Ramazan Yıldız, Developer in Istanbul, Turkey
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Ramazan Yıldız

Verified Expert  in Engineering

Full-stack Developer

Istanbul, Turkey
Toptal Member Since
January 20, 2020

Ramazan is a full-stack software developer and architect with over a decade of software development and a Master of Science degree in computer engineering. He is proficient in a wide variety of business applications and has proven expertise with Node.js, Java, Angular, and AWS technologies. Ramazan's contributed to mobile and web applications, including design, coding, and DevOps.


PrimeNG, Angular, Java, Microservices, Amazon Web Services (AWS)...
Cleardoc Inc.
Angular, Node.js, Socket.IO, Sequelize, NestJS, Redis, MySQL...
Angular, Apollo, GraphQL, Google Maps, RxJS, TypeScript, Web Development




Preferred Environment

Amazon Web Services (AWS), Angular, Java, Git, Node.js

The most amazing...

...project I've developed is the Siemens Digi Partner portal and mobile app.

Work Experience

Full-stack Java Developer for Global Investment Bank

2021 - 2022
  • Developing features and fixing bugs for a finance web application tool. PrimeNG and Angular 12 are used. Building unit tests for each change, using Jasmine and Karma.
  • Creating features and fixing bugs on many Java 11 microservices. Developing unit and integration tests.
  • Resynced an Angular project using its forked version. Created the Gitlab rebase branch from a forked repository, using the rebase branch as an upstream on the other project and managing a huge code propagation.
Technologies: PrimeNG, Angular, Java, Microservices, Amazon Web Services (AWS), Web Development, Java 8, Oracle, SQL, TypeScript, Test-driven Development (TDD), Algorithms

Full-stack Angular and Node.js Developer

2021 - 2022
Cleardoc Inc.
  • Implemented back-end features to the remote video creation product, creating REST and Socket.io APIs with NestJS and Socket.io, MySQL with Node.js and Sequelize, and video transcoding APIs together with Redis and Bul.
  • Worked on the web-based remote video capture product—a conferencing platform where participants join and capture 4K video remotely. Several scenarios are implemented for browser-based, end-to-end testing using Cypress.io and Puppeteer.
  • Developed UI features using Angular 12 and fxFlex layouts.
Technologies: Angular, Node.js, Socket.IO, Sequelize, NestJS, Redis, MySQL, Amazon Web Services (AWS), Cypress, Puppeteer, NgRx/store, Full-stack, Web Development, Java 8, SQL, TypeScript, Test-driven Development (TDD)

Angular Front-end Developer

2020 - 2022
  • Re-designed the PHP-based old portal as a new responsive Angular portal.
  • Used Google maps for displaying vehicles and animating vehicle movement histories.
  • Used an Apollo client for consuming GraphQL-based APIs.
Technologies: Angular, Apollo, GraphQL, Google Maps, RxJS, TypeScript, Web Development

Full-stack Angular and Java Developer

2021 - 2021
E4 Logics
  • Developed an Angular project with PrimeNG Poseidon theme and Angular 11, creating several complex pages following a responsive design. Jasmin and Karma are used for unit testing.
  • Developed back-end services with Spring Boot and Java 11. Financial data is processed with PostgreSQL and Postman is used for end-to-end testing.
  • Created a CI/CD pipeline and a quality system for testing. Angular and back-end services are deployed to AWS.
Technologies: PrimeNG, Material Design, Java 11, Spring Boot, PostgreSQL, Amazon S3 (AWS S3), Full-stack, Web Development, Java 8, Angular, SQL, TypeScript

Java Expert for a Ridesharing Platform

2020 - 2020
Fahrgemeinschaft.de GmbH
  • Contributed to the development of the ride2go.com ridesharing platform, a progressive web app with Ionic and Angular. Embedded to different portals and implemented several features and bug fixes during my 10-months engagement.
  • Used GitHub for issue tracking and preparing the PRs.
  • Responsively embedded ride2go.com in several portals using IFrame.
Technologies: Ionic 3, Angular, React, Gatsby, Spring Boot, Docker, Mobile App Development, Java 8, TypeScript

