Senior Backend Engineer

Senior Backend Engineer Branding Brand is hiring a Senior Backend Engineer for a 12-week contract engagement (June 2026 to August 2026) to design and ship a new backend service to production for one of our clients. You will own delivery end-to-end of a reactive Java service built on Spring WebFlux, deployed on Kubernetes, with Redis for caching and Databricks as the long-term data store. The workload is bursty and high throughput, so the role requires solid instincts for idempotency, at-least-once delivery, and scaling under burst load. This is a fully remote contract position. The candidate must be located in the United States and able to work as an independent contractor. No C2C. Key Responsibilities: Design and build: Own the design and end-to-end implementation of a new backend service in Java 21 and Spring WebFlux Build reactive, nonblocking endpoints that are racesafe and idempotent under retry Make architecture decisions on caching, write paths, error handling, and scaling, and document the tradeoffs Scale and operate: Design the Redis caching layer for hot reads, idempotency de-dupe, and readthrough patterns Design the async write path from the service to Databricks (queue or stream, batch writer, retry semantics) Configure Kubernetes deployments, horizontal pod autoscaling, and graceful shutdown for safe deploys Author K6 load tests for both steadystate and bursty traffic patterns Wire up structured logging, metrics, and alerting for production critical paths Support & maintain: Troubleshoot issues across the API, caching, and datawrite layers in development and production Participate in design reviews, code reviews, and Agile ceremonies Provide production support through the contract period, including issue triage and resolution Tech Stack: Language and framework: Java 21, Spring WebFlux, Project Reactor API Gateway: Apigee Caching: Redis Data store: Databricks (longterm, analytical), accessed via async batched writes Messaging and async: SQS, Kafka, or Kinesis Container platform: Kubernetes Performance testing: K6 Cloud: AWS or Azure Required Skills and Qualifications: 6+ years of backend development experience Hands-on experience with reactive programming and Project Reactor (Mono, Flux, non-blocking IO) Production experience with Java and Spring WebFlux building RESTful or reactive microservices Experience designing for idempotency, retries, and at least once delivery semantics Comfort designing and operating services under bursty, high throughput workloads Experience operating production services in a major public cloud such as Azure or AWS Familiarity with data warehouse or lakehouse platforms (Databricks, Snowflake, BigQuery) as integration targets from an application service Experience load testing services with K6, Gatling, Locust, JMeter, or equivalent Commitment to secure coding practices and ongoing security awareness Strong problem solving and communication skills Qualifications: Education: Bachelor's degree in computer science, Information Systems, Business, or related field Preferred Attributes: 6+ years experience About Us: Branding Brand launched in 2008 as an interactive marketing firm and quickly evolved into the largest and fastest growing provider of mobile commerce apps and sites for retailers. Branding Brand is a supporter of the Whitehouse Equal Pay Pledge, and a Top Workplaces award winner. Branding Brand is also an equal opportunity employer. We seek applicants of diverse backgrounds and hire without regard to race, color, gender, religion, national origin, ancestry, citizenship, individuals with disabilities, age, sexual orientation, protected veterans, or any other characteristic protected by law. The hourly rate for this position is $25/hr-$70/hr. Branding Brand