Kent Brewster | Pinterest engineer, Product

Not long ago, some friends and I were having lunch and talking about the upcoming election. As is the case with discussions centered around weather or politics, it ended the way they usually end: with all of us shrugging and saying “well, beyond remembering to vote, what can any of us do?”

Plenty, as it turned out. We work at Pinterest. We have one job: help people take action on their ideas. So we looked around and realized there was something else we could do: help get out the vote. The tools were already there, courtesy All we had to do was wire them up and get them in front of people.

We remembered a Wild West time when any arbitrary iframe could be embedded in the close-up view of a Pin. Together, we hacked three Pins and embedded’s power tools. We promoted them to a nationwide audience, and ultimately helped tens of thousands of voters check their status, get registered, and request absentee ballots.

How we did it

First we looked at and made sure their iframes were compatible with Pins. At a bare minimum the iframes had to be sent over SSL from end to end; happily, each includes a link to ExpeditedSSL’s simple SSL scanner, which gives them an A+ 6-out-of-6 rating. We also made sure they’d render nicely all the way down to 237px width, because Pins can be embedded in widgets and might potentially show up anywhere on the Web.

Then we made a high-resolution thumbnail image for each Pin, to have something to show in the grid for mobile devices, which don’t show iframes. Something else we had to think about: making mobile-friendly images. Media pins show a large Play button on the grid, which we had to work around.

We uploaded these three images as new Pins to a secret board, noted their Pin IDs, and then the fun began.

Since the very early days of attributed content on Pinterest, we’ve had an extra object to work with on the Pin model, called attribution. For most Pins, this is an empty object, but some Pins are special. Here’s one, with Flickr attribution:

{'url': '', 'provider': 'flickr', 'author_url': '', 'author_name': 'kentbrew', 'title': 'Next stop: Pinterest!'}

Attribution lets us show a tiny Flickr icon, plus a link to the photo and author page, with the right title and name. When we first shipped Pins with attribution, some containing playable media (like YouTube) had an embed object inside their attribution objects, specifying the size and source of their embedded iframes. To make iframes run inside Pins from, we added an embed member to their attribution objects, like this:

{'embed': {'src': '', 'width': 550, 'height': 1000}}

This makes an iframe 550px wide by 100px high, containing’s “Are You Registered to Vote?” form. We also sent along a campaign parameter in the URL, to help us understand the results. Hacking the Pins was done through an interactive Python console, running on a development server that had access to production data.

As you can imagine, we were very, very careful not to break Pinterest in the process.

Once we had Pins that looked good and worked well, we asked our bosses for some budget to promote those Pins and help save the planet.

And our bosses said yes! On Monday, October 3, three days after the idea first came up, our voting Pins went live on Pinterest’s Official News board, and we were off and running with a week-long promoted campaign.

How’d it go?

Quite well, we think. We were running an awareness campaign but it converted like a performance campaign, which is the sort of thing that usually asks readers to spend money.

Our standout Pin was the one that lets Pinners check their voter registration status; it had a .43 percent CTR and a very convincing .8 percent earned CTR. According to, we were the top referrer in our class, bringing in almost half the total traffic from all social networks combined.

“Pinterest was the hands-down winner in terms of terms of social-media driven traffic, even after Justin Bieber and Jack Dorsey both tweeted about,” said Debra Cleaver, founder of

The average completion rate for’s iframed tools is 31 percent, so we’re confident tens of thousands of Pinners checked their registration, requested an absentee ballot, and registered to vote, all because of three little Pins.

And remember….

Election Day comes every year, sometimes more than once. If you’re in the U.S. and you’re not sure if you’re all set to make your voice heard, please visit and find out! And if you’re lucky enough to work at a technology company, do your part and build features to help your community vote!

Pinterest Engineering Blog

Inventive engineers building the first visual discovery engine, 200 billion ideas and counting.

Pinterest Engineering

Written by | Inventive engineers building the first visual discovery engine |

Pinterest Engineering Blog

Inventive engineers building the first visual discovery engine, 200 billion ideas and counting.

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