UOL and BOL email checker: does this mailbox exist?
In short: Asks UOL's and BOL's own mail servers whether a uol.com.br or bol.com.br mailbox exists, without sending anything, after syntax, domain, disposable and role checks. Limit: A valid result shows the server accepted the mailbox today, not that anyone reads it.
To check if a UOL or BOL address exists, enter it here. The checker asks the provider's mail server about the mailbox at RCPT TO and disconnects before sending. Both rejected made-up addresses with 550 5.1.1 … User unknown in relay recipient table in October and again on 8 November 2026, so a missing mailbox comes back invalid and an accepted one valid.
Price: this tool is free. Checking a whole email list is from $9/mo, and the first 100 checks are free with Google, no card. Check your list free nowSee pricing
Tuned for uol.com.br, bol.com.br. Five checks a minute, no account needed. Nothing is sent to the address — we ask its mail server whether the mailbox exists, then disconnect.
What can a check confirm at UOL Mail, and what did we measure there? Can you verify an UOL Mail address? Also: BOL.
Sample result
[email protected] doesn't exist: UOL's server rejected it.
- [email protected]
- Reason
- Mailbox not found
- Mailbox check
- SMTP, nothing sent
What this means for you
Invalid means remove it; a real mailbox would come back valid.
- Asks UOL's server at RCPT TO
- Catch-all test with a random address first
- Catches typo domains with no mail server
- Flags disposable and role addresses
- UOL
- uol.com.br
- bol.com.br
By SimpleVerifier Team · Last updated
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How do I check a whole list of UOL and BOL addresses?
- Export the list as a CSV or copy the email column; UOL and BOL rows and every other domain can go in together.
- Upload or paste it at /verify. The first 100 email checks are free with a Google sign-in, no card.
- For every list after that, Pro includes unlimited email verification. Fair use: the first 100,000 checks a month at full speed, then slower, never cut off.
How do I check a UOL or BOL email address?
- Type or paste one address, such as
[email protected]or[email protected]. - Press Check. The tool checks the syntax and domain, asks the mail server about a random address that can't exist, then about yours, and disconnects before anything is sent.
- Read the verdict: valid means the server accepted the mailbox and rejected the made-up one, invalid means it said the user is unknown, risky means the check didn't get a clear answer.
- If it comes back risky, check again later before you drop the address.
Example
- You enter
- One address:
[email protected]. - You get
- Valid when UOL accepts the mailbox after rejecting a random address; invalid ("Mailbox not found") when it answers
550 5.1.1 … User unknown in relay recipient table; risky only when the check gets no clear answer. - Limits
- Five checks a minute per IP address, one address at a time, no account needed.
Can you check if a UOL email address exists?
Yes. On 8 November 2026 uol.com.br published mx.uol.com.br as its MX and bol.com.br published mx3.bol.com.br. When our checking server offered made-up addresses (uol.com.br on 12 October, bol.com.br on 13 October 2026), both answered at RCPT TO with 550 5.1.1 Recipient address rejected: User unknown in relay recipient table, word for word the same. Fresh made-up addresses at both were rejected again through this checker on 8 November.
So a missing UOL or BOL mailbox comes back invalid ("Mailbox not found"), and one the server accepts after rejecting a random address comes back valid. The UOL and BOL provider pages have the live DNS.
Why do BOL addresses need re-checking often?
BOL's help page says accounts are cancelled automatically after four months without use. That is a short window, so a @bol.com.br contact you haven't heard from since spring may no longer exist.
BOL is part of the UOL group, represented by Universo Online S.A. (UOL norms), which is why the two domains answer checks the same way. The checker treats them as one provider.
Can I check a whole list of Brazilian addresses?
Yes. Sign in and use the bulk verifier for a CSV or a pasted list; UOL and BOL rows get the same mailbox check as here, alongside Gmail, Hotmail and everything else. Terra, another Brazilian webmail, answered checks too; see terra.com.br.
For one Gmail address, the Gmail address checker works the same way, and the email checker handles any other domain.
What can this checker confirm at UOL?
Each row is something the check runs on an UOL address, and the result you can get from it.
| Check | Can we confirm it? | Result when it fails |
|---|---|---|
| Syntax (the address is written correctly) | Yes | Invalid |
| Domain and mail server (MX) | Yes | Invalid, with a typo suggestion where one fits |
| Disposable or role address | Yes | Invalid (disposable) or risky (role) |
| The mailbox exists | Yes: UOL answers at RCPT TO (550 5.1.1 User unknown) | Invalid, "Mailbox not found" |
| A temporary reply or timeout | No answer to read | Risky, worth checking again later |
| Someone reads the inbox | No checker can | Use opens, replies or a small first send |
Our checking server offered a made-up address and disconnected without sending, on 12 or 13 October 2026 and again through this checker on 8 November 2026.
Who uses this tool, and for what?
- Brazilian e-commerce and newsletters
- Drop cancelled bol.com.br accounts and mistyped uol.com.br rows before a campaign.
- Support teams
- Catch a typo domain like uol.com.bt before you reply.
- Lead buyers
- Confirm a handful of Brazilian webmail contacts before importing a list.
What can’t this tool tell you?
- A valid result shows the server accepted the mailbox today, not that anyone reads it.
- A temporary reply or a refused connection comes back risky, not invalid.
- UOL doesn't publish how its servers answer mailbox checks; the handling here is from our own checks, which can change.
- One address at a time, five a minute.
Common questions
- How do I check if a uol.com.br email is valid?
- Enter it here. The checker confirms the syntax and mail server, then asks UOL's server about the mailbox without sending. UOL rejects addresses that don't exist, so a missing mailbox comes back invalid.
- Is BOL part of UOL?
- Yes. BOL (Brasil Online) is part of the UOL group, and its mail server's rejection matched UOL's word for word in our checks.
- Does BOL cancel inactive accounts?
- BOL's help says accounts are cancelled automatically after four months without use.
- What does User unknown in relay recipient table mean?
- The mail server has no mailbox by that name. It is a permanent rejection (550 5.1.1), so treat it as a hard bounce and remove the address.
- Is this checker free?
- Yes, five checks a minute with no account. For a whole list, sign in with Google for 100 free email checks, no card, or use a monthly plan.
Sources
That was one address. Most people have a list.
The free checker does five addresses a minute, one at a time — fine for spot-checking, useless for a CSV of 40,000.
- Upload a CSV up to 100,000 rows
- Valid, risky and invalid exported as separate files
- Repeat checks free for 14 days, no new connections
Plans from $9 a month, cancel anytime, no contract. Sign in with Google and your first 100 email checks are free, no card. The free tools stay free either way.