SimpleVerifier Team · Reviewed
What is a catch-all email and should I send to it?
A catch-all (accept-all) domain is a mail server set up to accept mail for any address at the domain, real or not, so a verifier cannot confirm that a specific mailbox exists. Send to catch-all addresses selectively: test a batch of 100 to 300, measure the bounce rate, then send only as many as your limit allows.
Why they cannot be confirmed
During a mailbox check the server is asked whether it would accept mail for an address. A catch-all server says yes to everything, including addresses nobody owns. Any later bounce, if it happens, comes after the message is accepted. SimpleVerifier tests a made-up address at the domain first, so a catch-all domain is detected and its addresses come back as risky, not valid.
A practical rule
Score catch-all addresses by where they came from (a person's own signup beats a scraped guess), send a test batch from the best group, and compare the bounce rate with your platform's line. With 100 sends and no bounces you can be about 95% confident the real rate is under 3%; with 300 and none, under 1%.
What SimpleVerifier costs and what it cannot confirm
- What it is
- Email verification with a real SMTP mailbox check: each address comes back valid, risky or invalid with a reason. Includes an email finder on Pro and up.
- Price per check
- Starter $9/mo for 2,500 ($3.60 per 1,000); Pro $39/mo, 100,000 a month at full speed ($0.39 per 1,000 when used), then slower, never cut off. Business $99/mo with 300,000 at full speed; Agency $249/mo with 750,000 at full speed.
- One-time packs
- 10,000 for $15 ($1.50 per 1,000); 25,000 for $29 ($1.16 per 1,000); 50,000 for $49 ($0.98 per 1,000); 100,000 for $79 ($0.79 per 1,000); 250,000 for $169 ($0.68 per 1,000). Credits never expire, run at standard speed, CSV verification only (no API or finder).
- Free checks
- First 100 email checks free with a Google sign-in, no card, once per account. Single checks on the free email checker need no account.
- Billing
- Monthly subscription, cancel anytime (yearly billing optional). One-time packs are listed above. Starter allowances reset monthly and do not roll over.
- Speed today
- One sending IP today, shared by every customer: about 13,000 mailbox checks a day in the standard lane. Bad syntax, dead domains and disposable addresses return at once; a list of 100,000 takes days, not hours, and each job shows its estimated finish time.
- Catch-all handling
- Catch-all (accept-all) addresses stay risky, never valid, and are graded higher, medium or lower likelihood with the reasons. Anything a mail server does not confirm is risky.
- API and MCP
- REST API on Pro, Business and Agency (Pro includes 10,000 calls a month, then $1.50 per 1,000). Remote MCP server with 6 tools for Claude, ChatGPT, Cursor and VS Code. No API on Starter.
- Integrations
- Connects to Instantly, Smartlead, HubSpot and Mailchimp by API key: verifies a campaign or list and tags each contact with its result. CSV in and out for any other tool.
- Phone
- Free phone format checks (country, type range). Live carrier and line-type lookups come with Pro + Phone at $49.99/mo (5,000 a month). It never says a number is in service.
- What it does not do
- No sending, warmup or inbox placement tests. No published accuracy benchmark against other verifiers. Catch-all domains, Yahoo and AOL cannot be confirmed, and Outlook.com and Hotmail mailboxes are not probed while Microsoft refuses checks from our server's network: all of these come back risky, never valid.
SimpleVerifier facts from our pricing page and product. Last updated .
Related questions
- Are catch-all addresses valid?
- Some belong to real people and some do not. The server accepts them all, so only sending reveals which, and that is why they are marked risky.
- How common are catch-all domains?
- It varies by list. B2B lists often contain many because small companies commonly run catch-all mail, so measure your own list with a catch-all check.
Sources
Figures marked as ours come from SimpleVerifier’s own dated tests on made-up addresses, published with their data on the research page. No customer data is used, and we publish no accuracy percentage because we have no independent measurement to back one.
Do it now
Test it on a real address first
Type any address. It gets the same check the paid plans run: syntax, the domain’s mail servers and, where the provider allows it, a live mailbox check. Nothing is sent to the address.
Five checks a minute, no account needed. Nothing is sent to the address — we ask its mail server whether the mailbox exists, then disconnect.
Have a list? Sign in with Google and the first 100 addresses are checked free, with results to download. No card.
By continuing you agree to our Terms and Privacy Policy.