Callsign is seeking a Senior Software Engineer (Telco & Communications) to help secure digital identities across web, mobile, and physical interactions. The role requires writing production‑ready code in Java 17+ with Spring Boot and Spring Security, designing low‑level components, and representing the team in architecture reviews. You will threat‑model features and design authentication, authorization, and data handling from the outset, instrument systems before release, participate in on‑call rotations, and drive root‑cause analysis to prevent incidents. You will identify technical gaps, propose fixes with cost and benefit, and leverage AI tooling. You will mentor engineers, uphold testing standards and error handling, and interview candidates. The ideal candidate has 8+ years of experience with Java 17+, Spring Boot, and Spring Security, and can debug JVM and Spring issues from thread dumps, heap dumps, and traces. You will design and operate microservices for client traffic with API versioning and testing across unit, integration, contract, and load tests. You will design for failure and scale, including idempotency, retries, circuit breakers, and caching, and diagnose bottlenecks using data. Strong relational data modeling and query design in MySQL, with schema and index tuning under load, is essential. Security should be treated as a design input, covering OWASP Top 10, authentication and authorization, secrets management, and data handling. You will write designs that other engineers can implement and review peers' designs. You will deploy and run services on Kuberne

Callsign is seeking a Senior Software Engineer (Telco & Communications) to help secure digital identities across web, mobile, and physical interactions. The role requires writing production‑ready code in Java 17+ with Spring Boot and Spring Security, designing low‑level components, and representing the team in architecture reviews. You will threat‑model features and design authentication, authorization, and data handling from the outset, instrument systems before release, participate in on‑call rotations, and drive root‑cause analysis to prevent incidents. You will identify technical gaps, propose fixes with cost and benefit, and leverage AI tooling. You will mentor engineers, uphold testing standards and error handling, and interview candidates. The ideal candidate has 8+ years of experience with Java 17+, Spring Boot, and Spring Security, and can debug JVM and Spring issues from thread dumps, heap dumps, and traces. You will design and operate microservices for client traffic with API versioning and testing across unit, integration, contract, and load tests. You will design for failure and scale, including idempotency, retries, circuit breakers, and caching, and diagnose bottlenecks using data. Strong relational data modeling and query design in MySQL, with schema and index tuning under load, is essential. Security should be treated as a design input, covering OWASP Top 10, authentication and authorization, secrets management, and data handling. You will write designs that other engineers can implement and review peers' designs. You will deploy and run services on Kuberne