Short answer: Every verification result includes a score between 0.0 and 1.0 that reflects our confidence that the address is deliverable. Higher is better: closer to 1.0 means we are confident the address is good; closer to 0 means we are confident it is not.
How to read it
The score is best understood together with the status, not on its own:
validresults carry the highest scores (near1.0) — a confirmed, deliverable mailbox.invalidresults carry the lowest scores (near0) — a confirmed rejection.catch-allresults sit in the middle. The domain accepts all mail but won't confirm the specific mailbox, so confidence is moderate.unknownresults carry middling scores that signal "we couldn't confirm this," not "this is good." Do not read an unknown's score as a pass/fail grade.disposableresults carry low scores — technically reachable for now, but not worth sending to.
Using the score in practice
Treat the score as a confidence dial for building your own send/suppress rules. For example, you might send to everything scored above a threshold you're comfortable with, and hold back or manually review the rest. Where you set that line depends on how conservative you want to be — a transactional email to a paying customer justifies a lower bar than cold outreach at scale.
The score is a guide, not a guarantee. Always pair it with the status and, for borderline cases, your own knowledge of where the address came from.