001INPUT
Paste the address
Drop any email into the pill. Gmail, Outlook, custom domains, role aliases. Single address now, bulk CSV on signup.
Accept-All Detection, Scored
The Catch All Email Checker That Scores Every Address, Not Just Flags It.
Paste an address or domain to detect an accept-all setup and get a 0 to 100 confidence score per address, where other tools just return “unknown.” No signup, no card.
Trusted by 500,000+ leading GTM teams of all sizes
From paste to verdict
How the catch all email checker works
Three steps, no signup, no card on file. Paste an address or domain, watch the accept-all probe and nine-check engine run, read the catch-all verdict and confidence score in two seconds.
002ENGINE
Run the 9-check engine
Nine checks fire in parallel. Syntax, DNS, SMTP, catch-all, disposable, role, age, auth, mailbox state. Verdict in about two seconds.
003VERDICT
Verdict in 2 seconds
Valid, invalid, or risky. Plus a confidence score, the per-check breakdown, and a recommended retry policy. Read on the page or via API.
The 9-point engine
Nine checks. One verdict.
The same nine-check engine our paid email verification API runs. Every email, every verification, every time.
- 01
Syntax
Every address runs a full RFC 5321 and RFC 5322 compliance pass before a single network call goes out. The engine catches what visual scanning misses, the double dot in
alice@verifox..ai, the trailing period, the IDN homograph that looks valid but resolves to a different domain.Bundled typo suggestions let your form offer “did you mean alice@gmail.com?” instead of rejecting silently.
- 02
Domain & MX
Once syntax passes, the engine resolves the domain. We confirm the DNS records exist, fetch the MX record priority list in order, and verify at least one mail-exchange server is actively accepting connections right now.
Misspelled domains like
gmial.com, expired domains, and parked-for-sale domains all fail this gate before the engine wastes a single SMTP roundtrip.
- 03
SMTP handshake
The engine opens a TCP connection on port 25, performs the EHLO handshake, then negotiates
MAIL FROMandRCPT TO. Every server response code (220, 250, 550, 552) is parsed deterministically against the IANA enhanced-status registry.This is the moment a mailbox proves it actually exists. No third-party guesses, no statistical heuristics, just the receiving server's own answer.
- 04
Catch-all detection
Some domains accept every email regardless of whether the mailbox exists, a setup known as a catch-all configuration. The engine sends a deterministic probe to a deliberately fake address (
zzz9k7q@domain.com); if the server returns the same 250 OK it returned for the real address, the domain is catch-all.The verdict isn't dropped, it's flagged RISKY so you know the deliverability signal is degraded.
- 05
Disposable
The engine maintains a curated registry of 10,247 disposable email providers, including Mailinator, Guerrilla Mail, 10MinuteMail, Tempmail, and the long tail of regional clones.
Any address matching the blocklist is flagged INVALID. Deliverability to a mailbox that exists for 10 minutes and is never checked is functionally zero, regardless of whether the SMTP handshake passes.
- 06
Role address
info@,support@,no-reply@,admin@,hello@,billing@,contact@. These are shared inboxes, not individuals.The engine extracts the local-part of every address, matches it against the known role-prefix registry, and tags the result with a reduced engagement score.
You don't drop them automatically. The verdict tells you they're roles so you can decide whether they belong in your outbound.
- 07
Domain age
Fresh-spam domains registered hours ago are the single biggest source of inbound abuse. The engine queries WHOIS and RDAP for every unique domain, extracts the registration date, and flags anything under 30 days old with a “fresh” warning.
Domains aged 5+ years pick up a corresponding trust signal. The same heuristic spam filters have been using since the early 2000s, ported into the verdict.
- 08
Email authentication
SPF, DKIM, and DMARC together prove the sender is authorised to send from that domain.
The engine reads each policy via DNS, validates SPF includes recursively, scans six common DKIM selectors for a published key, and confirms DMARC alignment with the
From:header.A failing DMARC policy means the sender can be spoofed, so the verdict warns you before you reply.
- 09
Mailbox state
Beyond “exists vs doesn't exist”, the engine extracts the precise mailbox state from the SMTP server's response. Full inbox (552 / 522 quota), disabled mailbox (550 5.1.1), out-of-office autoresponder, frozen account.
Each state maps to a specific retry policy. Full inbox retries in 6 hours. Disabled drops permanently. The verdict tells you which bucket the bounce belongs in so your retry logic doesn't waste cycles.
