Full Stack Developer

Baran Kaplan

Full Stack Developer with a strong focus on Java and Spring Boot backend systems, practical DevOps and CI/CD work, and frontend development with React and Next.js.

Read my story

My background, career transition into software development, and life in Germany.

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Experience, education, and technical profile.

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Selected projects, demos, and implementation work.

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Work Areas

Backend is my core area. Around it, I work with delivery, infrastructure, and frontend pieces that help product features move from idea to running system.

Backend Engineering

I build Java and Spring Boot services that model business flows clearly and stay maintainable as systems grow.

My focus is the part behind the endpoint: service boundaries, API contracts, persistence, transactions, integrations, validation, security, observability, and tests that make behavior easier to change and debug.

Java and Spring Boot service design
Domain logic, use case flows, and boundaries
REST, SOAP, gRPC, and external API integrations
Persistence, migrations, and transactions
Security, validation, errors, and observability
Unit, integration, and API testing

Delivery & Infrastructure

I work on the delivery side where code becomes a running service: pipelines, environments, GitOps, configuration, and runtime feedback.

The goal is not to list tools, but to make releases understandable: clear stages, promotion gates, deployment automation, traffic routing, secrets, and operational checks.

CI/CD pipeline structure and quality gates
Build, test, and promotion flows
GitOps delivery with Argo CD
Deployment automation and environment strategy
Traffic routing, reverse proxying, and mesh concepts
Secrets, configuration, and SecOps awareness
Logs, metrics, health checks, and rollout support

Product Frontend

I build React and Next.js interfaces for features where the UI needs to understand backend behavior, not just display screens.

The emphasis is practical product UX: routing, data loading, forms, client state, auth, loading and error states, and components that keep full-stack features coherent.

React and Next.js product interfaces
Routing, SSR, and data loading
API-connected forms and client-side state
Loading, error, and auth flows
Responsive and accessible layouts
Reusable component patterns

Portfolio

Projects that show the kind of backend, integration, and product work I build in practice.

Case studyLive demoReact / Next.js

Quiet Spot Finder

A product case study built in React and Next.js around calm-place discovery, protected live data access, shortlist workflows, and compare mode.

Protected live mode
Provider-backed search
Shortlist and compare flows

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Product labJava / Spring BootK3s ready

Equality Lab

A Java and Spring Boot product lab for designing equals/hashCode rules, domain identity, inheritance behavior, JPA proxy safety, and collection contracts.

Interactive equality workbench
Domain-aware equality rules
JPA and inheritance failure modes

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Backend to platformGitOpsK3s

From Backend Developer to an Observable K3s Platform

How a backend developer moved beyond application code, built and operated a single-node K3s platform, struggled with production boundaries, and turned each incident into a reusable engineering lesson.

Commit-to-runtime delivery map
Real failure and recovery stories
Metrics, logs, traces, traffic, and cluster state

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Production trafficDefense in depthIstio / Envoy

Cloudflare, Istio and Envoy: An Explainable Defense Path

A production traffic case study showing where automated probes stopped, what each security layer could prove, and why Cloudflare and a Kubernetes service mesh solve different boundaries.

Anonymized runtime evidence
Control-plane and data-plane map
Security outcomes tied to resource impact

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Blog

Security

Privacy-First Event Forms: From Chaotic UI to a Trustworthy Boundary

Part one of a production case study: how a confusing event registration form became a clear, bounded, purpose-aware privacy boundary.

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Security

Removing Access Tokens from Browser JavaScript with an HttpOnly BFF

Part two of a production case study: moving bearer tokens behind a constrained same-origin BFF session and defending the new cookie boundary.

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Security

Encrypting Dynamic Form Answers with KMS Envelope Encryption

Part three of a production case study: protecting dynamic form answers with per-owner data keys, AES-GCM, bound context, and rotation-safe metadata.

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DevOps

Rolling Out Encryption Safely with Liquibase, Backfill, and K3s

Part four of a production case study: introducing encrypted storage without downtime through compatibility modes, bounded backfill, and explicit rollout gates.

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Backend

What AI Could Not Infer from the Error Message

A production debugging story about optimistic locking, missing API contracts, misleading green signals, and the evidence an engineer still has to own.

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Backend

Getting Started with DDD

A simple introduction to DDD and where it fits in backend systems.

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Backend

Building Backend Systems with Java and Spring Boot

A practical look at structure, validation, and API basics.

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DevOps

Starting Kubernetes with the Right Mindset and a First Realistic Lab

A mindset-first introduction to Kubernetes, covering cluster roles, scheduling rules, and a realistic first local lab with Minikube, PostgreSQL, Adminer, and Headlamp.

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DevOps

Kubernetes Terms and Concepts

A practical Kubernetes reference page with beginner, intermediate, and advanced concepts, plus a quick index for jumping between terms.

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Frontend

What to Know Before Learning React

The basics worth understanding before starting React.

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Contact

Let's talk about backend-focused full stack work.

If you are hiring for Java, Spring Boot, DevOps, or product-facing frontend work, send a message or start with the CV.

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