Esref Ozturk, Software Developer in Ankara, Turkey
Esref Ozturk

Software Developer in Ankara, Turkey

Member since February 8, 2018
Esref has been programming for several years now and has previously worked at Udemy. Currently, he's completing his master's degree in computer engineering at METU. Esref is eager to learn new things and excited to work on fantastic, cutting-edge projects. He joined Toptal because he wanted to work with a wider clientele on international projects.
Esref is now available for hire




Ankara, Turkey



Preferred Environment

Git, Vim Text Editor, Linux

The most amazing...

...thing I've built is a sleep-tracking system that detects a user's sleep states and disorders like apnea.


  • Co-founder

    2017 - 2020
    Drive Buddy
    • Implemented car accident detection using machine learning.
    • Developed the Android and iOS SDK for collecting sensor data.
    • Built the driver score dashboard with Angular.
    • Implemented driver data and Score API with DRF.
    Technologies: Machine Learning, Angular, MySQL, Django REST Framework, Django, Objective-C, Swift, iOS, Java, Android
  • Software Engineer

    2016 - 2017
    • Researched and developed a search functionality for
    • Designed and developed REST APIs.
    • Wrote unit and E2E tests.
    • Implemented Elasticsearch cluster provisioning.
    • Maintained the Django code running on CentOS.
    Technologies: Amazon Web Services (AWS), React, Angular, Django REST Framework, Elasticsearch, Django, Python
  • Software Engineer

    2016 - 2016
    STM Defence Technologies & Engineering, Inc.
    • Researched and developed an automated hardening platform for many systems including various operating systems (Windows, Linux, FreeBSD), web servers, and mail servers.
    Technologies: Django, Python
  • Software Developer

    2014 - 2016
    Cyber Warfare Lab, Labris Networks
    • Researched and developed Labris UTM, a CentOS-derived Linux distribution designed for unified thread management.
    • Patched a web content filtering program with C++.
    • Designed and developed configuration system for high availability using Python.
    Technologies: PHP, Unified Threat Management (UTM), LDAP, CentOS, PostgreSQL, Bash, Python, C++
  • Software Engineer

    2014 - 2014
    • Developed sample Hazelcast integration modules for Hibernate second level cache and Spring.
    Technologies: Spring, Hibernate, Apache Derby, Hazelcast, Java
  • Software Developer

    2014 - 2014
    TUBITAK (The Scientific and Technological Research Council of Turkey)
    • Developed a kernel module that provides multiple clipboards for Debian-based operating systems.
    • Wrote a configuration management script with Python.
    • Set up kernel hooks for detecting keyboard shortcuts.
    • Stored multiple clipboard items on Linux.
    Technologies: X11, Kernel, Python, C
  • Software Engineer

    2013 - 2013
    Kovan Research Lab
    • Developed a web application that lets instructors prepare exams according to their preferred criteria.
    • Created an automatic PDF generator which uses LaTeX.
    Technologies: LaTeX, MySQL, Django, Python, Ubuntu


  • Checkmate

    A web application for playing chess that runs GNUChess in the background.

    Technology Stack: Python, Django, JavaScript, Socket.IO

  • Book Chapter: Software-defined Network Security

    I have written a book chapter about software-defined network security.

    Abstract: The future networks are expected to lead a hyper-connected society with the promise of high social and economic value. The goal is to solve today's network problems and provide adequate security. Thus, future networks require a flexible infrastructure that is secure against cyber attacks. Software-defined networking (SDN) can be considered as one of the building blocks of upcoming networking technologies.

    In this chapter, the limitations of today's networks are first presented. Then, solutions to secure the networks with SDN components are given. This concept is referred to as “SDN for Security.” While SDN facilitates securing networks in general, it introduces additional challenges, mainly, the vulnerabilities of the SDN components such as the controller have to be addressed. Security for SDN aims at securing SDN assets and is discussed in the sequel. After reading this chapter, readers will obtain a comprehensive overview of the limitations of traditional networks, such as how SDN overcomes those limitations and the security issues thereof.

  • Nano Duel: Crypto Token-based Gambling Website

    I developed both back-end and front-end of the website from scratch. I also set up a nano server by myself to handle transactions and developed a dedicated transaction system for this website which was basically a primitive coin exchange system.

    Technologies: Python, Django, Nano, Vue.js, Semantic UI, MySQL

  • Content Management System for Hospital Screens

    Here, I developed a system where hospital staff can manage the content displayed on the screen throughout the hospital. The system also had the capability to give directions to patients.

    Technologies: Python, Django, Django REST Framework, Angular, PrimeNG, MySQL

  • Crypto Metrics Delivery Platform

    I have worked on a project for creating Crypto Data APIs. Data includes chain metrics like circulating supply and exchange metrics like volume data.

    Technologies: Python, AWS (Lambda, CloudWatch, Redshift, S3, Kinesis Firehose, EC2), Crypto Exchange APIs, Blockchain Nodes

  • Equine (Horse) Fitness Tracker

    I've worked on the maintenance and redevelopment of existing Equine Fitness Tracker apps for iOS and Android.

    Technologies: Android, iOS, Java, Objective-C

  • Hypnos

    This is a personalized sleep tracking and analyzing system that focuses on optimizing people's sleep.

