To compete in a crowded online retail landscape, Revolve has built an influencer army.

The company’s regular Instagram campaigns tap about 70 influencers each, who receive everything from event invites to free product to actual money in exchange for posts that use certain hashtags.

Some high-profile events call for even bigger brand placement: At Coachella, Revolve sends clothing and event invites to hundreds of influencers.

Led by chief brand officer Raissa Gerona, Revolve’s influencer strategy is a robust operation nearly 10 years in the making. The company, which now has 2.4 million Instagram followers, first began sending free clothing to early bloggers in 2009 and hired its first influencer relations team in 2014.

Revolve’s influencer strategy now pulls the most weight as part of the retailer’s overall marketing strategy, driving nearly 70 percent of all sales, according to Revolve. The rest is driven by more traditional marketing tactics, like social media retargeted and promoted posts on Facebook and Instagram, as well as Google ads. Gerona said that performance marketing and brand marketing are separate teams, and while she didn’t share the specific breakdown, she said influencer marketing takes up a “significantly smaller” piece of the overall marketing budget.

The company was projected to hit $1 billion in sales in 2017.

“We saw influencers as a direct pipeline to our customer. Our question is always: Are these people resonating with who we want to resonate with?” said Gerona. “We focus on millennial female consumers, and none of them are looking at magazines anymore, so we looked to who that customer was listening to.”

As the influencer marketing industry has swelled – Mediakix projects that in 2018, up to $6.2 billion worth of ad spend will go to influencers – brands accustomed to traditional marketing strategies have struggled to navigate the space. Tracking return on engagement, finding the most effective influencers to hire and making sure their follower counts aren’t fraudulent has prompted the rise of influencer agencies acting as mediators between brands and Instagram personalities.

“Influencer marketing has grown a lot, but most brands still haven’t fully jumped in with both feet,” said Evan Asano, the CEO of the influencer marketing agency Mediakix. “Brands are going to end up putting a lot more money into this space, in more creative ways.”

Rather than hire an influencer agency to help it scout and recruit Instagram talent and manage relationships, Revolve built it all in-house, which Gerona said was necessary to fully understand the burgeoning market and incorporate it into the marketing strategy. After hiring an influencer relations team — which now counts five employees — Revolve built a proprietary technology platform that measures influencers’ engagement over time, gauges their potential audience reach and matches them to potential Revolve campaigns.

While the platform can track Revolve’s influencer partnerships and performance, it also sets up a growing database from which Revolve can pull new influencers to partner with. The platform constantly picks new Instagram accounts that target a millennial following, before Revolve ever works with them, and follows their growth over time. The influencer team builds new relationships from there: After a few months of being in the Revolve database, an influencer with a few thousand followers may be invited to a Revolve event at Coachella or in the Hamptons. Once they’ve been tapped for a campaign, the database collects feedback on how much engagement the influencer drives, and then Revolve can decide whether or not to build on the relationship from there.

This way, Gerona said, Revolve has a constantly growing roster of influencers it can reach out to for different campaigns, from the smallest of micro-influencers to the most high-profile accounts. Big personalities, like Chiara Ferragni, Susie Bubble and Danielle Bernstein, will receive payment from Revolve to post on the company’s behalf, and score invites to Revolve’s most all-out influencer campaigns. In July, #RevolveSummer invited 75 influencers to vacation in Bermuda, wearing clothing provided by Revolve and blasting the hashtag to their followers.

As a result, Revolve also measures influencer performance differently. Gerona said it will work with an influencer over the course of two or three campaigns to accurately gauge engagement. Revolve looks at influencer marketing as a way to get traffic to the site at a much lower cost than other means of customer acquisition, with results that are amplified to more people than the company could reach on its own.

“Our belief is that influencers will generate and drive brand awareness. The No. 1 reason to keep working with them is that they bring eyeballs to the brand and traffic to the site. Getting customers to the site is a huge cost for a lot of companies, but for us, it feels like it’s free traffic because we’re using these influencers with millions of followers,” said Gerona. “They’re speaking to our customers in a way that amplifies that message tenfold, because they’re doing the same thing we’re doing everyday — promoting the brand, the lifestyle, the clothes — but on a personal level.”