Lead Backend Developer

This role is the core implementation owner for business logic and integrations. We are looking for an engineer who combines strong Python skills with disciplined production practices and can independently take complex workflows to completion. Permanent role scope: This is a core technology position supporting multiple digital products. The person will own work through delivery, production operations, continuous enhancements and future versions, and may move across projects as priorities evolve.

Responsibilities:

• Design and develop asynchronous APIs and services using Python and FastAPI with clear, versioned contracts.
• Build secure authentication, authorisation, tenant scoping and role-based access controls.
• Create PostgreSQL schemas, migrations, repositories and transactional workflows with attention to data integrity.
• Integrate external APIs, OAuth services and webhooks with rate-limit handling, retries, idempotency and reconciliation.
• Implement background jobs, scheduled processing and event-driven workflows using suitable queues or streams.
• Apply strict input validation, consistent error handling and safe handling of secrets and sensitive data.
• Add unit, integration and contract tests together with logs, metrics, traces and actionable alerts.
• Participate in design reviews, code reviews, performance tuning, incident response and root-cause analysis.
• Maintain owned services through enhancements, scaling work and future product versions.

Requirements:

• Advanced Python and practical FastAPI experience in production systems.
• Strong understanding of asynchronous programming, validation, dependency injection, API design and background processing.
• Good to have: PostgreSQL, SQL optimisation, ORM usage, migrations and transaction management.
• Experience integrating external REST APIs using OAuth 2.0, webhooks, retries, rate limits and idempotency.
• Testing experience with pytest and unit, integration, contract and mocked-provider tests.
• Secure engineering fundamentals including tenant isolation, least privilege, secrets hygiene and input validation.
• Git, pull-request workflows, CI/CD and clear technical documentation.

Preferred experience:

• Redis, Celery, Arq, Kafka, Redpanda or comparable asynchronous-processing technologies.
• Experience integrating AI services through structured, validated inputs and outputs.
• AWS, Docker, Kubernetes and observability with OpenTelemetry.
• High-volume data ingestion, analytics systems or complex workflow engines.