Comparison

Caliu vs Koku

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

Head to head
About

Caliu

A minimalist markdown notes app designed for writers, offering a distraction-free writing experience with features like nested tags, reminders, and cross-device syncing. It allows for easy export and integration with external tools.

Highlights
  • Markdown writing with live formatting
  • Nested and colored tags for organization
  • Cross-device sync across iPhone, iPad, and Mac
  • Reminders for notes
  • Export to various formats (Markdown, ePub, RTF)
  • REST API and MCP server for integration
  • Customizable themes
Features
Read full description

Caliu is a quiet place to write. Open it and start typing: no account, no setup, no clutter. Markdown takes shape as you type, everything works offline, and your notes stay on your device. When you want them everywhere, create a free account and they follow you across iPhone, iPad, Mac and the web. Sync is free, and it stays free. Writing comes first Headings, lists, tasks, quotes, code and links format as you write. There is no preview pane and no mode to switch: what you see is your note. The interface steps aside and leaves you with the page. Organised the way you think Tags instead of folders, because one idea can belong in many places. Nest them, colour them, and find any note in seconds. Link notes to each other and follow a thought from one to the next. Pin what matters now, and archive what you are done with without losing a word. There when you need it Native on iPhone, iPad and Mac, with a web app for everything else. Save things to Caliu straight from the share sheet, or add a thought from your Apple Watch. Yours, and only yours No ads. No tracking. Nothing you write is used to train AI. Your notes live on your device first and sync encrypted, and Caliu is built in the EU under GDPR. Export any note as Markdown or plain text whenever you like, share one as a public link when someone needs to read it, and delete your account at any time. Deleted means deleted. For tinkerers A full REST API and a built-in MCP server, so Claude, Cursor or your own scripts can read and write your notes, on your terms. Your first API key is free. Caliu Pro Writing, tags, sync and working offline are free. 50 notes free, forever, no account needed. Caliu Pro makes them unlimited and adds: • Version history: scroll back through any note and restore it in a tap • Every theme, font and app icon: 22 colour themes, each in light and dark, and 30 fonts • Drawing, right inside your notes • Unlimited attachments • More export formats: HTML, ePub, PDF, RTF and TextPack • Unlimited API keys, and connecting AI apps like Claude to your notes Subscribe monthly or yearly, or buy Pro lifetime once. Try it free before you decide. The monthly or yearly plan is an auto-renewing subscription: it renews unless you cancel at least 24 hours before the end of the current period, and you can manage or cancel it anytime in your App Store account settings. Made with care by a small, independent team of one. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://caliuapp.com/privacy

About

Koku

This app helps you focus on tasks with customizable work and rest intervals. It offers a simple, distraction-free interface and integrates with your home screen and Apple Watch for easy access and control. Enjoy deep work without accounts, streaks, or subscriptions.

Highlights
  • Customizable focus and rest sessions
  • Classic Pomodoro rhythm option
  • Home Screen widget for quick access
  • Live Activities on lock screen
  • Apple Watch companion app
  • Minimalist, distraction-free design
Features
Read full description

Koku is a focus timer for deep work. Focus. Rest. Repeat. Set your own session lengths or use the classic rhythm - twenty-five minutes of focus, five minutes of rest, a longer break every four sessions. Each minute is a dot. Watch them fill. - No accounts. - No streaks. - No subscriptions. Just time, and the work in front of you. Add Koku to your Home Screen for quick access - start, pause, and skip sessions right from the widget. Keep the timer visible on your lock screen with Live Activities. Koku also includes an Apple Watch companion app that works with the iPhone app, so you can check your timer and control sessions from your wrist. Designed for iPhone, with an Apple Watch companion. Light and dark mode. Works in any language. Koku (刻) is the Japanese word for a moment of time.

Screenshots

Caliu4 screens
Koku4 screens

Verdict

The call

The clearest difference is rating: Caliu at 5.0 against Koku's 3.0. Caliu also leads on ratings volume (5 vs 1) and device support (4 vs 2). Koku's advantage is in-app purchases (none vs 2) and update cadence (every 3 days vs weekly). On price, ads, monetization model 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. Caliu sells 2 in-app purchases, starting at $1.99 per month. Koku asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Caliu holds the better App Store score, 5.0 against 3.0. That said, the two scores are not equally well evidenced: Caliu has 5 ratings behind it against 1, so its average is the more settled of the two.

UpkeepUpdate frequency

Caliu ships an update weekly, Koku every 3 days. The most recent releases landed on October 21, 2026 and October 11, 2026 respectively.

Scorecard5 real differences · 5 level
Caliu versus Koku: the parameters behind the verdict, then further details
ParameterCaliuKoku
PriceFreeFree
Rating5.0 (5 ratings) — better3.0 (1 ratings)
Positive reviews100.0% of reviews—
Number of ratings5 — better1
Update frequencyWeeklyEvery 3 days — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFreeFree
DevicesiPhone, iPad, Mac, Apple Watch — betteriPhone, Apple Watch
Requires iOS26.0 — better26.4
Further details — not scored
Size197 MB10 MB
Age rating4+4+
DeveloperMarc TorrellesRodolfo Alberto Lopez Terriquez

Customer experience

Caliu

All ratings5 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews3 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Koku

All ratings1 ratings
Positive0.0%
Neutral100.0%
Negative0.0%

In-app purchases

2 purchases

Caliu

Subscriptions2
  • Caliu Pro - Monthly3 Days trial$1.991 Month
  • Caliu Pro - Yearly7 Days trial$17.991 Year
None

Koku

No in-app purchases

Questions

Is Caliu free?
Caliu is free to download, with in-app purchases available.
Is Koku free?
Koku is free to download, with no in-app purchases.
Which has better reviews, Caliu or Koku?
Caliu is rated higher. Caliu averages 5.0 out of 5 from 5 ratings, while Koku averages 3.0 from 1 ratings.
Do Caliu or Koku have ads?
Neither Caliu nor Koku shows ads.
Which is updated more often, Caliu or Koku?
Caliu ships an update weekly, and Koku every 3 days. Most recently, Caliu was updated on October 21, 2026 and Koku on October 11, 2026.

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