Principal Java Engineer / Technical Lead

Purpose

To set the engineering standard for the Java estate, demonstrate it through a reference implementation, and hold design authority over the External Applications subsystems. This is a hands-on technical leadership role — the post holder will write the reference implementation.

The subsystems in scope include the payment gateway, covering both fee collection and disbursement via the national settlement infrastructure; the USSD gateway; the email gateway service; device registry services with a lifecycle management interface; appointment booking; and a geospatial enrolment planning and coverage analytics module.

Key responsibilities

• Define engineering standards for the Java estate: service template, project structure, configuration externalization pattern, error contract, logging format, testing expectations and dependency policy.
• Implement the packaging and handoff standard in practice — GitLab CI pipeline templates producing container images and parameterized Helm charts, with the pipeline enforcing the standard rather than a document requesting it.
• Build one subsystem end to end to the standard as the reference implementation that other teams work from.
• Hold design authority over the External Applications subsystems through a review gate with a defined pass condition.
• Provide technical direction on the more demanding subsystem designs, including the payment gateway settlement integration and the USSD gateway, which is inbound, synchronous and session-based rather than message-queue driven.
• Establish and enforce the code review standard, including what blocks a merge.
• Develop the Java team, and the two nominated subsystem technical leads to independent capability.

Essential experience

• Java and Spring Boot at principal level, with production systems at national or tier-one scale.
• Has set engineering standards across multiple teams and enforced them through tooling and gates.
• Has built for handoff — produced packages deployed by another organisation, without production access, from supplied documentation. This is the differentiating requirement for this role.
• Kubernetes, Helm and GitOps sufficient to design the packaging contract.
• PostgreSQL at scale, and event-driven integration patterns including idempotency and dead-letter handling.
• Has developed engineers into technical leads.

Desirable experience

• Payments, particularly national settlement rails.
• Telecommunications channel integration — USSD, SMPP or aggregator platforms.
• Keycloak or OpenID Connect as a consumer.
• MOSIP or a comparable national identity implementation.
• Kafka as a log transport tier.
• Data protection and information security management standards relevant to a government client.

Expected hours: 40.0 – 45.0 per week

Application Question(s):

• Have you delivered software into a multi-party programme, where the organisation deploying it was not the one building it?
• Have you delivered production work in an on-premise or hybrid environment (not cloud-only)?
• Are you comfortable working within a settled technology

decision rather than proposing a consolidated platform?

Experience:

• On-premises: 10 years (Required)

Work Location: In person