Backstage Blog

• Android
• Mobile
• Release
• Testing
• Engineering

Once every two weeks, we prepare new versions of our mobile apps to be published to the app stores. Being confident about releasing software at that scale — with as many features and code contributions as we have and while targeting a wide range of devices like we do at SoundCloud — is no easy task. So, over the last few years, we have introduced many tools and practices in our release process to aid us.

In this blog post, I’ll cover some of the techniques we use to guarantee we’re always releasing quality Android applications at SoundCloud.

• Search
• Performance
• Engineering

In the past, the Search Team at SoundCloud had high lead times for making updates to Elasticsearch clusters, either during the implementation of a new feature or simply while fixing a bug. This was because both tasks require us to reindex our catalog from scratch, which means reindexing more than 720 million users, tracks, playlists, and albums. Altogether, this process took up to one week, though there was even one scenario where it almost took one month to roll out a bug fix.

In this post, I would like to share the concrete Elasticsearch tweaks we made so that we can now reindex our entire catalog in one hour.

• Engineering

Last month we launched SoundCloud Premier Distribution, which allows creators to distribute their music from SoundCloud to other streaming platforms and stores. For many of our users, this will be their first experience with the conventions and requirements of the music industry supply chain. Due to strict requirements regarding metadata and media, the barriers to entry to this world are very different than those to a creator uploading to SoundCloud. The aim of SoundCloud Premier Distribution is to make the path from SoundCloud upload to off-platform plays as frictionless as possible. Here we’ll look at how a system of automatic and manual validations allows users to get fast feedback as they prepare a release.

• Engineering
• Engineering Culture
• Engineering Management

Although it can be easy to know if you’ve messed up badly as a manager, it’s not always as easy to know if you’re doing a good job. In particular, the power dynamics at play can make it hard for people on your team to feel confident letting you know what’s working well and what’s working not so well. In this article, I’m going to talk about an approach I started using in the last few years that seems to strike the best balance of getting the input managers need while still promoting a healthy culture of direct feedback.

• Engineering
• JavaScript
• Redux
• React

This post describes why and how we implemented a garbage collector in our Xbox application on top of Redux and in addition to the JavaScript engine’s regular garbage collector.

• Engineering Culture
• Tech Debt

Almost every company accumulates tech debt as time goes on. Tight deadlines, changing requirements, scaling issues, poor or short-sighted system designs, knowledge silos, inconsistent coding practices, turnover of key staff — these things all happen and can contribute to tech debt. So what can be done about it once it’s there?

• iOS
• Swift
• Testing

Memory leaks are a common problem when writing iOS applications, and while we all know we should be on the lookout for them, it’s often too easy to miss a vital weak reference. By leveraging integration testing, we can catch these issues and spend more time actually building features.

• Engineering
• iOS
• Architecture

In 2017, our team of six engineers wanted to try out a clean architectural pattern and decided to use VIPER. In the text below, I’ll cover how the team worked on this.

• Engineering
• Microservices

We revisited our distributed tracing setup and incorporated Kubernetes pod metadata into it, significantly enhancing our engineers’ ability to troubleshoot problems that cut across microservices.

• Engineering
• Monitoring
• Testing

At SoundCloud, we follow best practices around continuous delivery, i.e. deploying small incremental changes often (many times a day). In order to improve the user experience, we’ve been exploring different ways of reducing the impact and the Mean Time to Recovery (MTTR) of faulty deployments. Enter canary releases.