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Know which emails will bounce before you send

SimpleCold checks every address and tells you if it's Deliverable, Risky or Undeliverable, with the reason in plain words. One at a time, a CSV, or through the API.

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simplecold.com / tools / email-checker
Free · 5 checks a day · No sign-up
Six checks, in order
  1. 01Format
  2. 02Mail servers
  3. 03Disposable and role
  4. 04Catch-all
  5. 05Connect
  6. 06Mailbox

Type an address and press Check email. Each check above lights up as it runs, and the result appears here with the reason.

  • Six checks on every address
  • A plain reason with every result
  • Slow servers never cost a second credit
  • 200 free credits, no card

Results

Three results. Every one comes with a reason.

No scores to decode. Each address is Deliverable, Risky or Undeliverable, and the reason says exactly what we found. Slow servers show Processing until the answer arrives.

Deliverable

The mail server confirmed the mailbox exists.

[email protected]The mailbox exists and accepts mail.
What to doSend.
Risky

It may deliver, but we can't promise it.

[email protected]The domain accepts mail for any address, so this mailbox can't be confirmed.
What to doRead the reason, then decide.
Undeliverable

Mail to this address will bounce.

[email protected]Possible typo. Did you mean [email protected]?
What to doRemove it or fix the typo.
Processing

The mail server is slow to answer. We're still asking.

[email protected]Still checking this mailbox.
What to doWait. The final result follows, with no second credit.

How it works

Follow one address through all six checks

Pick a step to see what we look for and an address that stops there.

STEP 01 OF 06 · FORMAT

Is it written like an email address?

We check the @, the characters, the length and the domain ending, and compare the domain with common misspellings so gmial.com gets a suggested fix.

EXAMPLE THAT STOPS HERE
Undeliverable[email protected]Possible typo. Did you mean [email protected]?

Ways to verify

However your addresses arrive, verify them the same way

Paste a few, upload a whole file, or check them in your own code. Same six checks, same results.

Paste up to 1,000

Copy addresses from a spreadsheet or a thread and check them as one list.

Paste a list

Upload a CSV

Every original column is kept. We add the category, the reason and the suggested fix to each row.

Upload a file

Use the REST API

Single checks for sign-up forms, batches for small lists, bulk jobs for big files.

Read the API docs

What we check

Six checks run on every address

They run in order and stop as soon as an address fails, so you never pay twice for the same answer.

  1. 01

    Syntax

    Is the address written correctly? Catches missing @, spaces and bad characters.

    Learn more
  2. 02

    Typos

    Is it a common misspelling like gmial.com? We suggest the likely fix.

    Learn more
  3. 03

    Disposable and role

    Is it a throwaway inbox, or a shared address like info@ or sales@?

    Learn more
  4. 04

    Domain and MX

    Does the domain exist and have a mail server? Dead and parked domains fail here.

    Learn more
  5. 05

    Catch-all

    Does the domain accept every address? If so, we say so instead of guessing.

    Learn more
  6. 06

    Mailbox

    We ask the mail server whether this exact mailbox exists, without sending an email.

    Learn more

Slow servers

A slow mail server never costs you a second credit

Some servers make unknown senders wait on purpose. You get an answer in about 12 seconds, and the final result follows by itself.

0 s

You click Check

Format, domain, typo, disposable, role and catch-all checks run, then we ask the mail server.

~12 s

You get an answer

If the server is still stalling, you see Processing instead of a guess.

1–2 min

The final result arrives

Usually within a minute or two. Ask again about that address for free for 30 minutes. No second credit.

For developers

Stop bad addresses at sign-up with one request

Send an address, get back the category, the reason and a typo suggestion you can show the user.

GET /single

Real-time checks

One address, answered in seconds. Built for sign-up forms and lead capture.

Docs
POST /batch

Small lists

Send a list in one request. Slow servers come back as processing and finish on their own.

Docs
POST /bulk

Big files

Upload a CSV, check the job's status and download the results when it finishes.

Docs
Get an API keyRead the API docs

Integrations

Verify contacts in the tools you already use

Import a HubSpot list, follow a guide for your sending tool, or build it in with the API. More connections are on the way.

Using Instantly, lemlist or Apollo? Export, verify and import in a few minutes.Read the guides All integrations

Pricing

Pay per credit. One credit checks one address.

Buy credits when you need them, from 5,000 at a time. The more you buy, the less each check costs. Start with 200 free credits.

CustomNeed more than 500,000 checks?Custom volume pricing, invoicing and a direct contact for your team.
Contact salesBook a demo
  • Every feature on every pack
  • Single checks, lists, CSV and API
  • Asking again about a slow server costs nothing
  • Compare every pack

FAQ

Straight answers

What people ask before they upload their first list.

We found the address, but we can't promise it will deliver: the domain accepts every address, it's a shared role inbox, or it's a throwaway service. The reason tells you which, so you can decide whether to send.

Still have a question? Talk to us.

Check your list before you send it

Start with 200 free credits. Pay per credit after that.

Start freeBook a demo