Email Validation Logic

MailInsightX doesn't just check if an email looks right - it performs deep verification to ensure deliverability. Every address passes through a series of checks designed to catch bad emails before they bounce, with several checks happening before the deepest, most thorough check is ever attempted.

1. Checking the Email Is Formatted Correctly

The first step checks that the address is written correctly.

• We check for invalid characters, consecutive dots, and proper @ symbol placement - if this fails, it's marked Invalid Syntax.
• We separately check that the domain (after the @) is written correctly - if not, it's marked Invalid Domain. Either failure stops processing immediately.

2. Checking the Domain Can Receive Email

We check whether the domain (the part after the @) is actually set up to receive email at all.

• If the domain isn't set up to receive any email, it's marked Invalid Domain (No MX).
• If the domain belongs to a known "parked" (unused, for-sale) domain provider rather than a real mail service, the address is marked Parked (Risky) here - before InsightX+'s enhanced verification is ever attempted.

3. Disposable Email Detection

We check the domain against a maintained list of temporary/throwaway email providers.

• Users registering with these emails typically have zero intent to convert.
• We flag these as Disposable.

4. Role-Based & Gibberish Detection

Two pattern checks run on the part of the address before the @, regardless of which credit type you're using:

• Emails like admin@, support@, sales@, and info@ are role-based and are flagged Role-Based (Risky).
• Addresses that look randomly generated rather than a real name (e.g. [email protected]) are flagged Gibberish (Risky).

5. Enhanced Verification (InsightX+ only)

This is the most thorough check MailInsightX offers, and it's only performed for InsightX+ verification - standard-credit jobs never reach this stage. We connect directly to the recipient's mail server to confirm whether the specific address actually exists, without ever sending an actual message.

• If the server accepts the address, it's marked Valid.
• If the server rejects it outright (for example, saying no such address exists), it's a Hard Bounce (SMTP).
• A server that temporarily defers the check is marked Greylisted (Temporary); one that appears to be deliberately stalling the connection is marked Tarpitted (Risky); a full inbox is marked Mailbox Full (Temporary).
• If we can't get a definitive answer at all (for example, the destination blocks connections from our network), the result is marked Unverified (Port Blocked) rather than guessed at.
• If something else unexpected interrupts the check, it's marked Unverified (Error) rather than guessed at.

See Two Credit Pools: Standard vs. InsightX+ for exactly which checks each pool includes.

6. Catch-All Detection

Some mail servers accept any address at their domain, even ones that don't exist. During an InsightX+ check, we test this directly by checking whether the mail server also accepts a made-up address at the same domain - no message is ever sent.

• If the domain accepts everything, we can't fully confirm the original address is real, so it's flagged Catch-All (Risky) rather than Valid.