Bilgesu Çakır Portfolio

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Bilgesu Çakır

Bilgesu Çakır

Software Development Engineer based in Istanbul. I build backend systems by day, currently at Hepsiburada, and spend my off hours shipping small side projects, crocheting, and hunting down the next film to watch.

bilgesucakir@gmail.com bilgesucakir bilgesucakir

Where it started

B.S. Computer Science & Engineering

Sabancı University · Graduated June 2023 · GPA 3.01/4.00

  • 75% scholarship, ranked in the top 2,500 nationally in the YKS university entrance exam
  • High Honour certificate ×2 terms, Honour certificate ×2 terms

Coursework that stuck

AlgorithmsData StructuresOperating Systems Computer NetworksComputer & Network SecurityDatabase Systems Software EngineeringMachine LearningArtificial Intelligence Mobile App Development

Where I've worked

Software Development Engineer

Hepsiburada, Istanbul · Aug 2026 - Current ·

  • Backend engineer on Customer Care, working on the core product agents use to resolve issues of sellers and customers
  • Built and maintained Java/Spring Boot microservices backed by PostgreSQL, using Kafka for async event-driven communication alongside REST APIs for synchronous calls between services
  • Used Docker for containerization, OpenSearch for logging and search, and BigQuery/SQL for data-side analysis
  • Owned features end-to-end: picked up tasks, fixed bugs, and handled database-level operations directly
  • Building domain experience in large-scale e-commerce

Software Development Engineer

Amadeus, Istanbul · Feb 2024 - Jun 2026 · 2 yrs 5 mo

Associate Software Development Engineer · Jul 2025 - Jun 2026

Junior Software Development Engineer · Feb 2024 - Jun 2025

  • Worked in the Order Management System under Nevio, building one unified order per traveller per IATA's One Order standard
  • Covered end-to-end travel processes, from flights to hospitality, working with airlines like Finnair, Air France-KLM, and Saudia
  • Built event-driven, service-oriented Java microservices (Spring, Quarkus, Maven) on Kubernetes/OpenShift
  • Wrote unit and integration tests with Quarkus + JUnit; diagnosed and fixed defects in mission-critical distributed systems handling live airline traffic
  • Proposed and led internal projects to streamline the department's dev process
  • 1st place, internal security/privacy bug bounty · 2nd place, Community Impact Hackathon (accessibility app, Flutter + Java)

Long Term Intern

Vodafone, Istanbul · Feb 2023 - Jul 2023 · 6 months

  • Part of the Payment Solutions team within Core IT, building and maintaining backend features with Java and Spring Boot
  • Gained first hands-on agile experience: sprint rituals, planning, and team collaboration

Information Systems Intern

Oyak-Renault, Bursa · Jul 2022 - Sep 2022 · 3 months

  • Joined the Information Systems department as part of the Orville Summer '22 programme, gaining first-hand experience with agile development practices
  • Designed and built a task management web app from scratch using Angular, Node.js, MongoDB
  • Took part in Orville Spark, a reverse mentorship programme connecting managers with younger colleagues

Learning Assistant

Sabancı University, Istanbul · Oct 2021 - Jun 2022 · 9 months

  • Supported instructors on CS201, Introduction to Computing
  • Helped students with course concepts and ran office hours, hands-on with C++

A year on one problem

Privacy-preserving MQTT messaging

Sabancı University · Sep 2022 - Jun 2023

MQTT is the messaging protocol half the IoT world runs on, and it leaks more than people assume. Working in a pair, we picked apart the protocol's weaknesses and designed three schemes to close them, covering confidentiality, authentication, authorisation, integrity and user privacy.

We then implemented all three across the server and client modules: ephemeral Diffie-Hellman for key exchange, authenticated encryption with AES, HMAC signatures and salting.

PythonMQTTDiffie-Hellman X.509AESHMACTopic hashing
Project report PDF · 120 pages Client Broker

What I build for fun

Shipped

Wingmark

Java · Spring Boot · Swift · iOS · Cloudflare R2 · MongoDB

Now on the App Store! A personal bird-logging iOS app. Log a sighting with photo, species, life stage, gender, location and notes, browse past logs on a map, look species up in a guide with photos and live call/song recordings, and earn badges along the way.

wingmarkapp.com iOS app Backend

What We'll Watch Tonight

Java · Spring Boot · Vue · Jsoup · TMDB API

Compares 2-4 people's Letterboxd watchlists and returns the films everyone already wants to see, linking straight back to each film's page.

whatwewillwatchtonight.comCode on GitHub

stitch-grapher

Java · Spring Boot · Treejs · Cytoscape

Parses text crochet patterns (repeats, increases, decreases, magic rings) into a stitch connectivity graph, then lays it out as a 2D or 3D visualization.

stitch-grapher.onrender.comCode on GitHub

In progress

veni-vidi-emi

Java · Spring Boot · Vue

“I came, I saw, I bought”: a map-based aggregator pulling secondhand listings from 2nd hand marketplaces, plotted by area.

Code on GitHub

Shaker

Java · Spring Boot · Vue · MongoDB

A cocktail app: recipes, guidelines, a personal diary, socializing and events

Code on GitHub

account-singularity

TypeScript

The ultimate extension. One master identity for signing up everywhere else, backed by an encrypted vault.

Code on GitHub

Jetlag Reset

Java

Reads flight details from your calendar and builds a sleep, rest and meal-timing plan around the trip.

Code on GitHub

stitch-modeller

Java

stitch-grapher's planned sequel: a comprehensive 3D modeller that takes the connectivity graph as input and renders the piece in three dimensions.

Code on GitHub

What I build with

Languages

Java Python C C++ C# Dart TypeScript JavaScript HTML CSS

Frameworks & platforms

Spring Boot Quarkus Hibernate / JPA Kubernetes Kafka RabbitMQ .NET Vue.js Angular Flutter Node.js

Databases

MySQL PostgreSQL MongoDB

Tooling

Maven JUnit Git Docker OpenShift Jira Jenkins SonarQube Postman Grafana

Beyond the code

Crochet

One of my passions. I make bags, plushies, clothing, scarves and berets, one project at a time. Documented (slowly) on Instagram

a_crocheters_diary

Film

Enjoying arthouse, especially Mediterranean cinema. Active on Letterboxd, which is what started the What We'll Watch Tonight project.

Flute

Classically trained on flute for almost ten years, with 20+ live performances, even one abroad. This is where I rest my soul.

Travel

Love historical sightseeing. Places visited so far:

GermanyFrankfurt AustriaVienna BulgariaSofia, Plovdiv, Stara Zagora FranceParis ItalyRome HungaryBudapest GreeceAthens, Chios

Video games

Mostly a fan of action-adventure and roguelike games. My favorite lately is Red Dead Redemption 2.

Birdwatching

Amateur bird watcher, and owner of the cutest pacific parrotlet.

Mixology

Trying out classical recipes as well as coming up with my own experimental ones.

Baking

Like trying new recipes and seeing a dessert come together from scratch.

Painting

Acrylic painting, mostly small canvases.

Fencing

Was a fencer for 8+ years as a national athlete, representing Türkiye at international tournaments.

Time given away

Make-A-Wish Türkiye

Volunteer · Jul 2026 - current ·

  • Helping plan and carry out wish-granting experiences that bring moments of joy and hope to children facing critical illnesses

Civic Involvement Projects

Sabancı University · Volunteer · Sep 2019 - Jan 2020 · 5 months

  • Ran weekly activities for primary school students as part of a university volunteer group, aimed at engaging kids in hands-on learning and creativity