Enriching live events with audience engagement at scale

There are no second chances when it comes to live events: Mentimeter's solutions have to work perfectly every time. Their audience engagement features must be accessible via mobile devices without user sign-in. They must also be fast. And they need to scale effortlessly to cope with huge spikes in demand; a single event can drive connections from zero to 70,000+ participants in a matter of seconds.

Mentimeter's engineers designed their systems to cope with those exacting demands, but as the business experienced rapid growth, its realtime infrastructure provider struggled to keep pace. The platform's performance at scale started to suffer.

Eventually, a tipping point came when a spike of a relatively small number of concurrent connections – ~35,000 – caused part of their realtime system provider's network to crash. Luckily, Mentimeter had fallback solutions in place for realtime communication so their services continued to operate, but with a degraded user experience for several hours. According to CTO Johan Bengtsson: "An outage like that affects the entire customer experience because the core of efficient audience engagement requires reliable and fast feedback from the audience. A degraded service in this area shakes customer confidence in our service. The provider was unwilling to guarantee to fix these scaling and reliability issues, nor could it provide dependable SLAs. We knew it was time to move on."

Bengtsson swiftly dismissed the possibility of building realtime infrastructure in-house due to the time and cost to build, along with significant ongoing operating costs and engineering burden. His team set out to identify a new partner that could meet Mentimeter's exacting demands while supporting all Mentimeter's current and future use cases.

Any new realtime provider needed seamless integration with Mentimeter's React front end, Ruby and Node.js backend, and AWS Kinesis for analytics. Performance, scalability, and reliability were essential requirements, particularly as Mentimeter had ambitions to raise its concurrent connections limit and cater for events of up to 150,000 participants or more. What's more, a new provider needed to provide Bengtsson with scope to innovate in bringing new features to the platform.

Mentimeter identified Ably as the ideal solution based on a market comparison exercise and a recommendation from existing Ably customer Split.io. According to Bengtsson: "Ably is very transparent about engineering for reliability and scalability with its Four Pillars of Dependability. Along with a solid five-nines SLA and clear pricing, that gave me a lot of confidence. I also felt that Ably wanted to be more than a supplier. There was a real sense that it would be a true partner that would work closely with us, listening and responding to our needs and supporting our innovation roadmap."

Bengtsson was able to get a proof of concept up and running within two hours. Even though Mentimeter's developer team was stretched at the time, migration to Ably was complete inside a month, thanks to expert and fast support and a wealth of documentation.

The decision to move to Ably has been crucial for Mentimeter to deliver a consistent, high-quality customer experience. Bengtsson and his team are confident they can rely on its services to help them deliver business value through improved communication and audience engagement.

First and foremost, Ably's meticulous design for elastic scale and high availability has solved the scalability and reliability issues that had become an issue previously. Bengtsson explains: "Ably has been super reliable, a part of our stack I know I can depend on. It copes easily with big loads generated by multiple presentations happening simultaneously across the globe. We put the reliability of presentation experience front and center. If Ably had issues, we'd know about them, but now we don't have to worry about stability, even when we get huge traffic spikes. Ably is a key partner for us, one that we refer to as 'Enably' because it allows us to innovate at pace to elevate our core proposition. In fact, we're so confident now, we're looking to triple our concurrent connections limit to 150,000."

Mentimeter has used Ably to innovate as it seeks to enhance and extend the value its platform delivers to customers. For instance, the Mentimeter team builds upon the Ably presence feature to ensure customers collaborating upon interactive presentations can see who is online and carrying out edits. Before adopting Ably, this was functionality the team was going to build in-house.

Bengtsson said: "We're delighted with the range of capabilities Ably gives us, while the support and documentation have helped to spark ideas at our end. The limitations with leaderboard scaling were hurting us in terms of our ability to innovate the core product. With Ably, those limits are a thing of the past."

Finally, moving to Ably has helped Mentimeter find efficiencies, spend less time on maintenance and realtime incidents, and allow its engineers to develop the core platform.

"It's part of our ethos that if there is a service providing the capabilities we need, we'll use it rather than trying to build and maintain ourselves," Bengtsson explained. "With Ably in place, our engineers can focus on what they are good at. They don't have to worry about realtime any more, which makes for a happier, more productive team."