Senior Backend Engineer in London

watchTowr is the Preemptive Exposure Management capability trusted by Fortune 500 companies and critical infrastructure providers. By combining proactive threat intelligence, real attacker telemetry, and automated red teaming, watchTowr continuously identifies and validates real exposure - so security teams can outrun real-world threats. When exploitation happens in hours, watchTowr delivers what no one else can: time to respond.

We are a global team of operators, researchers, and engineers who have spent years thinking like attackers - and we are now building the technology to stop them. Our work is recognised across the industry, with original vulnerability research from watchTowr Labs and innovations like Instinct and Attacker Eye shaping the future of cybersecurity. Backed by $29M in funding, recognised by Gartner, and scaling fast across the globe, we are in a high-growth phase of our journey. We are a young, high-energy, and research-driven team, obsessed with building world-class technology - and we want exceptional people to join us.

We are looking for a Senior Backend Engineer with a strong foundation in backend architecture and data infrastructure to help us build and scale the core systems that power our offensive security platform. You will be part of a high-impact team working to help some of the world’s largest enterprises understand their real-time security exposure. Your work will directly shape how our platform ingests, processes, and serves critical vulnerability data at scale.

• Design, build, and maintain backend services and data pipelines that support our backend system which powers our cybersecurity platform.
• Architect scalable microservices and APIs to handle large volumes of data relating to millions of assets belonging to our clients.
• Work closely with frontend engineers and product teams to integrate backend systems with the user interface and reporting layers.
• Continuously improve our systems, from deployment to monitoring, as we scale rapidly.

• Backend: FastAPI, Airflow
• Database: Postgres, MongoDB
• Message Queues: Kafka

• 5 or more years of experience designing and maintaining mission-critical backend applications using microservices architecture.
• Proficiency in working with both relational (e.g. Postgres) and non-relational (e.g. MongoDB) databases.
• Familiarity with event-driven architectures, event sourcing, and managing asynchronous data processing at scale.
• Comfortable writing clean, testable code and applying automated testing practices.
• Experience working with data workflows and asynchronous task queues (e.g. Kafka, Airflow, etc).
• Demonstrated ability to thrive in fast-paced startup environments, showing a strong sense of ownership and initiative.
• A can-do attitude with the willingness to take on ambiguous challenges, wear multiple hats, and drive projects forward independently.

• Experience working with large-scale data processing or streaming systems, especially for security analysis.
• Familiarity with data engineering tasks like building ETL pipelines and schema versioning.
• Exposure to DevOps practices and CI/CD tooling for automated deployment and monitoring.
• Familiarity in Cloud-based services & able to leverage Cloud-based services as part of service deployments.
• Prior work in an Agile, DevOps-driven engineering culture.

• Competitive compensation - we believe that hard work, skills and ambition should be fairly compensated.
• Meaningful role in a company - You will be a key and early contributor to a fast-growing cybersecurity business.
• The best tools and powerful kit - we enable you with the tools to effectively fulfil your role.
• Endless opportunities – we are in a high-growth phase of our journey, and plan to promote from within as we scale.
• Work with cyber security experts – we are solving cutting-edge industry-wide cyber security challenges.

Equal Opportunity: watchTowr is proud to be an Equal Opportunity Employer. At watchTowr, we’re dedicated to fostering an inclusive, respectful, and diverse environment where every individual is recognised for their talent and potential. Our hiring decisions are guided by your capabilities, experience, and what you bring to the role - not by unrelated personal attributes. We have a zero-tolerance approach to any form of discrimination or harassment.