat log. Ask about what is already on your board and Rex can see it. ONE BOARD FOR THE WHOLE CLASS Notes, PDFs, drawings, timers, recordings, graphs, checklists and web research sit side by side on one canvas. Stop switching between five apps to study one subject. 3D SCENES AND LIVE CHARTS Explore over 70 interactive charts and 20 explorable 3D scenes across biology, physics, chemistry, earth science and computing. Zoom from a whole body down to a single molecule. Change the inputs and watch what happens. RECORD THE LECTURE, GET THE NOTES Rex transcribes while you record, so your notes write themselves. LISTEN INSTEAD OF READING Any note, PDF or scanned page can be read aloud in a natural voice, each sentence highlighted as it is spoken. Photographed pages work too. SPEAK A NEW LANGUAGE Practise in twenty languages by walking through real scenes and talking with characters who answer back. STUDY TOGETHER Share a board and work on it live with classmates. FREE TO START The whiteboard and the core study tools are free. SUBSCRIPTIONS Pro, $11.99 per month. Pro Annual, $99.99 per year, which is about 36 percent less than paying monthly. Premium AI features, higher daily limits, class memory that persists between sessions, premium voice, study video generation and live board sharing require an auto-renewing Pro subscription. Prices are charged from day one and there is no free trial. Payment is charged to your Apple ID at confirmation of purchase. Subscriptions renew automatically unless cancelled at least 24 hours before the end of the current period, and your account is charged for renewal within 24 hours of the end of the current period. Manage or cancel in your App Store account settings. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://rexstudyapp.com/privacy.html

Screenshots

Scollr4 screens
Rex4 screens

Verdict

The call

The clearest difference is in-app purchases: Scollr at none against Rex's 2. Scollr also leads on iOS requirement (15.1 vs 18.6). On price, update cadence, 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Rex sells 2 in-app purchases, starting at $12.99 per month. Scollr asks for nothing beyond the download.

UpkeepUpdate frequency

Scollr ships an update fortnightly, Rex weekly. Both last shipped on October 24, 2026.

Scorecard2 real differences · 7 level
Scollr versus Rex: the parameters behind the verdict, then further details
ParameterScollrRex
PriceFreeFree
Rating—5.0 (1 ratings) — better
Number of ratings—1 — better
Update frequencyFortnightlyWeekly — better
AdsNoNo
In-app purchasesNo — betterYes
Monetization—Free with in-app purchases
DevicesiPhone, iPad, iPodiPhone, iPad, Mac
Requires iOS15.1 — better18.6
Further details — not scored
Size32 MB108 MB
Age rating4+12+
DeveloperChris ColpittsOran Egbuchunam

In-app purchases

None

Scollr

No in-app purchases

2 purchases

Rex

Subscriptions2
  • Pro$12.991 Month
  • Rex Pro Annual$99.991 Year

Questions

Is Scollr free?
Scollr is free to download, with no in-app purchases.
Is Rex free?
Rex is free to download, with in-app purchases available.
Do Scollr or Rex have ads?
Neither Scollr nor Rex shows ads.
Which is updated more often, Scollr or Rex?
Scollr ships an update fortnightly, and Rex weekly. Most recently, Scollr was updated on October 24, 2026 and Rex on October 24, 2026.

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