Short answer: No — not within a 24-hour window. If you verify the same email address again within 24 hours, the second check does not cost you an additional credit. You are billed once per address per 24-hour period.
How it works
When you verify an address and we return a billable result, we remember that you've paid for that address. For the next 24 hours, re-verifying the same address (for example, because it appears again in another list, or you run the same file twice) returns the result without charging you again.
This dedup is tied to your account and the specific address — it does not depend on anyone else's verifications. After 24 hours, the address is treated as a fresh check and is billed normally, because email deliverability can change over time and a day-old answer should be re-confirmed.
When you will be charged again
- After 24 hours have passed since the last billable check of that address.
- When you request a force-refresh (
force_refresh=true). A force-refresh deliberately skips all caching and dedup to run a brand-new live verification, so it is always billed according to its fresh result. Use it when you specifically want an up-to-the-second answer and don't mind paying for it.
Interaction with free results
The 24-hour rule only matters for results that are billable in the first place. Results that are already free — unknown, disposable, and syntax-only invalids — cost nothing regardless of how many times you check them.
What we recommend
- Don't worry about accidental duplicates in a list — you won't be double-charged inside the 24-hour window.
- Only use
force_refresh=truewhen you truly need a live re-check; otherwise you'll pay again for an address you already verified today.