    Technologies: Deep Learning, Machine Learning, Big Data, Python, Django, JavaScript, Android, Arduino, Raspberry Pi

  • Multiclip | Multiple Clipboards

    This is a kernel module that provides multiple clipboard capabilities using X11 on Debian-based operating systems.

    Technology Stack: C, Kernel Hooks, Python

  • Deep Learning Social Media Comment Classification

    This classifies user comments in social media groups with opposing views. The goal of this project is classifying user comments into social media groups with opposing views. In the scope of this project, comments on Turkish and English pairs of Facebook pages are classified with decurrent neural networks and convolutional neural networks.

    Technologies: Deep Learning, LSTM, CNN, Keras, Python, Django

  • Integrity and Origin Authentication of QR Codes

    I added an authentication layer to QR code encoding and decoding parts. It prevents man-in-the-middle attacks.

    Technologies: Python, Cryptography, Asymmetric Key Encryption, RSA

  • PDF AutoBookmarker Application

    I developed an application for Windows and Mac OS to add the table of contents bookmarks to PDFs automatically. I also developed a packaging system for both Windows and Mac OS.

    Technologies: Python, wxPython, PDFMiner, PyPDF2

  • Photicon

    I developed a mobile application, called Photicon that detects what emotion is on your face and filters your photo by adding related emojis. It also gives a score for the emotion showing on your face. You can get great filters with emojis that shows your current emotion.

    You can see your dominant emotion emojis and the percentage of each emotion. It eight different emotion categories.

    Photicon detects the following emotions: happiness, sadness, fear, anger, surprise, disgust, contempt, and neutrality.

    Photicon lets you use photos that contain more than one face. Get a photo of a group of people and let the Photicon handle it.

    Technologies: iOS, Swift, Microsoft Emotion API

  • Wubble

    Wubble is a movie-themed social network built for Android.

    Wubble has a Twitter-like user interface, where you can follow other users, send Wubbles, and read their Wubbles. You can share your thoughts about a movie via Wubble. You can follow people, read, like, dislike their Wubbles. You can start a discussion about a movie by commenting one of your friends Wubbles and see movie scores from different websites such as IMDB, Rotten Tomatoes, and Metacritic.

    Technologies: Android, Java, Parse, Rotten Tomatoes, TMDb, OMDb

  • Color Crunch

    Color Crunch is the simplest but the hardest game. All you have to do is match the colors with their names in a limited amount of time.

    Technologies: Android, Java

  • Cubix Game | Cube Catch

    This is a casual arcade-type game. Tap the right colored buttons when the cubes are in the middle of the rectangle.

    Technologies: iOS, Swift

  • Space Utilization Visualization

    I developed a website that shows off a room's assets (chair, table, and so on) using visualizations. A lambda function gets raw data from AWS S3 bucket and returns visualization data which is used by the static web page.

    Technologies: AWS, Python, HTML, CSS, JavaScript, PowerBI, AWS Lambda, AWS ELB, AWS S3

  • Device Management System

    I developed a web page for companies to manage their devices (computers, monitors, and so on). They can import users from Google Suite, then assign devices to them. They can also easily track all operations of devices on a dashboard.

    Technologies: AWS, Python, Django, DRF, React, Docker, PostgreSQL


  • Languages

    C++, C, SQL, Python, Java, PHP, HTML5, HTML, JavaScript, Swift, Bash, Objective-C
  • Frameworks

    Django REST Framework, Django, Angular, Spring, Hibernate, ASP.NET MVC
  • Libraries/APIs

    REST APIs, Django ORM, Facebook Open Graph API, Alamofire, React, Azure Blob Storage API, Node.js, Vue, CocoaPods
  • Tools

    Apache, Vim Text Editor, NGINX, Gradle, PyCharm, Android Studio, Xcode, wxPython, Crashlytics, Git, AWS SDK, LaTeX, Travis CI
  • Paradigms

    Object-oriented Programming (OOP), Object-relational Mapping (ORM), Agile, REST
  • Platforms

    iOS, Android, Linux, Ubuntu, Apache2, Azure, Blockchain, CentOS, Kernel, Amazon Web Services (AWS), MacOS
  • Storage

    JSON, MySQLdb, Elasticsearch, PostgreSQL, MySQL, NoSQL, Azure Blobs, Relational Databases, Hazelcast, Apache Derby
  • Other

    APIs, Ubuntu Server, Blockchain Development, Data Visualization, Data, Machine Learning, Lambda Functions, X11, Ajax, SMTP, Python Performance, Unified Threat Management (UTM), LDAP, Asymmetric Encryption, RSA, Cryptography, Cryptocurrency, Encryption


  • Google Developer Challenge Scholarship in Android Development
    2017 - 2018
    Udacity - Online
  • Master's Degree in Computer Engineering
    2016 - 2018
    Middle East Technical University - Ankara, Turkey
  • Bachelor's Degree in Computer Engineering
    2011 - 2016
    Middle East Technical University - Ankara, Turkey
  • Certificate in MCNA - Network (Fast)
    2014 - 2015
    METU Continuous Education Center - Ankara, Turkey


  • Google Developer Challenge Scholarship
    NOVEMBER 2017 - FEBRUARY 2018
  • MCNA — Network (Fast)
    MAY 2014 - PRESENT
    Middle East Technical University — Continuous Education Center

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