Backstage Blog

• Announcements
• Recommendation System
• Machine Learning
• Data Science

With more than 125 million tracks from over 12 million creators heard each month on our platform, SoundCloud is uniquely positioned to offer listeners a full spectrum of music discovery.

Classic hits, the latest releases, gems from underground talent and the best of what’s up-and-coming – all in one place.

How can you make great content discoverable and available at ease? How can you create a unique experience for every single user?

• Open Source
• Hadoop
• Big Data
• Crunch

With Java 8 now in the mainstream, Scala and Clojure are no longer the only choices to develop readable, functional code for big data technology on the JVM. In this post we see how SoundCloud is leveraging Apache Crunch and the new Crunch Lambda module to do the high-volume data processing tasks which are essential at early stages in our batch data pipeline efficiently, robustly and simply in Java 8.

• Announcements
• API

We previously introduced new playlist representations. The compact representation returns only the playlist itself without any of the tracks. For most users, this is preferable – the compact representation significantly reduces the size of the JSON payload for large playlists and provides faster API response times.

Beginning July 15, 2016, all queries using the q parameter will only return this compact representation for playlists. Other playlist representations will no longer be available when using the q…

• Android
• Mobile

Last week, we open-sourced LightCycle, an Android library that helps break logic out of Activity and Fragment classes into small, self-contained components called LightCycles.

Components that typically need to be aware of Activity and Fragment lifecycle events include presenters, UI tracking code, input processors and more. We’ve been using LightCycle extensively in the SoundCloud Music & Audio and SoundCloud Pulse apps over the last year.

• Android
• Mobile

In part one we described how running into Android’s method limit may leave you unable to build, and offered strategies you can employ to make your app fit into a single DEX file. In this part we share an alternative option: using multiple DEX files.

• Announcements
• API
• JavaScript
• SDKs

We are happy to announce version 3.0.0 of our SoundCloud JavaScript SDK.

The new SDK improves stream security and content uploading functionality, and modernizes the technology stack.

Version 3 of the SoundCloud JavaScript SDK is a major update and is not backwards compatible. That said, the changes that you need to make your web app work with the new SDK are easy to implement. Please refer to Migrating to JavaScript SDK 3.0.0 to upgrade.

ECMAScript 2015 and CommonJS

The original version of the…

• Android
• Mobile

At SoundCloud we have been building for the Android platform since 2010. Much has changed since then: the team has grown, the list of features has grown, and our audience has grown. Today, eight engineers are working full time on the official SoundCloud app, across various areas, with contributions pouring in from other parts of the organization. Due to the growing complexity and number of contributions, the app’s size has grown substantially. Currently the app consists of approximately 1200 Java source files, not counting tests, containing approximately 86000 lines of code. This doesn’t include native code, such as our playback or recording stacks.

We’re not the first to run into Android’s limits in terms of build tools. An internal limitation of Dalvik’s byte code format (DEX), which I will explain in more detail, can leave you unable to build after your codebase reaches a certain size. If you fail to anticipate this, it might happen during the most inconvenient time, such as when you are preparing for a release. Part of our job in Core Engineering at SoundCloud is to make sure our developers are happy and productive; not being able to build our app anymore makes for neither happy nor productive developers.

While there are a number of posts on this topic, I would like to describe in more detail what we have done to combat Android’s method limit, what things worked well and what didn’t work so well, what it actually means to use the dx tool’s --multi-dex switch and what you can do to improve application health with regards to size.

• Announcements
• API

At SoundCloud, we’re building an ecosystem where creativity thrives. Developers are an important part of that ecosystem. We’re continually inspired by how you use the SoundCloud API to support creators and listeners in innovative ways.

But as the ecosystem has grown, we’re dealing with an increasing number of applications that abuse creator content by violating our developer Terms of Use. To help control this type of behaviour, we’re introducing a daily rate limit on API play requests.

Beginning…

• Announcements
• API

Requests for playlists have always included the full track objects contained within. This representation may be convenient for playlists with ten or twenty tracks but can cause problems for playlists that contain hundreds or thousands of tracks. Requesting such large playlists could result in requests that take a long time to respond and that eventually timeout.

Today, we introduce two new representations for the /playlists resource: compact and id.

If you add representation=compact to a playlist request, the request will return only…

• Announcements
• API

In October 2014, Apple announced that all submissions to the App Store must include 64-bit support by June 1, 2015. The SoundCloud API for Cocoa contains 32-bit dependencies and will not be updated, because it has been discontinued. Anyone using the SoundCloud API for Cocoa will need to will need to migrate away from it if they wish to update their app after June 1.

To ease this transition we have built a sample app that demonstrates how to authorize a user via OAuth using only built-in…