Performance Engineer - Javascript

Performance Lisbon, Lisboa


Who we are:


Farfetch is unlike anything in the world of fashion and technology.
Our mission: to revolutionize the way the world shops.
To do it, we need innovators. People who challenge convention and dare to dream.
We’ve gone from a start-up to a billion dollar business. But we’re not done yet. Far from it.
Be bold.
Be brilliant.
Together, we can be extraordinary.


We have rapidly grown into a truly global company since our launch in 2008 and we’re continuing to grow. Our family now includes partner boutiques and brands across Europe, North and South America and Asia; we demonstrate our ‘Think Global’ value in everything we do.

We are a global team of over 1,500 people and have offices based in London, New York, L.A., Porto, Guimaraes, Lisbon, Sao Paulo, Shanghai, Moscow, Hong Kong & Tokyo.

 We are a company with an entrepreneurial spirit and innovative culture. We are positive, passionate and live our values: Be Human, Be Brilliant, Todos Juntos, Be Revolutionary, Think Global and Amaze Customers day to day.

The Team:

Our world class Technology team is at the core of what we do- they both help support the running of the current business as well as explore new and exciting technologies that keep Farfetch truly revolutionizing the industry. Split across 3 main offices- London, Porto and Lisbon, the tech hub is the fastest growing team working across all touchpoints, Web, Mobile and Instore. The teams are committed into turning the company into the leading multi-channel platform and are constantly looking for brilliant people who can help be part of the experience.


The performance and scalability team is responsible to monitor and analyze the performance of all platforms of Farfetch, identifying problems and being a part of the solution. With experienced Engineers able to work as a Taskforce to help all system to run performant and able to scale to the millions of users we have.

The Role:

The client side is crucial to have a smooth user experience. The latest years brought so many innovations on the browser that having perfect knowledge how a browser works and how you can improve every small detail is extremely important.

You will be using tools that allow you to measure the speed, the latency and the bottlenecks on the client side, defining how to fix and improve them constantly. You will be working closely with the architecture team to make sure the strategy for performance is defined and executed for all teams.

As a member of the team, you will integrate our Performance and Scalability team, having responsibilities in client performance testing and application performance testing.

What you'll do:               

  • Work along with other teams in order to assure Performance best practices;
  • Actively participate on product conception focused on performance related topics;
  • Do the continuous monitoring of performance on production environments;
  • Create and run load tests, and analyze applications performance during development life cycle;
  • Research and Development of internal tools to support performance analysis;
  • Create proof of concept to solve know-issues and support other teams on its implementation;
  • Identify JavaScript Parse & Compile bottlenecks helping to remove them by creating guidelines;
  • Empower teams and engineers to monitor their applications and apply the best concepts for client-side performance.


Who you are:

  • Proactive on performance updates;
  • Experienced working in agile environments with SCRUM methodologies;
  • Deep knowledge in JavaScript (different frameworks and libraries appreciated), HTML, CSS and how a browser works;
  • Knowledgeable in test automation with Selenium, Jenkins, Visual Studio or any other test automation tool is a plus;
  • Knowledge in webpage test and similar tools to test different pages and applications. Also test automation with Selenium is a plus;
  • Passionate about delivering quality software, defending the customer/end-user perspective and performance above all things;
  • Good communicator and a teamwork believer;
  • Detail oriented and resilient to stress;
  • Interested in automating/breaking/debugging things.

We love hearing from you and want you to be as ambitious as we are, but before applying please ask yourself the following…

  • Is this role a good match for me and my long term goals? We want to really know why you have chosen this career.
  • Do I have all the skills and experience required for this role? Be realistic. We will only consider applications that demonstrate relevant skills or the potential to match the role requirements.
  • Spell Check. As simple as it sounds make sure your application is to the highest standard. You will be surprised at how many applications we receive with spelling mistakes on them.


We are committed to equality of opportunity for all staff, applications from individuals are encouraged regardless of age, disability, sex, gender reassignment, sexual orientation, pregnancy and maternity, race, religion or belief and marriage and civil partnerships.