Trainline

Responsibilities Deliver new functionality or features, using the most appropriate tools & techniques Ensure quality is at the heart of everything you and your team do Continuously improve the code base Keep our customer as the number one priority Actively identify blockers, boulders, time sinks and waste, and actively attempt to remove them Make significant contribution to technical decisions Act as a coach and mentor to others in the team Take full ownership of the development lifecycle from code to production, including deployment and monitoring Tech Stack Languages & Frameworks: C# (.NET 6-10) Databases: DynamoDB, PostgreSQL Cloud & Infrastructure: AWS Cloud, Docker, Terraform CI/CD & DevOps: GitHub Actions Monitoring & Logging: New Relic, ELK Stack Qualifications Experience mentoring less experienced engineers and comfortable pair-programming with colleagues Hands on experience with C# .NET and the latest features Experience collaborating with front-end engineers and other disciplines to deliver end-to-end features and cross-functional epics Experience working with identity and authentication systems (e.g. IdentityServer, OpenID Connect, OAuth2) Experience designing and maintaining CI/CD pipelines (e.g. GitHub Actions, TeamCity, Spacelift or similar tools) Experience with cloud platforms (AWS preferred; Azure or GCP also valuable) Hands-on experience with Infrastructure as Code, particularly Terraform Strong experience with observability practices (logging, monitoring, alerting) Familiarity with tools such as New Relic and ELK stack (or equivalents) Curiosity about AI and emerging tools Experience supporting production systems and improving reliability Strong experience building and operating microservices architectures Experience with event-driven systems and asynchronous messaging patterns Solid understanding of distributed systems and scalability challenges Have excellent communication skills Benefits Enjoy fantastic perks like private healthcare & dental insurance, a generous work from abroad policy, 2-for-1 share purchase plans, an EV Scheme to further reduce carbon emissions, extra festive time off, and excellent family-friendly benefits. We prioritise career growth with clear career paths, transparent pay bands, personal learning budgets, and regular learning days. We're operate a hybrid model to work and ask that Trainliners work from the office a minimum of 60% of their time over a 12-week period. We also have a 28-day Work from Abroad policy.

Trainline is looking for a dedicated Developer to join our team in Greater London. The role involves delivering high-quality software solutions, mentoring junior engineers, and overseeing the development lifecycle from coding to deployment. Candidates should have strong expertise in C# .NET and experience with CI/CD, AWS, and microservices architectures. The company offers a hybrid work environment, private healthcare, share purchase plans, and a strong focus on career growth and personal development.

