Know why an address is risky

Each result has a score from 0 to 100, a category, a safe-to-send flag, and the reason codes behind them.

Get started free Catch-all domains explained

Fig. 1Scores on one scale

Score: 0 to 100
Categories: Valid, risky, invalid, unknown
Reason codes: 17
Flag: safe_to_send

§ 1

Why it matters

Risky is not one thing

A catch-all company domain, a disposable address, and a full inbox are different risks. A single label treats them the same.

A single label hides too much. We show the score and every reason, so your team can set its own rules.

Fig. 2Without and with Verifier

WithoutWith Verifier

Without: Each tool uses different labels, so send rules differ by team.With Verifier: One score from 0 to 100 and one of four categories.
Without: A yes-or-no answer hides why an address is risky.With Verifier: Reason codes tell why the score went down.
Without: Catch-all and role addresses get the same treatment as people.With Verifier: One safe_to_send flag for your send rules.

§ 2

How it works

One score, many signals

We combine format, domain, mail server, and mailbox signals into one score. Reason codes show what moved it.

2.1Run a check or a list.
2.2Read the score, the category, and the safe-to-send flag.
2.3Use the reason codes to build your own rules.

Fig. 3Two addresses, one scale

[email protected]

{  "score": 100,  "category": "valid",  "safe_to_send": true,  "reason_codes": ["deliverable"]}

[email protected] · catch-all domain, role address

{  "score": 65,  "category": "risky",  "safe_to_send": false,  "reason_codes": ["catch_all", "role_account"]}

Valid 80–100 · risky 50–79 · unknown 1–49 · invalid 0

§ 3

What you get

What you get.

3.1Catch-all domains gradedDomains that accept every address get a severity tier, so a clean free-provider address is not treated like a risky corporate one.
3.2Policies that match the sendSet the policy for your workspace in Settings: growth, deliverability, or signup protection. The same signals give a decision that fits.

Table 3 · Reason codes

Code	What the check found
deliverable	No problem was found.
invalid_syntax	The address format is not valid.
possible_typo	The domain looks like a typo of a known domain.
no_mx	The domain has no mail server (MX record).
smtp_unreachable	The mail server could not be reached.
smtp_error	The mail server returned an error.
smtp_undeliverable	The mail server did not accept the mailbox.
invalid_recipient	The mailbox does not exist.
disabled_mailbox	The mailbox is disabled.
full_inbox	The mailbox is full.
catch_all	The domain accepts every address.
disposable	The domain gives out throwaway addresses.
role_account	The address belongs to a role, such as info@ or support@.
spam_trap	The domain is a known spam-trap domain.
free_provider	The address is at a free mail provider.
unknown_deliverability	The mailbox could not be confirmed.
provider_rejected	The mailbox provider rejected the address.

§ 4

In practice

Typical uses.

Case 4.1
Segment by risk
Send to safe addresses now, and hold risky ones for a smaller send.

Works with the tools you send from.

All integrations

Questions

Before you start.

What is a catch-all domain?

A domain that accepts mail for any address. A check cannot confirm the mailbox, so we grade the risk instead of guessing.

Risky is not one thing

A catch-all company domain, a disposable address, and a full inbox are different risks. A single label treats them the same.

A single label hides too much. We show the score and every reason, so your team can set its own rules.

Fig. 2Without and with Verifier

WithoutWith Verifier

Without: Each tool uses different labels, so send rules differ by team.With Verifier: One score from 0 to 100 and one of four categories.
Without: A yes-or-no answer hides why an address is risky.With Verifier: Reason codes tell why the score went down.
Without: Catch-all and role addresses get the same treatment as people.With Verifier: One safe_to_send flag for your send rules.

One score, many signals

We combine format, domain, mail server, and mailbox signals into one score. Reason codes show what moved it.

2.1Run a check or a list.
2.2Read the score, the category, and the safe-to-send flag.
2.3Use the reason codes to build your own rules.

Fig. 3Two addresses, one scale

[email protected]

{  "score": 100,  "category": "valid",  "safe_to_send": true,  "reason_codes": ["deliverable"]}

[email protected] · catch-all domain, role address

{  "score": 65,  "category": "risky",  "safe_to_send": false,  "reason_codes": ["catch_all", "role_account"]}

Valid 80–100 · risky 50–79 · unknown 1–49 · invalid 0

What you get.

3.1Catch-all domains gradedDomains that accept every address get a severity tier, so a clean free-provider address is not treated like a risky corporate one.

3.2Policies that match the sendSet the policy for your workspace in Settings: growth, deliverability, or signup protection. The same signals give a decision that fits.

Table 3 · Reason codes

Code	What the check found
deliverable	No problem was found.
invalid_syntax	The address format is not valid.
possible_typo	The domain looks like a typo of a known domain.
no_mx	The domain has no mail server (MX record).
smtp_unreachable	The mail server could not be reached.
smtp_error	The mail server returned an error.
smtp_undeliverable	The mail server did not accept the mailbox.
invalid_recipient	The mailbox does not exist.
disabled_mailbox	The mailbox is disabled.
full_inbox	The mailbox is full.
catch_all	The domain accepts every address.
disposable	The domain gives out throwaway addresses.
role_account	The address belongs to a role, such as info@ or support@.
spam_trap	The domain is a known spam-trap domain.
free_provider	The address is at a free mail provider.
unknown_deliverability	The mailbox could not be confirmed.
provider_rejected	The mailbox provider rejected the address.

From a raw listto a safe send.

Know why an address is risky

Risky is not one thing

One score, many signals

What you get.

Typical uses.

Works with the tools you send from.

Before you start.

From a raw listto a safe send.

Know why an address is risky

Risky is not one thing

One score, many signals

What you get.

Typical uses.

Works with the tools you send from.

Before you start.