John Eric

Currently building at Merck Group

Hi, I'm Kwan Rimorin John Eric, a full-stack developer.

Fifteen years building apps that look good, run fast, and keep working. I work on the front end, the back end, and the servers behind them.

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About

Across the whole stack

Kwan Rimorin John Eric

I have built and looked after software for more than fifteen years. The work has ranged from big company web systems running on Oracle databases, to real-time apps that teams use together, to search powered by AI.

Frontend, backend, ops: I've done almost all of it. These days that means React and TypeScript on top of Go, NestJS, and Python services, running on AWS and Kubernetes.

15+ Years experience
5 Companies
20+ Technologies

Experience

Where I've worked

Enterprise systems, ad tech, developer tools, and site reliability. Newest first.

Full-stack Developer

Aug 2025 — Present

Merck Group

  • Built end-to-end analytics features including PCA, correlation, and survival analysis, with interactive Vega visualisations
  • Integrated the platform with Palantir Foundry — reading datasets and ontology objects, managing dataset-based permissions, and building Contour dashboards for monitoring
  • Designed and shipped LLM-powered features using AWS Bedrock
  • Built a logging pipeline streaming application logs from CloudWatch into Foundry
React Palantir Foundry AWS Bedrock Vega-Lite AWS CloudFormation CloudWatch

Full-stack Developer

Sep 2023 — Jul 2025

Cognizant

  • Full-stack development using NestJS and React
  • Investigated and resolved production issues to maintain system stability
  • Security analytics and remediation with SonarQube, Nexus IQ, and Fortify on Demand
  • Collaborated with DevOps engineers on system maintenance, analytics, and monitoring modules
NestJS React SonarQube Nexus IQ Fortify

Senior Global Service Reliability Engineer

Apr 2022 — Oct 2023

Data.ai

  • Maintained and enhanced products across multiple tech stacks with the engineering teams — Flask/Django, TypeScript/React/Next.js, and the Snowflake data platform
  • Frontend and backend troubleshooting, resolving major and critical issues affecting stakeholders
  • Maintained smoke-test automation with the QA team to ensure service reliability
  • Monitored system health with AWS CloudWatch, Sentry, and Datadog
  • Voted 2022 top performer of the APAC team
Flask Django TypeScript React Next.js Snowflake Datadog

Full-stack Developer

Nov 2020 — Apr 2022

Adgorithmics

  • iOS and Android mobile app development using Flutter
  • Full-stack development using Python (Django and Flask) and JavaScript (React and Node.js) frameworks
  • Search engine development and optimisation using Elasticsearch and Typesense
  • Blockchain NFT development using Solidity, Ethers.js, and WalletConnect
  • Wrote automated test scripts and managed CI/CD with GitHub Actions
  • Managed GCP infrastructure — Kubernetes Engine, Compute Engine, and Cloud SQL
Flutter Django Flask React Node.js Solidity GCP

Programming Analyst

Nov 2009 — Nov 2020

NovaSPRINT Systems Pte Ltd

  • Developed multi-tiered web applications using Java (Spring Boot and EJB) and mobile applications with React Native
  • Managed stages of the SDLC and took part in systems review with the project manager
  • Provided maintenance support to customers
Java Spring Boot React Native Oracle Database

Independent product

Ministry Mapper

A free, open-source tool that helps congregations plan and track their door-to-door ministry. Hundreds of people use it, and it keeps track of more than a million addresses.

Why I built it

Congregations plan door-to-door visits on paper. Each slip lists the homes in one block. Someone hands the slips out, volunteers work through them, then hand them back. It works, but it does not scale. Two people can knock on the same door an hour apart. A lost slip takes months of notes with it. And whoever keeps the records cannot see how far along a territory is until every slip comes back.

I built Ministry Mapper to put all of that in one place. Everyone sees the same thing at the same time.

Four years and two complete rewrites in, it's the work I'm proudest of.

How it helps
  • Nobody knocks twice. Mark a home as done, not home, or do not call. Everyone on that map sees it right away.
  • No accounts needed. The person in charge shares a link to one map. The link expires, and each congregation chooses how long it lasts.
  • Nothing gets lost. Every change is saved. Past visits and do-not-call requests carry over instead of starting again.
  • Progress at a glance. Organisers can see how much of each map and territory is covered, without chasing paper.
  • Each congregation sets its own rules. They choose the status options, the roles, and how long links last.
How it's built

This is the second version. The first one ran on Firebase and is now retired. The new one uses a Go backend built on PocketBase, a TypeScript front end, a separate analytics service, and SQLite copied live by Litestream.

Go PocketBase TypeScript React SQLite Litestream

At a glance

  • Real-time sync Everyone working a map sees the same thing, instantly
  • Shareable links Share one map with a link that expires. No account needed
  • Full audit trail Every change is saved, and can be undone
  • Role-based access Administrator, conductor, and read-only roles
  • Configurable per congregation Each congregation picks its own status options and time limits
  • Self-hostable One Go program plus SQLite, copied live by Litestream
Frontend Backend Documentation More on GitHub

8 stars on the archived v1

Skills

What I work with

Languages

TypeScript JavaScript Python Go Java Dart Solidity Swift SQL Strongest in TypeScript and Python; Go for services.

Frontend

React Next.js TanStack Flutter React Native Sass React and TypeScript day to day.

Backend

NestJS Node.js Django Flask Spring Boot PocketBase NestJS and Django in production.

Data & search

Snowflake PostgreSQL Oracle Elasticsearch Typesense SQLite / Litestream Palantir Foundry Vega-Lite From Snowflake warehouses to embedded SQLite.

Cloud & DevOps

AWS AWS Bedrock CloudFormation GCP Kubernetes Docker GitHub Actions CloudWatch Datadog Sentry AWS primary, GCP and Kubernetes in anger.

Quality & security

SonarQube Nexus IQ Fortify on Demand Test automation CI/CD SAST, SCA, and CI gates.

Credentials

Education & certifications

Certifications

Issued Jun 2023

KCNA: Kubernetes and Cloud Native Associate

The Linux Foundation

Kubernetes, cloud native

Issued Mar 2022

AWS Certified Cloud Practitioner

Amazon Web Services

Issued Nov 2020

Certificate in Swift Development

Nanyang Polytechnic

Swift, iOS

Issued Aug 2019

Certificate in Machine Learning, TensorFlow & Keras

Tertiary Infotech Pte Ltd

Issued Mar 2017

Certified Big Data Analyst

Global Science and Technology Forum

Education

Jun 2003

Higher Diploma in Computer Science

FTMS Global Academy, Singapore

Contact

Get in touch

Working on something interesting, or need a hand with a system that's already running? I read every message.

[email protected] Connect on LinkedIn