Senior Node.js and Golang Developers

About the job role

Who are we looking for?

We’re looking for seasoned developers who write clean, maintainable code and enjoy solving complex technical problems. You’re comfortable with both backend architecture and implementation, and you bring a thoughtful, pragmatic approach to building software. You’ve worked in cross-functional teams, contributed to product decisions, and understand the balance between speed and scalability.

If you're experienced with Node.js, and have some exposure to Go, you’ll feel right at home here.

What are we working on?

Train tickets. We sell them online, through our own platform and for other companies. It’s way more technically challenging than it sounds, with a mix of business logic, third-party integrations, and a strong focus on reliability and user experience. We deal with large volumes of search queries and large amounts of data.

What you’ll need to have

• Proficiency in Node.js (5+ years of experience)
• Good understanding of Go (2+ years of experience)
• Experience in designing and maintaining REST APIs and event-driven systems
• English at an advanced level (written and spoken)

What you’ll be doing

You’ll work across our core platform and on custom integrations for partners. You’ll help shape our architecture, lead by example in code quality, and collaborate closely with QA, product, and design teams.

• Design and develop scalable backend services
• Contribute to technical planning and architecture
• Improve performance, reliability, and maintainability
• Review code, mentor team members, and share knowledge
• Collaborate on DevOps and CI/CD processes

What we offer

• Flexible working hours; we care more about what gets done than when.
• Remote-first culture; communicate daily on Slack and Google Meet
• Work with like-minded people who are eager to solve problems and share ideas
• Opportunity to grow, develop, learn and move your career forwards
• Attend conferences and continue your professional development
• Regular team events in the UK, Poland and Switzerland

About Assertis

Assertis is a profitable, privately-owned company with a focus on building sustainable, high-quality software for public transport - especially for journey planning and rail ticket retailing and real-time info.

We’ve been established for 25 years; are lean, profitable, and product-focused; and have a fantastic international team with team members in England, Poland and Italy that values autonomy, accountability, and collaboration. On average, our technical team members have been with us for eight years.

We provide online journey planning and train ticket retailing in the UK. Our customers include train operating companies and partners like travel aggregator Omio. We are growing rapidly, both organically and through the acquisition of new customers. We process over 1 million journey searches every day, and sell over £200m worth of UK train tickets every year - about 5% of all train tickets sold online in the UK. We successfully compete with much larger companies, drive innovations in our space, and are well-known within the wider rail industry.

Every year we make a tangible difference to the lives of millions of people, by helping them to find and buy better value train tickets, and by being with them as they travel. We want to go much further, and to make public transport ticketing accessible, easily understood and friction-free.