Documentation

Everything you need to ship

Guides, status codes, and integration patterns for the MailGuard verification platform.

Create a free account, claim your 100 starter credits, and verify your first email in under a minute.

Single-address checks via the dashboard. Returns syntax, MX, SMTP, and risk classification in real time.

Upload CSV or TXT. We auto-detect the email column, run all checks in parallel, and produce a downloadable result file.

REST endpoint for real-time signup verification. Sub-2s p95 response. Authentication via API key (request access via support).

One column required. Headers optional. UTF-8. Up to 1M rows per upload. Empty rows are skipped silently.

Verify on signup, re-verify dormant lists every 6 months, exclude 'invalid' and 'disposable' before sending, send confirmation to 'risky'.

Verification statuses reference

Every result row includes a status. Here's what each one means.

Status	Meaning
valid	Mailbox exists and accepts mail.
invalid	Syntax invalid, domain unreachable, or mailbox confirmed missing. Do not send.
risky	Mailbox may exist but signals suggest deliverability risk (catch-all, role, low-quality).
unknown	SMTP server did not return a definitive answer. Treat with caution.
catch-all	Domain accepts all addresses. Existence cannot be confirmed individually.
disposable	Temporary inbox provider (e.g., 10minutemail). Almost always low value.
role	Shared mailbox like info@, support@. Often unsubscribed quickly.
mailbox_full	Account exists but is over quota. Will bounce until cleared.
blacklisted	Address appears on a known blacklist or honeypot list.

Have questions the docs don't answer? Reach out to support.