JUSTINE FINCH: This morning, TikTok CEO set to defend his company in front of Congress as the app faces a potential ban in the US. Lawmakers and TikTok users speaking out ahead of today's testimony. - TikTok as a platform has created a community and a space for free speech for 150 million Americans. - We can solve the issues without taking away something so precious to us all. JUSTINE FINCH: Some argue their small businesses would close without the exposure the app has given them. But one Republican lawmaker fired back with this response. - Those influencers Congressmen who it's their livelihood, what's your message to them? - Find another job. JUSTINE FINCH: Opponents of the app say TikTok poses a serious threat to national security. The Chinese-owned company collects users data, including biometric information. Critics worry that data could be handed over to China's government. But TikTok's CEO is expected to tell lawmakers today that nearly all US TikTok data is stored on servers owned by Oracle inside the US. He says TikTok has created a US-based firewall to protect users, saying the data is stored on American soil by an American company overseen by American personnel. But many critics aren't buying it. - I'm going to trust the American intelligence community a lot more than I trust the CEO. JUSTINE FINCH: The White House recently told TikTok's parent company it must sell its shares in the company or face a ban. - You can ban TikTok, but there are still data brokers who sell our data to other countries and businesses in other countries. It poses about the same threat that companies like Facebook and Instagram and YouTube and Twitter pose. JUSTINE FINCH: The Senate Intelligence Committee chair Mark Warner claims TikTok can't be trusted due to what he calls a lack of transparency.