OGUZ KAAN DERE
ENDE
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Engineering

Products with explicit rules and visible proof.

I work across Java microservices, typed frontend architecture, native Android products, and document-heavy AI workflows. The common thread is explicit state, resilient boundaries, and software that can explain what it is doing.

The projects below separate implemented behavior from future scope and use contracts, tests, and operational evidence instead of relying on architecture claims alone.

Featured engineering project

Completed system

LedgerFlow

A complete Java microservice platform demonstrating a durable, eventually consistent bank-transfer workflow.

System design, backend engineering, and operations UI

  • Implemented account, transfer, risk, and notification services with independent PostgreSQL ownership and guarded workflow state.
  • Built Kafka orchestration with transactional outboxes, idempotent consumers, reservations, settlement, compensation, and Redis-backed protective controls.
  • Added Keycloak authorization, observability, generated API clients, a role-aware React console, and real-stack Playwright verification.

Phases 0–5 are implemented. Production deployment, real banking integrations, and regulatory certification remain explicitly outside the portfolio scope.

LedgerFlow transfer lifecycle from pending through completion or compensated rejection

Java 25 · Spring Boot · Kafka · PostgreSQL · Redis · Keycloak · React · Playwright

ArchitectureGitHub

Selected systems

Backend, Android, frontend, and AI product engineering

Tip Tracker mobile dashboard with monthly earnings, work time, and recent shifts

Native Android product

Google Play preparation

Tip Tracker — Earnings Log

An offline-first shift and earnings ledger for couriers, hospitality workers, freelancers, and people working across multiple jobs.

Product design and native Android engineering

  • Designed fast accessible shift entry with job presets, paired wheel controls, breaks, deductions, tips, and trustworthy hourly-rate calculations.
  • Built local persistence with Room migrations and DataStore, plus calendar history, monthly insights, and conflict-safe editing.
  • Generated private German/English A4 timesheets locally and prepared the product architecture for a Google Play release without accounts or tracking.

Kotlin · Jetpack Compose · Room · DataStore · Hilt · Coroutines · Material 3

Project overview

3D operations simulation

Documented build

Physical Ops Simulator

A browser-based discrete-event simulation platform for modeling physical service operations, starting with cafés and quick-service restaurants.

System design, simulation engineering, and 3D product development

  • Built an editable 3D venue model with persisted geometry, operational stations, recipes, workforce constraints, and versioned project schemas.
  • Implemented deterministic SimPy customer, queue, staff, and spatial-movement simulation behind FastAPI contracts while keeping rendering non-authoritative.
  • Added obstacle-aware pathfinding, congestion and travel metrics, reusable café fixtures, end-to-end verification, and frontend/backend quality gates.

React · TypeScript · Three.js · React Three Fiber · Python · FastAPI · SimPy · Playwright

ArchitectureGitHub

Editorial platform migration

Live

blog.okdere

A standalone editorial application that replaced a long-running Blogger site while preserving historical URLs and search continuity.

Product architecture, migration engineering, and full-stack implementation

  • Built a deterministic Blogger import and exact legacy-path preservation layer so historical articles remain addressable during and after migration.
  • Designed Supabase Postgres/Auth/Storage with RLS, server-only admin authorization, moderated comments, rate limiting, and a private TipTap authoring workflow.
  • Added resilient snapshot fallback, noindex preview boundaries, production-analytics isolation, trusted server-generated story cards, URL validation, tests, build checks, and operational cutover documentation.

Next.js 16 · React 19 · TypeScript · Supabase · TipTap · Vercel

View projectArchitectureGitHub
Berlin forecast rendered as a blue WebGL atmosphere

Interactive frontend

Live

Weather with Shaders

Live forecast data drives a custom WebGL atmosphere instead of sitting inside a conventional weather card.

Frontend architecture and WebGL rendering

  • Mapped normalized Open-Meteo data to bounded shader uniforms.
  • Kept the renderer outside React with explicit lifecycle cleanup.
  • Built accessible search, geolocation, units, and resilient forecast caching.

React · TypeScript · WebGL2 · GLSL · Open-Meteo

View projectGitHub
Rendering laboratory comparing naive Context with an optimized store

React systems experiment

Live

context-api-but-it-scales

A measurable comparison between shared React Context and a selector-based external store.

State architecture and rendering instrumentation

  • Implemented selector subscriptions with useSyncExternalStore.
  • Measured committed component renders without contaminating the result.
  • Added bounded history, safe persistence, and loop-free cross-tab synchronization.

React · TypeScript · Vite · Vitest · useSyncExternalStore

View projectGitHub
Germany Path Finder command center with route comparison and sources

AI-assisted product

Live

Germany Path Finder

A local-first RAG tool for comparing Germany residence and career paths against curated official sources.

Product design and full-stack implementation

  • Separated official source retrieval, user data, and AI explanation.
  • Added PDF ingestion, citations, and explicit uncertainty handling.
  • Kept documents and BYOK credentials local to the browser.

React · TypeScript · RAG · IndexedDB · pdfjs · BYOK AI

View projectGitHub
Admission Fit Checker dashboard showing extracted academic profile data

Document workflow

Live

Admission Fit Checker

A conservative admission-fit workflow that extracts academic profiles and compares them with program requirements.

Product design and full-stack implementation

  • Combined PDF extraction and Tesseract.js OCR for profile intake.
  • Made extracted fields reviewable before fit evaluation.
  • Kept local storage and AI explanation separate from the final user decision.

React · TypeScript · OCR · Tesseract.js · pdfjs · Zod

View projectGitHub