Full-stack Software Developer and Architect

2019 - 2019
  • Contributed to the development of a middleware integration software and implementation of a layer on top of a legacy telnet speaking airline ticketing system and this layer is finally opened as a modern Rest API. It handled flight booking, canceling, querying with pagination using telnet protocol; then mapping this telnet data with GSON library into Java POJO objects; and finally serving data as Rest services.
  • Designed and developed the management web site for flight disruptions of an airline company. This web application is used in the customers' intranet to automatically handle reservations (PNRs) of disrupted flights or manually handle these PNRs with the aid of SVG graphics. The site was developed in collaboration with a colleague of mine. The disruption solution algorithm was developed by another team. Mock rest services were created as integration points using Angular-in-memory-web-API. Swagger API is documented for the back-end team.
Technologies: Snap.svg, Swagger, Bootstrap, Angular, GSON, Telnet Protocol, RESTful Services, Spring Boot, Full-stack, Java 8, SQL

Full-stack Software Developer and AWS Architect

2018 - 2019
  • Architected, designed, and developed www.siemensdigipartner.com, www.russiadigipartner.com, Siemens Partner Web Portal, and Siemens DiGi Partner iOS and Android mobile apps from scratch. This portal and its mobile apps are designed for partners of Siemens and for customers of the targetted Siemens partners. The site was initially developed for Siemens Turkey then rolled out for Russia, Italy, and Brazil. The project has several modules for logged in users such as user and partner management, SAP stock query, stock share, partner performance dashboard, orders and logistics tracking, product price list, project special price request, sales campaigns, trainings, online support, marketing videos, shopping catalog, news feed, survey, email, and mobile push notifications. The development team consisted of one architect (me), two senior software developers, and one SAP expert.
Technologies: SAP, VPN, Amazon Virtual Private Cloud (VPC), Amazon EC2, Load Balancers, AWS Lambda, Amazon Cognito, Amazon Cognito User Pools, API Gateways, Amazon Route 53, Amazon CloudFront CDN, Amazon S3 (AWS S3), Amazon Web Services (AWS), MySQL, Spring Boot, Ionic 3, Bootstrap, Angular, Full-stack, Amazon API Gateway, Java 8, SQL, Cordova, TypeScript

Full-stack Software Developer and Architect

2018 - 2018
  • Implemented the Boto 3 Cognito Identity Provider flows with Python for runtime interaction with Cognito.
  • Deployed as AWS Lambda functions with serverless architecture.
  • Implemented also AWS Lambda custom authentication and authorization functions with Python for AWS API GW based web and mobile applications.
Technologies: AWS Lambda, API Gateways, Python, Amazon Cognito, Boto 3, Amazon Cognito User Pools, Full-stack, Mobile App Development, Amazon API Gateway, Amazon Route 53, Java 8, SQL, Production Support, Spring Boot, Cordova, TypeScript

Software Architect

2018 - 2018
  • Installed and configured a Docker-based Gitlab Runner instance on an Ubuntu AWS EC2 server which is located in a private AWS VPC subnet. Then registered this runner to the corporate GitLab Server via Secure VPN tunnel only.
  • Automated CI/CD pipeline for AWS Based applications (Java, Angular Web) of Siemens Turkey IT. Also automated legacy intranet Tomcat applications with this CI/CD pipeline using Cargo deployments. I designed and developed the entire process on my own.
Technologies: Docker, Continuous Delivery (CD), Continuous Integration (CI), GitLab, Git, Full-stack, Mobile App Development, Amazon Route 53, Web Development, Java 8, Oracle, SQL, SSL, Jenkins, Spring Boot, Cordova, TypeScript

Full-stack Software Developer and Architect

2017 - 2018
  • Architected, designed, and developed the www.kariyerlianne.com web site on AWS from scratch. The goal of this site was to help mothers with professional careers to find part-time, freelance, periodic, or project-based job opportunities that allow mothers to stay in business life while continuing to care for their children.
Technologies: MySQL, GitLab CI/CD, Amazon Web Services (AWS), Node.js, Bootstrap, Angular, Full-stack, Amazon API Gateway, Amazon Route 53, Web Development, Java 8, AWS DevOps, TypeScript

AWS DevOps Architect

2017 - 2018
  • Created an AWS VPN tunnel connected to the Siemens intranet in collaboration with global Siemens cloud team. Attached this VPN connection, and created an AWS VPC environment having four subnets with required resources; three of these subnets were private—routed only to the VPN gateway, and their resources were reachable from Siemens intranet and 1 is public-facing having a bastion host, internet gateway, and NAT gateway. This VPC was used for running Siemens Turkey IT applications. Mobile and web applications were developed based on this environment. And ongoing legacy intranet web applications (Tomcat web apps) and Oracle DB were migrated to this environment. The target was to reduce the running cost of IT applications to 10%.
Technologies: Amazon Virtual Private Cloud (VPC), VPN, Amazon Web Services (AWS), Full-stack, Amazon API Gateway, Amazon Route 53, AWS DevOps

