Transforming Billetto's Architecture with Event Sourcing and Event-Driven Design

Event Platform Case Study

Billetto × Arkency

Executive Summary

Billetto, a leading subculture event marketplace and ticketing platform in the Nordics, faced challenges with maintaining a large codebase, high response times, and handling traffic spikes. Arkency provided full-stack software architecture expertise, transitioning Billetto to an event-driven approach, improving CI/CD pipelines, and optimizing system performance.

Key Results:

  • Achieved full CI/CD – each commit is deployed to production automatically after passing tests.
  • Enabled rolling deploys – zero downtime, no maintenance mode needed.
  • Optimized response times – migrated operations to background jobs.
  • Enhanced maintainability – modularized codebase with clear context separation.

About Billetto

Billetto is a leading event marketplace and ticketing platform in the Nordics, catering to subcultures, independent event organizers, and communities. The platform enables users to discover events, purchase tickets, and manage event logistics seamlessly.

Challenges and Objectives

Billetto faced three major challenges with their platform:

  • Legacy Codebase Complexity:

    • A large and complex legacy codebase that made feature development slow and challenging.
    • An aging, custom-built system that was difficult to maintain and scale.

  • Performance Issues:

    • High response times, affecting user experience and performance.
    • Traffic spikes that could overload the system, especially during popular event launches.

  • Deployment Challenges:

    • Slow and risky deployment processes requiring maintenance windows.
    • Difficulty in implementing new features without disrupting the existing system.

Billetto's objective was to modernize their architecture, improve performance, and enable rapid, reliable deployments while ensuring long-term maintainability.

What Services Have Been Provided

Software Architecture

Transition to an event-driven architecture

Backend & Frontend Development

Refactoring and modularization

DevOps & CI/CD Optimization

Enhancing deployment pipelines

Collaboration with Product Owners

Planning new features with scalability in mind

What Was the Technology and Tools Used

Ruby on Rails

Core web application framework

Resque → Sidekiq

Efficient background job processing

Custom EventStore

Foundation of RailsEventStore (RES)

How Big Was the Team

A small team of 4-6 developers to maintain and develop the platform efficiently.

How Long the Cooperation Lasted

12 years and ongoing.

How Service Helped

Arkency's approach focused on incremental, high-impact improvements rather than disruptive "big-bang" changes. Key innovations included:

  • Shifting from a CRUD-based system to an event-driven architecture to improve scalability and maintainability.
  • Introducing background job processing to reduce response times and handle heavy workloads more efficiently.
  • Developing a custom EventStore, which provided a solid foundation for audit logs and historical tracking of user operations.
  • Implementing a fully automated CI/CD pipeline, allowing every successful commit to be deployed without manual intervention.

Results

1. Deployment & Infrastructure Improvements

  • Continuous Deployment: Every commit goes directly to production after passing the test suite.
  • Rolling Deployments: Updates are applied with zero downtime.
  • Live Data Migrations: Schema changes no longer require maintenance windows.

2. Performance Enhancements

  • Improved Response Times: Moving tasks to background jobs significantly reduced frontend latency.
  • Optimized Read Operations: Introducing read models improved response times for data-heavy pages.

3. Development & Maintainability

  • Faster Feature Development: Clear modularization and separated contexts enabled easier expansion.
  • Improved Maintainability: Despite the platform's large codebase, a small team of 4-6 developers efficiently maintains and develops it.
  • Enhanced Observability: Event-driven architecture provided full audit logs of user operations.

It is rare to find a technical partner where the collaboration feel like an extension of our own company.

Having worked +12 years alongside Arkency building out the Billetto platform I can endorse Arkency as a trusted strategic and operational partner.

profile picture
Patrick Borre
CEO at Billetto

Benefits

Technical Benefit

  • A more scalable, event-driven architecture.
  • Better system resilience with background job processing.
  • Easier maintenance and debugging due to clear separation of concerns.

Business Benefits

  • Faster time-to-market for new features.
  • Reduced operational costs by enabling a smaller team to handle a large codebase.
  • Higher platform reliability, leading to a better user experience and increased sales.

Why Choose Arkency?

Event Sourcing Expertise

Deep knowledge in Event Sourcing and Domain-Driven Design to build scalable architectures that last.

Long-Term Partnership

Proven track record of long-term collaborations, helping businesses evolve their platforms for over a decade.

Ruby on Rails Mastery

Deep expertise in Ruby on Rails and modern architectures to build robust, maintainable systems.

Full-Stack Capabilities

Comprehensive expertise from architecture and backend to CI/CD and DevOps for complete system transformation.

Incremental Improvement

Focus on incremental, risk-free improvements rather than disruptive "big-bang" rewrites.

Ready to Transform Your System?

If you're facing challenges with a legacy system, scalability issues, or want to modernize your platform with Event Sourcing & Event-Driven Architecture, get in touch with Arkency today.

Get in touch today!