Flickr PuSH: Real-time Updates on the Cheap for Fun and Profit

Neil Walker (Flickr), Nolan Caudill (Yahoo/Flickr)
Location: Conference Room E Level:
Average rating: ****.
(4.40, 5 ratings)

Launched in 2004, Flickr was part of the first wave of Web 2.0 sites. While boasting a pioneering and industry-leading API, it has always operated in a passive rather than active mode when it comes to delivering content; come to (or talk to the API) and get some photos. Now real-time is the new hotness. With the ever-decreasing time between when events occur and when the people that care about those events wish to observe them, repeatedly polling an API to get those events becomes less and less practical.

Learn how Flickr recently added PubSub features to its API. We’ll take a look at what we built, why, and how. In particular we’ll focus on how to add real-time features to an existing site without adversely affecting performance, requiring major investments in new infrastructure or re-architecting large chunks of code. Node.js, websockets, and Redis are some of the technologies we used. We’ll discuss the reasons behind these technology choices, the trade-offs required when using them and the types of features they enable.

Photo of Neil Walker

Neil Walker


Neil works on the storage and infrastructure layers at Flickr, where he has spent the past 3 years building, scaling, maintaining and sometimes breaking the plumbing that makes the world’s largest kitten photo repository a reality. Before that he dabbled in GIS, worked in the financial sector and somehow spent 2 years in a biology lab helping to map the salmon genome.

Nolan Caudill


Nolan Caudill is a backend engineer at Flickr, the world’s best photo sharing website. At Flickr, he works on building new user-facing features as well as behind-the-scenes infrastructure work and keeping a very big site running smoothly.

He comes to San Francisco from North Carolina where he worked at a busy local news organization as a web engineer and then leading software development at a small web agency.

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