Software Engineer - Orchestration

Russian hacker, Vladimir Leonidovitch Levin, attempted the biggest bank heist the world had ever seen via dial-up internet in 1994, Zia Hayat, Callsign CEO and founder, was hooked - armchair fraud became a real possibility. From this moment, Zia knew he wanted to play a part in stopping the bad guys and securing the internet for all. Founded In 2012, Callsign's mission has been to make Digital Identity simple and secure for everyone and everything. In that time, we've grown to over 250 employees, opened offices in UK and Abu Dhabi, been recognised as a WEF Global Innovator and our technology is being used by many of the world's leading financial institutions to keep millions of consumers safe. But we aren't stopping here. The identity revolution has only just begun, and we are looking to hire the brightest and inquisitive minds to help us make every web, mobile and physical Interaction seamless and secure. If this sounds like you, lets chat. As a Software Engineer at Callsign, you will design, build, and maintain components of our highly transactional Java platform. You'll work in an Agile, fast‑paced environment, collaborating with cross‑functional teams to deliver secure, scalable, and performant software. You'll take ownership of features from development through deployment, proactively improving code quality, reliability, and efficiency. Responsibilities Design, develop, test and maintain Java‑based services and APIsWrite clean, testable, and maintainable code following engineering best practicesUnderstand requirements before writing code by participating in refinement sessions with peers, QA and Product to deliver high‑quality featuresParticipate in code reviews and contribute to continuous improvementPerform end-to-end testing of pushed codeSupport production deployments and troubleshoot issues with SRE/App SupportIdentify and address technical debt and performance bottlenecks Requirements 3-6 years of commercial experience in Java developmentStrong knowledge of Java (8+/17+), Spring Boot, and RESTful API designExperience with relational databases (PostgreSQL/MySQL/Oracle) and SQLFamiliarity with DynamoDB or other noSQL databasesFamiliarity with Docker, Linux, and CI/CD pipelinesUnderstanding of software testing principles (unit, integration, contract and regression)Understanding of OOP fundamentals and SOLID principlesUnderstanding of space and time complexityProduction experience of Metrics for reliable observabilityExperience with rules engines, expression languages or workflow enginesExperience with orchestration and workflow patterns such as Saga, Process Manager or state machinesExposure to microservices architecture, distributed caching with Redis, and event streaming with KafkaAwareness of secure coding practices and application security fundamentalsStrong communication, analytical thinking, and collaboration skills Good to have : Familiarity with observability tools (Prometheus, Grafana, ELK, OpenTelemetry)Experience with message queues (Kafka, RabbitMQ)Basic knowledge of Kubernetes, AWS, or TerraformExperience in high‑growth or startup environmentsExposure to crypto practices and encryption/decryption Understanding of distributed system patterns such as Circuit Breaker, Idempotency and OutboxExposure to reactive programming (Spring WebFlux / Project Reactor) or Java Virtual ThreadsUnderstanding of applied cryptography (encryption, hashing, digital signatures, TLS/mTLS) Benefits Private Premium Health InsuranceVisa costs including 1 month paid hotel stay on arrivalAnnual Airfare Allowance for the home country3 months full pay maternity leaves & 2 weeks full pay paternity leaves25 days of annual leave + Callsign Bank Holiday (not included in holiday allowance)Competitive SalaryGratuity as EOSB