Comparison

Zone 2 Buddy vs Private Diary

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

Head to head
About

Zone 2 Buddy

Features
Read full description

Zone 2 Buddy is an app that will give you real-time feedback based on your zone 2 max heart rate. The watch application plays a sound or vibrates when your heart rate goes above zone 2 max to assist in zone 2 training.

About

Private Diary

Features
Read full description

Scriptum is a daily journal with no account and no server. Your writing stays on your phone, and nothing leaves it unless you ask it to. ONE PAGE A DAY • A question is waiting each morning, so you never open to a blank page. • Write a line or a thousand words. The day is one page, of any length. • Missed a day? Open the calendar and write it whenever you like. WRITE HOWEVER SUITS YOU • Type, or speak and watch your words land on the page. • Add a photograph to remember the day by. • Note where you were, when that is part of it. FIND IT AGAIN YEARS LATER • Search every entry you have ever written. • A calendar of the days you wrote, and the days you did not. • Open any date and read it exactly as you left it. PRIVATE, NOT MERELY ENCRYPTED • No account. Nothing to sign up for, nothing to sign in to. • No analytics, no trackers, no advertising inside the app. • Most diaries keep your writing on a server. This one has no server to keep it on. AND STILL IMPOSSIBLE TO LOSE • A copy of your journal is kept in your own iCloud, so deleting the app no longer takes it with it. • Nothing is sent to us. The copy sits in your iCloud Drive, where you can see it. • Or save the whole diary, words and photographs, as one file only you hold. SCRIPTUM COMPLETE An optional upgrade, for when the free journal is not enough. • Lock your diary behind Face ID, a fingerprint, or a passcode. • Up to ten photos on a page, arranged for you. • Sketch over the paper in ink. • Stickers to decorate a page, every pack of them. • Have a rambling entry tidied by AI into something you will want to reread. • Colour the whole app to suit you. • Turn your journal into a printable PDF book, typeset page by page. Scriptum Complete is offered monthly or yearly, or as Lifetime, a one-off purchase. Subscriptions renew automatically until cancelled. Lifetime does not renew. Terms of Use: https://annrstudio.com/scriptum/terms/ Privacy Policy: https://annrstudio.com/scriptum/privacy/

Screenshots

Zone 2 Buddy4 screens
Private Diary4 screens

Verdict

The call

The clearest difference is in-app purchases: Zone 2 Buddy at none against Private Diary's 3. Private Diary's advantage is update cadence (weekly vs every 2 months) and iOS requirement (15.1 vs 18.0). On price, 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. Private Diary sells 3 in-app purchases, starting at $2.99 per month. Zone 2 Buddy asks for nothing beyond the download.

UpkeepUpdate frequency

Zone 2 Buddy ships an update every 2 months, Private Diary weekly. The most recent releases landed on September 18, 2026 and September 17, 2026 respectively.

Scorecard3 real differences · 3 level
Zone 2 Buddy versus Private Diary: the parameters behind the verdict, then further details
ParameterZone 2 BuddyPrivate Diary
PriceFreeFree
Update frequencyEvery 2 monthsWeekly — better
AdsNoNo
In-app purchasesNo — betterYes
DevicesiPhone, Apple WatchiPhone, iPod
Requires iOS18.015.1 — better
Further details — not scored
Size1 MB42 MB
Age rating4+4+
DeveloperAnderson DayANNR Studio

In-app purchases

None

Zone 2 Buddy

No in-app purchases

3 purchases

Private Diary

Subscriptions2
  • Monthly$2.991 Month
  • Yearly$17.991 Year
One-time1
  • Lifetime$34.99

Questions

Is Zone 2 Buddy free?
Zone 2 Buddy is free to download, with no in-app purchases.
Is Private Diary free?
Private Diary is free to download, with in-app purchases available.
Do Zone 2 Buddy or Private Diary have ads?
Neither Zone 2 Buddy nor Private Diary shows ads.
Which is updated more often, Zone 2 Buddy or Private Diary?
Zone 2 Buddy ships an update every 2 months, and Private Diary weekly. Most recently, Zone 2 Buddy was updated on September 18, 2026 and Private Diary on September 17, 2026.

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