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For Companies At a Glance
- Tasks: Build and scale backend systems for a global AI-first benefits platform.
- Company: Join Happl, a top UK startup backed by leading investors like YCombinator.
- Benefits: Competitive salary, equity, flexible working, and wellbeing budget.
- Why this job: Make a real impact on employee benefits while working with cutting-edge technology.
- Qualifications: 3+ years in backend engineering with strong API and database skills.
- Other info: Rapid career progression in a dynamic, supportive engineering team.
The predicted salary is between 36000 - 60000 £ per year.
We're building the next generation of employee benefits infrastructure. At Happl, we help global teams design, manage, and scale benefits that actually work for their people by using AI, across flex allowances, benefits, insurance, recognition, and wellbeing, all in one intelligent platform. Happl is backed by leading investors such as YCombinator, 6Degrees Capital, and more, known for backing leading companies such as Deel, Rippling, Airbnb, Coinbase, Dropbox, and most recently was awarded a place in the UK's top 100 startups for 2026.
About The Role
As a Backend Engineer at Happl, your mission is to build the systems that power a global, AI-first benefits platform. You'll design, build, and scale backend services that are reliable, secure, and performant, enabling our product teams to move fast while supporting complex real-world use cases across payroll, finance, and employee benefits. This role is for someone who enjoys ownership, thrives in fast-moving environments, and wants to build foundational systems that directly impact how companies support their people.
What You'll Be Doing
- This role sits within our Engineering team and works closely with Product, Frontend, Data, and Customer teams across the full development lifecycle.
- You'll help shape how we build and scale our backend by focusing on:
- Designing and scaling the backend architecture powering a global, AI-first platform
- Building and owning core services across benefits, allowances, payments, and reporting
- Developing scalable data models and ensuring integrity across systems
- Improving platform reliability, performance, security, and observability
- Automating workflows and Go Rules to streamline complex operations
- Collaborating closely with product and frontend teams to ship end-to-end features
- Writing clean, well-tested, production-ready code
- Using AI tools to accelerate development and iteration
- Contributing to architecture, technical decisions, and engineering standards
You'll play a key role in ensuring Happl's backend scales as our customer base, features, and global footprint grow.
What We're Looking For
- 3+ years experience as a Backend or Software Engineer
- Strong experience with modern backend languages and frameworks (e.g. Typescript, Golang)
- Experience designing and consuming APIs (REST, event-driven systems)
- Solid understanding of databases (SQL / PostgreSQL) and data modelling
- Experience building and scaling production systems
- Familiarity with cloud infrastructure and CI/CD workflows
- Comfortable working with integrations and third-party services
- Experience using AI tools (e.g. ChatGPT, Claude) as part of your workflow
- Clear communicator who works well with both technical and non-technical stakeholders
- Proactive, detail-oriented, and comfortable taking ownership
If you don't meet every requirement but feel this role fits your trajectory, we'd still love to hear from you.
Why join Happl
- Help shape the future of employee benefits
- Competitive base salary and commission
- Meaningful equity in an early stage growing business
- Flexible hybrid working from day one
- Access to your own Happl benefits platform
- Optional enrolment in Private Health Insurance
- Optional enrolment in Dental insurance, including family cover
- A flexible Wellbeing budget to spend on whatever wellbeing means to you
- Learning & Development (L&D) allowance
- Pension scheme from day one
- Rapid career progression in a scaling engineering team
About The Interview
- Call 1: 20-min Intro call with Ben (COO & CoS)
- Call 2: 30-min deep dive with Lee (Head of Engineering)
- Short Task
- Call 3: 30-min deep dive with Ben T (CEO & Founder)
Additional Details
- Location: London, Waterloo
- Team: Engineering
- Working arrangement: Hybrid (3+ Days in Office)
Backend Engineer in London employer: Happl
Contact Detail:
Happl Recruiting Team
StudySmarter Expert Advice 🤫
We think this is how you could land Backend Engineer in London
✨Tip Number 1
Network like a pro! Reach out to folks in your industry on LinkedIn or at meetups. We all know that sometimes it’s not just what you know, but who you know that can help you land that Backend Engineer role.
✨Tip Number 2
Prepare for those interviews! Research Happl and understand their mission. We want to see how your skills can directly impact their AI-first benefits platform. Tailor your examples to show how you can contribute to their goals.
✨Tip Number 3
Show off your projects! If you’ve built any cool backend systems or worked with modern languages like Typescript or Golang, make sure to highlight them. We love seeing real-world applications of your skills!
✨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’re always on the lookout for passionate candidates who want to shape the future of employee benefits.
We think you need these skills to ace Backend Engineer in London
Some tips for your application 🫡
Tailor Your Application: Make sure to customise your CV and cover letter for the Backend Engineer role. Highlight your experience with backend languages like Typescript or Golang, and showcase any relevant projects that demonstrate your skills in building scalable systems.
Showcase Your Problem-Solving Skills: In your application, don’t just list your technical skills; share examples of how you've tackled complex problems in past roles. This will help us see how you approach challenges and contribute to our mission at Happl.
Be Clear and Concise: When writing your application, keep it straightforward. Use clear language and avoid jargon where possible. We appreciate a well-structured application that gets straight to the point while still showcasing your personality.
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’re considered for the role. Plus, it shows you’re keen on joining our team!
How to prepare for a job interview at Happl
✨Know Your Tech Stack
Make sure you’re well-versed in the modern backend languages and frameworks mentioned in the job description, like Typescript and Golang. Brush up on your API design skills and be ready to discuss how you've built and scaled production systems in the past.
✨Showcase Your Problem-Solving Skills
Prepare to share specific examples of how you've tackled complex real-world use cases, especially in areas like payroll and employee benefits. Highlight your experience with databases and data modelling, as this will demonstrate your ability to handle the technical challenges at Happl.
✨Communicate Clearly
Since you'll be working closely with both technical and non-technical teams, practice explaining your past projects in a way that’s easy to understand. This will show that you can bridge the gap between different stakeholders and contribute effectively to team discussions.
✨Embrace Ownership and Proactivity
Happl is looking for someone who thrives on ownership. Be prepared to discuss times when you took initiative on a project or improved a process. This will highlight your proactive nature and fit with their fast-moving environment.