Senior Java Backend Engineer

Sinch; Madrid; Remote; EUR 90,000 - 120,000; Full time

Job summary

Sinch is seeking a Senior Software Engineer to design and build the next generation of our Contacts Platform. You will design backend services, work with Java, Spring, Kafka, MongoDB and OpenSearch, and help scale distributed systems.

You’ll develop internal tools for monitoring and debugging, ensure observability and security, collaborate with cross-functional teams, and contribute to code quality. This role is 95% remote for candidates based in Spain, with quarterly office days in Madrid.

Qualifications

• Deep understanding of distributed systems and experience building high-scale microservices and event-driven architectures.
• Production-level experience in backend development using Java.
• Familiarity with cloud platforms (AWS, GCP, or Azure) and containerized deployments (Docker, Kubernetes).
• A problem-solving mindset with the ability to debug complex distributed systems.
• Strong communication skills and the ability to work effectively in a collaborative environment.
• Strong background in database design and optimization, particularly with MongoDB, Cassandra, or other distributed databases.
• Experience with observability, logging, and monitoring tools for debugging and performance analysis.
• Experience with modern Frontend frameworks like React.
• Knowledge of message brokers like Kafka and RabbitMQ.

Responsibilities

• Design, develop, and maintain backend services for Contacts Platform and contribute to frontend applications.
• Build high-performance, scalable, and distributed systems.
• Work with Java, Spring, Kafka, MongoDB, OpenSearch to enhance our product.
• Develop internal tools for monitoring, debugging, and optimizing applications at scale.
• Ensure observability, reliability, and fault tolerance across all services.
• Collaborate with cross-functional teams including Software Engineers, UX Designers and Product Managers.
• Maintain a strong focus on code quality, security, and best practices in software development.

Skills

Distributed systems

Java

Spring

Kafka

MongoDB

OpenSearch

Docker

Kubernetes

React

RabbitMQ

Cloud platforms

Observability

Tools

Java

Spring

Kafka

MongoDB

OpenSearch

Docker

Kubernetes

React

RabbitMQ

AWS

GCP

Azure

Job description

• As a Senior Software Engineer, you will play a key role in designing and building the next generation of our Contacts Platform. You will work in a dynamic, collaborative environment to develop scalable distributed systems. Your contributions will directly impact the efficiency, performance, and safety of conversations at scale
• Design, develop, and maintain backend services for Contacts Platform, while contributing to our frontend applications
• Build high-performance, scalable, and distributed systems
• Work with Java, Spring, Kafka, MongoDB, OpenSearch to enhance our product, ensuring safety, efficiency, and responsiveness
• Develop internal tools for monitoring, debugging, and optimizing applications at scale
• Ensure observability, reliability, and fault tolerance across all services
• Collaborate with cross-functional teams including Software Engineers, UX Designers and Product Managers
• Maintain a strong focus on code quality, security, and best practices in software development
• This is a 95% remote role. You must be based in Spain and we will bring you to the office in Madrid for some days every quarter

Deep understanding of distributed systems and experience building high-scale microservices and event-driven architecturesProduction-level experience in backend development using JavaFamiliarity with cloud platforms (AWS, GCP, or Azure) and containerized deployments (Docker, Kubernetes)A problem-solving mindset with the ability to debug complex distributed systemsStrong communication skills and the ability to work effectively in a collaborative environmentStrong background in database design and optimization, particularly with MongoDB, Cassandra, or other distributed databasesExperience with observability, logging, and monitoring tools for debugging and performance analysisExperience with modern Frontend frameworks like ReactExperience with MongoDB and OpenSearchKnowledge of message brokers like Kafka and RabbitMQ