Senior Software Engineer (Python/AWS) - SaaS & FinTech - London (Hybrid working) - £85,000 - £95,000

We're looking for an experienced Senior Software Engineer to join a collaborative, high-performing engineering team developing market-leading SaaS products used to analyse and visualise some of the world's largest financial datasets.

This is an opportunity to work on cutting-edge cloud technology, solve complex engineering challenges and help shape the future of a modern SaaS platform. You'll work alongside talented Python and TypeScript engineers, partnering closely with Product to design and deliver scalable, high-quality software that makes a real impact.

If you're passionate about building cloud-native applications, embracing AI-assisted development tools and working in a collaborative environment where your ideas are valued, we'd love to hear from you.

What You'll Be Doing

• Design, develop and enhance scalable, secure microservices for enterprise SaaS applications.
• Build and evolve cloud-native solutions across both single-tenant and multi-tenant architectures.
• Collaborate closely with Product to translate complex business requirements into robust technical solutions.
• Leverage AI engineering tools, coding assistants and automated workflows to improve productivity and code quality.
• Contribute to AWS cloud infrastructure, monitoring and operational excellence using services including CloudWatch.
• Write clean, maintainable, well-tested code and contribute to CI/CD best practices.
• Participate in architecture discussions and influence technical decisions.
• Mentor and support junior engineers through code reviews, knowledge sharing and technical guidance., * TypeScript and modern Front End development.
• Financial services, capital markets or FinTech.
• Additional AWS services such as SQS, SNS, Step Functions, EventBridge or Secrets Manager.
• Big data technologies including DuckDB, pandas, Spark, Databricks or Snowflake.
• AI/ML technologies including vector databases, semantic search or LLM orchestration frameworks.
• Continuous delivery and modern development workflows.
• Data science applications or financial data visualisation.

What We Offer

• The opportunity to work on technically challenging, large-scale SaaS products.
• A collaborative and supportive engineering culture where knowledge sharing is encouraged.
• Hybrid working with regular time together in our London office.
• Weekly team lunches and regular social events.
• Exposure to modern cloud technologies and AI-assisted engineering practices.
• The chance to influence technical direction and help shape the future of a growing platform.

You'll have strong commercial experience developing cloud-native SaaS applications and enjoy working in a collaborative, fast-paced environment.

Essential Skills & Experience

• Strong Python development experience building REST APIs and distributed microservices.
• Experience delivering B2B SaaS products, including single-tenant and multi-tenant architectures.
• Hands-on experience with AWS services including Cognito, Lambda, Fargate, API Gateway, S3 and IAM.
• Experience using Terraform or other Infrastructure as Code tooling.
• Strong PostgreSQL knowledge, including database design and query optimisation.
• Experience using AI-assisted development tools such as GitHub Copilot, Claude, Cursor or similar.
• Comfortable owning features from design through to deployment.
• Strong communication skills with the ability to collaborate effectively across engineering and product teams.
• Passion for writing high-quality, maintainable software and continuously improving engineering standards.
• Experience mentoring or supporting other engineers through collaboration and code reviews.