Senior Software Engineer - Backend

Company Description Swiftly is on a mission to help cities move more efficiently. We are the leading transit data platform for agencies to share real-time passenger information, manage day-to-day operations, and improve service performance. Today, over 200 transit agencies in 12 countries – including LA Metro, MARTA, SEPTA, and MBTA – rely on Swiftly to improve on-time performance by up to 40% and increase passenger information accuracy by up to 50%. The result is better service reliability, increased ridership, and more efficient transit operations.   Even though Swiftly's HQ office is located in San Francisco, CA, we are open to candidates in most locations across the U.S. as well as Ontario and British Columbia, Canada. At this time we are unable to provide Visa sponsorship.   Engineering at Swiftly Engineering at Swiftly is not only about writing code – we believe in creating empowered product teams that work together to conceptualize new features and bring them to life. Each team aims to strike a balance between delivering incremental improvements, creating prototypes to test new ideas and mitigate risks, and building scalable software using industry best practices. We’re guided by a mission to positively impact transit riders, and we embrace humility and intentionality in how we make technical decisions so that we best meet our customers’ needs.   About the Role This person will join the team that owns the real-time source of truth for our system, developing predictive algorithms that power accurate passenger information. From map-matching and vehicle location processing to ETA predictions and disruption detection, your work will drive the tools transit professionals use every day to manage service, improve operations, and keep riders informed through partner apps and integrations. We're a full-stack team building real-time data pipelines, backend services, APIs, and client-side web apps for visualizing networks and adjusting service. Our goals include delivering complete and trustworthy data, surfacing better options for managing service, scaling predictive insights, and supporting more and larger agencies. Experience with backend data systems, real-time processing, and designing cloud-based Java services and APIs makes you a strong fit. As a full-stack team, we also value experience collaborating across frontend and backend to deliver end-to-end products. Most importantly, we're looking for teammates who are excited to push the accuracy and reliability of our predictions forward, experiment rapidly, and solve problems holistically. We encourage you to apply if the above is exciting to you and if you meet half or more of the requirements below. Above all else, we value candidates who angle toward growth, leveraging a positive attitude and the aptitude to relentlessly seek and solve problems to deliver impact. We know the tech landscape is ever-changing and strongly support individual growth. If this sounds like you, we'd love to talk. What You'll Do Design, evaluate, build, and maintain real-time algorithms and systems for vehicle tracking, map-matching, ETA predictions, and disruption detection. Contribute to Swiftly's real-time data pipelines, APIs, and cloud services that power customer-facing products. Build data infrastructure to support rigorous algorithm development, validating changes at scale before they reach production. This may include pipelines for capturing and replaying real-time data, offline evaluation frameworks, and shadow testing infrastructure. Collaborate with product managers, designers, and engineers to prototype solutions, validate approaches, and deliver incremental value. Break down complex problems into smaller, testable pieces to help the team move quickly and reliably. Share designs and technical decisions openly, weighing tradeoffs and documenting for alignment. Apply modern engineering practices to deliver robust, maintainable, and extensible code. Support and elevate teammates through code reviews, pairing, and knowledge sharing. Take ownership of your work and team outcomes, continuously reflecting and improving. What Will Set You Up for Success 5+ years of software engineering experience, ideally with data-intensive or real-time systems. Experience with Java and cloud-native backend services (AWS preferred). You've taken algorithms from idea to implementation, delivering production-ready systems that drive real-world impact. Strong understanding of real-time data processing, such as streaming, event-driven, or predictive systems. Comfortable building and consuming APIs; proficient with SQL. Curiosity and excitement about applying predictive algorithms to solve real-world problems in transit. Growth mindset and adaptability in a fast-changing technical landscape. Collaborative, humble, and open to feedback; thrives in blameless, team-oriented environments. Bonus: experience with Apache Kafka, Python/JupyterHub, JavaScript/Vue.js, or AWS Step Functions.