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Implementing Dark Mode Using the Observer Pattern

November 8th, 2019 by Matias Villaverde

Last week’s update to the SoundCloud iOS app includes support for Dark Mode. This took several months of work and collaboration between design and engineering teams across the company, so we wanted to share our approach to implementing Dark Mode and some of the obstacles we encountered along the way.

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Solving Remote Build Cache Misses by Annoying Your Colleagues

October 1st, 2019 by Nelson Osacky

Part of a build engineer’s role is to speed up builds. Improving build performance and avoiding work with caching is one way to achieve this, but another tool in the build engineer’s belt is that of disallowing slow builds. This is part two in a series about solving Gradle remote build cache misses.

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Gradle Remote Build Cache Misses

August 30th, 2019 by Nelson Osacky

Until recently, one of the top technical risks facing SoundCloud’s Android team was increasing build times. Our engineering leadership was well aware of the problem, and it was highlighted in our company’s quarterly goals and objectives as modularization. Faster build times means more productive developers. More productive developers are happier and can iterate on products more quickly.

Modularization is key to decreasing build times, but avoiding work is another important part of the puzzle, and build caching is one way to avoid that work. Gradle, our tool for building Android, has a local file system cache that reuses outputs of previously performed tasks. We have been using the Gradle remote build cache in order to save our developers’ time. It helps us avoid redoing work that other teammates have already done or switching to old branches. However, to get the full benefits of caching, you have to go beyond simply setting it up.

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SoundCloud Is Playing the Oboe

June 21st, 2019 by Miloš Pešić and Julio Zynger

Media and playback are at the core of SoundCloud’s experience. For that reason, we have established and grown an engineering team that is specialized in providing the best possible streaming experience to our users across multiple platforms.

To do this, we combine the industry’s best-fitting solutions with our own custom technologies, libraries, and tools. In this article, let’s dive into how we improved latency in our Android application by leveraging a new engine for our player’s audio sink.

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Alerting on SLOs like Pros

June 4th, 2019 by Björn “Beorn” Rabenstein

If there is anything like a silver bullet for creating meaningful and actionable alerts with a high signal-to-noise ratio, it is alerting based on service-level objectives (SLOs). Fulfilling a well-defined SLO is the very definition of meeting your users’ expectations. Conversely, a certain level of service errors is OK as long as you stay within the SLO — in other words, if the SLO grants you an error budget. Burning through this error budget too quickly is the ultimate signal that some rectifying action is needed. The faster the budget is burned, the more urgent it is that engineers get involved.

This post describes how we implemented this concept at SoundCloud, enabling us to fulfill our SLOs without flooding our engineers on call with an unsustainable amount of pages.

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Playback on Web at SoundCloud

May 3rd, 2019 by Tom Jenkinson

Maestro is a library we have developed to handle all playback across SoundCloud web applications. It successfully handles tens of millions of plays per day across soundcloud.com, our mobile site, our widget, Chromecast, and our Xbox application. We are considering open sourcing it, and this blog post is a technical overview of what we’ve achieved thus far with Maestro.

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Taking Our Bug Bounty Program Public

April 18th, 2019 by Tobias Schmidt

We’re excited to announce the launch of our public bug bounty program with Bugcrowd — the #1 crowdsourced security platform. This public program is open to Bugcrowd’s full crowd of top, trusted whitehat hackers, and we will award up to $1,500 per vulnerability identified on our website, API, and mobile apps.

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Release Quality and Mobile Trains

April 3rd, 2019 by Julio Zynger

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.

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How to Reindex One Billion Documents in One Hour at SoundCloud

March 21st, 2019 by Qaiser Abbasi

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.

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Off-Platform Validation

March 6th, 2019 by Joe Kearney

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.

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