Some e-commerce start-ups begin with an explosion and keep turning on the fireworks, while others become duds and slowly burn out. Add to that a subscription membership, and the challenges are even greater to maintain.

JustFab is one of those smart, lucky and successful fashion brands that feature a VIP membership. At the moment, the brand is sitting pretty with more than 4 million subscription members around the globe, according to an article in the latimes. Not bad for a young online retailer that offers trendy shoes, handbags, clothing and accessories.

Co-founders Adam Goldenberg and Don Ressler are not new at this game. They are known for being genius branding people for online stores with subscription programs, and the model is really working. In the first quarter of 2016, JustFab turned a profit for the first time. This year, the women’s fashion brand is expected to draw in revenue of $650 million, up from $505 million last year.

That’s not all; Just Fab is ready to go public with an IPO or initial public offering. The company has recently hired an IPO expert in the name of Todd Tappin, adding him as their chief financial officer.

According to Bloomberg, JustFab is created and produced in their large Los Angeles headquarters, and the brand has its own design team. They are constantly turning out lots of new, on-trend styles for shoppers each month. VIP members get cool perks and great value, saving up to 30% off regular pricing and earning points towards free loyalty items.

The shopper is always king. In other words, it is up to the shopper to buy or not buy each month. If a member has decided not to purchase, then all they need to do is click the “Skip The Month” button in their boutique by the 5th of each month. That way, they won’t be charged $39.95. Plus, if a VIP member is dissatisfied with the JustFab experience, they can cancel membership at any time.