Markian Mumba Mwangi

I Used Postgres as a Cache Instead of Redis. Here's What Happened.

Over-Engineered on Purpose — Part 10: Unlogged Tables, JSONB, and Why I Tried the Wrong Tool on Purpose. This is Part 10 of a series where I'm building a microservice platform from scratch.

Apr 7, 2026·9 min read·Caching

I Used Postgres as a Cache Instead of Redis. Here's What Happened.

Markian mumbainTech blog

The Config Server Needs the Service Registry. The Service Registry Config Is in the Config Server.

Over-Engineered on Purpose — Part 9: Centralized Configuration, Distributed Tracing, and a Chicken-and-Egg Problem This is Part 9 of a series where I'm building a microservice platform from scratch. Part 8 covers the common module and gRPC token infrastructure.

Mar 26, 2026·8 min read·config server

The Config Server Needs the Service Registry. The Service Registry Config Is in the Config Server.

Markian mumbainTech blog

A User Clicks 'Book Now' and Their JWT Travels Through Four Services. Here's How.

Over-Engineered on Purpose — Part 8: The Common Module, Auto-Configuration, and Making gRPC Authentication Invisible This is Part 8 of a series where I'm building a microservice platform from scratch. Part 7 covers the authorization server and OAuth2.

Mar 25, 2026·17 min read·interceptor

A User Clicks 'Book Now' and Their JWT Travels Through Four Services. Here's How.

Markian MumbainTech blog

Half of My OAuth2 Login Flow Is Code I Never Wrote

Over-Engineered on Purpose — Part 7: Setting Up an Authorization Server and Understanding What Spring Does Behind Your Back This is Part 7 of a series where I'm building a microservice platform from scratch. Part 6 covers why monolith security assumptions break in microservices.

Mar 24, 2026·10 min read·OAuth

Half of My OAuth2 Login Flow Is Code I Never Wrote

Markian Mumba inTech blog

Everything I Knew About Spring Security Was Built for a Monolith

Over-Engineered on Purpose — Part 6: Authentication in Microservices, and Why My First Approach Was Wrong This is Part 6 of a series where I'm building a microservice platform from scratch. Part 1 covers the architecture, Part 5 covers gRPC load balancing.

Mar 24, 2026·10 min read·Microservice

Everything I Knew About Spring Security Was Built for a Monolith

Markian MumbainTech blog

Eureka Promises Load Balancing. gRPC Has Never Heard of Eureka.

Over-Engineered on Purpose — Part 5: Custom Name Resolution, Client-Side Load Balancing, and the Triple-Slash Mystery This is Part 5 of a series where I'm building a microservice platform from scratch. Part 1 covers the architecture, Part 4 covers the BFF and service discovery setup.

Mar 21, 2026·7 min read·Name Resolver

Eureka Promises Load Balancing. gRPC Has Never Heard of Eureka.

Markian MumbainTech blog

I Thought I Was Building an API Gateway. Turns Out It's a BFF.

Over-Engineered on Purpose — Part 4: Service Discovery, gRPC Routing, and the Layer Between Your Frontend and Your Microservices This is Part 4 of a series where I'm building a microservice platform from scratch. Part 1 covers the architecture, Part 2 the gRPC contracts, Part 3 the Catalog Service.

Mar 21, 2026·8 min read·Microservice

I Thought I Was Building an API Gateway. Turns Out It's a BFF.

Markian MumbainTech blog

The First Service That Actually Does Something — Wiring Up gRPC, Flyway, and JPA

Over-Engineered on Purpose — Part 3: Building the First Service, the Hard Way This is Part 3 of a series where I'm building a microservice platform from scratch. Part 1 covers the architecture, Part 2 covers the gRPC contracts.

Mar 21, 2026·6 min read·sql

The First Service That Actually Does Something — Wiring Up gRPC, Flyway, and JPA

Markian Mumba inTech blog

Designing gRPC Contracts Before Writing a Single Service

Over-Engineered on Purpose — Part 2: Why Proto-First Design Forces You to Think This is Part 2 of a series where I'm building a microservice platform from scratch. Part 1 covers the idea, architecture, and tech stack.

Mar 20, 2026·9 min read·Microservices

Designing gRPC Contracts Before Writing a Single Service

Markian mumba inTech blog

Over Engineering on Purpose

Over Engineering on Purpose For the longest time, i’ve built applications as a monoliths. And honestly.

Mar 19, 2026·7 min read·Microservices

Markian MumbainTech blog

Explain Garbage Collection (CMS vs G1 GC)?

In an earlier article I had mentioned about the Java interview question. well this happens to be the second question on the list.

Sep 29, 2025·8 min read·Tech

Explain Garbage Collection (CMS vs G1 GC)?

Markian MumbainTech blog

What is the difference between HashMap, Hashtable and ConcurrentHashMap?

As I was scrolling through my usual YouTube feed and watching developer talks, a video was suggested on my homepage. The title was something like "JP Morgan interview questions for Java developers.

Sep 21, 2025·6 min read·Tech

What is the difference between HashMap, Hashtable and ConcurrentHashMap?

Markian MumbainTech blog

Building an Image Upload Service with Azure Blob Storage (and a Few Tangents Along the Way)

Currently most of the company’s stack is still based on VPSs. The bigger goal is to move services to the cloud (some are already there).

Sep 1, 2025·5 min read·Tech

Building an Image Upload Service with Azure Blob Storage (and a Few Tangents Along the Way)

Markian MumbainTech blog

Scaling Databases, CAP Theorem, and the Magic of Quorum

This week, I stumbled on a few articles that got me thinking about scaling and managing large-scale databases. Inevitably, that takes you straight into the CAP Theorem conversation.

Aug 11, 2025·3 min read·Daily

Scaling Databases, CAP Theorem, and the Magic of Quorum

Markian MumbainTech blog

The Day I Learned About Short Polling (Thanks to Mobile Money Payments)

So, I was implementing payments in my app when I ran into a very real problem. Here’s the setup: most mobile money providers these days have implemented STK Push.

Aug 11, 2025·3 min read·Tech

The Day I Learned About Short Polling (Thanks to Mobile Money Payments)

Markian MumbainTech blog

How to Solve the Dual Write Problem in Distributed Systems

One of the sneakiest pitfalls in distributed systems is the dual write problem. This happens when you try to perform two separate writes — one to your database and one to your message broker — without any atomic guarantees.

Aug 11, 2025·3 min read·Daily

How to Solve the Dual Write Problem in Distributed Systems

Markian MumbainTech blog

From Vercel to VPS: How I’m Deploying My Smart Garbage Collection App

For the longest time, all my app deployments lived comfortably on PaaS (Platform-as-a-Service) platforms—Vercel, Render, Heroku, and the like. They were fast, simple, and beginner-friendly.

Aug 3, 2025·3 min read·Tech

From Vercel to VPS: How I’m Deploying My Smart Garbage Collection App

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