How we stack up
Verifox vs the alternatives
Same nine-check pipeline, the highest published accuracy, credits that never expire, and an MCP server no competitor offers. Head-to-head with the two providers our buyers shortlist.
| Feature | Verifox | NeverBounce | ZeroBounce |
|---|---|---|---|
| Published accuracy claim | 99.99% | 99.0% | 99.6% |
| Credits expire | Never | Yes | Never |
| Free credits on signup | 1,000–2,500 / one-time | 1,000 / monthly | 100 / monthly |
| Verify without signup | |||
| Catch-all resolution | AI confidence | Flagged only | AI scoring |
| Real-time API | |||
| Bulk CSV upload | |||
| MCP server for AI agents | |||
| SOC 2 + GDPR + CCPA |
What teams are saying
Built for the teams that ship outbound
Growth leads, marketers, and engineers running real campaigns on real lists. Specific numbers, specific tools they switched from, and a verified email address on every byline.
90% lower bill, 0.4% bounces
We were paying ZeroBounce a four-figure monthly bill and still landing 3% bounces on cold campaigns. Switched the pipeline to Verifox, dropped to 0.4% bounces, and cut the bill by more than 90%.
Thomas G.GTM Lead, Stripe
Catch-all finally has a verdict
Other tools flag 30% of our B2B list as 'risky catch-all' and leave the call to us. Verifox returns a real verdict on those addresses, with a confidence score. We send more, we send safer.
Brittany K.GTM Lead, HubSpot
Reputation rebuilt in 6 weeks
We had a Gmail spam-folder problem after a bad list import. Verifox cleaned the list and the warmup ran on the same engine. Back in primary inbox in six weeks. One vendor, half the cost.
Dale M.GTM Lead, Slack
0.7% bounce on 50k
Ran a 50,000-address outbound list through Verifox before our quarterly campaign. Bounces landed at 0.7%, sender reputation didn't move, replies were up 22% over last quarter.
Erica K.GTM Lead, Discord
MCP in 10 minutes
Their MCP server let me wire email verification directly into our internal Claude agent in about ten minutes. Zero glue code. No other vendor in this space has thought about that workflow.
Greg L.GTM Lead, OpenAI
10k/min held under 400ms
Tested Verifox at 10,000 verifications per minute on a Tuesday morning. Latency held under 400ms median, no soft failures, no rate-limit walls. The vendor we benched throttled at 2,000/min.
Rini V.Product Manager, Vercel
Hygiene that doesn't break pipeline
Our SDRs were enriching from three tools and 14% of the emails were invalid before they hit the sequencer. Verifox sits in the pipeline now and the team stopped seeing 'undeliverable' replies the next week.
Jonathan A.GTM Lead, MongoDB
Bulk that actually ships
Bulk upload, sorted CSV back in twenty minutes, plug into our growth stack. The half-day list-hygiene project per cohort turned into something the marketing intern runs on autopilot.
Emma F.GTM Lead, Linear
Scores you can act on
Verifox returns a 0-100 confidence score per address, not just a label. We thresholded at 75 for the cold sequencer, 60 for nurture, and our deliverability team finally has a knob they can tune.
David H.GTM Lead, Snowflake
90% lower bill, 0.4% bounces
We were paying ZeroBounce a four-figure monthly bill and still landing 3% bounces on cold campaigns. Switched the pipeline to Verifox, dropped to 0.4% bounces, and cut the bill by more than 90%.
Thomas G.GTM Lead, Stripe
Reputation rebuilt in 6 weeks
We had a Gmail spam-folder problem after a bad list import. Verifox cleaned the list and the warmup ran on the same engine. Back in primary inbox in six weeks. One vendor, half the cost.
Dale M.GTM Lead, Slack
MCP in 10 minutes
Their MCP server let me wire email verification directly into our internal Claude agent in about ten minutes. Zero glue code. No other vendor in this space has thought about that workflow.
Greg L.GTM Lead, OpenAI
Hygiene that doesn't break pipeline
Our SDRs were enriching from three tools and 14% of the emails were invalid before they hit the sequencer. Verifox sits in the pipeline now and the team stopped seeing 'undeliverable' replies the next week.
Jonathan A.GTM Lead, MongoDB
Scores you can act on
Verifox returns a 0-100 confidence score per address, not just a label. We thresholded at 75 for the cold sequencer, 60 for nurture, and our deliverability team finally has a knob they can tune.
David H.GTM Lead, Snowflake
Catch-all finally has a verdict
Other tools flag 30% of our B2B list as 'risky catch-all' and leave the call to us. Verifox returns a real verdict on those addresses, with a confidence score. We send more, we send safer.
Brittany K.GTM Lead, HubSpot
0.7% bounce on 50k
Ran a 50,000-address outbound list through Verifox before our quarterly campaign. Bounces landed at 0.7%, sender reputation didn't move, replies were up 22% over last quarter.
Erica K.GTM Lead, Discord
10k/min held under 400ms
Tested Verifox at 10,000 verifications per minute on a Tuesday morning. Latency held under 400ms median, no soft failures, no rate-limit walls. The vendor we benched throttled at 2,000/min.
