Rumors of Snapchat building some mysterious hardware have been passed along for a couple of years already, but more recent events can probably be qualified as the strongest clues supporting the "Snapchat building hardware" theory so far. Apparently, Snapchat recently joined the Bluetooth Special Interest Group (Bluetooth SIG), which is technically a strong indication that Snapchat is working on a device capable of Bluetooth connectivity.
Snapchat was first suspected of planning to join the hardware market back in late 2014 after the company acquired Vergence Labs for $15 million; a start-up company that was working on creating a pair of smart glasses akin to Google Glass called Epiphany Eyewear. Snapchat's CEO Evan Spiegel was then photographed by the paparazzi later this summer while he was wearing a pair of smart glasses resembling the first prototype from Vergence Labs, and evidently, this fueled the rumor mill even further. Now, however, a new clue strongly hints at the possibility that Snapchat is building smart hardware, as the company recently became a member of Bluetooth SIG. Becoming a member of the Bluetooth Special Interest Group is key for any company wishing to create hardware capable of utilizing Bluetooth's connectivity standards, and purely as a software company, Snapchat would have no reason to join Bluetooth SIG. According to analysts quoted by The Financial Times, the only companies to join Bluetooth SIG are those who have plans to develop hardware, and needless to say, currently Snapchat doesn't fit in this category.
As for the type of hardware Snapchat is interested in building, it's possible that the company might be working on augmented reality-enabled smart wearables with Bluetooth connectivity, including smart eyewear or full-fledged VR/AR headsets. However, according to the source quoting "a person who works with several device makers", earlier this summer Snapchat had been discussing with third party manufacturers about the creation of a prototype headset, which further suggests that if Snapchat is indeed working on hardware, the project is still in the early stages of development. As such, whatever products will be created by Snapchat's research & development department, it's likely that the device(s) won't see the light of day by the end of this year. Either way, there's no official word on the matter so the story remains subject to change.