About us We are champions of rail, inspired to build a greener, more sustainable future of travel. Trainline enables millions of travellers to find and book the best value tickets across carriers, fares, and journey options through our highly rated mobile app, website, and B2B partner channels. Great journeys start with Trainline Now Europe's number 1 downloaded rail app, with over 125 million monthly visits and £5.9 billion in annual ticket sales, we collaborate with 270+ rail and coach companies in over 40 countries. We want to create a world where travel is as simple, seamless, eco-friendly and affordable as it should be. Today, we're a FTSE 250 company driven by our incredible team of over 1,000 Trainliners from 50+ nationalities, based across London, Paris, Barcelona, Milan, Edinburgh and Madrid. With our focus on growth in the UK and Europe, now is the perfect time to join us on this high-speed journey. Introducing Machine Learning & AI at Trainline Machine learning is at the heart of Trainline's mission to help millions of customers make sustainable travel choices every day. Within our AI & ML community, we build and operate production-grade systems that power search, pricing, personalisation, marketing optimisation, and increasingly, intelligent AI agents that transform customer support and journey discovery. You'll join a cross-functional team of Machine Learning Engineers and Data Engineers working on some of our most exciting GenAI initiatives. We're building agentic systems such as our Travel Assistant, an AI-powered experience that helps customers with refunds, journey updates, and ticket conditions and expanding into Voice AI agents to intelligently handle and redirect customer queries. This is a team that combines strong ML fundamentals with cutting-edge LLM frameworks (LangGraph, LangChain), RAG architectures, MCP integrations, and production monitoring tools like Braintrust, all deployed on AWS. We value ownership, curiosity, and thoughtful experimentation in a healthy, supportive environment. About The Role This role is focused on designing, building, and operating LLM-powered and predictive ML systems in production. You'll work on agentic AI systems, including our Travel Assistant and Voice AI initiatives, while also contributing to more traditional ML services that the team owns. If you're passionate about GenAI, LLMs, NLP, and shipping robust ML systems end-to-end, this is an opportunity to work at the forefront of applied AI in a high-impact consumer platform. As a Machine Learning Engineer at Trainline, you will Design and build LLM-powered agentic systems using frameworks such as LangGraph and LangChain Develop and optimise RAG pipelines, tool-using agents, and multi-step workflows with appropriate guardrails and validation Monitor and evaluate model and agent performance using appropriate ML metrics (e.g. precision, recall) and production monitoring tools Maintain and improve traditional ML models alongside newer GenAI capabilities Partner closely with stakeholders to frame problems, define success metrics, and deliver measurable business impact Take ownership of technical initiatives, driving delivery from ideation through to production and iteration Contribute to our wider AI & ML community through knowledge sharing, experimentation, and continuous learning We'd love to hear from you if you Have strong experience in Machine Learning with solid foundations in the ML lifecycle, evaluation methodologies, and statistical thinking Have hands on experience with GenAI, Large Language Models, and NLP techniques, including RAG and agent-based systems Are proficient in Python and common ML libraries (e.g. PyTorch, scikit-learn, XGBoost, Pandas) Have experience deploying and operating ML or AI systems in production environments Understand ML Ops and DevOps principles (e.g. Docker, CI/CD, infrastructure as code) Have experience working with cloud infrastructure (preferably AWS) Take ownership of technical tasks and proactively drive solutions forward More information: Enjoy fantastic perks like private healthcare & dental insurance, a generous work from abroad policy, 2-for-1 share purchase plans, an EV Scheme to further reduce carbon emissions, extra festive time off, and excellent family friendly benefits. We prioritise career growth with clear career paths, transparent pay bands, personal learning budgets, and regular learning days. Jump on board and supercharge your career from day one! We're operate a hybrid model to work and ask that Trainliners work from the office a minimum of 60% of their time over a 12-week period. We also have a 28-day Work from Abroad policy. Our values represent the things that matter most to us and what we live and breathe everyday, in everything we do: Think Big - We're building the future of rail ️ Own It - We focus on every customer, partner and journey Travel Together - We're one team ️ Do Good - We make a positive impact We know that having a diverse team makes us better and helps us succeed. And we mean all forms of diversity - gender, ethnicity, sexuality, disability, nationality and diversity of thought. That's why we're committed to creating inclusive places to work, where everyone belongs and differences are valued and celebrated. Interested in finding out more about what it's like to work at Trainline? Why not check us out on LinkedIn, Instagram and Glassdoor!

A leading travel technology company in Greater London is searching for a Machine Learning Engineer to design and build LLM-powered systems. The role includes working on GenAI initiatives and traditional ML services. Candidates should have experience with Python, GenAI, large language models, and cloud infrastructure. Excellent benefits include private healthcare, a flexible work model, and career growth opportunities. Join our diverse team and contribute to sustainable travel solutions.

Trainline in Greater London is looking for a Software Developer to join their team. Key responsibilities include delivering new features, ensuring quality throughout the development lifecycle, and mentoring junior engineers. Ideal candidates will have hands-on experience with C# .NET, Agile methodologies, and CI/CD practices. The role offers benefits such as private healthcare, a generous work from abroad policy, and clear career paths. Join a diverse and inclusive team dedicated to collaboration and innovation.