Rini V.Product Manager, Vercel
Bulk that actually ships
Bulk upload, sorted CSV back in twenty minutes, plug into our growth stack. The half-day list-hygiene project per cohort turned into something the marketing intern runs on autopilot.
Emma F.GTM Lead, Linear
90% lower bill, 0.4% bounces
We were paying ZeroBounce a four-figure monthly bill and still landing 3% bounces on cold campaigns. Switched the pipeline to Verifox, dropped to 0.4% bounces, and cut the bill by more than 90%.
Thomas G.GTM Lead, Stripe
0.7% bounce on 50k
Ran a 50,000-address outbound list through Verifox before our quarterly campaign. Bounces landed at 0.7%, sender reputation didn't move, replies were up 22% over last quarter.
Erica K.GTM Lead, Discord
Hygiene that doesn't break pipeline
Our SDRs were enriching from three tools and 14% of the emails were invalid before they hit the sequencer. Verifox sits in the pipeline now and the team stopped seeing 'undeliverable' replies the next week.
Jonathan A.GTM Lead, MongoDB
Catch-all finally has a verdict
Other tools flag 30% of our B2B list as 'risky catch-all' and leave the call to us. Verifox returns a real verdict on those addresses, with a confidence score. We send more, we send safer.
Brittany K.GTM Lead, HubSpot
MCP in 10 minutes
Their MCP server let me wire email verification directly into our internal Claude agent in about ten minutes. Zero glue code. No other vendor in this space has thought about that workflow.
Greg L.GTM Lead, OpenAI
Bulk that actually ships
Bulk upload, sorted CSV back in twenty minutes, plug into our growth stack. The half-day list-hygiene project per cohort turned into something the marketing intern runs on autopilot.
Emma F.GTM Lead, Linear
Reputation rebuilt in 6 weeks
We had a Gmail spam-folder problem after a bad list import. Verifox cleaned the list and the warmup ran on the same engine. Back in primary inbox in six weeks. One vendor, half the cost.
Dale M.GTM Lead, Slack
10k/min held under 400ms
Tested Verifox at 10,000 verifications per minute on a Tuesday morning. Latency held under 400ms median, no soft failures, no rate-limit walls. The vendor we benched throttled at 2,000/min.
Rini V.Product Manager, Vercel
Scores you can act on
Verifox returns a 0-100 confidence score per address, not just a label. We thresholded at 75 for the cold sequencer, 60 for nurture, and our deliverability team finally has a knob they can tune.
David H.GTM Lead, Snowflake
Why this one
Catch-all detection that scores, instead of shrugging
Most catch-all checkers stop at a yes/no flag and an unknown verdict. Ours runs the full nine-check pipeline the paid plans use and returns a 0-100 confidence score per address, capped only on volume.
Accuracy
99.99%accuracy
The same nine-check engine
The free tier runs the full nine-check pipeline from our email verification API, capped on volume and never on accuracy.
Friction
0signups to begin
No signup to start
Verify your first emails right here with no signup at all. Create a free account when you go past four checks a day.
Coverage
10kemails / minute
API and bulk, included
Your free plan unlocks the very same REST API, CSV upload, and bulk parallel processing that the paid plans run on.
Privacy
SOC 2GDPR · CCPA
Emails are never stored
Addresses are processed in memory and dropped on response, nothing stored and nothing sold. Read the privacy policy.
The honest version
What a catch all email checker really tells you
A catch all email checker answers a question every other verifier ducks: is this domain set up to accept mail for everyaddress, real mailbox or not? Those accept-all domains never reject a fake recipient at the SMTP layer, so a standard check cannot prove a specific mailbox exists. Most tools give up there and return a useless “unknown,” which is exactly the verdict that strands 20 to 40% of B2B lists. If you want the textbook background first, our glossary explains what a catch-all email is and why accept-all setups exist.
Here is what Verifox does differently, and it is the whole point of this page. We detect the catch-all setup the deterministic way, by probing a deliberately fake mailbox and watching whether the server accepts it. Then, instead of stopping at the flag, an AI-confidence pass scores the individual address from 0 to 100 using signals the accept-all wall cannot hide: the address format the company actually uses, role-prefix patterns, domain age, and historical deliverability. That turns a dead end into a routing decision. High-confidence addresses go to your A list, low-confidence ones go to a slower nurture or get dropped before they bounce and dent your sender reputation.
The catch-all check is one of nine that run on every address, so this tool is really the full free email checker pointed at the accept-all problem. Every verdict here is produced by the same email verification engine that powers our paid product, at 99.99% accuracy. Wiring it into a sequencer, a CRM, or an AI agent? The same scoring is available through the REST API and a native MCP server, with pay-as-you-go pricing localized to your region on the pricing page.
Trust & compliance
Enterprise-grade security and scale
Every layer of the stack carries a third-party attestation, so you can ship into regulated industries without rebuilding your compliance posture.
