A mailbox is ready when its domain has mail servers, one SPF record that covers your provider, a DMARC record and a DKIM key. Type the address you already send from to check all four, get the exact record to add for anything missing, and a starting daily limit. Free, no signup. Only the domain is sent, to Cloudflare's public DNS resolver.
Your mailbox
Is the mailbox new?
A mailbox that has not sent much yet starts lower and climbs. This only changes the starting limit.
Only the domain is sent, to Cloudflare's public DNS resolver (cloudflare-dns.com), and nowhere else. The part before the @ never leaves your browser. Nothing is stored. The domain goes in the page address so you can share the result.
Result
Type the address you would send cold email from. The check reads its public DNS records (mail provider, SPF, DMARC and DKIM) and says what to fix before you send.
Send from the mailbox you already have.
Monty sends from your own Gmail or Outlook mailbox, so there are no new domains or mailboxes to buy. It never sends more than the daily limit you set, and it sends in your recipient's working hours.
Start with your listHow it is checked
v=DMARC1; p=none; rua=mailto:dmarc@yourcompany.comThe verdict. Ready when nothing fails. Fix first when SPF or DMARC is missing or broken. Not suitable for a consumer address or a domain with no mail servers. When a lookup does not answer, there is no verdict: a record that could not be read is not a missing record.
The starting limit. A mailbox already in use starts at 40 cold emails a day, the figure our mailbox capacity planner starts from. A failing SPF halves it, a failing DMARC halves it again, and no DKIM key at a common selector takes a quarter off. A new mailbox starts at 5, the first step of the warm-up ramp. The result is rounded down to a multiple of 5 and never goes below 5. This is our starting point, not an industry rule and not a guarantee of where your email lands.
Providers' own daily ceilings: Google Workspace 2,000, consumer Gmail 500, Microsoft 365 (Exchange Online) 10,000, Outlook.com 300. These are the most an account may send, not advice for cold email.
Check four things in your domain's DNS. It has mail servers (an MX record), so replies arrive. It has one SPF record that covers your mail provider. It has a DMARC record. And your provider signs mail with DKIM. If any of those is missing, fix it before you send; most fixes are one DNS record.
Add a TXT record at the host _dmarc with the value "v=DMARC1; p=none; rua=mailto:dmarc@yourcompany.com", using a mailbox you read for the reports. p=none only monitors, so it blocks nothing. Once the reports show only your own senders, move to p=quarantine.
A DKIM key sits under a selector name that whoever set it up chose, and selectors are not published anywhere. The checker tries the common ones (google, selector1, selector2, k1, default, s1, s2, mail). Not finding a key there does not prove there is none. To be sure, send yourself an email and look for "dkim=pass" in the original message headers.
It is not suitable. You cannot publish SPF, DKIM or DMARC for gmail.com or outlook.com, and consumer accounts have lower sending ceilings: 500 a day for consumer Gmail and 300 for Outlook.com, against 2,000 for Google Workspace and 10,000 for Microsoft 365. Those are the providers' ceilings, not figures for cold email. Use a mailbox on your company's domain.
There is no single safe number. This checker starts a mailbox already in use at 40 a day when every check passes, lowers that when a check fails, and starts a new mailbox at 5 a day to climb from there. It is a starting point. Hold the limit or lower it if you see bounces or spam complaints.
Only the domain, to Cloudflare's public DNS resolver (cloudflare-dns.com), from your browser. The part of an address before the @ never leaves your browser, and nothing is stored. DNS records are public, so the check reads nothing a mail server receiving your email cannot already see.
Before you book
The price
$1,399 a month. No setup fee.
Prices shown in USD. Billed in the same currency at checkout.
If it does not work
Cancel inside 30 days and your payment comes back in full. No usage deduction, no form to fill in.
How you leave
Monthly, and you cancel from inside the product. No contract, no notice period, no minimum term — the tools this replaces mostly ask for a quarter or a year up front.