PrivyID · 2024 · Go
2h 5m
Wallet ID generation
Rebuilt in Go with goroutines and distributed workers for the core wallet service.
Open the case →Backend Engineer · Bandung, Indonesia
I make production backends faster, safer, and easier to change.
5+ years across fintech, healthcare, SaaS, and AI. Now building the scheduling backend at CheckProof AB, a SaaS platform used in 35+ countries.
legacy scheduler one switch scheduling tool
- tasks load-tested
- 1M
- failures or deadlocks
- 0
- DB calls per status change
- −75%
02 / Before → after
Luce · 2025 · Rails
errors −73%
Rails reliability overhaul
A Rails 7.0 → 7.2 upgrade and every high-severity security issue removed on a large monolith.
Open the case →D’Health · 2022 · Team lead
team of 5 10+
Hospital system for 10+ hospitals
Led five engineers building a hospital information system used by more than ten hospitals.
Open the case →03 / How I work
- Principle 01
Agents write the code. I own the decisions.
An agent studies the ticket, records it in a knowledge wiki, and drafts a plan that I and a fresh agent review. The executor agent proves each change with tests it runs locally, such as characterization tests before a refactor. The merge request stays a draft until the reviewer agent and I have both checked it.
Fig. 3.1 - 01 understand the ticket agent
- 02 record it in the wiki agent
- 03 draft the plan agent
- 04 review the plan ↺ me + agent
- 05 implement agent
- 06 prove it with tests agent
- 07 review the code ↺ agent
- 08 review the draft MR ↺ me
- 09 open the MR, update the wiki me
2× reviews on every plan and every change
- Principle 02
Pin down the old behavior before replacing it.
Captured CheckProof's legacy scheduler in characterization tests, then moved customers' live schedules to the new system with a rollback switch that worked at any point.
See the proof →Fig. 3.2 legacy newrollback at any point
1 switch to roll back the cutover
- Principle 03
Make code safe to change, then change it.
Upgraded Luce's Rails monolith from 7.0 to 7.2 by resolving transaction rollback, encryption, and dependency issues, with RSpec and VCR tests as the safety net.
See the proof →Fig. 3.3 - transaction rollback
- encryption
- dependency issues
Rails 7.0 → 7.2
26% → 83% backend dependencies up to date
- Principle 04
Code is cheap now. Proof isn't.
Load-tested CheckProof's task lifecycle monitor against a 1M-task backlog before trusting it: zero failures or deadlocks, and 75% fewer database calls per status change.
See the proof →Fig. 3.4 tasks in the backlog 1,000,000
- failures
- 0
- deadlocks
- 0
−75% database calls per status change
04 / Timeline
05 / Side project
themx
Gives AI coding agents the design context they need, so the UI they build follows one consistent theme.