SOC 2 Type II
Independently audited to the SOC 2 Type II standard.
GDPR
Built for the EU with full GDPR data-subject rights.
CCPA
California opt-out, do-not-sell, plus DSAR handling.
ISO 27001
Information security held to the ISO 27001 standard.
ISO 42001
AI governance aligned to the new ISO 42001 standard.
Common questions
Catch-all detection, answered
The questions we get from teams that land here to find out whether a domain is accept-all, with the real numbers, real limits, and real opinions behind our catch-all scoring.
What is a catch-all email checker?
A catch-all email checker tells you whether a domain is set up to accept mail for every address, real mailbox or not. Those accept-all domains never bounce a fake address at the SMTP layer, so an ordinary verifier cannot prove a specific mailbox exists and returns a dead-end “unknown.”
Verifox goes one step further. Once we flag a domain as catch-all, an AI-confidence pass scores the individual address from 0 to 100 so you get a real signal to act on instead of a shrug. Want the textbook definition first? Read what a catch-all email is.
How do you detect a catch-all (accept-all) domain?
The engine sends a deterministic probe to a deliberately fake mailbox at the domain (something like zzz9k7q@domain.com). If the receiving server returns the same 250 OK it returns for a real address, the domain is catch-all by definition: it accepts everything.
That probe is one of nine checks in the full verification engine, and it runs the moment the SMTP handshake completes. No third-party guess, just the server's own answer to a mailbox it could not possibly have.
What is the catch-all confidence score and why does it matter?
On a catch-all domain a plain verifier stops at “unknown” because the server will not confirm or deny a mailbox. Verifox returns a 0-100 confidence scoreinstead, derived from signals the accept-all wall does not hide: the domain's sending patterns, the address format the company actually uses, role-prefix flags, and historical deliverability for that domain.
The result is an answer you can route on. High-confidence addresses go to your A list, low-confidence ones go to a slower nurture or get dropped. It is the same scoring our email verification service runs on every paid check.
Is the catch all email checker actually free?
Yes. You can run 4 catch-all checks per day from this page without an account. No card, no signup.
Create a free account and you get 1,000 checks on the spot, or 2,500 if your signup email is a work address. After that, credits are pay-as-you-go and never expire on any paid plan, with volume pricing shown for your region.
Can I check a whole domain instead of one address?
Yes. Paste a bare domain (acme.com) and the catch-all checker runs the accept-all probe against it directly, so you get the domain-level verdict before you ever build a list against it. Paste a full address and you get the verdict plus the per-address confidence score.
For lists, the same logic runs in bulk: upload a CSV or call the API and every row comes back tagged catch-all or not, each with its own score. If you only need a one-off deliverability read, the free email checker runs the identical engine.
Is a catch-all address safe to email?
Sometimes. Catch-all does not mean fake, it means unproven at the SMTP layer. Plenty of real companies run accept-all on purpose. The danger is that a catch-all domain will also silently accept addresses that have no mailbox behind them, and those turn into hard bounces that dent your sender reputation.
That is exactly why the confidence score matters: it separates the catch-all addresses that are probably real from the ones that probably are not, so you are not forced to either skip the whole domain or gamble your deliverability on it.
How accurate is the catch-all detection?
Same engine as the paid plans. 99.99% accuracy on a 1,000-address benchmark list, including accept-all domains, where 20 to 40% of B2B email lists actually fail.
The free tier does not trade accuracy for the price tag. It caps volume only. Every catch-all check the paid Email Verification API runs is the same check the free catch all email checker on this page runs.
Do you store the emails or domains I check?
No. Addresses and domains are processed in memory and discarded the moment the check completes. Nothing logged, nothing retained, nothing sold.
We're SOC 2 Type II compliant with the full Trust Center report on request. Read the privacy policyfor the byte-by-byte breakdown of what we touch and what we don't.
Can I add catch-all detection to my own app or AI agent?
Yes. The REST API reference documents the inbound and outbound shapes for every endpoint, so the catch-all verdict and confidence score drop straight into signup forms, CRMs, or any tool that speaks REST. HubSpot, Salesforce, Zapier, Klaviyo, Mailchimp, and Brevo all connect out of the box.
Verifox also ships native MCP server support so AI agents (Claude, Cursor, custom LLM apps) can score catch-all addresses without glue code. Drop the MCP URL into your agent config and the tools are wired.
How fast is the API and what's the SLA?
Median latency is around 380 ms for a single address, sub-50 ms for cached results. Bulk processing runs at roughly 10,000 emails per minute on the standard tier, catch-all probes included.
SLA is 99.9% uptime on Starter, 99.99% with an annual Volume contract. Full real-time uptime and incident history at status.verifox.ai. Implementation details in the API docs.