Features
What VeriMail Pro checks, and what the results mean
The checks
Each check is a column in the results table: OK, Check, Failed or Skipped, with a short explanation.
| Check | What it does |
|---|---|
| Hygiene | Trims, lowercases and converts international domains (punycode), then merges duplicates. |
| Syntax | Checks the address format against RFC 5321 and 5322 (a practical subset). |
| Risk lists | Flags disposable domains, role accounts (such as info@) and free providers, and suggests fixes for likely typos. |
| DNS | Confirms the domain exists and accepts mail: MX records, A/AAAA fallback and null MX (RFC 7505). The app queries public nameservers itself. |
| SMTP | Asks the mail server whether the mailbox exists with a single RCPT TO probe over STARTTLS, with catch-all detection, greylist retries and MX fallback. Paid plans only. |
The four statuses
- Valid
A mail server confirmed the mailbox exists. Only the SMTP check can say this.
- Needs review
May work but is not guaranteed, and each result says why: Catch-All, Disposable, Role-Based, Greylisted, or Not Checked (Free plan: format and domain are fine, the mailbox was not checked).
- Unknown
Could not be checked: a timeout, the mail server blocked or throttled the check, or the probe server was unreachable. Try again later.
- Invalid
Confirmed bad: wrong format, the domain does not exist or accepts no mail, or the mail server said the mailbox does not exist.
Every result also carries a reason, such as “Mailbox does not exist” or “Domain accepts every address”, and a score from 0 to 100. The screen and every export use the same words.
A careful mailbox check
Most home and office networks block outbound port 25, so paid plans run the mailbox check through VeriMail's probe server, which connects to the mail server from its own IP.
- Stops at RCPT TO and never sends DATA, so no email is ever transmitted.
- Each provider group (Gmail, Outlook and others) has its own concurrency and per-minute limit.
- Pauses the run after repeated blocked or throttled replies, so the checking IP is not burned.
- Pauses instead of marking addresses when your own internet connection drops.
- Checks that a public mail server is reachable on port 25 before an SMTP run starts.
If the probe server cannot be reached, addresses are marked Unknown, never Invalid. Read the acceptable use policy.
Free and paid
| Free | Premium and Lifetime | |
|---|---|---|
| Hygiene, syntax, DNS and risk-list checks | Yes | Yes |
| Mailbox (SMTP) checks | No | Yes, through the built-in probe server |
| Addresses per run | 500 | Unlimited |
| History, dashboard and export (CSV, XLSX, JSON) | Yes | Yes |
In the app
- Verifier
- Paste or drop a list, choose whether to save it, run it and watch results arrive.
- Results
- Paging, sorting, filters and a detail drawer showing what each check found.
- History
- Saved runs: open, rename, re-run or delete them.
- Dashboard
- Totals across saved runs and a status breakdown.
- Diagnostics
- Whether your network can run mailbox checks: port 25, public IP, reverse DNS, blocklists.