Should You Pay for an ATS Checker?
How to tell if an ATS checker is worth your time and money.
Generally, the only thing you can reliably expect from an ATS checker is to find gaps between your resume and a job description. Systems that promise success may not be worth it.
ATS providers have their own proprietary logic they apply to extract data from documents, there is no universal score that a checker can assign, so if your ATS checker claims it can offer you an ATS score, it's probably something to think about.
If the ATS check doesn't require a job description, it is probably a bad sign. Unless the company you're applying to uses an ATS made by the same company as the checker, you will gain little value from the use of such a system.
An ATS checker normally just compares a job description to a resume or CV. If they're boasting about success rates without disclosing how they measure it, ask yourself: How would the company be able to measure that without having access to the actual hiring systems?
I see all of these as red flags. For a free checker, you might get some marginal value for your time, especially if you use a combination of free checkers, but I'd think twice before paying for a service that has these claims about ATS checks.