Full-stack Software Developer and Architect

2016 - 2018
  • Designed and developed the Siemens Pocket mobile app and its back-end services. Ported Siemens TR intranet IT web applications as mobile apps inside this single Siemens Pocket mobile application.
  • Implemented the Annual Leave Request app where employees can see their remaining annual leave day balances, request a new annual leave request, and more.
  • Implemented the Business Approvals App where employees can see all their pending approvals raising from the different processes within the company. This app is a dashboard for all pending approvals of any employee.
  • Implemented the Lead Together mobile app for site technicians; when they are at a customer's for maintenance or service, they can negotiate with the customer and catch new maintenance, service, or project opportunities.
  • Implemented the Technician Intervention mobile app. Onsite maintenance operations are logged (expanses, hours, operations, pictures, and more) via this application and signed by the customer. PDF reports are generated and delivered via mail.
  • Implemented the 3i app. Employees have the possibility to suggest improvement ideas; upon measurable income, the idea owner earns money. With this process, high income has been obtained in the company.
  • Implemented the Shuttle Search app. Company shuttles, their destinations, and chauffeur contact info can be looked up.
  • Implemented the Meal Menu of the Day app, the most frequently used app within the company.
  • Implemented the Training Evaluation app. Corporate on-site training was evaluated with this app, saving paper and digitizing employee feedback.
Technologies: MySQL, Oracle Database, Spring Boot, Angular, Ionic, Full-stack, Mobile App Development, Amazon Route 53, Java 8, Oracle, SQL, Cordova, TypeScript

Full-stack Software Developer and Product Manager

2015 - 2018
  • Architected, designed, implemented, and managed the whole PDR process, the project execution system, and a web application for financial execution of ongoing projects of energy divisions in Siemens. More than 120 projects are managed on this system.
  • Completely designed and coded the PDR product. The PDR is highly complex in terms of business logic, consisting of around 120,000 lines of Java code churn. I also developed SAP interfaces and Excel data upload-export interfaces.
  • Acted as a product owner, organizing several meetings with in-company customers, defining the product roadmap, and executing the development.
Technologies: Oracle Database, Apache Tomcat, Hibernate, Spring, Vaadin, Full-stack, Java 8, Oracle, SQL

Full-stack Software Developer

2017 - 2017
  • Implemented the Purchase Order Survey web application and mobile responsive Vaadin application. The app is used by supply chain management (SCM) of Siemens Turkey. Survey questions with categories are prepared on this system and addressed to the SCM users for evaluation. The system has an SAP interface (SAP JCO) and SCM portal interface; surveys are manually prepared, automatically triggered by events from SAP system or SCM portal then sent via mail.
  • Implemented the ESP, Employee Search Page web application. ESP provides an employee search facility. Employee records on this page are linked to an LDAP database search page of Siemens Global as well which is useful to see further details of an employee. All Siemens employees are allowed to access this page. The application consists of a single web page including search criteria area, lazy loading listing table, and pagination widgets.
Technologies: Oracle Database, Spring Data, Spring Boot, Vaadin, Full-stack, Java 8

Full-stack Software Developer and Architect

2017 - 2017
  • Implemented the Siemens Turkey mobile app designed for partners of Siemens Turkey. For the admin area, a responsive web application was developed with Angular 4 and Angular Material Design components. Apache CouchDB NoSQL and Offline PouchDB JavaScript Database were used. CouchDB provided great Rest interfaces and delivered change notifications making the application very interesting.
Technologies: Ionic, Angular, Google Maps, JavaScript, PouchDB, NoSQL, CouchDB, Spring Boot

Full-stack Software Developer and Architect

2016 - 2016
  • Implemented the Oracle SCD Downloader app. This is a VB.Net middleware service developed for Siemens AG Österreich - Transformers Factory in Weiz city. The app connects to Oracle Database over ODP.NET (Oracle Data Provider for .NET), reads all of the employee data from an Oracle view, and stores it in a staging table on the SQL server. It then reads a subset of records from the staging table and updates/inserts these records into the target table on the same schema on SQL Server. The strength of this application is that no Oracle-specific client is needed to be installed in the release platform which is undesired and painful. This application is portable itself and uses Oracle Managed Data Access Client included in the release package which is sufficient for connecting to the Oracle at runtime.
Technologies: Microsoft SQL Server, Oracle 12c, ODP.NET, VB.NET, Spring Boot

