My Secret Diary with Lock

Review by eFreeware

Keeping a diary on a phone sounds simple until you think about who else might pick the phone up. A paper notebook can be hidden in a drawer, but a notes app sits on a home screen where a friend, a sibling or a curious partner can stumble across it. The gap between wanting to write honestly and wanting nobody else to read it is where most journaling apps either succeed or fall apart.

My Secret Diary with Lock is Firehawk's attempt at that balance. It is a free Lifestyle app for Android with a 4.8 average from more than 314,000 ratings and over 10 million installs, first released in January 2018 and updated as recently as September 2025. The pitch is straightforward: a personal journal that is locked down, customizable and pleasant enough to return to daily.

What follows is a look at what the app offers and where the trade-offs sit for anyone considering it.

A calendar at the center of the writing habit

The core of the app is a main screen calendar. You tap a date and write, and the developer places no limit on how many entries you can make. That structure suits people who think of journaling as a daily ritual: the calendar becomes a record of which days you showed up, and gaps are visible at a glance. It also works for someone who writes in bursts, since nothing stops you from adding several entries to the same date.

Entries are not fixed once written. You can create, modify and delete them whenever you like, which matters more than it sounds. Journals are full of half-finished thoughts and entries written in the wrong mood, and being able to go back and tidy or remove them keeps the record useful rather than a source of mild embarrassment.

A reminder function rounds out the habit side of things. If you are the sort of person who intends to journal and then forgets by evening, a nudge is the difference between a diary with three entries and one with three hundred.

Locks, and the intruder selfie

Security is where this app puts most of its weight. You can protect the diary with a password, a pin, a pattern, a safe or biometrics, and the choice is yours rather than fixed by the developer. For most people the fingerprint option will be the least friction, but having a pattern or pin as a fallback is useful on a phone whose sensor is unreliable or whose owner prefers not to rely on it.

The feature that stands out is the intruder selfie. If someone tries to get into the diary, the app can capture a photo of the attempt, and you can check whether anyone has been trying. It is a small thing, but it changes the psychology of the app: instead of only keeping people out, it tells you when someone tried. For anyone who shares a home or a workspace, that record can be more reassuring than the lock itself.

It is worth being clear about what this is. A lock on a phone app is a barrier against casual snooping. The developer frames the app as a guardian of private writing, and the lock and selfie features support that framing.

Photos, moods and a voice recorder

A written entry is only one way to capture a day. The app lets you add photos from your gallery and mood emojis, so a page can carry an image of where you were and a quick signal of how it felt. The developer also includes a voice recorder, which is handy on days when writing a paragraph feels like too much effort but saying a few sentences does not.

Search is the other practical addition. You can look up entries by date or by keyword, which turns a long-running diary from a sentimental archive into something you can actually consult. If you have written about a trip, a job or a person over several months, being able to pull those entries together is more valuable than scrolling back through a calendar.

The recent update added a guided journal alongside new themes and customization options. Guided journaling usually means prompts to respond to rather than a blank page, and for anyone who has ever opened a diary, stared at the cursor and closed it again, that is a meaningful addition.

Making the diary look like yours

Personalization runs through the whole app. There are various papers, themes and fonts to choose from, and you can set the theme color, the paper style and the font to suit your taste. You can also change the first day of the week, which is a small setting that makes the calendar match how you actually plan your time.

The app supports multiple languages, including English, German and Spanish, among others. That widens who can use it comfortably, and it also means the interface can match the language you think in, which matters for something as personal as a diary.

The developer markets the app partly as a diary for girls, and the pink and purple themes in the latest update fit that framing. The feature set itself is not restricted by it: photos, moods, voice notes and locks are useful to anyone who wants a private record of their days. It is better read as a styling emphasis than a boundary.

What it asks of you, and what it costs

The app is free to download, and it carries ads and in-app purchases. The sensible approach is to install it and use the free version for a while before spending anything. Anyone who has used free journaling apps will recognize the pattern.

The other consideration is the nature of the app itself. A diary only rewards you if you write in it, and no amount of themes, reminders or mood emojis will do the writing for you. The calendar makes the habit visible, which helps, but the value comes from the entries you put in.

There is also the question of what you are trusting the app with. A journal is among the more personal things you can keep on a phone, and the lock options and intruder selfie are real features. If you want to keep a diary on a phone at all, this one takes the privacy question seriously.

Who gets the most from it

This suits someone who wants a diary they will actually keep. The calendar, the reminders and the guided journal all push toward regular writing, and the customization options make the app pleasant to open. If you have tried journaling before and drifted away, the combination of a visible record and a nudge is a reasonable attempt at fixing that.

It also suits anyone who shares their phone or lives with people who borrow it. The lock options and the intruder selfie are aimed at exactly that situation, and they are the features that distinguish this app from a plain notes page. Someone who writes about family, relationships or work and would rather those thoughts stayed private has a clear reason to use it.

Finally, it suits people who like their tools to look a certain way. Papers, themes, fonts, colors and a choice of first day of the week are not essential to journaling, but they make the app feel personal, and for a diary that is part of the point.

A private diary worth keeping

My Secret Diary with Lock handles the important things well: it gives you unlimited entries on a calendar, lets you edit and delete them, locks them behind a password, pin, pattern or biometrics, and tells you when someone tried to get in. Photos, moods, voice notes, search and a guided journal fill out the experience, and the personalization options are broad enough that the app can look how you want it to.

The trade-offs are the ones that come with the category. It is free but ad-supported and offers in-app purchases, and a diary still depends on you writing in it. The 4.8 average from a large number of ratings suggests the approach has landed with its users, though that is a measure of satisfaction rather than a promise about your own experience.

If you want a private, customizable journal on Android and you are comfortable with ads and the option to buy more, this is a well-established choice. If you want a diary that keeps its focus on writing and reflection rather than doubling as a full note-taking system, this one is built around the diary itself.

What's new in version 1.1.1

🔥 New features are just piling up 🔥 The GUIDED JOURNAL is here now 🎉 PINK, purple and many more themes and customization options 💅 Catch the intruder trying to read through your stuff 🪤 And that’s not all! 👀