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- Tasks: Design and build robust backend systems using Python for a cutting-edge AI platform.
- Company: Join a dynamic Series A tech company focused on real-world AI automation.
- Benefits: Competitive salary, meaningful equity, and a high ownership role.
- Why this job: Make impactful decisions and tackle complex engineering challenges in a supportive team.
- Qualifications: Strong Python and SQL skills with experience in backend systems.
- Other info: Intellectually stimulating environment valuing quality and clear communication.
The predicted salary is between 120000 - 160000 £ per year.
Location: London based - hybrid
Salary: £100,000 - £160,000 + equity
Tech Stack:
- Backend: Python (FastAPI)
- AWS
Are you a backend engineer who cares more about building robust systems than chasing AI hype? We are working with a recently funded Series A technology company building AI powered automation for real world, critical workflows. Their platform captures operational knowledge and turns it into production grade systems that AI can interact with safely and reliably.
This is not applied machine learning, not foundation model development, and not experimental agent playgrounds. The work is focused on the engineering around AI: evaluation, control, reliability, and building systems that behave predictably in production. Engineers work closely with users, own problems end to end, and shape both the technical and product direction in a small, high trust team. It is an intellectually demanding environment where quality, correctness, and long term system design genuinely matter.
Responsibilities
- Design and build backend systems that power a complex, evolving platform using Python
- Own data models, schemas and database design with a strong focus on correctness and scale
- Build ingestion pipelines and integrations with production customer systems
- Develop tooling that enables AI capabilities while maintaining strong control and evaluation standards
- Work directly with customers to understand workflows and translate them into reliable systems
- Contribute to architectural decisions and long term platform evolution
Requirements for Success
- Strong experience as a backend or systems focused engineer
- Deep Python experience with excellent engineering fundamentals, or equivalent depth in a strongly typed language
- Strong SQL skills and experience designing schemas
- Experience building complex backend systems that evolve over time
- Comfort working in ambiguous, early stage product environments
- Experience with data ingestion pipelines or internal tooling for AI or data teams
The engineering team is currently small and senior, with a strong academic and systems background. There is no formal product team. Engineers own user experience, technical decisions and delivery. The culture values thinking time, technical rigour and clear communication over speed for its own sake.
Benefits
- Salary between £120,000 and £160,000 depending on experience
- Meaningful equity
- High ownership role with direct influence on product and technical direction
This role will not suit engineers who want to build flashy demos or constantly switch problems. It will suit someone who enjoys hard systems, deep thinking, and building things that actually hold up in the real world.
If you’re looking for a role where you can make meaningful decisions, work on incredibly interesting and complex problems, and be part of an exceptional team, get in touch at imogen@sr2rec.co.uk.
Principal Software Engineer in London employer: SR2 | Socially Responsible Recruitment | Certified B CorporationTM
Contact Detail:
SR2 | Socially Responsible Recruitment | Certified B CorporationTM Recruiting Team
StudySmarter Expert Advice 🤫
We think this is how you could land Principal Software Engineer in London
✨Tip Number 1
Network like a pro! Reach out to your connections in the tech industry, especially those who work with Python or in backend engineering. A friendly chat can lead to insider info about job openings that aren't even advertised yet.
✨Tip Number 2
Show off your skills! Create a portfolio showcasing your best backend projects, especially those involving Python and FastAPI. This gives potential employers a taste of what you can do and sets you apart from the crowd.
✨Tip Number 3
Prepare for technical interviews by brushing up on your systems design knowledge. Be ready to discuss how you've built robust systems in the past and how you approach problem-solving in ambiguous environments.
✨Tip Number 4
Don't forget to apply through our website! It’s the best way to ensure your application gets seen by the right people. Plus, we love seeing candidates who take the initiative to connect directly with us.
We think you need these skills to ace Principal Software Engineer in London
Some tips for your application 🫡
Tailor Your CV: Make sure your CV reflects the skills and experiences that align with the Principal Software Engineer role. Highlight your backend engineering experience, especially with Python and FastAPI, to show us you’re the right fit.
Craft a Compelling Cover Letter: Use your cover letter to tell us why you care about building robust systems. Share specific examples of how you've tackled complex backend challenges in the past, and let your passion for engineering shine through!
Showcase Your Problem-Solving Skills: In your application, don’t just list your technical skills; demonstrate how you've used them to solve real-world problems. We love seeing candidates who can think critically and own their projects from start to finish.
Apply Through Our Website: We encourage you to apply directly through our website. It’s the best way for us to receive your application and ensures you don’t miss out on any important updates during the process!
How to prepare for a job interview at SR2 | Socially Responsible Recruitment | Certified B CorporationTM
✨Know Your Tech Stack Inside Out
Make sure you’re well-versed in Python, FastAPI, and SQL. Brush up on your engineering fundamentals and be ready to discuss how you've applied them in past projects. This role is all about building robust systems, so be prepared to share specific examples of your experience with backend development.
✨Understand the Company’s Mission
Research the company’s focus on AI-powered automation and their approach to building reliable systems. Be ready to discuss how your values align with theirs, especially regarding quality and long-term system design. Showing that you care about their mission will set you apart from other candidates.
✨Prepare for Problem-Solving Questions
Expect to face questions that assess your problem-solving skills, particularly in ambiguous situations. Think of scenarios where you’ve had to own a problem end-to-end and how you approached it. Highlight your ability to think critically and design solutions that are both effective and scalable.
✨Showcase Your Communication Skills
Since the role involves working closely with customers and shaping technical decisions, clear communication is key. Practice articulating your thoughts on complex topics simply and effectively. Be ready to demonstrate how you’ve successfully collaborated with others in previous roles.
