Hi ! i’m an indie dev and I wanted to share the journey of building my app, Keyri — a strict local-first digital vault for Android.



**The Problem: Privacy vs Convenience**

I’ve always been pretty paranoid about privacy. For years, I refused to use cloud-based password managers (and seeing breaches at major companies didn’t exactly help).

So my solution was… honestly terrible.

I kept all my passwords inside a password-protected zipped Word document stored only on my PC.

And because I was also terrified of losing everything, I kept a backup copy on a USB drive too.

This made the whole process even more painful:  
every password update had to be manually synchronized between the PC copy and the USB backup.

Every time I needed to log into something on my phone or update a password, I had to:

\- boot up my PC

\- unzip the file

\- enter the master password

\- search for the entry

\- update it manually

\- remember to update the USB backup too.

At some point I realized I desperately needed a mobile solution, but I still didn’t want my sensitive data sitting on someone else’s servers.



**The Journey: From Python Script to Flutter App**

I’ve always loved coding, but never really had the time to go deep into app development. So I used this problem as an excuse to finally learn.

The first version of Keyri was actually just a local Python script running on my PC. It worked, but it obviously didn’t solve the mobile problem.

That’s when I decided to learn Flutter.

I spent months rebuilding the logic into a proper Android app during evenings and weekends. As I kept adding features for myself, I realized there were probably other privacy-focused people looking for a completely local alternative too.

So eventually I polished it up and published it on the Play Store.



**Technical Challenges & Lessons Learned**

here are a few interesting problems I had to solve without relying on a backend:

**Handling images locally**  
I wanted users to store ID cards, receipts, and sensitive documents. Images are compressed on-device, encrypted locally using ChaCha20, and stored entirely inside the app sandbox.

**Password breach checks without exposing passwords**  
I integrated the HaveIBeenPwned API using k-anonymity. Passwords are hashed locally and only the first 5 hash characters are sent. The real password never leaves the device.

**Barcode & QR scanning**  
I used Google ML Kit for barcode scanning while ensuring image processing stays entirely on-device.

**Data migration without cloud sync**  
Since there’s no traditional cloud account system, I built encrypted JSON backup/import support and CSV import tools to migrate from browsers like Chrome.

**Backup experimentation**  
I’m currently testing optional encrypted backup integrations with Google Drive while trying to keep the app’s local-first philosophy intact.



**What the app does today**

Keyri (formerly SilentSaver) is now a full local-first digital vault for:

\- passwords

\- payment cards

\- secure notes

\- encrypted images/documents



It also includes:

\- biometric unlock

\- Android Autofill integration

\- local breach checks

\- encrypted backups

\- zero ads

\- zero tracking

\- zero mandatory accounts



Play Store Link:  
[https://play.google.com/store/apps/details?id=com.nick.applab.silentsaver](https://play.google.com/store/apps/details?id=com.nick.applab.silentsaver)



I’d genuinely love to hear your feedback, especially from people who care about privacy, security, or local-first software.

Thanks for reading!

How I went from a password-protected Word document to publishing my own local-first password manager for Android [FREE]