Google may have introduced its quest for a Pokémon Master with a wink earlier today in honor of April Fools’ Day. But the internet giant also has a serious reason to celebrate: today, its revolutionary Gmail service turns 10.

On this very day in 2004, Google unveiled Gmail as an invite-only, beta rollout. Clearly a fan of holiday-centric launches, the company then made the service available to everybody on Valentine’s Day in 2007.

By offering a game-changing 1 GB of storage, speedy interface, highly effective spam filter and an integrated search tool (all for free), Gmail quickly eclipsed competing mail platforms of the day, including those from AOL, Hotmail, Microsoft and Yahoo.

Though it would go on to become one of the company’s most revolutionary achievements, many within Google initially regarded Gmail with some skepticism, reports Time.

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Though founders Larry Page and Sergey Brin supported the project, many perceived it as deviation from Google’s search engine specialism.

Paul Buchheit, the creator of Gmail -- and Google’s twenty-third employee -- was at the helm of Caribou, which was the project’s code name. Though it was barely ready in time for its initial launch, Brin was particularly tickled by the idea of unveiling an actual product under the guise of a trick.

Upon its introduction, Gmail was so hot that coveted invitations were being offered on eBay for up to $150. And a decade later, it still remains the gold standard, and hasn't deviated much from its original design.

“I can’t think of another app that has existed so close to its original form for 10 years,” Google designer Kevin Fox told Time. “Someone who had only used Gmail in its first iteration and suddenly used it today would still understand Gmail.”

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