Apply now: Senior Backend Software Engineer (Java/Go), Hybrid - Onsite 4 Days/Week. Start date is ASAP for this Contract position. Job Title: Senior Backend Software Engineer (Java/Go) Location-Type: Hybrid - Onsite 4 Days/Week, Remote Fridays - Philadelphia, PA Start Date: ASAP Duration: Until end of 2026 Compensation Range: $90-105/hr W2 Benefits: Eligible for Health, Dental, Vision, and 401K Visa Sponsorship: Not eligible for visa sponsorship Job Description: The client is seeking a Senior Backend Software Engineer to design, develop, and maintain scalable backend microservices and event-driven systems that power critical product functionality across the organization. Job Summary Design, develop, and maintain backend microservices using Java/Spring Boot and Go Build and support high-performance RESTful APIs and distributed services Develop and maintain event-driven architectures utilizing Kafka and similar messaging platforms Work within containerized, cloud-native environments using Docker and Kubernetes Collaborate across engineering teams while maintaining ownership of assigned workstreams Leverage AI-powered development tools such as GitHub Copilot and Claude to accelerate delivery Troubleshoot complex production issues and drive resolution through root cause analysis Minimum Requirements: 7 years of backend software engineering experience Strong hands-on experience with Java, Spring Boot, and Go (Golang) Proven experience designing and building RESTful APIs and distributed systems Experience with Kafka or comparable event-driven messaging platforms (JMS, RabbitMQ) Strong experience with Docker and Kubernetes in cloud-native environments Experience with one or more of the following databases: PostgreSQL, MongoDB, or Couchbase Demonstrated ability to independently ramp on complex systems and deliver results with minimal oversight Preferred Qualifications: Experience with performance and load testing tools such as K6 Experience implementing BDD frameworks, including Cucumber Familiarity with Istio, AWS EKS, or AWS MSK Background in startup or smaller-company environments where engineers owned multiple responsibilities Exposure to service mesh architectures and operating large-scale cloud-native applications