Full-stack Software Developer and Freelancer

2015 - 2016
  • Developed the IGO4HEALTH Health Tourism portal. Designed and sold to an international customer, it contains an admin panel, a hospital access panel, a website, and a mobile application for iOS and Android. It targets health tourism and packages services for people seeking health services.
Technologies: MySQL, NGINX, Ionic, AngularJS, Node.js

Full-stack Software Developer and Product Manager

2014 - 2016
  • Implemented the ITA-MOR web app. The app is used for IT device management, management of PCs, and smart mobile assets of Siemens AG. The product is used in Austria, Russia, and Turkey regions of Siemens.
  • Managed the development process of the Milion project. Incorporated the business strategy management and business strategy process of Siemens Turkey on this web application product. Defined the software development guideline, inspected delivered codes and documents, and imposed standards on developers to ensure product quality.
  • Took product owner responsibility of several IT Java web applications. These applications were handed over and several CR packages were developed for these products and provided support to the customers.
Technologies: Oracle Database, MySQL, Apache Tomcat, Spring, Hibernate, Bootstrap, PrimeFaces, JSF

Senior Software Developer

2013 - 2014
Nortel Networks - Netaş
  • Analyzed the project's base modules, database design (using power designer), and mockup design for customer negotiation. Worked on proof of concept (POC) studies of tricky modules such as DB logging POC with Spring aspect-oriented programming, organization Chat POC (XMPP chat server and WebLogic server integration, web push technologies, chat DB design), Mailbox POC (DB and API design), and Spring EhCache integration.
Technologies: XMPP, Oracle Database, WebLogic, PrimeFaces, OmniFaces, JSF, Spring, Apache Maven, Spring Boot

Full Stack Software Developer & Architect

2012 - 2013
Nortel Networks - Netaş
  • Developed the KKTC E-Nüfus project, a population registration system for the Turkish Republic of Northern Cyprus (KKTC). The project was developed with one former senior developer (me), two testers, and three other developers hired later. This is the civil registration of vital events in Cyprus like birth, death, marriage, divorce, adoption, legitimation, recognition, etc. Acts like immigration, emigration, and change of residence are registered in the system. Also, all the population registries of the country are digitalized with this product.
Technologies: JAX-WS, Web Services, jQuery, PrimeFaces, JSF, Spring JDBC, Apache Maven, PostgreSQL, Spring Boot

Senior Software Developer

2010 - 2012
Nortel Networks - Netaş
  • Implemented a Swing framework-based JNLP client for Turkcell Technology. This Swing Client was developed for Turkcell Ayna Project and provides management, monitoring, paginated lazy data listing, filtering, and reporting modules; also developed a perfect dynamic auto-refreshing dashboard within this client using JfreeChart library.
  • Implemented a GSM service manager product for Turkcell Technology. Different IP-based services of Turkcell and their underlying application layer delivery protocols are defined with a common pattern named “Extensible Service Definition Language” (ESDL) which is basically an XML-based definition language that uses a basic XML Schema Definition (XSD) as a template for all service definitions. A user interface was developed for such a requirement with jQuery/UI and CSS3.
  • Contributed to the Turksat E-Devlet Secure XML Gateway project. Developed system management user interface phase. JSF2.0 framework and Primefaces 3.2 component suite are used.
  • Developed and designed several POC codes with jQuery and JSP Servlet stack for Turkcell, Turksat, and THY projects in national R&D of Netaş.
Technologies: Balsamiq, Wireframing, XML, Servlet, Jakarta Server Pages (JSP), CSS3, User Interface (UI), jQuery, JFreeChart, Java Natural Language Processing (JNLP), Swing, Spring Boot

Senior Software Developer

2010 - 2012
Nortel Networks - Netaş
  • Developed the UI and services of the Turkcell End To End Monitoring project. This is a GSM service data monitoring and management, deep packet inspection project, developed with two other colleagues.
Technologies: Oracle Database, Jakarta EE, WebLogic, PrimeFaces, JSF, Spring Boot

Senior Software Design and Development Engineer

2008 - 2010
Nortel Networks - Netaş
  • Intensively worked on an ATCA (advanced telecommunications computing architecture) project. The ATCA project is the hardware and operating system migrations of the next generation VoIP call server of Nortel Networks, namely gateway controller product (consists of 8 million lines of mainly C/C++ code).
Technologies: VoIP, Linux, C++, C

Researcher and Software Developer

2007 - 2008
Liris-CNRS, Lyon France
  • Developed an object description and detection algorithm using local image features like SIFT and SURF.
Technologies: Tracking, Object Detection, Sift Science, Image Processing

IEEE Conference

R. Yildiz, T. Acarman, Image Feature Based Video Object Description and Tracking, IEEE International Conference on Vehicular Electronics and Safety, July 24-27 2012, Istanbul Turkey

Book Chapter

Feature-Based Robust Description and Monocular Detection: An Application to Vehicle tracking.

