Backend Engineer
Role Description
A senior Java engineer on an eight-person delivery team building a video media planning platform. The role owns the core back-end services that support campaign setup, plan generation and optimisation, scoring orchestration, plan versioning, and the production of client-facing and operational outputs. Java and Spring Boot are the primary delivery technologies.
Strong production Java experience is essential. AdTech experience is required at a solid general level; familiarity with media planning or measurement is highly valuable, but deep TV-measurement expertise is not a gate.
About the Project
Client: a global media network, engaged through a delivery partner. End users are media planners at one of the network’s agencies.
Product: a video-only, omnichannel media planning web application. A planner defines a campaign — advertiser, budget, flight dates, target audience, objectives — through a six-step wizard. The platform generates budget-optimised plans across video channels, scores them using two deterministic engines, and exports a client-facing Media Plan (PDF) and an operations Activation Plan (XLSX).
Channels in scope: linear TV, BVOD, SVOD, AVOD/FAST, YouTube, social video, video out-of-home. The market is primarily UK/EMEA.
Scoring: two deterministic engines. A weighted channel quality index built from sub-dimension scores, and a reach and frequency model using exponential saturation against effective spend with cross-channel de-duplication. No machine learning is used.
The team covers delivery management, solution architecture, back-end, data, front-end, DevOps and QA automation.
Required Qualifications
Experience
- 5+ years of production back-end development with Java, including ownership of business-critical services from design through deployment and support.
- Strong experience delivering Spring Boot applications and REST APIs in a service-oriented or modular architecture.
- Experience implementing business workflows or calculation-heavy systems where correctness, traceability, and reproducibility matter.
- Delivery experience within a team working to a fixed timeline and defined scope.
- Direct working contact with external stakeholders such as client teams, partners, or vendors.
- English: strong written and spoken, effectively C1+. The role involves client sessions, technical discussion, and written documentation.
Technical Acumen
- Java: expert-level production development with modern Java, including collections, concurrency, error handling, performance considerations, and maintainable object-oriented design.
- Spring Boot: REST services, dependency injection, validation, configuration, persistence, security integration, and production diagnostics.
- REST API design and integration: OpenAPI contracts, versioning, backward compatibility, third-party integrations, retries, timeouts, and fallback handling.
- PostgreSQL: relational modelling, transactional consistency, indexing, query optimisation, and persistence of versioned and effective-dated data.
- Persistence: strong practical experience with JPA/Hibernate or an equivalent Java persistence approach, including awareness of transaction boundaries and query behaviour.
- Testing: JUnit, mocking, integration testing, contract testing, and validation of deterministic computational output.
- Containerised cloud services: Docker and cloud deployment; Azure preferred, with AWS or GCP acceptable.
- Observability: structured logging, metrics, distributed tracing or correlation, and diagnosis of production failures.
- CI/CD and source control: pull-request workflows, automated quality checks, build pipelines, and deployment automation.
Domain Knowledge — required
- AdTech at a solid general level — how media is planned, bought, delivered, and measured; the main platform types and their roles; and how campaign and audience data moves between them.
- Understanding of the core entities in a media-planning workflow: campaigns, audiences, budgets, flight dates, channels, inventory constraints, plans, and activation outputs.
- Ability to implement deterministic scoring and optimisation workflows accurately from a specification, even when the methodology is owned by another team.
- Awareness of reach, frequency, audience denominators, and cross-channel de-duplication sufficient to reason about API behaviour, validation, and obviously invalid outputs.