New RelicThis sponsored post is part of a new series called “The Future of Modern Software” and is brought to you by New Relic. Read the series here

There’s nothing easier than losing a user. All it takes is a couple seconds of lag and your first-time user might just change their mind, delete your app, and move on to the competition. Knowing where, and why, your app is slowing down — and potentially losing you users — is key to growing a user base instead of having customers disappear into the void like the majority of mobile apps.

We got in touch with each of these cool apps to ask how New Relic helps them identify and address problems, whether sluggish API calls or buggy code, before their users become someone else’s.

Started in 2008, Airbnb, the online marketplace for short-term rentals, has grown to offer listings in 33,000 cities in 192 countries across the globe. When you get to the point where your company is used as the archetypal descriptor of disruption (such as “the Airbnb of office space“), things need to run smoothly. According to Ben Hughes, a software engineer at Airbnb, keeping tabs with New Relic has made that possible.

“I’ve used New Relic for years, and I consider it to be an essential tool for any developer. I keep New Relic open on one monitor at all times so that I can quickly detect and respond to incidents in flight,” says Hughes. “It’s definitely the first tool to use while formulating theories as to what could be happening.”

Hughes says that a good part of his day is spent watching New Relic and doing what it tells him to do and that it all comes down to visibility when you’re trying to keep an app up and running.

“It’s kind of hard to point to specific benefits as I can’t imagine doing the work I do without the level of visibility that New Relic provides,” says Hughes. “It strikes a good balance between granularity and information overload, so that I can identify trends at a high level. Other tools are sometimes necessary to get at the specifics, but I usually use those after identifying hypotheses in New Relic. We definitely benefit from faster time to detection and resolution because of New Relic.”

MeetMe is a social networking app that helps its users meet new people both on the Web and on iOS and Android devices, with more than 60% of its traffic coming from mobile users. In 2012, the app was ranked highly among Deloitte’s 2012 Technology Fast 500, which lists the 500 fastest growing tech companies in North America.

According to CTO Richard Friedman, MeetMe’s development team previously used multiple independent and homegrown tools for measuring their apps’ performance, costing them time and energy. Friedman says that switching to New Relic has allowed them to focus on launching applications instead of building monitoring tools.

“We use NewRelic to find our bottlenecks in real-time, allowing us to narrow in on the problems, deploy quickly, and run more tests,” says Friedman. “We have scaled applications to tens of thousands of concurrent users by letting NewRelic’s reports identify where we spend our time, saving us development effort and increasing our confidence in launching applications.”

HotelTonight, the mobile app for finding last-minute hotel bookings, was built from the ground up as a mobile service. Launched in 2011, the app serves more than 6 million users across 12 countries in North America and Europe.

HotelTonight COO Chris Bailey says that performance monitoring is essential to keeping everything running at top speed, monitoring not only daily performance, but comparing performance week over week to ensure it doesn’t degrade as they build new features. Beyond simple monitoring, Bailey says New Relic allows them to react quickly if a problem arises.

“A recent example was a case where New Relic performance monitoring alerted us to a significant performance degradation in a particular API. This was not causing errors, or even a noticeable customer experience impact. However, it alerted us to an unusual database issue,” says Bailey. “Thanks to New Relic we were able to quickly identify and fix the issue.”

Wanelo, short for “Want, Need, Love,” is a social shopping app with a community of ten million dedicated users across numerous devices and platforms. CTO Konstantin Gredeskoul says that watching performance with New Relic has allowed Wanelo to track errors, traffic, and latency for their API backend as well as their website.

“The New Relic mobile SDK connects that with the data coming from our mobile apps and allows us see the picture from the client’s viewpoint — all the way deep into the stack,” says Gredeskoul. “As we deploy many times a day, we often monitor New Relic and other graphs to ensure the release is solid and didn’t break anything. New Relic also allows us to see a breakdown of mobile OS versions, device types, and even carriers, allowing us to make optimizations with the largest impact first.”

Beyond being able to track errors over multiple deploys, Gredeskoul says that New Relic’s full-stack monitoring allows them to find slow transactions or API endpoints and adjust and optimize their stack to account.

“As Wanelo is a shopping site and has a large following among Internet-savvy users, the speed and ‘snappiness’ of the application- – perceived or actual — are extremely important,” says Gredeskoul. “We strive to optimize every part of the stack to be able to render products and other app views as quickly as possible.”