Vassar Labs is a fast‑growing climate‑technology startup that builds critical public‑sector platforms for Indian state governments. Their solutions power flood early‑warning systems, reservoir operation dashboards, urban water‑supply management, and digital agriculture services. Backed by a mix of government contracts and private investors, Vassar Labs combines deep domain expertise in water resources with cutting‑edge software engineering. The company prides itself on a mission‑driven culture where engineers get to see the real‑world impact of their code on millions of citizens. The Java Hireathon 2026 is a unique hiring event designed to identify engineers who can not only write clean Java code but also own the end‑to‑end lifecycle of a data‑intensive service. The process consists of a one‑hour online test, a full‑day onsite hackathon at the Hyderabad office, and, for successful candidates, two technical interview rounds. There is no traditional multi‑stage screening; instead, your ability to build, operate, and explain a production‑grade system is the core evaluation metric. **Key Responsibilities** 1. Design and implement RESTful services using a Java web framework. 2. Model relational data in SQL and choose appropriate NoSQL stores for high‑velocity workloads. 3. Build and tune streaming pipelines using a message‑log and stream‑processing framework. 4. Install, configure, and troubleshoot self‑hosted open‑source infrastructure (e.g., Kafka, Cassandra, Elasticsearch). 5. Write unit, integration, and performance tests to ensure reliability. 6. Participate in code reviews and mentor junior team members (for senior tracks). 7. Monitor services in production, set up alerts, and resolve incidents. 8. Contribute to architectural discussions and documentation. 9. Collaborate with product, data science, and UI teams to deliver end‑to‑end features. 10. Continuously improve CI/CD pipelines and deployment automation. **Tech Stack**: Java 17/21, Spring Boot (or similar), Hibernate/JPA, PostgreSQL with geospatial extensions, MongoDB / Cassandra, Redis, Elasticsearch, Apache Kafka, Flink/Spark Structured Streaming, Docker, Kubernetes, Linux, Git, Prometheus/Grafana for observability, and occasional Python for AI/ML services. **Growth Path**: Freshers start as Software Engineers (Track 1) and can progress to Senior Engineer, Lead Engineer, and eventually Tech Lead or Architecture roles within 3‑5 years, given the high‑impact nature of the products. The company encourages internal mobility across platform, data, and infrastructure teams. **Why Join Vassar Labs?** You will work on mission‑critical systems that directly affect public safety and resource management, gain hands‑on experience with end‑to‑end production pipelines, and grow alongside seasoned engineers who value mentorship and technical depth. The hireathon format gives you a fast‑track to a full‑time role without endless interview loops, letting you focus on building real solutions from day one.