Joakim Nylén
Backend Developer
Stockholm, Sweden
Backend Developer with 15+ years of experience architecting scalable systems and high-throughput data pipelines using Ruby on Rails and Elixir. Founded XMLTV.se, building EPG infrastructure that processes 460GB daily and serves major Swedish media companies. Proven track record delivering mission-critical platforms across gaming, finance, and government sectors while optimizing performance and ensuring GDPR compliance.
Work Experience
Backend Developer
- • Architected and developed a comprehensive outdoor adventure platform serving Nordic municipalities and counties, managing full-stack implementation from backend infrastructure to brand presence
- • Led successful migration from legacy Rails application to modern Elixir-based architecture, improving system performance and maintainability
- • Designed and implemented CDN strategies to optimize content delivery and enhance user experience
- • Executed GDPR-compliant infrastructure migration, transitioning services from US-based providers to EU data centers
Senior Ruby on Rails Consultant
- • Serving as Senior Backend Consultant for enterprise clients across financial services and non-profit sectors
- • Architecting scalable APIs and optimized database schemas for high-traffic production applications
- • Partnering with industry leaders including Borgo (Swedish bank), Volontärbyrån (Volunteer Agency), and Blendow Lexnova (legal news platform) to deliver mission-critical web platforms
Senior Ruby on Rails Consultant
- • Served as Senior Backend Consultant for enterprise clients across financial services and non-profit sectors, delivering production-grade applications
- • Architected scalable APIs and optimized database schemas for high-traffic applications
- • Partnered with industry leaders including Borgo (Swedish bank), Volontärbyrån (Volunteer Agency), and Blendow Lexnova (legal news platform) to deliver mission-critical web platforms
Founder & Developer
Pixelmonster
- • Founded and scaled EPG data infrastructure serving major Swedish media companies, establishing market-leading platforms including Honeybee.it and XMLTV.se
- • Built high-throughput data pipelines processing 460 GB daily with sub-second latency requirements
- • Delivered technical consulting and project management services, translating complex business requirements into scalable technical solutions
- • Managed end-to-end financial operations including client invoicing, payment processing, and fiscal compliance
Backend Developer
- • Worked on backend systems for gaming and nature platforms, handling high-volume concurrent users while maintaining performance and quality
- • Optimized heavily used code to reduce client expenses by $1,000 USD monthly
- • Led infrastructure migration from US to EU provider
- • Managed framework and language version migrations across multiple projects
- • Built and maintained internal systems for project management and GDPR (PII) data compliance
- • Served as technical liaison between clients and third-party providers (banks, municipalities) for feature requests and data integration
- • Maintained development environment including GitHub Actions and Docker
Education
Web Developer E-commerce
Changemaker Educations
Comprehensive program covering web development, e-commerce solutions, digital marketing, UX/UI design, and both frontend and backend programming. Included industry knowledge, project methodology, and practical work experience (LIA).
Open Source Projects
mrml-rails
Handle MJML templates in Ruby on Rails with ease. A popular gem for building responsive email templates.
String Matcher
Match strings to valuable data in Elixir. Powerful string matching and parsing utilities.
xler
Parse Excel files in Elixir using Rust. High-performance XLSX parsing with native bindings.
Vind
The project that handled the import of TV data for XMLTV.se. Robust data pipeline architecture.
Metagraph
A metadata database in Elixir. Flexible schema for storing and querying metadata at scale.
PST
Paste and Share Tool - A Rust command-line application for uploading files and pastes to multiple sharing services with automatic prioritization and fallback.
Skills
Expertise
Languages & Frameworks
Languages
Key Achievements
Founded XMLTV.se and built EPG data infrastructure processing 460 GB of incoming EPG files from TV channels daily, serving thousands of users and major Swedish media companies for 15 years
Created mrml-rails gem, now used by thousands of developers for responsive email templates in Ruby on Rails
Architected high-throughput data pipelines handling millions of records daily for media distribution
Delivered production systems for multiple enterprise clients as Senior Ruby on Rails consultant