Up until now, you could only do ad targeting on TikTok by targeting certain cities/DMAs 

This created a challenge for retail support or geo-targeted Aisle campaigns

While it is still in Beta, TikTok is finally rolling out zip code targeting and will allow a bulk upload feature, similar to Meta, to save time on building audiences 

You can target up to 1500 zip codes per ad group

TikTok is warning that targeting ad campaigns to small geographic areas or sets of zip codes can significantly reduce the number of impressions and clicks delivered, and yield a higher CPA, which is important to keep in mind when wanting to target a super small number of zip codes