Senior Ruby on Rails Developer

Full-time · Johannesburg (hybrid) · Engineering

Your code clears the gate at Ultra while sixty thousand people are standing in front of it.

Howler builds the technology behind live experience — ticketing, access control and cashless payments in one system, trusted across more than 20 countries and used by some of South Africa's biggest events: Ultra South Africa, Comic Con Africa, Black Coffee Weekender, MTN Bushfire. Millions of tickets, payments and check-ins flow through the platform every year, and a great deal of it has to work with no network and no second chance.

We are hiring a Senior Ruby on Rails Developer to take ownership of significant areas of that platform — leading the technical implementation of complex product work, shaping the architecture underneath it, and raising the engineering bar for everyone around you.

This is a hands-on product engineering role. Most of your time is spent building: features, APIs, data models, the tooling that makes the next feature faster. It is not a management track.

The job

• Own an area. Design, build and maintain features across our Rails applications, and lead complex initiatives from planning through to deployment.
• Turn ideas into product. Work directly with Product and Design to make intuitive, scalable customer experiences — not to receive tickets.
• Design the seams. Clean APIs and integrations, internal and third-party, that hold up when a partner changes something without telling us.
• Make it fast and keep it up. Improve performance, scalability and reliability, and optimise data models for high-volume transactional workloads.
• Write Rails other people enjoy inheriting. Clean, well-tested, conventional code, and the judgement to know when a convention should be broken.
• Use AI properly, and teach it. Use AI across the development lifecycle to move faster, then critically review, test and improve what it produces. Help the team adopt it without letting standards slip.
• Keep the architecture honest. Evolve it deliberately and keep technical debt a decision rather than an accident.
• Ship the whole way. Contribute to deployment pipelines, infrastructure and developer tooling; help investigate production issues and fix the cause, not the symptom.
• Prototype what's next. Explore AI-powered product capabilities where they create measurable value for organisers and fans.

You, ideally

• 6+ years of professional software development, with deep production experience in Ruby on Rails
• Strong Ruby, Rails conventions and the wider Rails ecosystem
• Building and consuming REST and GraphQL APIs
• Strong SQL and PostgreSQL — you reach for `EXPLAIN` before you reach for a cache
• Designing scalable application architecture and domain models
• Background job processing and asynchronous workflows (Sidekiq or equivalent)
• Cloud-hosted applications, automated testing and CI/CD
• Comfortable across the full stack, including modern JavaScript
• A product mindset — you care what the change does for the customer, not only that it merged
• Excellent communication, and genuine enjoyment in mentoring other engineers

AI fluency, and we mean it. At Howler this is table stakes for a senior engineer, not a bonus line. You should already be using AI assistants — Claude, Copilot, Cursor, ChatGPT or similar — as part of daily work: prompting well enough to get reliable engineering output, using AI for debugging, refactoring, documentation, test generation and architecture exploration, and reviewing what comes back with more scepticism than you would give a human colleague. We care far more about how effectively you use it than which tool you picked.

Our stack

Backend — Ruby on Rails · PostgreSQL · Redis · Sidekiq · REST & GraphQL · OpenTelemetry · Sentry · New Relic · Datadog

Frontend — Hotwire (Turbo & Stimulus) · JavaScript · TypeScript

Infrastructure — AWS · Docker · GitHub Actions · CircleCI

AI tooling — Copilot, Cursor, Claude, ChatGPT, MCP-compatible tools, LLM APIs

You do not need every item on that list. You do need curiosity and a habit of leaving tools better configured than you found them.

Bonus points for AI-powered product features, LLM APIs, agents and workflow automation, MCP, prompt evaluation, high-volume transactional systems, payments or fintech, Terraform, or serious performance profiling.

What success looks like

Within six to twelve months you are delivering complex initiatives with minimal oversight, trusted as a technical voice across the team, visibly improving the maintainability and performance of our Rails applications, and mentoring other developers — including on how to use AI without losing the plot.

Why this seat

Howler is small enough that a senior engineer's decisions stick. You will not spend a year negotiating your way to an architectural change. The systems are genuinely hard — real money, real concurrency, offline-tolerant hardware at the gate, and an immovable deadline called doors open — and the work is visible the moment it ships, because a crowd walks through it.

Howler is an equal opportunity employer. We welcome applications from all backgrounds and are committed to building a diverse team.