Full Stack Lead Engineer

The Role

The Full Stack Lead Engineer is a vital role within Modulr, where you will be responsible for building an autonomous, high performing engineering squad to foster an environment where decisions are delegated, made and communicated effectively. You will drive technical strategy with a strong emphasis on Python and FastAPI backend development while remaining deeply hands-on with core development. The role is a blend of hands-on Python development, technical leadership, mentoring, and operational excellence. You will lead the architecture and implementation of robust, scalable backend systems using FastAPI, cloud infrastructure on AWS, and coordinate full-stack solutions with frontend teams.

Specific duties

• Lead a squad of software engineers, driving technical excellence through code reviews, architectural guidance, pair programming, and mentoring with strong emphasis on Python and FastAPI best practices.
• Technically efficient to write production-quality Python code, designing high-performance REST APIs, managing databases, async operations, and establishing coding standards.
• Own backend architecture decisions and lead the design of scalable, robust systems using Python, relational databases (PostgreSQL/MySQL), caching layers, and message queues.
• Lead technical strategy for AWS cloud deployments, ensuring security, reliability, scalability, and operational excellence.
• Mentor team members to develop deep full stack expertise for both backend & frontend through 1-2-1s, code reviews, and pair programming, fostering their technical growth and career progression.
• Plan squad deliverables and delegate responsibilities clearly, ensuring the team has well-defined goals, unblocked paths to success, and regular progress tracking.
• Collaborate with Frontend, DevOps, and Product teams to deliver integrated solutions, ensuring seamless API integration between backend and frontend.
• Drive agile practices and conduct productive ceremonies (stand-ups, sprint planning, reviews, retros), promoting continuous improvement and team autonomy.
• Drive hiring and recruitment, conducting technical interviews, assessments, and candidate evaluations while representing Modulr's engineering culture and values.
• Report on squad progress, outcomes, and technical achievements to leadership; share knowledge and best practices across the broader Engineering organisation.

About you

Must Have:

• Expert-level proficiency in Python (9+ years), with deep knowledge of Python frameworks, async programming, and backend development best practices.
• Strong, hands-on experience with FastAPI, including building high-performance REST APIs, dependency injection, validation, and async operations.
• Solid experience with React and modern JavaScript/TypeScript, with understanding of full-stack integration and frontend-backend communication patterns.
• Hands-on experience designing, building and deploying systems on AWS (EC2, S3, Lambda, RDS, API Gateway, etc).
• Proven software development and technical team leadership experience, with a strong understanding of backend engineering practices and processes.
• Strong understanding of system design, microservices architecture, database design, and cloud-native application patterns.
• Experience with relational databases (PostgreSQL, MySQL) and understanding of data modeling, optimization, and migrations.
• Strong testing discipline (unit, integration, and end-to-end testing) with TDD mindset for backend systems.
• Demonstrated ability to mentor engineers and lead technical decision-making in a collaborative environment.
• Experience with Docker, Kubernetes, and container orchestration.
• Knowledge of DevOps practices, CI/CD pipelines, and Infrastructure as Code.

Good to have:

• Experience with caching solutions (Redis), message queues (RabbitMQ, Kafka), and async task processing.
• Experience in the fintech or payments domain.

Key Attributes:

• Strong problem-solver with deep analytical and critical thinking skills; ability to balance pragmatism with technical excellence.
• Excellent communication skills; ability to articulate complex technical concepts to both technical and non-technical stakeholders.
• Self-directed and proactive, with a drive to continuously learn and innovate in Python and backend technologies.
• Passionate about code quality, performance optimization, and building scalable, maintainable systems.
• Team player with strong collaborative and leadership presence, comfortable guiding the team through technical decisions.