SYSTEMS_ONLINE·JVM: OpenJDK 21 LTS·RUNTIME: Spring Boot 4.1.0 · Kafka 4.2 · K8s 1.30

EDGE: SIN1

RTT: —

99.998%

Available for Advisory & Core Systems

Senior Java Engineer &
Systems Architect

// Achmad Yusuf Ramadhan · BTC_ENGINEER

Architecting fault-tolerant distributed topologies, sub-millisecond event-driven streams, and mission-critical telemetry mesh at multi-million transaction scale.

GitHub LinkedIn Medium YouTube Website

Explore Case Studies Book Systems Review / RFC

LIVE MESH

ACTIVE_ARCHITECT

Achmad Yusuf Ramadhan

Senior Java Engineer & Systems Architect

FOCUS

Distributed Systems

LOCATION

Jakarta (UTC+7)

SYSTEMS_ARCHITECTURE // 01

Featured Production Topologies

Architecture case studies built and shipped in production — problem statement, system topology, failure modes, and verified scale metrics.

#01EVENT_STREAMING

P99 latency lowered from 1,200ms to 42ms under 8,500 continuous RPS with zero dual-debit events.

High-Throughput Financial Transaction Gateway

ISO-8583 banking switch processing real-time transactions with strict zero-loss consistency.

PROBLEM_STATEMENT

A legacy monolithic transaction routing system suffered severe head-of-line blocking during traffic surges, experiencing P99 latency spikes exceeding 1,200ms and database connection pool starvation.

SCALE_METRICS

P99 latency lowered from 1,200ms to 42ms under 8,500 continuous RPS with zero dual-debit events.

JavaRedisSpring BootOpenTelemetryApache Kafka

Source Demo

Architecture Details

#02EVENT_STREAMING

Ingested 40k spans/sec; cut production MTTR by 65% across 22 microservices.

Distributed Real-Time Log & Trace Telemetry Pipeline

Multi-region observability aggregator handling 40,000 trace spans/second with Grafana Tempo integration.

PROBLEM_STATEMENT

Engineering teams lacked end-to-end trace correlation across polyglot microservices (Java, Go, and Node.js), causing mean time to resolution (MTTR) for critical production incidents to exceed 4 hours.

SCALE_METRICS

Ingested 40k spans/sec; cut production MTTR by 65% across 22 microservices.

Performance TuningKubernetesOpenTelemetryApache Kafka

Source

Architecture Details

#03EVENT_STREAMING

Zero orphan transactions recorded across 1.2M peak daily orders.

Resilient Microservices Order Saga Orchestrator

Event-driven compensation engine ensuring eventual consistency across inventory, payment, and logistics.

PROBLEM_STATEMENT

Distributed microservices encountered partial failure states during high-volume promotional sales, resulting in uncompensated credit card authorizations when downstream warehouse inventory locks failed.

SCALE_METRICS

Zero orphan transactions recorded across 1.2M peak daily orders.

JavaSpring BootApache KafkaPostgreSQL

Source

Architecture Details

SHIPPED_PRODUCTS // 02

Shipped Applications & Products

End-to-end applications, Website, Mobile apps built and shipped for real-world production use.

www.experienceoz.com.au/en

WEB

Experience Oz Booking Platform

Microservices for High Throughput Booking Platform

Role/Scope: Backend & Microservices Engineer Description: Maintains and Develop New Feature for a high-concurrency booking engine built on a microservices architecture using Spring Boot and Micronaut to handle rapid, low-latency tourism and travel reservations.

STACK & ARCHITECTURE

ReactSpring BootJDK 11MicronautJenkins

Launch Application

9:41

CROSS_PLATFORM

Waste Not

Waste_Not by BRING is a next-generation reuse app that aims to combine convenience and sustainability.

Role/Scope: Backend Developer & Mobile App Engineer Description: Built a cross-platform mobile marketplace app (Android & iOS) for curated pre-owned luxury items, powered by a scalable NestJS REST-API backend and a fluid Flutter client.

STACK & ARCHITECTURE

Nest JSNext JS 16Flutter

Launch Application

app.breakthecode.xyz

WEB

Helpdesk Bank Sulteng

Ticket and Customer Support System

Role/Scope: Full-Stack & Backend Architecture Description: Architected an enterprise-scale ticketing and support system using a modular NestJS backend paired with an interactive management dashboard built in Next.js.

STACK & ARCHITECTURE

Next JS 16Nest JS

banksulteng.co.id

WEB

Bank Sulteng Website

Company Profile of Bank Sulawesi Tenggara

Role/Scope: Web Development & Modernization Description: Developed and upgraded the corporate website modernization project for a regional banking institution using Laravel, focusing on data security, performance optimization, and robust content management workflows. Patch to latest version to prevent latest PHP2Shell Vulnerability

STACK & ARCHITECTURE

PHP 8.5Laravel 12

Launch Application

app.breakthecode.xyz

WEB

Kafalah

Syari'a Micro Financing Platform

Role/Scope: Full-Stack Development Description: Engineered a web-based financing guarantee platform leveraging FastAPI for a high-performance, asynchronous backend and Next.js for a responsive frontend, ensuring secure and real-time financial data management.

STACK & ARCHITECTURE

Next JS 16FastAPIPython 3.12

app.breakthecode.xyz

WEB

Hexacore

Delivering Top Candidate Platform

Role/Scope: Full-Stack Development Description: Developed a high-throughput modular core system platform utilizing FastAPI for clean asynchronous APIs and Next.js for a modern, dynamic user interface. Managing Connector and Prompt for Candidate Evaluation and Tracking Learning Progress

STACK & ARCHITECTURE

Next JS 16FastAPIPython 3.12

TECHNOLOGY_RADAR // 03

Stack & Toolchain

Hexagonal topology matrix: Adopt (production-proven daily drivers), Trial (active in secondary systems), Assess (evaluated in POCs).

Technology Radar // Topology Matrix

Concentric hexagonal domains: core production tier to emerging evaluations.

NODE_INSPECTORHOVER_NODE

◉

Hover a node to inspect

production rationale & ring

ENGINE: SVG_HEX19 NODES

KNOWLEDGE_BASE // 04

Technical Deep-Dives & Series

Engineering articles and multi-part series on distributed systems, Kafka, JVM performance tuning, and cloud architecture — published on Medium.

4 items

Medium ArticleJava #1

The N+1 Catastrophe: How “Clean” Code Destroys Your Connection Pool Under Load

Behind the scenes of HikariCP starvation, why FetchType.EAGER is a trap, and what actually happens inside PostgreSQL when JPA lazy loading runs wild.

9 min read

Read on Medium →

Medium Article

Monolith First, Microservices Later

How to Build a Scalable Feed Without Killing Your Startup

4 min read

Read on Medium →

Medium Article

From Intermediate to Expert: Building High-Performance, Scalable Systems with Kotlin

One of the clearest distinctions between an intermediate and an expert software engineer is not how fast they can build an application, but how well they understand performance under pressure.

9 min read

Read on Medium →

Medium Article

Understanding CPU-Heavy vs IO-Heavy Operations: A Practical Guide to Kotlin Coroutines

In this article, I’ll show you exactly when and how to use Kotlin Coroutines through a real-world pension benefit simulation system. By the end, you’ll understand the difference between CPU-heavy and IO-heavy operations and know exactly when coroutines will (and won’t) help you.

11 min read

Read on Medium →

VERIFIABLE_CREDENTIALS // 05