Panagiotis Kanellidis profile photo

Panagiotis Kanellidis

Senior Backend Engineer & Open-Source Maintainer @ GitLab

panagiwthskan@gmail.com LinkedIn GitLab GitHub
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Engineering leader and open-source maintainer with experience scaling distributed systems, CI/CD platforms, and cloud infrastructure. At GitLab I work on CI pipeline architecture serving 10M+ daily workloads, lead security & compliance efforts, and build AI tooling for CI. Previously delivered cross-team AWS and data infrastructure at Babbel. Focused on resilient systems, mentorship, and measurable business impact.

Professional Experience

GitLab — Senior Backend Engineer
Sep 2023 — Present
  • Manage and scale CI pipeline system handling 10M+ pipelines/day and millions of daily transactions
  • Architected and optimized features across billion-row database tables, improving performance and reliability
  • Partitioned the CI database, doubling query performance, reducing system load and operational costs, and boosting customer satisfaction
  • Spearheaded security and compliance initiatives under tight deadlines, ensuring business continuity in restricted regions
  • Designed and implemented key roadmap features, contributing to a 20% increase in team revenue and customer acquisition
  • Built AI-powered tools for CI, now serving 10M+ daily requests
  • Drove and mentored community contributions, supporting open-source engagement
Ruby on Rails PostgreSQL Redis Kubernetes Docker GitLab CI/CD AI/ML Python
Babbel — Senior Software Engineer
Nov 2021 — Aug 2023
  • Led the introduction of user analytics to the B2B platform, delivering on schedule with full cross-team alignment
  • Designed end-to-end architecture including event pipelines, AWS services, and Infrastructure as Code, enabling seamless service integration
  • Ensured seamless and secure communication of services with AWS, achieving zero security incidents
  • Drove cross-team collaboration and objective setting, improving delivery efficiency
  • Adopted and hosted knowledge-sharing processes to enable effective contributions across teams
AWS Terraform Event Pipelines Ruby on Rails Infrastructure as Code Microservices
Babbel — Full Stack Engineer
Nov 2020 — Nov 2021
  • Introduced online migrations on the B2B project, eliminating deployment downtime
  • Main interviewer for mid and senior engineers; assisted in interviewing product managers, helping grow the team by 40%
  • Mentored and guided fellow engineers, improving team productivity
  • Contributed to architectural split initiative, dividing a product into two separate codebases, reducing complexity and improving maintainability
  • Tech stack: Ruby on Rails, React, AWS, Terraform, Docker, PostgreSQL, MySQL
Ruby on Rails React AWS Terraform Docker PostgreSQL MySQL RSpec Cypress GitHub Actions
Pest Pulse — Full Stack & Mobile Engineer
Apr 2020 — Oct 2020
  • Migrated organization portal from React.js to Stimulus.js, reducing load time by 1s
  • Optimized SQL queries, leading to load time improvements up to 50%
  • Implemented and maintained IoT Device Management Suite consisting of 3 portals, serving 1000+ IoT devices
  • Delivered performance-driven features, increasing traffic by 10,000 requests per day
Ruby on Rails React.js Stimulus.js PostgreSQL Flutter Dart Sidekiq Kubernetes RSpec GitLab CI/CD
INTRASOFT International — Java Software Engineer
Apr 2019 — Apr 2020
  • Built multinational social insurance product modules, with 4 countries showing interest before production
  • Jointly managed development of file parsing and data injection modules, integrated into 15+ other modules
  • Designed and optimized complex batch processes supporting more than 1M records
  • Ensured transaction security and stability in 5 different modules, each containing close to 100 transactions, achieving 99.9% uptime
Java EE Kafka Oracle SQL Hibernate Maven JSF JavaScript REST APIs JUnit JIRA