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Flash Sale Sites & Website Performance: How 3 Major Sites Stack Up


Next-generation Business

Flash sale retailer customers show a 385% spending growth potential within their first year of being a customer. If this number doesn’t mean much to you, consider this: by comparison, customers of traditional online retailers clock in at around 94% (RJMetrics).


About 9 in 10 flash sale shoppers say that after redeeming their most recent offer they either made another transaction with the same company (44%) or plan to do so (47%), making these businesses a hotspot for customer retention and spending growth.

But this kind of “next-generation” business is highly dependent on website performance. Flash sales happen for a set period of time, making accessibility a huge factor. Mainly, these sites are concerned about:

  • Website scalability to handle traffic spikes
  • Maintaining 100% uptime
  • Site speed to enable visitors to quickly add items to their carts
  • Security for all customers

Because of the underlying urgency of flash sale sites, customers are even more effected by the website speed and what it means for their purchasing ability. This means that in order to create the long-lasting relationships that these sites have the potential to, they must maintain uptime and ensure fast-loading sites.

We ran multi-location tests on three of the top flash sale sites to see how their speed stacks up globally, and what these sites can teach us about web performance.


Gilt, a NYC-based, high-end site geared to lovers of designer labels, delivers to over 100 countries, making international accessibility a priority.

While Gilt performed well in some major U.S. cities, including Dallas, Chicago, and DC, their global performance lagged with slow load times in Sydney, Amsterdam, Tokyo, and more.


Gilt’s website has a poor backend connection time, but is mainly slowed by numerous heavy CSS and JavaScript files, which adds to a 6 second frontend time (for reference, most internet users expect a load time of under 3 seconds). With 1.8MB of content, the website is massive, slowing frontend performance in many international (and some national) cities.


Too many of these assets in individual files and without any kind of concatenation can easily drag down website performance.

Key takeaway: don’t let heavy files drag you down

Rue La La

Rue La La is a popular Boston-based flash sale site with a great reputation. Equally impressive is their website performance, which, on average, is the closest to what customers are looking for.


Rue La La has less content complexity, a shorter Time to First Byte, and just over 3 seconds of frontend loading time. There were only a few problematic JavaScript issues that slowed some international cities to over 12 seconds on the front end within our data collection. All in all, they’re rocking…


… until their website crashed last week, leaving many customers without the ability to access the site altogether, or to save products to their carts and complete purchases. Many customers experience their carts being wiped clean; in most cases, this means losing the product in the appropriate size altogether, as limited quantities and a set allotted time in cart make site speed crucial.

Rue La La’s support team handled this situation incredibly well. But this is the worst case scenario for flash sale sites, especially on “big name” sale days like this one, which included customer favorite Lily Pulitzer.


Ensuring 100% uptime is even more important for flash sale sites, which rely so heavily on the idea of snatching up a deal ASAP. When customers don’t have the ability to do this, your site loses credibility. Luckily, Rue La La got the site back up and running quickly.

Key takeaway: 100% uptime during peak hours is crucial


Fab customers who come to the site through a mobile device are 4x more likely to make purchase (InsideFMM). This makes website performance especially important to Fab, an “everyday design” flash sale site know for it’s interesting vendors and totally unusual products.

Of the three sites tested, Fab had far and away the slowest loading site.


With 8x as much content as Gilt and an average of 10 seconds load time on the front end, Fab’s site (and design) relies much more on a variety of individual image files and third-party assets from Google, Facebook, and others.


Fab delivers to a highly visually-oriented audience, making their site deeply designed and reliant on a lot of image, CSS, JavaScript, and third party assets to communicate a coherent brand message. Unfortunately, this means their site performance suffers from an overload of assets.

Key takeaway: beware of chatty assets and third parties

Have you had any poor experiences with flash sale sites? Or any website performance challenges of your own? Let us know in the comments section!

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