Comparison

O3 vs Zenodot

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

Head to head
About

O3

Discover and access 24/7 study cafes designed for focused work and social interaction. Book spaces, connect with others, and enhance your productivity in a unique cafe environment.

Highlights
  • Unlock 24/7 study cafes
  • Book study spaces
  • Work and study environments
  • Meet new people
  • Socialize in cafes
Features
Read full description

Giant 24/7 cafes you can unlock with one app. Study, work, hang out, and meet new people at O3! https://www.o3space.org/terms-of-use

About

Zenodot

Features
Read full description

Zenodot is an AI-powered note-taking app that helps you organise ideas and ask questions about your own notes. Build a second brain that keeps the context behind what you’re learning, deciding, and making. Good ideas shouldn’t disappear into notes you never revisit. Turn scattered thoughts, research, and everyday observations into a personal Library you can return to and build on. CAPTURE IDEAS WHILE THEY’RE FRESH Write or dictate a note before the thought slips away. Capture something you learned, the reasoning behind a decision, or an idea you want to develop. ORGANISE WITH AI, STAY IN CONTROL Let Zenodot help organise raw notes into Pages and Folders. Keep related ideas together and review proposed Library changes before they’re applied. ASK QUESTIONS ABOUT YOUR NOTES Chat with the Librarian, Zenodot’s AI assistant, to find information and explore connections across your Library. Ask questions such as: • “What did I learn about this topic?” • “What research informed this decision?” • “How does this idea connect to my other notes?” Answers are grounded in your Library, helping you pick up the thread without starting from scratch. MAKE YOUR NOTES USEFUL LATER Bring your research, study notes, project ideas, and everyday observations into a Library that grows with your thinking. Revisit what you learned, recover the reasoning behind past decisions, and find a starting point for your next piece of work. With Zenodot, you can: • Capture notes by typing or dictating. • Use AI to help organise notes into Pages and Folders. • Explore connections between related ideas. • Ask questions grounded in your own Library. • Review proposed changes before they’re applied. • Access your Library across supported devices with a linked account. Start with one note. Build a second brain you can return to. EULA: https://www.apple.com/legal/itunes/appstore/dev/stdeula/ Terms of Service: https://zenodotapp.com/legal/terms-of-service/index.html Privacy Policy: https://zenodotapp.com/legal/privacy-policy/index.html

Screenshots

O34 screens
Zenodot4 screens

Verdict

The call

O3 and Zenodot are too close to call on the numbers: across 6 compared parameters — price, update cadence, ads and in-app purchases among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

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. O3 sells 1 in-app purchase, starting at $6.00 per 7 days and Zenodot sells 1 in-app purchase, starting at $9.99 per month. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

O3 ships an update every 9 days, Zenodot every 8 days. The most recent releases landed on October 30, 2026 and October 19, 2026 respectively.

ScorecardNo meaningful differences
O3 versus Zenodot: the parameters behind the verdict, then further details
ParameterO3Zenodot
PriceFreeFree
Rating4.9 (7 ratings) — better—
Positive reviews90.9% of reviews—
Number of ratings7 — better—
Update frequencyEvery 9 daysEvery 8 days — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchases—
DevicesiPhoneiPhone
Requires iOS16.0 — better16.4
Further details — not scored
Size171 MB99 MB
Age rating4+4+
DeveloperO3 Platforms LimitedJACKIE CHEN

In-app purchases

1 purchases

O3

Subscriptions1
  • 10HR COMBO$6.007 Days
1 purchases

Zenodot

Subscriptions1
  • Zenodot Pro (1 Month)$9.991 Month

Questions

Is O3 free?
O3 is free to download, with in-app purchases available.
Is Zenodot free?
Zenodot is free to download, with in-app purchases available.
Do O3 or Zenodot have ads?
Neither O3 nor Zenodot shows ads.
Which is updated more often, O3 or Zenodot?
O3 ships an update every 9 days, and Zenodot every 8 days. Most recently, O3 was updated on October 30, 2026 and Zenodot on October 19, 2026.

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