Backstage Blog

We just signed the corporate contributor license agreement (CCLA). SoundCloud always was big on open source – we nearly exclusively use open source software in our company and use a lot of Apache projects like Hadoop, Solr, Flume, Zookeeper and Cassandra on our large scale production site.

As SoundCloud is using a lot of Apache projects and started to contribute to project we decided to sign the CCLA and enable all our developers to contribute to Apache projects even during work time if that…

When we started the Mobile project early 2011, unit testing JavaScript was one of the goals to tackle on the technical side. The history of custom JavaScript code at SoundCloud up until then rarely included unit tests, so providing references and the necessary ground research was important for both the project at hand as well as for other projects at SoundCloud.

This articles aims to provide an overview of the tools we use, what worked well and what we need to improve.

Tools

When we started the Mobile project, there were just two developers on the team, Matas and Jörn. With Jörn already maintaining and supporting QUnit for three years, this particular choice was an easy one. If you haven’t yet heard of it: Among available unit testing frameworks, QUnit is among the most popular ones. There’s a comprehensive tutorial over at ScriptJunkie…

• Announcements
• SDKs
• Android

Are you an Android developer and want to integrate SoundCloud in your own app? With the new Android Sharing Kit this has become very easy.

Berlin is playing host to the oh-so-sold-out JSConf.eu conference happening October 1-2. Some members of the SoundCloud engineering crew well be on-site and we thought it would be great if you could come too.

We have an extra ticket for the JSConf.eu conference that we are going to raffle away in a hack competition. The rules of engagement are simple: use this podcast on the periodic table from Roman Mars and build a page that presents it in an awesome way. Be it with a very creative playback…

A quick virtual heads-up for developers, hackers and coding enthusiasts in the Berlin-area: SoundCloud is very happy to support the upcoming Hack and Tell event at the C-base bar on Tuesday, August 30. The Hack and Tell is a monthly meet up where participants have the chance to get on stage for five minutes present their personal or professional projects. For those not presenting, it’s a great evening to mix it up with Berlin-based hackers, meet some members of the SoundCloud development team…

The recent outage of SoundCloud was the result of everybody doing the right thing. This totally jives with John Allspaw’s message that looking for a root cause will lead to you finding smart people simply doing their jobs.

This is what happened.

The technologies at play

The number of interactions that escalated to the outage should be interesting for other Rails/MySQL shops out there. We’re using many idiomatic patterns within Rails that ended up having devastating consequences.

Cache keys that…

The Problem

The mobile version of SoundCloud is a consumer of our own API dog food. That decision was made with the intention to deploy a self-sufficient client application that depends only on a static provider. Our early experiements showed that the attempt we made had some downsides. For example, the implementation of redirects in CORS is not behaving properly and therefore can’t be used with many of the endpoints in our API where we rely on the correct handling. Also classic XHR…

Until early this year, there was a gap. A gap between the desktop-targeted main SoundCloud site, what we call the ‘mothership’, and the native iOS (iPhone, iPod touch) and Android applications. A common and frustrating use-case was mobile Twitter: Someone would share a new favorite or upload on Twitter, you tap on it, and it tried to load the regular site on your tiny smartphone screen. Pushing the whole desktop site over a mobile connection would be a waste of precious bandwidth, if you only…

• Events

The venerable O’Reilly Velocity Conference is coming to Berlin on the 8th and 9th of November. SoundCloud is doing what we can to help organize the speaker program and want YOU to speak.

• Have you turned an operations challenge into a opportunity?
• Does web performance matter to you, and you’ve done something to prove it?
• Do you transform your running systems raw data into meaty information?

This is an amazing opportunity to share your world class experience with European peers!

Achtung! The call for proposals ends August 9th so hurry to send your proposals in to the official website…

• Announcements

It is now possible to share all public tracks and playlists to the connections of the authenticated user. So if a user is already connected e.g. with Facebook on SoundCloud, this connection can be used from your app to share a track.