Senior Java API Engineer (Backend)

About the role

PubMatic is looking for a senior Java API developer to build high‑performing, scalable backend systems for digital advertising products. You will design, develop, and optimise services that power Mobile Ad SDKs, recommendation engines, and other AI‑driven platforms.

Key responsibilities

• Design and develop secure, high‑performance RESTful APIs using Java 11+ and Spring Boot.
• Own end‑to‑end solution design, planning, execution, and release of backend features.
• Build and maintain services supporting AI initiatives such as recommendation systems and predictive analytics.
• Productionise machine‑learning models and integrate them into real‑time decisioning pipelines.
• Develop efficient data models and optimise MySQL/PostgreSQL queries for reliability and speed.
• Implement API security with OAuth2, JWT, and role‑based access controls.
• Design systems for high concurrency, large data volumes, and low latency.
• Apply observability best practices: logging, monitoring, tracing, and alerting.
• Participate in code reviews, design discussions, and technical decision‑making.
• Collaborate with Analytics, Product, SDK, UI, Ad Server, DevOps, and QA teams.

Required profile

• 3–6 years of Java development experience in Linux/UNIX environments.
• Strong proficiency in Core Java, OOP, data structures, and J2EE technologies.
• Hands‑on experience with Spring, Spring Boot, Hibernate, and REST microservices.
• Solid SQL skills, schema design, indexing, and performance tuning (MySQL/PostgreSQL).
• Experience with Docker, Kubernetes, Jenkins, Maven, Git, and CI/CD pipelines.
• Working knowledge of Python and integration with AI/ML services.
• Understanding of advanced AI concepts such as RAG, agentic AI, model fine‑tuning, and recommendation systems.
• Bachelor’s degree in engineering or equivalent.

Required skills

• Java (Java 11+)
• Spring Boot & Spring Framework
• Hibernate
• RESTful API development
• Microservices architecture
• MySQL / PostgreSQL
• OAuth2 & JWT
• Docker & Kubernetes
• Jenkins, Maven, Git
• CI/CD pipelines
• JUnit & TDD
• Python (working knowledge)
• AI/ML integration

What we offer

• Hybrid work schedule (3 days in office, 2 days remote).
• Paternity/maternity leave and healthcare insurance.
• Broadband reimbursement.
• On‑site kitchen with healthy snacks and catered lunches.
• Inclusive, diverse workplace culture.