As with many social media platforms, the public TikTok API provides limited access and the TOS bans all automated scraping. However, the TikTok API is even more restricted than the APIs offered by Meta. You may notice that the TikTok Developers page only offers the options to use TikTok as a sign-in option on your site, post videos via other apps, share music to TikTok's library, and embed TikTok videos on other platforms. None of these options are helpful for research uses.
Additionally, the mostly-video content of TikTok poses a further challenge to collection and analysis of datasets compared to text-heavy platforms like Twitter or Reddit. These factors, combined with the relatively recent arrive of the platform on the social media juggernaut scene, mean studies of TikTok have been difficult and limited.
The TikTok client uses a sophisticated system of signed requests to prevent third-party systems from making requests of TikTok servers. This is part of TikTok's broad efforts to track users, which also includes IP address tracking, browser fingerprinting, and tracking cookies. A few web scrapers or unofficial APIs, which query the private internal TikTok API by simulating a web browser to circumvent the signed request challenge, can be found. Some are quite robust, but require setup and/or coding knowledge and violation of the TikTok TOS. TikTok will also attempt to block your connections as soon as it detects scraping. The report from Mozilla linked at the bottom of this page details some of the difficulties of automatic data collection.
TikTok, as the newest platform on this list, has not had the benefit of a decade or more of academic study and the development of research tools. Additionally, with virtually no useful public API, automated data collection necessitates violating the TOS with web scraping or complex browser-simulating reverse-engineered calls to TikTok's private API.
Like Instagram, at this time (05/2022) any tools for automated extraction of videos, or text accompanying videos, are likely to violate TOS. Additionally, the ones that do exist require at least some coding or command line knowledge. The automated tools on this list - drawrowfly's TikTok scraper and the Bellingcat Hashtag Analysis Toolset built on top of it - are provided as an example of this sort of tool, but they are complex, risk a ban from TikTok, and require coding or command line knowledge. Researchers are encouraged to explore manual collection methods.