Trainline is looking for a Mid Level Web Engineer to enhance our platform with innovative features. You will work with React, Typescript, and various modern tools to maintain a high-quality codebase and ensure customer satisfaction. This position offers fantastic benefits such as private healthcare, generous work from abroad policy, learning opportunities, and a hybrid working model requiring 60% in-office presence. If you're a proactive team player passionate about technology, this role is for you.

Responsibilities Deliver new functionality or features, using the most appropriate tools & techniques Ensure quality is at the heart of everything you and your team do Continuously improve the code base Keep our customer as the number one priority Actively identify blockers, boulders, time sinks and waste, and actively attempt to remove them Make significant contribution to technical decisions Act as a coach and mentor to others in the team Take full ownership of the development lifecycle from code to production, including deployment and monitoring Tech Stack Languages & Frameworks: C# (.NET 6-8) Databases: DynamoDB, PostgreSQL Cloud & Infrastructure: AWS Cloud, Docker, Terraform CI/CD & DevOps: GitHub Actions Monitoring & Logging: New Relic, ELK Stack Qualifications & Experience Have hands on experience with C# .NET and the latest features Love using Agile development practices Have hands on experience working on software development of high-volume transactional applications Have experience in asynchronous service/processing Test your solutions effectively Enjoy mentoring less experienced engineers Have experience with CI/CD Thrive in a diverse, open and collaborative environment Have great communication skills Are proactive, focused, supportive, honest and a team player Have a passion to learn new skills Benefits Private healthcare & dental insurance Generous work from abroad policy 2-for-1 share purchase plans EV Scheme to reduce carbon emissions Extra festive time off Excellent family-friendly benefits Clear career paths, transparent pay bands, personal learning budgets, and regular learning days We know that having a diverse team makes us better and helps us succeed. We are committed to creating inclusive places to work, where everyone belongs and differences are valued and celebrated.

As a Mid Level Web Engineer at Trainline, you will Deliver new functionality or features, using the most appropriate tools & techniques Ensure quality is at the heart of everything you do Continuously improve the codebase Keep our customer as the number one priority Use A/B Testing to find the most valuable solution for customers Take ownership of the development lifecycle from code to production, including deployment and monitoring Our Tech Stack JavaScript, CSS, HTML React, Typescript Node, GraphQL AWS Cloud Docker, Terraform, Github Actions We'd love to hear from you if you Thrive in a diverse, open and collaborative environment Love using Agile development practices Have strong experience with React and Typescript Have hands on experience in software development and delivery Have good testing practices Have great communication skills Are proactive, focused, supportive, honest and a team player Have a passion to learn new skills Interview process Recruiter Call Competency based interview with 2x Engineers (60 mins) Pair Programming interview with 2x Engineers (90 mins) Meet the team you'll be joining (45 mins) More information Enjoy fantastic perks like private healthcare & dental insurance, a generous work from abroad policy, 2 for 1 share purchase plans, an EV Scheme to further reduce carbon emissions, extra festive time off, and excellent family friendly benefits. We prioritise career growth with clear career paths, transparent pay bands, personal learning budgets, and regular learning days. Jump on board and supercharge your career from day one! We operate a hybrid model to work and ask that Trainliners work from the office a minimum of 60% of their time over a 12-week period. We also have a 28-day Work from Abroad policy. We know that having a diverse team makes us better and helps us succeed. And we mean all forms of diversity - gender, ethnicity, sexuality, disability, nationality and diversity of thought. That's why we're committed to creating inclusive places to work, where everyone belongs and differences are valued and celebrated.

Trainline is looking for a Product Security Engineer Analyst to embed security into the product development lifecycle and handle vulnerability management. The role involves supporting secure development practices, participating in threat modeling, and reviewing security issues. Candidates should have relevant experience in cyber/information security or software development, knowledge of security risks, and strong analytical skills. Benefits include hands-on experience with modern security practices and a supportive environment for continuous learning.