Mustafa Özpinar
Verified Expert in Engineering
Full-stack Developer
Ankara, Turkey
Toptal member since August 10, 2021
Mustafa is a highly motivated software developer and architect with 16 years of experience. He has led teams, architected and developed scalable microservice applications, and built DevOps environments, and his technical expertise includes Java, Spring Boot, Kafka, and cloud patterns. Mustafa values communication, agility, simplicity, and efficiency.
Portfolio
Experience
Availability
Preferred Environment
Kubernetes, Java, React, Spring Boot, C#.NET, Microservices, Back-end Development, Full-stack, REST APIs, Apache Kafka
The most amazing...
...things I've built were cloud tech stacks without an internet connection where it was challenging to develop and deploy microservices to on-premise servers.
Work Experience
Java Engineer
Enterprise Insurance Company
- Documented generation service based on Kafka events and REST requests.
- Collected data from other microservices, aggregated into a unified structure, rendered document with Aspose library, and uploaded to Amazon S3 storage.
- Featured based development with Split flags. Sent email, uploaded to SFTP, and set notification of partners via Webhooks.
- Set up a multitenancy, secure via Okta using JSON Web Token (JWT). It's a growing platform with new partners.
- Developed a new version of services with SAGA, CQRS, Event Modelling patterns, and new microservices for better scalability.
Software Engineer
Vishwam Corp
- Architected and developed SAML and OIDC-based IdP solutions for face recognition APIs.
- Designed the flow for both web and mobile applications.
- Developed authentication and user storage plugins for Keycloak.
- Integrated with external IdP solutions such as Okta, Google, and Microsoft.
- Created client applications for Android, Node.js, and Java.
- Provided load tests with JMeter, integration tests with Selenium, and test containers.
Principal Software Engineer
Priceline
- Developed a high-throughput microservice that transforms received data and publishes it back to Kafka.
- Tuned Akka, resources, and Kafka parameters, resulting in processing three times faster.
- Prepared New Relic dashboards; ran and analyzed load tests.
Software Technical Lead
Trendyol
- Developed payment back-end microservices for an eCommerce platform.
- Used Go for gateways and Java, Spring Boot, PostgreSQL, and Couchbase for back-end services.
- Scaled microservices to handle hundreds of thousands of requests per day.
Software Technical Lead
ASELSAN
- Served as the technical lead on a highly available and scalable operational and strategic-level C4I project based on microservices architecture.
- Led architects to design and build scalable microservices infrastructure to be used by many projects in the directorate.
- Created RESTful APIs and Kafka messaging for an eventually consistent system.
- Developed a release and version management tool for microservice-based applications.
- Participated in many NATO interoperability missions.
- Operated as a technical lead for teams when they needed advice, architectural guidance, complex scenario management, or help with debugging.
- Built the DevOps infrastructure for the team: created pipelines, managed repositories, and set up Sonatype Nexus and SonarQube. Also created an automated integration testing environment for the project.
- Delivered many company presentations on microservice architecture, DevOps, and coding best practices.
Lead Software Engineer
ASELSAN
- Developed a prototype infantry situational awareness system.
- Led a team of up to five developers to build a unit tracking system for the army. The system was integrated with other systems over REST, Web Services, and radio communication.
- Participated in many NATO interoperability missions. Used WS-Eventing, WS-Resource Framework, and REST APIs.
- Developed an RFID-based inventory management application.
Senior Full-stack Developer
ASELSAN
- Developed front-end and back-end parts for many standalone WinForms-based C4I systems containing launchers, artillery, and messaging software, using C#.
- Implemented many communication protocols based on TCP, UDP, and Web Services.
- Architected and became the most active developer in building the software product line (SPL) in the fire support domain and developed an SPL release management tool.
Full-stack Developer
LST
- Worked at the Turkish Patent Institute (TPI), maintaining many projects containing Java desktop applications, such as trademarks, patents, designs, laws, publications, and attorneys, and web applications for online requests.
- Developed new client-server-based projects, such as accounting, personnel, documents, and publication, using Java, Swing, J2EE, and Oracle.
- Built an XML-based online system for patent companies to apply for new applications using the website.
- Integrated online signing to existing online applications.
- Built an attorney tracking system used by attorneys to conduct their business.
Full-stack Developer
Sebit Information & Education Technologies Inc.
- Developed the UI and back-end services for the configuration feature of the administrator panel in the adaptive curriculum project.
- Handled load balancing for the application with Apache HTTP Server and Apache Tomcat using sticky sessions.
- Integrated with a business partner using SSO with a SAML protocol.
