SG
04Engineering Work

PlaceMate

I kept forgetting where I had stored important belongings.

Problem

People frequently forget where they have stored important physical possessions. Traditional inventory applications often require cloud storage and compromise user privacy.

Context

Goal: build a privacy-first physical inventory management system that stores sensitive information entirely on the user's device. Philosophy: sensitive physical inventory should never leave the user's control.

Engineering Decisions

Prioritised privacy, offline capability, local ownership, and security over convenience features like sync or collaboration.

Trade-offs

Accepted no cloud sync, no collaboration, and no remote access in exchange for keeping data entirely local.

Architecture

Client-side, browser-only architecture. No server component; all data is stored and encrypted on-device.

Implementation

Natural language storage and conversation-based retrieval. AES-256 encryption with PBKDF2 key derivation for encrypted local storage. Recovery phrase system and password rotation.

Lessons Learned

Security is only valuable when it remains usable.