Portfolio
Denis Mandic
Based in Europe: Zagreb, Croatia
Status: Happily Employed. Open to interesting opportunities.
I build thoughtful and resilient systems.
This site is a snapshot of my work: projects I'm proud of, experience across teams and products, and the skills I bring to new problems.
About
Leadership and Architecture
I’m a product oriented software engineer with more than 10 years of experience building high–performance backend systems and developer–facing tools and APIs.
I lead teams that deliver classification algorithms, APIs, and public–facing websites, aligning technical work with business priorities.
The most recent project that I've led over the last four years is building secure.software and the surrounding infrastructure from the ground up.
I’m comfortable designing architecture, building new projects as well as maintaining legacy ones.
I have managed multiple engineering teams end–to–end, from recruitment to performance management.
Skills
Strengths
- Led engineering teams bridging strategy and hands–on execution.
- Architectured, built and maintained SLO–driven, scalable, distributed ELT systems.
- Led cross-department projects spanning multiple teams and delivered on schedule.
Interests
- Designing simple and elegant backend systems and APIs.
- Building high–volume, high–performance services that handle large event streams and scale reliably.
- Improving developer experience, tooling, and automating repetitive work.
Projects
A small sample of work.
Distributed systems built for real-world impact.
Spectra Assure Community
Community User Accounts
Experience
Roles and responsibilities.
A quick overview of my most relevant roles.
- 1
Team Lead
ReversingLabs
Jan 2023 — Present
Tech Lead and people manager for two engineering teams: one building and maintaining the public secure.software site and another building core classification algorithms and APIs. Defining roadmaps, designing system architecture, and contributing hands-on to ensure delivery aligns with business goals. Managing people, conducting 1:1s, tracking goals and evaluating performance.
- 2
Principal Software Engineer
ReversingLabs
Feb 2022 — Jan 2023
Led the Cloud Algorithms team: owned architecture and delivery of distiributed backend services. Collaborated with stakeholders to design scalable, reliable microservices and improve system observability. Responsibilities included both hiring to expand the team and people management.
- 3
Senior Software Engineer
ReversingLabs
Feb 2020 — Feb 2022
Led the Cloud Algorithms team: designed features, mentored teammates, developed and maintained distributed microservices. Improved classification algorithms by measuring accuracy and reducing false positives/negatives.
- 4
Software Engineer
ReversingLabs
Jan 2018 — Feb 2020
Built and maintained Python microservices for malicious-file classification in an event-driven, Docker-based environment. Integrated services via queues and exposed functionality through REST APIs.
- 5
Junior Software Engineer
ReversingLabs
Mar 2017 — Jan 2018
Contributed to Threat Intelligence tooling. I developed internal data extraction tools and several Dockerized microservices, including a public REST API.
- 6
Data Analyst
ReversingLabs
Feb 2015 — Mar 2017
Student internship. Supported tier-2 customer support while automating reports and building internal tools for data analysis and operational reporting.
Get in Touch
Open to exceptional opportunities
I'm currently focused on my role and not actively seeking new work. However, I'm always open to discussing full-time roles that offer significant growth, competitive compensation, and top-tier benefits. If you have a high-impact role in mind, I'd love to hear from you.

