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Doesn't the iOS App Store also have third party Snapchat clients? I'm not really sure what Snapchat's stance is on these clients is, but I'd be weary of using any of them given the high potential for abuse.

According to the developer's website, he claims to be a sophomore engineering student. So I wouldn't place too much faith in his ability to create a secure app that abides by Snapchat's usage rules for their APIs.
 
I didn't think that they were allowed... I logged in and everything seems to work really well. And I used little snitch to see if they were going to any other servers other than Snapchat's server, but it all seemed to be good...
 
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