Slaven Ostojić.



Software engineer with more than 10 years of professional experience in designing and developing enterprise software solutions in fintech, telco and health industries.

Passionate about software design and architecture, enjoy writing clean and well-tested code.

Active in local community, equipped with strong communication and leadership skills.

In love with my guitars, vinyl records, nature, snowboarding and chess.


ZIRA, Tuzla » Senior software engineer

May 2023 - Present

  • Working on client-facing, microservice, distributed, enterprise solution for the leading provider of telecommunications services in Saudi Arabia.
  • Working on electronic invoicing product integrated with ZATCA.
  • Designing and developing new services and features in order to improve solution functionality.
  • Supporting and fixing existing solution.
  • Improving existing system through automation and optimisation (i.e. speed-up validation step up to 100 times).
  • Developing internal tools to improve software support process and reporting.

Salt Square, Tuzla » Senior software engineer

March 2022 - May 2023

  • Designing and developing large-scale projects for different clients, working on front-end, back-end, database and infrastructure layers.
  • Designing and developing a full-stack solution as a central consumer portal for one of the leading domestic appliances company.
  • Creating architecture and design, developing and testing feature flag service with custom and non-trivial condition logic used in the health-care industry.
  • Working and owning a few features in a large-scale, full-stack and HIPAA-compliant solution for COVID testing management.
  • Creating inventory register with Google SSO.
  • Creating web scrapers deployed in AWS with Terraform.
  • Mentoring younger colleagues and teaching them Unit testing and Spring Boot.

University of Tuzla, Tuzla » Developer / Contractor

February 2021 - December 2021

  • Developing tool for quality estimation at the university.
  • Defining requirements and scope of the project, front-end and back-end development, deployment and maintenance.

Infobip, Tuzla » Software engineer

April 2019 - February 2022

  • Working on distributed, data intensive enterprise microservice applications with main focus on stability, high availability, geo-redundancy, scalability and security.
  • Development and maintenance of Mobile number portability system for collecting raw data from FTP, SFTP, HTTP, HTML, email, S3, etc. sources, uniforming and storing processed data in permanent memory.
  • Maintaining and improving the USSD platform with over 3 million concurrent sessions.
  • Development of Voice bot solution with DTMF functionality, with focus on end-to-end testing.
  • Analyzing Email platform in order to redesign it to scale up and support 10x more traffic.
  • Mentorship and internship organization.

Marvelsoft, Tuzla » Senior software developer

September 2014 - March 2019

  • Developing solutions for algo trading and monitoring.
  • Working on a heavy legacy project; improving it to work as a plugin for the client’s order management system.
  • Starting a company’s major project from scratch, defining software architecture.
  • Working on FIX gateways and feed handlers to support different data sources.
  • Working as a project lead: defining requirements, organizing development cycles, prioritizing tasks, communicating with clients.
  • Working as a team lead: mentoring, tracking developers’ progress and empowering younger colleagues.

Other Activities

Agora center, Tuzla » Volunteer, teacher, trainer, mentor

March 2013 - Present

Faculty of electrical engineering, Tuzla » Teacher assistant

September 2018 - September 2021

Pecivo & Kafa, Tuzla » Coffee shop co-owner

February 2016 - November 2016


Faculty of electrical engineering, Tuzla » Master’s degree - Computer Science

September 2018 - Present

Faculty of electrical engineering » Bachelor’s degree - Computer Science

September 2010 – September 2014


  • C++, Java, Python, JavaScript, TypeScript;
  • C++ Actor Framework, Spring Boot, Flask, FastAPI, Node.js, Express.js, Next.js;
  • Unit testing, Integration testing, Testcontainers;
  • Hazelcast, Redis, Relational databases, NoSQL databases, Kafka, ActiveMQ Artemis;
  • Angular, React, Redux;
  • Git, Linux, Bash, Docker, AWS, Terraform, Kubernetes, Github actions, Jenkins, Prometheus, Grafana, New Relic;
  • Asterisk, FreeSWITCH;