Senior Full-stack Engineer in Madrid


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Job Description

We are the world´s largest language learning community with over 100m users from 190 countries, growing at up to 30,000 new users per day. We make learning a language easy by combining AI-powered courses with instant feedback from our global community of native speakers. Our mission is to break down language barriers across the globe.

What does a Full Stack Engineer do at Busuu?

As a Full Stack Engineer, you will be working on a new and exciting initiative at Busuu. You will work on features from ideation, implementation, and release collaborating with all departments of the company. Once released to users your work will be seen by millions and from there you will measure, evaluate, and evolve what you just released.

You'll be working on implementing new features working in sprints. We're looking for people who have passion for the user (UI, UX) but also who are interested in performance and code scalability. We're looking for candidates who have a desire to work with Front-end technologies using frameworks like React as much as working with Back-end technologies. Our APIs are split into services, the majority of our APIs are Symfony based, however we have a few written in NodeJS.

You will ship often without sacrificing the quality of code and you'll collaborate extensively with the other engineers in the team. We are a team of experienced developers that rely heavily on data to make decisions about where to go next. We strive to write simple and readable code while still developing highly scalable systems.

What we are looking for in a Senior FullStack Engineer:


  • Extensive experience working with PHP/OOP and experience with a modern web framework (we use Symfony 3 to 5).
  • Good expertise in data modeling and performance optimisation using relational databases (we use MySQL and PostgreSQL).
  • Solid knowledge of REST API design.
  • Exposure to the architecture of high traffic web platforms.
  • Experience with testing methodologies, performance debugging and benchmarking.

Nice to have:

  • Experience with writing performant and scalable services in NodeJS with TypeScript.
  • Experience with a modern framework such as NestJS and solid understanding of how to model and architect backend services and requirements.


  • Strong knowledge of ES5 and ES6.
  • Experience and understanding of the React ecosystem.
  • Experience with testing methodology using Mocha, Jest, or similar.
  • Knowledge of HTML Semantic and CSS.
  • Experience in building complex layouts and working with responsive applications.
  • Awareness of cross-browser compatibility issues and client-side performance considerations.
  • Demonstrated design and UX sensibilities.

Being a part of Busuu - How do things work:

We are acutely aware that we are in unprecedented times and like all companies we need to adapt to this in order to safeguard our Busuu community. In order to do this we are constantly reviewing the government guidelines and adapting accordingly to accommodate the physical and mental wellbeing of our employees. In the current global climate, some of our team events are virtual and some of our benefits have been amended.

At Busuu we want to ensure that you have access to some great benefits:

  • We have an amazing office which is available for you to work from if you would like to do so, this is completely optional at the moment in the current environment. If you would like to be in the office we have put in place lots of important social distancing practices to ensure you are safe to meet with your colleagues in person
  • The office is well-equipped with free breakfast, plenty of snacks, fresh fruit and free dinner of your choice if you need to stay late
  • Social interaction is really important to us so we have lots of remote activities for you to join into such as team events, socials, online weekly quiz, etc
  • There is a personal training budget just for you, so you can learn more in your field, attend virtual conferences and events that you find interesting
  • To keep you active and help your mindfulness we offer weekly virtual yoga sessions
  • Busuu offers a great private health insurance scheme
  • We like to support our teams with their work life balance so we offer flexible working hours

What happens next

We aim to have a simple and speedy hiring process and we want to make sure that we are right for you as much as the other way around. The hiring process for Full Stack Engineer is the following steps:

  1. CV application review - We will review it as quickly as possible.
  2. Let’s chat - Quick chat with our recruiter about your experience and the role.
  3. Backend Video Technical Interview - Technical call with the backend engineering team.
  4. Backend Take home test - We will send you a technical test to complete in your time.
  5. Backend Home Test Task Review - Technical interview and pair programming with the backend team.
  6. Frontend Video Technical Interview - Technical call with the frontend engineering team.
  7. Culture fit interview - Video call with the Engineering and Product Manager.

Our platform is for everyone, and so is our workplace. We pride ourselves on embracing our differences, whether they're cultural, racial, religious or otherwise. This means each one of us comes to work knowing that we have a voice – and a safe, judgement-free zone to speak freely.

If you like the sound of that, join us. We'd love to hear what you have to say.


About Busuu

  • Social Network

  • London, UK

  • 50-200

  • 2008


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