Pierre Teo

I'm a software developer based in Singapore. I build CashJot, an offline-first iPhone expense tracker designed for people who want to keep track of their spending without linking bank accounts or setting up complex budgeting software.

Think of it like Apple Notes, but designed specifically for daily spending: you jot down an expense in two seconds at the counter, see today's total on your home screen, and keep your data completely private.

How I approach expense tracking

• Speed is the only habit feature that matters: If logging a coffee takes more than two taps, the habit breaks. Opening straight to the keypad keeps logging as fast as jotting a quick note.
• Present awareness over historical guilt: The value of tracking is knowing what today cost while you can still adjust your choices, not looking back at last month with regret.
• Privacy by architecture: What you spend is personal, like a private notebook. CashJot runs with no user accounts, operates fully offline, and syncs solely through private iCloud.

Research & writing

A selection of product breakdowns, comparisons, and low-friction iOS setups:

• Why Budgeting Apps Fail

  A study analyzing 1,586 critical App Store reviews across nine major budgeting applications.

• What Happens When an App Connects to Your Bank

  An engineering analysis of financial data aggregators, OAuth vs screen scraping, and regional open banking regulations.

• Is Manual Expense Tracking Still Worth It?

  When direct mobile logging beats automated bank feeds.

• How to Track Expenses on iPhone

  A complete low-friction iOS setup using widgets, Back Tap, and Apple Pay shortcuts.

Elsewhere

Outside of software and design, I write essays on language acquisition, cognition, and mental models on my personal site, Semifluent.

You can also connect with me on LinkedIn.