Comparison

Readwise vs Project Chiron

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

Head to head
About

Readwise

This app helps you retain more of what you read by centralizing and revisiting your highlights from various reading platforms. It uses spaced repetition and active recall techniques to improve memory and offers features like tagging, note-taking, and OCR for physical books.

Highlights
  • Synchronize highlights from multiple platforms
  • Daily review habit via app and email
  • Spaced repetition and active recall
  • Tag, note, and search highlights
  • OCR for paper book highlights
  • Convert highlights to flashcards
Features
Read full description

Readwise helps you get the most out of what you read by making it fun & easy to revisit your highlights from all your favorite reading platforms in one place. Quickly synchronize your highlights from Kindle, Apple Books, Instapaper, Pocket, Medium, Goodreads, and even paper books. Then start building a daily review habit using the app and daily email. By reviewing your highlights every day, you'll retain dramatically more and you'll finally stop forgetting all the details from books you just finished! --- “Readwise is my favorite new service this year. Save highlights from Kindle, Instapaper, and now tweets... one of the best long-term personal learning tools I’ve come across.” — Caleb Hicks “Besides my Kindle, Readwise has been the most influential tech for improving my reading process.” — Blake Reichmann “If you use Kindle or Instapaper or just enjoy keeping and reading highlights, please sign up to Readwise. It will become one of your cherished services.” — Christopher Galtenberg --- ACTUALLY USE YOUR HIGHLIGHTS Highlighting is great, but why bother if you're never going to see any of your highlights again? Readwise makes it easy to quickly liberate all your highlights into one place, ensuring that you'll actually see and use them, including highlights from: • Amazon Kindle • Apple iBooks • Instapaper • Pocket • Medium • Goodreads • Twitter • Physical Books (using OCR) • Manual Input • CSV Upload STOP FORGETTING WHAT YOU READ How often do you finish a book, only to forget the key ideas two weeks later? We don't remember things by just reading them once. Readwise solves this problem using scientifically proven learning techniques called Spaced Repetition and Active Recall. Readwise resurfaces the right highlights at the right times using a daily email and an app. Readwise even makes it possible to convert your best highlights into flashcards for added retention. TAG, NOTE, SEARCH, AND ORGANIZE With your highlights all in one place, Readwise enables you to organize and connect these ideas in new ways. Use search to find a highlight instantly; use tag to organize highlights within your library; use notes to add your own annotations. HIGHLIGHT PAPER BOOKS Readwise also makes it possible to take highlights from your physical books and papers using your phone’s camera. Just snap a pic, highlight with your finger, and have your favorite highlights saved forever. --- If you are not already a Readwise subscriber, you can get started immediately with a 30-day free trial with no credit card upfront. At the end of the trial, you will not be charged unless you choose to subscribe to Readwise Full or Readwise Lite. Price may vary by location. Manage your subscription from your dashboard. --- Support: Check out readwise.io/faq or email us at hello@readwise.io Privacy Policy: https://readwise.io/tos Terms of Service: https://readwise.io/privacy

About

Project Chiron

Features
Read full description

Stuck on a math problem you refuse to give up on? Chiron writes the smallest hint on your page, just enough to keep you thinking, without spoiling the math. Write your working by hand. Chiron reads every line as you go and steps in only when it helps: a nudge when you're stuck, a question when you're close, a quiet check when you're not sure. It teaches. It never lectures. KEEP THINKING • Hints sized to the moment: the smallest push that keeps you moving • Get pointed at the slip, not handed the answer • Ask out loud, "where do I even start?", and talk it through DOES THE MATH PROPERLY • Every check is grounded in a real symbolic engine, so feedback is exact, never a chatbot's guess • Catches the sign you flipped, the solution you gained, the step that doesn't follow • Built for real work: algebra, trigonometry, calculus, ODEs, logs and more BRING YOUR OWN • Snap any problem with the camera and start working • Upload your notes and Chiron works from your course, not a generic one Best with an Apple Pencil. Chiron. Keep thinking.

Screenshots

Readwise4 screens
Project Chiron4 screens

Verdict

The call

The clearest difference is in-app purchases: Project Chiron at none against Readwise's 8. Project Chiron also leads on update cadence (every 5 days vs every 2 weeks). On price, ads, device support and iOS requirement 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. Readwise sells 8 in-app purchases, starting at $4.99 per month. Project Chiron asks for nothing beyond the download.

UpkeepUpdate frequency

Readwise ships an update every 2 weeks, Project Chiron every 5 days. The most recent releases landed on September 24, 2026 and September 17, 2026 respectively.

Scorecard2 real differences · 8 level
Readwise versus Project Chiron: the parameters behind the verdict, then further details
ParameterReadwiseProject Chiron
PriceFreeFree
Rating4.8 (1.5K ratings) — better—
Positive reviews72.2% of reviews—
Number of ratings1.5K — better—
Update frequencyEvery 2 weeksEvery 5 days — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases—
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.5 — better16.0
Further details — not scored
Size110 MB144 MB
Age rating12+4+
DeveloperReadwise, IncJames Booth

Bugs and requests

Readwise

Reported bugs

3 issues
  • Frequent app crashes
  • Sync failures with certain accounts
  • Unreliable highlight capture

Requested features

5 requests
  • Add support for more reading apps
  • Improve sync and import capabilities
  • Introduce more customization options
  • Enhance search and organization tools
  • Develop a more intuitive mobile interface

Project Chiron

Not enough reviews yet to summarise bugs or requests.

In-app purchases

8 purchases

Readwise

Subscriptions8
  • Readwise Lite Monthly$4.991 Month
  • Readwise Lite Monthly$6.991 Month
  • Readwise Full Monthly Plan$8.991 Month
Show 5 more
  • Readwise Full Monthly$12.991 Month
  • Readwise Lite Yearly$52.991 Year
  • Readwise Lite Yearly$66.991 Year
  • Readwise Full Yearly$94.991 Year
  • Readwise Full Yearly$119.991 Year
None

Project Chiron

No in-app purchases

Questions

Is Readwise free?
Readwise is free to download, with in-app purchases available.
Is Project Chiron free?
Project Chiron is free to download, with no in-app purchases.
Do Readwise or Project Chiron have ads?
Neither Readwise nor Project Chiron shows ads.
Which is updated more often, Readwise or Project Chiron?
Readwise ships an update every 2 weeks, and Project Chiron every 5 days. Most recently, Readwise was updated on September 24, 2026 and Project Chiron on September 17, 2026.

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