Backstage Blog

• Events

Late last year, six women crowded in to a Mitte cafe booth and listened to Berlin Geekettes founder Jess Erickson share her idea: Berlin’s first all-women hackathon. With SoundCloud’s Amelie Anglade the then newly-appointed the Berlin Geekettes Tech Ambassador, we agreed that it was a great idea to produce the hackathon as a partnership between the Geekettes and the women developers of SoundCloud.

Fast forward to the first weekend of March, when the vision became reality: after 24 hours of hacking, 80 women demoed 29 projects across a range of different platforms, from a belt transformed into a game controller to an app aimed to help toddlers learn to do everyday tasks.

• Announcements

The /tracks endpoint has traditionally accepted an order parameter for ordering results by either creation date or ‘hotness’. The method for calculating a tracks ‘hotness’ has never been clearly explained, but generally speaking is based on the number of likes and listens a track receives.

Recently we started to experience problems with the query that returns tracks ordered by hotness. In the past weeks, these problems started to effect and even cause outages for API users.

We have decided that the best way forward is to remove this parameter. Starting soon, GET requests to the /tracks endpoint will ignore the order…

• Events
• Hacks

Last weekend, we sponsored and attended our first PennApps, the world’s largest student run hackathon held at the University of Pennsylvania in Philadelphia. Nearly 500 students participated from a variety of universities across the US and elsewhere. Students were given 36 hours to get into teams, hack on projects, then show them off to the judges. The results were astounding. In total, over 100 hacks were submitted. Here are some of my personal favourites.

• Search and Discovery
• Architecture

Search is front-and-center in the new SoundCloud, key to the consumer experience. We’ve made the search box one of the first things you see, and beefed it up with suggestions that allow you to jump directly to people, sounds, groups, and sets of interest. We’ve also added a brand-new Explore section that guides you through the huge and dynamic landscape of sounds on SoundCloud. We’ve also completely overhauled our search infrastructure, which helps us provide more relevant results, scale with…

• Guides

The web has come a long way. We have APIs that allow developers to create amazing applications quickly, and browser technologies have advanced to the point where JavaScript / HTML and CSS are necessary tools for creating apps. Despite this, there’s still a skills gap and companies are having an increasingly hard time hiring for technical positions.

This is the main reason the folks at GOOD teamed up with the Apollo Group to launch Coding for GOOD. A series of coding lessons and final project…

• Events

On Saturday, we hosted Story Hack Boston along with P2PU and Mashery at the MIT Media Lab. About 50 people from content and technical backgrounds joined us to create new story telling experiences. The crowd was pretty evenly split, which made for a lot of awesome collaboration.

• Announcements

We’re making some changes to how we manage our App Gallery and wanted to take some time to explain them to you, our developer community.

The App Gallery is where we highlight interesting and useful SoundCloud powered apps and services for our users. As our developer community continues to grow, it’s even more important that we keep a high bar for apps found in App Gallery. Having a high standard protects the value of being featured in App Gallery for all of our developers while giving our users…

• Events
• Hacks

Just over a week ago we had our first internal hackathon at SoundCloud. You can read (and listen!) about it on our community blog or read some of the awesome press coverage the event received.

We had over 60 people attend and over 20 projects were demoed. I joined a team organized by Josh Devins to build ToyBox, a children’s toy that plays sounds from SoundCloud in response to physical events. The team consisted of myself, Horaci Cuevas, Josh Devins, and Oliver Hookins.

The first task was to come up with a design for our project. An Arduino fitted with gyro, accelerometer and motion sensors provided the interface between real world events and the rest of the system. A Raspberry Pi…

• API
• Architecture
• Open Source

This is a story of how we adapted our architecture over time to accomodate growth.

Scaling is a luxury problem and surprisingly has more to do with organization than implementation. For each change we addressed the next order of magnitude of users we needed to support, starting in the thousands and now we’re designing for the hundreds of millions.  We identify our bottlenecks and addressed them as simply as possible by introducing clear integration points in our infrastructure to divide and…

• Post Mortem

As some of you might know, we had an outage yesterday. We believe that in every mistake there is something to learn from, so after each outage we are writing post-mortems. Usually we do this internally because the issues we run into are very specific to our infrastructure.

This time we ran into a quite nasty issue which could affect everyone running a linux system with a lot sessions on it and we thought you might be interested to know about that pitfall.

What happened?

At 4:40pm CEST, we got reports about Yikes (503/504 errors) on SoundCloud. Around the same time, our monitoring alerted for a high amount of 503s at our caching layer and right after that one of our L7 routing nginx instances was…