Comparison

IsleMark vs Cat Letter

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

Head to head
About

IsleMark

Customize your device's dynamic island with text, emojis, and decorative patterns. This app also serves as a convenient memo tool to help you remember tasks.

Highlights
  • Dynamic island text input
  • Emoji support
  • Upload decorative patterns
  • Minimized and expanded view customization
  • Memo tool for tasks
Features
Read full description

Now you can really edit the dynamic island! Want to leave your mark on every screenshot with the Dynamic Island? Or do you constantly have tasks to complete, only to forget them moments later? With IsleMark, your Dynamic Island is no longer just a distant system feature but something you have full control over. IsleMark lets you freely input text, emojis, and even upload decorative patterns¹ to display on your Dynamic Island. Whether it’s the minimized or expanded version, you define how it looks. Besides beautifying the Dynamic Island, IsleMark also functions as a handy memo tool. As my first independently designed and developed app, IsleMark is available for free, with no in-app subscriptions.

About

Cat Letter

Features
Read full description

Some days are worth keeping. A birthday. An anniversary. The day you moved in. Or just a date you can't quite let go of — you're not even sure why. Cat Letter is a quiet app for those days. You place them into a little home. Mantou, a small pixel cat, watches over them. When a day draws near, Mantou delivers a letter. Waiting becomes something gentle. --- Place a day Any date — past memories, future hopes, today's rituals. Type: Birthday · Anniversary · Journey · New Home · Custom Choose an object: envelope · cake · calendar · frame · flower · star · heart Mantou does three things Keeps watch: after you save, Mantou stays with your day in the little home. Delivers: when the day arrives, Mantou brings the letter to you. Stamps: for past days, a paw print is sealed on the memory postcard. Countdown & Memory Future days: shows how long until arrival (tomorrow · three days · still far away…) On the day: Mantou picks up the letter and delivers it. Past days: become memory postcards with a paw stamp, kept in your little home. Give the little home a new look The Corner Shop is open. Give your little home new weather, new light, a new season. --- Mantou is here, waiting for your first day.

Screenshots

IsleMark4 screens
Cat Letter3 screens

Verdict

The call

The clearest difference is price: Cat Letter at Free against IsleMark's $1.99. Cat Letter also leads on update cadence (every 5 days vs every 2 weeks). On ads, in-app purchases, 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

Cat Letter is free to download; IsleMark costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

IsleMark ships an update every 2 weeks, Cat Letter every 5 days. Both last shipped on October 24, 2026.

Scorecard2 real differences · 8 level
IsleMark versus Cat Letter: the parameters behind the verdict, then further details
ParameterIsleMarkCat Letter
Price$1.99Free — better
Rating4.8 (6 ratings) — better—
Positive reviews88.9% of reviews—
Number of ratings6 — better—
Update frequencyEvery 2 weeksEvery 5 days — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaid—
DevicesiPhoneiPhone
Requires iOS17.016.0 — better
Further details — not scored
Size72 MB8 MB
Age rating4+4+
DeveloperPop Up LimitedLONG VOYAGE TECHNOLOGIES PTE. LTD.

In-app purchases

None

IsleMark

No in-app purchases

None

Cat Letter

No in-app purchases

Questions

Is IsleMark free?
IsleMark costs $1.99, with no in-app purchases.
Is Cat Letter free?
Cat Letter is free to download, with no in-app purchases.
Do IsleMark or Cat Letter have ads?
Neither IsleMark nor Cat Letter shows ads.
Which is updated more often, IsleMark or Cat Letter?
IsleMark ships an update every 2 weeks, and Cat Letter every 5 days. Most recently, IsleMark was updated on October 24, 2026 and Cat Letter on October 24, 2026.

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