Dimitrios Apostolakis

QA Automation & Performance Engineer

I build systems that make quality inevitable.

About

Dimitrios Apostolakis - QA Automation Engineer

Born in Athens, raised in Metamorphosis Lakonias — a small village near Monemvasia that teaches you patience, resilience, and the value of doing things properly. I hold an MEng in Electrical & Computer Engineering from the Technical University of Crete, where my thesis applied reinforcement learning to optimize building energy systems, reducing electricity costs by 31%.

Today I design and build test infrastructure at enterprise scale. From 400+ E2E tests at Österreichische Post to performance frameworks processing millions of requests at HF Markets — I obsess over the systems that make quality a property of the architecture, not an afterthought.

When I am not engineering test systems, I am exploring AI orchestration, reading about systems thinking, or planning my next move from my apartment in Athens.

Experience

HF Markets

Jan 2026–Present

QA Automation / Performance Engineer

Built enterprise k6 load testing framework from scratch covering 8+ microservices with automated Jenkins execution, gRPC metric collection, Vault integration & database-backed trend analysis
Delivered 20+ load test campaigns in 6 months validating AWS migration, Redis cluster refactoring, and wallet API rewrite across prod & pre-prod
Engineered self-service Jenkins pipeline with Active Choices for dev teams, automating 6+ hours/week of weekend performance runs and eliminating manual overtime
Designed Cloudflare WAF validation suite covering rate limiting, custom firewall rules, OWASP core ruleset, and bot mitigation with zero false positives on legitimate traffic
Supported MT4/MT5 parallel trading load tests using Locust with 12 terminal instances and database-driven execution schemas

Openbet / Opap

Apr 2024–Jan 2026

QA Automation Engineer

Automated API & UI testing using Java, JUnit, Selenium, and Cucumber — cutting manual effort by 70% with 85% regression coverage across component, app group, and integration levels
Executed containerized test workflows using Docker, Kubernetes & ArgoCD, achieving 75% faster environment setup and parallel test execution across service versions
Maintained Jenkins CI/CD pipelines running 3,000+ automated tests per release cycle at 95%+ pass rate, identifying flaky tests via trend analysis
Led peer code reviews and mentored 3 engineers; validated backend systems using SQL, Spring RestTemplate, AssertJ & Postman

Agile Actors / Österreichische Post

Feb 2023–Apr 2024

Software Engineer in Test

Optimized CI/CD test runtime by 80% (25 min → 5 min) and local runtime by 90%, cutting infrastructure costs and raising developer productivity
Developed 400+ E2E tests for critical user flows in C#/.NET & Playwright, building nightly pipelines for cross-browser testing across 5 device profiles
Introduced WireMock backend integration tests covering 30+ API endpoints and axe-core accessibility automation for WCAG AA compliance across public pages

Hellenic Army IT Center

Mar 2022–Dec 2022

Software Engineer

Engineered Python web scraper recovering and migrating content from 45 WordPress sites while preserving data integrity during full infrastructure transition
Automated R simulation reports, reducing manual data processing time by 90% and accelerating strategic coordination exercises

Skills & Tools

Languages & Core

TypeScriptJavaScriptPythonJavaC#/.NETSQLBashgRPCGitHTML/CSS

Testing & Automation

k6LocustPlaywrightSeleniumCucumberJUnitWireMockPostman

Cloud & Infrastructure

JenkinsDockerKubernetesAWSAzureCloudflare WAFHashiCorp VaultGitLab CI/CDArgoCD

Observability & Metrics

GrafanaPrometheus

Practices & Strategy

Performance TestingLoad TestingSecurity TestingCI/CDTest Automation StrategyDevOpsAgile/ScrumBDD

Featured Projects

Playwright Test Automation Suite

Cross-browser end-to-end test automation suite using Playwright, Page Object Model (POM) architecture, and parallel test execution in JavaScript.

PlaywrightJavaScriptNode.jsE2E Testing

Selenium Automation Framework

Robust UI test automation framework and workshop codebase with Selenium WebDriver, Docker Grid support, and cross-browser testing patterns in Java.

SeleniumJavaDockerJUnitTest Automation

JUnit 5 & Mockito Testing Suite

Comprehensive Java testing suite demonstrating deep Mockito mocking patterns, parameterized testing, lifecycle extensions, and AssertJ assertions.

JUnit 5MockitoJavaAssertJMaven

TDD by Example Patterns

Hands-on implementation of Test-Driven Development (TDD) principles, incremental unit test design, and continuous refactoring in Java.

TDDJavaJUnit 5Clean CodeRefactoring

Data Structures & Algorithms

Algorithm implementation library covering graph traversals, sorting techniques, search optimizations, and data structure benchmarks in Java.

JavaAlgorithmsData StructuresPerformance

FundRaiser Platform

Cloud-enabled crowdfunding web application featuring campaign management, pledge tracking, and responsive web layout.

C#ASP.NETBootstrapCloud Architecture

Philosophy

Systems over scripts. I do not write tests — I build infrastructure that makes quality inevitable.

The best testing framework is one developers actually use without being asked.

Taste, direction, and relationships — the three things AI cannot replace.

From a small village in the Peloponnese to building systems that handle millions of requests. The path was never linear, but it was always intentional.

Get In Touch

Have a project in mind, a question about test automation, or want to discuss engineering infrastructure? Send me a message below.