SAT validation API for Mexico — what are the options?

I'm comparing SAT validation API providers for our compliance platform. We need to validate RFC codes, check taxpayer status, and pull fiscal regime data. The problem is SAT doesn't expose a clean public API — so we're dependent on third-party providers who scrape or have agreements with SAT.

Questions: How do these providers get SAT data — is it scraped, licensed, or via a government agreement? Does that affect reliability? And how do you evaluate SLAs when the upstream data source (SAT) can be unpredictable?

Also curious about pricing models — per-call vs subscription for a SAT validation API?