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- Tasks: Build and scale backend systems for a global, AI-first benefits platform.
- Company: Join Happl, a forward-thinking company revolutionising employee benefits.
- Benefits: Competitive salary, equity options, flexible working, and wellness budget.
- Other info: Fast-paced environment with rapid career growth and learning opportunities.
- Why this job: Make a real impact on how companies support their employees with innovative tech.
- Qualifications: 4+ years in backend engineering, strong coding skills, and API design experience.
The predicted salary is between 60000 - 80000 ÂŁ per year.
As a Senior 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.
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:
- 4+ 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 commercial team
Location: London, Waterloo
Team: Engineering
Working arrangement: Hybrid (3+ Days in Office)
Senior Backend Engineer employer: Happl
Contact Detail:
Happl Recruiting Team
StudySmarter Expert Advice 🤫
We think this is how you could land Senior Backend Engineer
✨Tip Number 1
Network like a pro! Reach out to folks in the industry, attend meetups, and connect with current employees at Happl. A friendly chat can sometimes lead to opportunities that aren’t even advertised!
✨Tip Number 2
Show off your skills! Create a portfolio or GitHub repository showcasing your projects, especially those using modern backend languages like Typescript or Golang. This gives you a chance to demonstrate your expertise beyond just a CV.
✨Tip Number 3
Prepare for the interview by brushing up on your API design and database knowledge. Be ready to discuss how you’ve built and scaled production systems in the past. We love seeing candidates who can articulate their thought process!
✨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, it shows you’re genuinely interested in joining our team at Happl.
We think you need these skills to ace Senior Backend Engineer
Some tips for your application 🫡
Tailor Your CV: Make sure your CV reflects the skills and experiences that align with the Senior Backend Engineer role. Highlight your experience with backend languages, API design, and any relevant projects that showcase your ability to build scalable systems.
Craft a Compelling Cover Letter: Use your cover letter to tell us why you're passionate about this role at Happl. Share specific examples of how you've taken ownership in past projects and how you can contribute to our mission of building an AI-first benefits platform.
Showcase Your Technical Skills: Don’t forget to mention your proficiency with modern backend frameworks and cloud infrastructure. If you've used AI tools in your workflow, give us a shout-out about that too! We love seeing how you leverage technology to enhance your work.
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 us 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 examples of how you've tackled complex real-world use cases, especially in areas like payroll and finance. Be ready to explain your thought process and the impact of your solutions on previous projects.
✨Communicate Clearly
Since you'll be collaborating with both technical and non-technical teams, practice explaining your ideas in a straightforward manner. Think about how you can convey complex concepts simply, as this will demonstrate your ability to work across different teams.
✨Emphasise Ownership and Proactivity
Happl is looking for someone who thrives on ownership. Prepare to discuss instances where you took charge of a project or initiative, highlighting your proactive approach and attention to detail. This will show that you're not just a coder, but a key player in driving success.