Putting the Spotlight on our technical employees

My beat is a blog series that turns the spotlight towards technical employees across various desciplines and roles to showcase what a typical day as a Spotifier consists of.

Wrapped Fred

Fred Wang: Senior Backend Engineer

As a Senior Backend Engineer at Spotify New York, Fred’s role on 2021 Wrapped involved serving data stories content for iOS and Android. Here, he shares some of the most memorable moments…

Tell us more about working on Spotify Wrapped… 

I’m part of the Mambas team at Spotify, which is responsible for all the animation, presentation and personalized data in the Wrapped interactive mobile app. My job is to take the raw data from the backend and enrich it, translate it and format it for different regions before it goes to the frontend mobile engineers. That includes deciding what music to play during data stories and what images and localised text to display – all the things we serve from the backend to help iOS and Android show the data stories correctly. 

What were the biggest challenges? 

Load-testing was definitely the most challenging aspect of working on this project. In the first few hours after launch, Wrapped gets a high volume of unique visitors – all with their own unique data stories, all served to different types of mobile devices. 

So we can’t just roll it out and hope for the best – we have to simulate that load and make sure we can withstand all the requests we’re going to get at peak usage. 

During load test sessions, we process a high volume of requests and try to uncover as many issues across our dependencies as possible. It’s a big job, but really helps discover all weak links in the chain

What were the best moments? 

In the first two hours after the launch of Spotify Wrapped, we saw unprecedented traffic from around the world – yet we scaled without any major issues. It was nerve-wracking, but also extremely exciting to see all our hard work pay off like that.

What made it a fun project to be part of? 

I really enjoyed collaborating with all the great engineers and localization teams to make the data stories work cleanly across every region, language and format. And I loved the moment when the data pipelines started working – we all turned on live data for our endpoints and got to see our own Wrapped stories for the very first time. We were all so giddy and excited – all we could do was play around and compare notes for a good few hours afterwards! 

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Published by Spotify Engineering