One line, 50+ SF billboards, every surface live in a week

HackerRank was launching Chakra, its AI interviewer, on a fixed date, because a San Francisco billboard campaign was already booked. We ran the campaign as a Growth Sprint and the site as a Relaunch. In eight weeks we wrote one line and put it on freeway billboards, transit shelters, coffee cups, the new Chakra page and a new hackerrank.com homepage, all live in the same week. Try Chakra conversion rose about 200 basis points and peaked 40% above its best before launch.

Chakra's launch was tied to an outdoor campaign across San Francisco, booked for 5 October.

The goal was to get developers talking about HackerRank again, and to give the ones who looked it up a page worth landing on. Lead volume was not the measure.

We started with a four-hour working session in San Francisco on 5 August. That gave us eight weeks to find the idea, design every surface and ship the site.

The campaign ran as a Growth Sprint: one idea, on every surface, by a fixed date.

HackerRank built its name on the coding tests developers practise for. Chakra changes how those interviews work, so the launch opens with an apology:

Sorry, we made you grind L**tcode. We've changed.

We explored many routes and dropped the safer ones, because San Francisco is full of tech billboards and a cautious line would blend in. HackerRank tested the shortlist with engineers, and the apology came out on top.

The line ran in three versions, each named after a common interview topic: L**tcode, Linked List and Binary Tree.

The same line ran across San Francisco:

• The freeway digital board and a north-facing board on the 101
• Wall 307, a wall-sized spot in the city
• 53 transit shelters, plus elevators, trucks and a bus
• Corgi Café, with branded cups and sleeves

Every placement pointed to the new Chakra page.

The site ran as a Relaunch, alongside the campaign. Static mockups couldn't show how the Chakra page would move, so we switched to animated staging builds early and ran reviews in the browser.

We shipped the Chakra page, a "Why we're sorry" page that explains the campaign, and a new homepage for hackerrank.com in two versions. Each page shows Chakra in real interview moments and scorecards.

The Chakra page went live on 2 October. The new hackerrank.com homepage went live on 5 October, the same day as the billboards.

Changing the hackerrank.com homepage in launch week carried risk, so we launched it on 5 October as an A/B/C test: the old homepage against two new versions.

• Variant A won on demo requests and community signups.
• Variant B, which puts Chakra front and centre, drove the most Try Chakra clicks.