Senior Python Software Engineer - £90k - £100k

We’re looking for a Senior Software Engineer with deep experience in Python and AWS to help design, build, and scale distributed, data-driven Ad-Tech systems. You’ll lead the delivery of cross-service features within a modern cloud platform, making pragmatic architectural choices and setting high standards for engineering quality, reliability, and performance.

You’ll play a key role in shaping technical direction, mentoring engineers, and ensuring the systems you build are secure, observable, and resilient.

Key Responsibilities

Lead complex delivery: Drive the end-to-end design and implementation of Python-based microservices and cloud-native solutions hosted on AWS.

Architect and optimise systems: Define service boundaries, data ownership, and failure-recovery patterns for scalable, high-availability systems.

Raise engineering quality: Champion best practices for testing, observability, and security. Review critical PRs and guide technical decisions across the team.

Operate and improve production systems: Monitor performance, reliability, and cost efficiency. Lead incident response and drive continuous improvement.

Mentor and grow others: Support engineers through pairing, feedback, and documentation to strengthen technical capability across the team.

Contribute to technical roadmap: Collaborate with Product, Design, and Data teams to align on priorities and ensure value is delivered incrementally.

Core Tech Stack

Languages: Python (FastAPI, Flask, or Django)

Data & Messaging: PostgreSQL, Redis, Kafka or SQS

CI/CD & Infrastructure: Docker, Terraform, GitHub Actions, CloudFormation

Testing: Pytest, integration and load testing frameworks

Proven experience designing and delivering production systems using Python on AWS.

Strong understanding of distributed systems, API design, and event-driven architectures.

Deep knowledge of system observability, logging, and performance optimisation.

Familiarity with modern security and data-privacy best practices.

Excellent communicator who can document and articulate technical trade-offs clearly.

Ownership: Takes full responsibility for systems from design to operation.

Pragmatism: Balances long-term architecture with delivery velocity.

Influence: Raises standards and mentors others across engineering disciplines.

Growth Mindset: Continuously improves processes, tools, and team capability.

Success Indicators

Reliable delivery of complex Python/AWS initiatives.

Reduction in latency, error rates, and infrastructure spend.

Strong incident management and operational excellence.

Documented technical decisions and clear architectural rationale.

Evident impact through mentoring and team enablement.