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

PythonDistributed SystemsEvent driven environmentTechnology LeadershipMentoring & Team LeadershipSystem design & SLO-driven developmentMicroservicesDockerDocker SwarmKubernetesArgoCDRabbitMQKafkaMQScyllaDBClickHousePostgreSQLFlaskREST APIsopenapiGrafanaLinuxCentOSRockyOSJenkinsGitLab CIGithub ActionsArtifactoryHigh-volume processingExtract, transform, load

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.

RL Classification Algorithm

Building and maintaining ReversingLabs classification backend. This is a high volume, event driven set of reliable services that classify billions of files.
PythonScyllaDBKafkaMQK8

Spectra Assure Community

We built secure.software, a platform for assessing and monitoring open-source packages and software supply-chain security. This was a greenfield project that I've led from its beginnning.
REST APIsMicroservicesQueues

Community User Accounts

When we were adding user accounts to secure.software, I researched best practices, defined recommended approaches with possible alternatives, build and present a POC and then quickly implemented it.
Auth0OAuth2.0ResearchPOC

Experience

Roles and responsibilities.

A quick overview of my most relevant roles.

  1. 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. 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. 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. 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. 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. 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.