Email Verification
Before you send to an address, find out whether it can actually receive mail. Renidly checks the mailbox itself — not just the format — and tells you plainly whether it's deliverable, undeliverable, or too risky to trust, with the reason attached.
Every bounce is a small tax on your sender reputation, and enough of them get your mail filtered or blocked outright. Email verification is how you pay that debt down before it accrues: check an address up front, keep the ones that will land, and hold back the ones that won't. It works on a single address at a form or checkout, and across an entire list at import time.
What a check actually does
Verification goes past the surface. Anyone can see that an address is well-formed; Renidly goes on to confirm the domain is set up to receive mail and that the specific mailbox will accept it. The result isn't a vague score — it's a clear verdict with a stated reason, so you always know why an address was flagged, not just that it was.
What a verdict can tell you
Each address comes back as deliverable, undeliverable, or risky, together with the reason behind the call:
| Verdict | What it means | What to do |
|---|---|---|
| Deliverable | The mailbox exists and accepts mail. | Safe to send. |
| Undeliverable | The mailbox does not exist and will bounce. | Drop it, or don’t send. |
| Disposable | A throwaway / temporary provider — the kind used to dodge real contact. | Reject at signup; don’t add to a list. |
| Role address | A shared inbox (info@, support@, sales@) rather than a person. | Fine for some flows, poor for one-to-one outreach. |
| Relay / forwarding | A forwarding address that redirects mail elsewhere. | Treat with caution; deliverability is indirect. |
| No mail servers | The domain has no mail setup and can’t receive email at all. | Undeliverable — drop it. |
| Catch-all | The domain accepts mail for any address, so a single mailbox can’t be confirmed. | Treat as risky (see below). |
| Risky | Couldn’t be confidently confirmed and may bounce. | Send only if a bounce is acceptable. |
Catch-all domains, handled honestly
Some domains are configured to accept mail for everyaddress, whether the mailbox exists or not. That makes a naive "does it accept?" check meaningless — it always says yes. Renidly detects these and tells you the domain is catch-all rather than pretending an address is confirmed. Where it can still resolve the specific mailbox it will; where it genuinely can't be sure, it says risky instead of guessing. You get the truth, including "we can't be certain," which is far more useful than false confidence.
Where it earns its keep
- List cleaning. Run an existing list through verification and strip the dead, disposable, and dead-domain addresses before your next campaign.
- Signup & form gating. Reject throwaway and undeliverable addresses at the point of entry so they never enter your database.
- Bounce reduction. Keep your bounce rate under the threshold that mailbox providers use to throttle or block senders.
- Lead quality. Score and route leads by whether their address is a real, individual, deliverable mailbox versus a role or throwaway one.
Speed, caching, and cost
A repeat check of the same address is served instantly from a short-lived cache and costs nothing — re-verifying the same list twice in a window doesn't double your bill. A live check is priced per address, for any verdict, because the work runs whether the answer is yes or no; invalid input and failed calls are never charged. See Data Freshness for how caching works and Endpoint Costs for the current price.