Projects — Production Systems & Microservices

Super App (Identity & Verification Platform) - Preview 1

Distributed Systems

Code Repository

Technologies & Infrastructure

Java 21

Spring Boot 4

Spring Cloud Gateway

Spring Security

Apache Kafka

PostgreSQL Redis

Redis

S3 (Object Storage)

Python (FastAPI)

OpenCV / DeepFace Docker

Docker

Testcontainers Flyway

Flyway

01.

Super App (Identity & Verification Platform)

Architected and implemented a distributed backend of five isolated microservices (API Gateway, Identity, User, Notification, KYC) following Hexagonal Architecture / DDD principles and the Database-per-Service pattern. Features asynchronous event-driven Kafka messaging, reactive gateway routing, and AI-powered biometric verification.

Architectural Highlights & Decisions

API Gateway (Spring Cloud Gateway / WebFlux) with reactive JWT validation, client header sanitization, and Redis-backed token blacklist checks
Identity Service managing complete Access/Refresh token lifecycle, active session tracking, and password reset flows
Asynchronous transactional notification delivery powered by Apache Kafka and an isolated Notification Service
S3 API integration for isolated and secure storage of user verification files and identity scans
Auxiliary Python (FastAPI) microservice leveraging EasyOCR, ICAO 9303 MRZ parser, and DeepFace for automated document extraction and facial matching
Database schema versioning via Flyway migrations and Docker Compose local environment orchestration with health-check dependencies

Zovik CI/CD Engine (Distributed DAG Platform) - Preview 1

DevOps & CI/CD

1 / 3

Code Repository

Technologies & Infrastructure

Java 21 (Virtual Threads)

Spring Boot 4.1 Go 1.22

Go 1.22

Docker (DooD)

PostgreSQL

WebSockets (STOMP)

Eclipse JGit Vue 3.5

TypeScript Vite

Vite

Testcontainers JaCoCo

JaCoCo

Flyway

02.

Zovik CI/CD Engine (Distributed DAG Platform)

Architected and built a distributed CI/CD platform using a Master-Worker topology with declarative YAML pipeline definitions. Powered by a Directed Acyclic Graph (DAG) execution engine that parses step dependencies with Kahn's algorithm and executes independent stages in parallel.

Architectural Highlights & Decisions

DAG execution engine using Kahn's topological sort algorithm with cycle detection and parallel execution of non-dependent build stages
Standalone Go build agent utilizing a Pull-model (long-polling) — zero open inbound ports needed, operating securely behind NAT/firewalls
Docker-out-of-Docker (DooD) container sandboxes with isolated volume mounting and automated artifact extraction
Real-time build log streaming via STOMP WebSockets with regex-based LogSanitizer to mask secrets and tokens
Project-scoped secret management with AES-256-GCM encryption and bidirectional GitHub integration (HMAC-SHA256 webhooks & Commit Status API)
Interactive pipeline DAG visualizer built with Vue 3.5 (Composition API) + Vue Flow + TypeScript

Go / Backend

Live Service Code Repository

Technologies & Infrastructure

Chi

PostgreSQL pgx

pgx

Docker

React

React Query

Web Push (VAPID)

03.

Nucla

High-performance backend engineered completely from scratch to enable founders to discover co-founders, match based on complementary skills, and interact in real time. Built with resilience, security, and strict clean architecture principles.

Architectural Highlights & Decisions

Chi Router with modular layered architecture (handler → service → repository)
High-throughput PostgreSQL access using pgx connection pooling and prepared statements
Embedded database schema migrations via go:embed and golang-migrate
Stateless authentication via secure JWT tokens stored strictly in HttpOnly SameSite cookies
Asynchronous notification worker with Web Push (VAPID) and SMTP email dispatching
Vite + React frontend with optimistic updates powered by React Query

Performance & Resilience Benchmark (k6 Load Testing)

Real-World Benchmark

Stress-testing real-world system throughput: identifying the practical backend ceiling, resource bottlenecks, and hardware interaction under resource-constrained conditions.

InfrastructureVPS (2 vCPU, 1 GB RAM)

Service StackGo, PostgreSQL, Docker Compose

k6 ScenarioLinear ramp-up 20 → 150 VU (3 min)

Monitoringdocker stats, pg_stat_activity, latency percentiles

Benchmark Insights & Results:

Resource Utilization Profile

At peak concurrency (150 VU), CPU became the primary bottleneck: the three main containers simultaneously reached 90–116% utilization. Memory consumption remained steady without approaching capacity limits. Initial hypotheses regarding RAM starvation were disproven — profiling confirmed a strict CPU saturation profile rather than memory pressure.

Throughput Ceiling

The system reliably sustains up to ~130 concurrent active virtual users (VU) without performance degradation or latency spikes. This threshold reflects the physical constraints of the host hardware (2 vCPU VPS) rather than architectural flaws or algorithmic inefficiencies. Highly acceptable for the current MVP stage.

Localized Degradation

The test isolated an endpoint-specific issue: under peak saturation, packet loss reached ~4%. Log analysis revealed an isolated latency drop caused by a single unindexed/unoptimized SQL query under heavy contention.

💡 Early load testing demonstrates how runtime configurations and database connection pools behave under resource constraints, preventing premature infrastructure over-provisioning.

Go / Backend

Live Service Code Repository

Technologies & Infrastructure

WebSockets

Redis Pub/Sub

Docker Compose Docker

Docker

React

04.

NektoKZ

Distributed real-time messaging platform enabling anonymous peer matching and instant chat rooms with minimal latency. Handles concurrent WebSocket sessions with Redis Pub/Sub backplane.

Architectural Highlights & Decisions

Goroutine-per-connection WebSocket hub with bounded channels to prevent slow-client backpressure
Redis Pub/Sub multi-node message fanout allowing horizontal scaling across cluster nodes
Session state coordination and automated inactive connection heartbeats (ping/pong)
Containerized with multi-stage Docker builds and orchestrated via Docker Compose

Java / Enterprise

Code Repository

Technologies & Infrastructure

Java

Spring Boot

PostgreSQL

Hibernate / JPA Docker

Docker

REST API

Swagger

05.

UniReview

Academic rating portal providing transparent course feedback, professor reviews, and rating metrics. Built with Java Spring Boot following enterprise patterns and strict data integrity standards.

Architectural Highlights & Decisions

Spring Security with role-based access control (RBAC) and OAuth2 institutional authentication
Complex aggregation queries and caching for professor scoring algorithms
PostgreSQL full-text search for fast university and course lookup
OpenAPI 3 / Swagger documentation with automated contract validation

Productivity

Code Repository

Technologies & Infrastructure

SQLite / PostgreSQL Docker

Docker

React

Tailwind CSS

06.

Focus Tracker

Minimalist, distraction-free productivity app designed specifically for engineers. Combines Pomodoro intervals, custom soundscapes, and analytics on deep-focus streaks.

Architectural Highlights & Decisions

Lightweight Go API syncing session intervals and daily streaks
Offline-first client synchronization with optimistic local state
Containerized lightweight deployment with minimal resource footprint

Production Systems & Projects

Super App (Identity & Verification Platform)

Zovik CI/CD Engine (Distributed DAG Platform)

Nucla

NektoKZ

UniReview

Focus Tracker

Looking for a robust backend system?