You can check authenticity by eye, within limits. Look for a believable engagement-to-follower ratio, comments from real accounts rather than bot phrases, steady growth over sudden spikes and an audience whose location fits the creator's content. It works for a few accounts, though it slows down at scale.
Whether you can vet a creator's follower authenticity by hand and what signals to look for.
Manual vetting is genuinely useful for a short list. Open a creator's recent posts and read the comments, because bought engagement tends to be generic and repetitive while real audiences ask questions and disagree. Check the follower growth chart for unnatural jumps, then sample a handful of followers to see whether they look like real people. The limit is time, since doing this properly across dozens of creators does not scale. That is where an automated score helps. Flinque gives every creator a fake-follower score and audience data, which turns the manual read into a quick confirmation rather than the whole job. The free checker at /free-tools/ scores a single account fast.