Experience
Microservice for Enterprise Company (Toptal Client)
Custom Identity Provider (Toptal Client)
Payment with Wallet
http://www.trendyol.com• Event sourcing with Axon framework
• CQRS pattern (PostgreSQL for events and commands and Couchbase for reading)
• Live system with high traffic
Java Kafka Library
Configurable features:
• Inbox/outbox pattern
• Priority queue
• Message retry
• Security with KeyCloak integration
• Log enrichment
• Message header transmission over REST to Kafka and Kafka to Kafka
• Breadcrumbs for messages
• Annotation-based command and event and command result handlers
• Annotation-based error handling
• Message transmission with large payload automatically over Redis
• Message tracing enabled with follow-up
Microservice Release Management Tool
It has the following features:
• CRUD on microservice definitions.
• CRUD on projects/products/product versions.
• Projects contain products. Products consist of microservices and selected versions.
• CRUD on release management. Users can define releases, select microservices and deploy to specified Kubernetes environments.
• Users can define Kubernetes environments (SSH connections).
• Release process can be monitored live.
• Users can log in.
• UI developed with React and PrimeReact library. Redux is used for state management.
• Back end exposes REST APIs as Spring Boot applications.
Quran Android Application
It has the following features:
• User can read and listen to pages.
• Pages and sounds can be downloaded optionally.
• Music can be controlled from the notification bar and lock screen.
• Selected play configuration can be saved to quickly use later.
• Page translation and commentary can be read.
• Page, translation, and commentary sources can be selected.
• Search from translation.
• Indexed search
• Settings contain font, storage, downloaded file management, background, etc.
• Share selected verse(s)
• Manage cache for performance
• Downloaded files are encrypted and decrypted when used.
Situational Awareness
Key activities:
• Developed an Android application for smartphones with GIS capabilities.
• Built an Android application for smartwatches.
• Designed and implemented software for smart glass.
• Integrated all hardware using the Bluetooth protocol.
• Published and gathered data with the team and C4I system.
A Software Product Line in the Fire Support System Domain
Sixteen different projects were produced from this SPL in five years with an average of 80% reuse. The team developed many of the tools that were required to manage the SPL.
Friendly Force Tracking System
Attorney Tracking System
Features:
• CRUD on trademark, patent, design, and geographical indications
• Bulletins published by the TPI can be loaded into the system
• Detailed search and alert mechanisms are available on existing bulletins
• Client management
• Workflow management
• Alert management
• Many kinds of reports based on the JasperReports tool
• Integration with TPI's XML-based application feature
• Payment tracking
Turkish Patent Institute Applications
Adaptive Curriculum
https://www.adaptivecurriculum.com/Education
Master's Degree in Information Systems
Middle East Technical University - Ankara, Turkey
Bachelor's Degree in Computer Science
Middle East Technical University - Ankara, Turkey
Certifications
AWS Partner: Cloud Economics Accreditation
Amazon Web Services Training and Certification
AWS Partner: Accreditation (Technical)
Amazon Web Services Training and Certification
Skills
Libraries/APIs
Windows Development, REST API, Smart GWT, Node.js, Akka Streams, React.js, Protobuf, Aspose Components
Tools
IntelliJ IDEA, Apache Maven, Apache Tomcat, Subversion (SVN), SonarQube, DOORS, IBM Rational ClearQuest, GIS, Keycloak, Apache HTTP Server, RabbitMQ, Android, Google Kubernetes Engine (GKE), OC4J, JDeveloper, Visual Studio Development, Git, Gradle, Apache, Git, Kibana, Grafana
Languages
Java, JavaScript, HTML, .NET, C, C++, CSS, Go, SAML, JavaScript
Frameworks
Spring, Spring Boot, Java, Hibernate, Angular, AngularJS, Android SDK, Akka, Java, .NET
Paradigms
Azure DevOps, Agile Development, Microservices Development, REST, Unit Testing, DevOps, Design Patterns
Platforms
Linux, Windows Development, Nexus, Eclipse, JavaFX, Docker, Kubernetes, Jakarta EE, Oracle Development, Apache Kafka, Bluetooth Low Energy (LE), Cloud Engineering, Visual Studio Development, Android, New Relic, AWS, Web Development, AWS
Storage
PostgreSQL, SQLite, MongoDB, Couchbase, Redis, Amazon S3
Other
Programming Languages, Software Engineering, Algorithms, Software Development, Web Services, Sparx Enterprise Architecture, Bluetooth, WS-Eventing, APIs, Architecture, Integration Testing, Verification, Networks, Ajax, RFID, Radio, Testcontainers, Computer Graphics, Data Science, Data Structures, SSO Engineering, Back-end Developers, Full-stack, OpenID Connect (OIDC), E-commerce marketing, SAML-auth, Business Services, AWS Cloud, AWS Partner Network (APN), Message Queues, Amazon WorkDocs, Prometheus, Cloud FinOps
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