Ramazan Yıldız, Tankut Acarman, Pages: 187–203, 2017 Published Online: 14 AUG 2017, DOI: 10.1002/9781119242963.ch8

Puppeteer App with Node.js 12 and AWS Lambda Serverless

I have developed a web portal that is deployed to AWS. This portal is running on AWS and it has a sign-up feature for B2B customers. B2B customers fill out their pieces of information during sign-up. They provide their tax numbers, tax office. Using these inputs their validity is checked with a Node.js application that I developed. Tech stack used include: Puppeteer, Node.js 12, AWS Lambda Serverless Deployment with AWS API GW. Basically, this Node.js app does web scrapping and validates applying B2B users company details from the public portal of the Revenue Administration Portal.


Java 8, Java, TypeScript, SQL, TypeScript 3, TypeScript 2, VB.NET, Python, CSS3, XML, C, C++, Python 3, JavaScript, HTML5, GraphQL, Java 11


Ionic, Angular, Spring Boot, Angular Material, Vaadin, Ionic 3, Spring, Swagger, Hibernate, Bootstrap, Spring JDBC, Swing, Jakarta Server Pages (JSP), AngularJS, JSF, PrimeFaces, NestJS, Cypress


Apache Maven, GitLab, Amazon Virtual Private Cloud (VPC), Amazon CloudFront CDN, Angular CLI, AWS SDK, Amazon EBS, Amazon Cognito, AWS CLI, Git, GitLab CI/CD, IntelliJ IDEA, Amazon Simple Email Service (SES), Apache Tomcat, Zuul, VPN, NGINX, Boto 3, Servlet, Balsamiq, Sift Science, Amazon Simple Queue Service (SQS), Eclipse IDE, Apple Push Notifications, Sequelize, Jenkins


Amazon Web Services (AWS), Amazon EC2, Oracle, AWS Lambda, Docker, Linux, Oracle Database, Jakarta EE, Firebase


Spring Data, Spring Data JPA, Spring Data REST, Amazon S3 (AWS S3), CouchDB, Amazon DynamoDB, PouchDB, PostgreSQL, Microsoft SQL Server, NoSQL, Oracle 12c, MySQL, Firebase Realtime Database, Redis


Amazon Cognito User Pools, Amazon API Gateway, AWS Certificate Manager, Web Development, Mobile App Development, AWS DevOps, Full-stack, Production Support, Cordova, Angular Bootstrap, SSL, Algorithms, Amazon Route 53, API Gateways, Load Balancers, SAP, RESTful Services, Telnet Protocol, ODP.NET, VoIP, Web Services, User Interface (UI), Wireframing, OmniFaces, XMPP, Image Processing, Object Detection, Tracking, Web Scraping, DocumentDB, WebLogic, Gatsby, Apollo, Material Design


RxJS, jQuery, Restify, Node.js, GSON, Snap.svg, Google Maps, JAX-WS, Java Natural Language Processing (JNLP), JFreeChart, Puppeteer, React, PrimeNG, Socket.IO, NgRx/store


Test-driven Development (TDD), Mobile Development, REST, Microservices, Continuous Integration (CI), Continuous Delivery (CD), Functional Reactive Programming, Functional Programming

2011 - 2013

Master of Science Degree in Natural Language Processing and Information Retrieval, Human Machine Interaction, Software Engineering, Performance Analyse of Computer Networks, Robotics.

Galatasaray University - Istanbul, Turkey

2007 - 2008

Master of Science Degree in Image Analyze, Image Synthesis, Advanced Modelization, Algorithmic & Discret Geometry, Document Image Analyze, Multimedia Compression.

INSA of Lyon (National Institute of Applied Sciences of Lyon) - Lyon, France

2003 - 2007

Bachelor of Science Degree in Computer Engineering

Galatasaray University - Istanbul, Turkey