Real-time verification

Real-Time Email Verification for Signup, Checkout and Lead Forms

Real-time email verification checks an address when someone enters it in a form, before it reaches your database. As a real-time email verification service, CampaignKit works through the API, Zapier, n8n or an Auth0 Action: 200 free validations, then pay as you go.

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What real-time email verification does

Real time email verification checks an email address when someone enters it in your form, not weeks later in a bulk clean. Some call it real-time email validation; it's the same thing. The point is to catch a bad address while the person is still there to fix it.

For each address you get one of three results: valid, risky or invalid. When the address looks like a typo of a well-known email provider, such as gmai.com, you also get a suggested correction.

To check a whole list instead, use the bulk email verifier. To check one address by hand, without an account, use the free email verifier.

Signup, checkout and lead forms

  • Signup forms. Catch typos and throwaway (disposable) addresses before your welcome email goes out. Ask the person to correct the address, so the account starts with an address you can reach.
  • Checkout. Catch typos and undeliverable addresses before the order is placed, so order confirmations arrive.
  • Lead forms. Keep bad leads out of your CRM and your sales team's queue. A lead with an invalid address can be dropped or sent back for review.

Four ways to add real-time email verification

Route Best for Where to start
Real-time email verification API Your own signup, checkout or lead form, checked while the person is on the page Email validation API reference, developers
Zapier Form tools such as Google Forms or Typeform, no code Validate emails in Zapier
n8n Webhook or form workflows, no code Validate emails in n8n
Auth0 Action Sign-ups through Auth0 Email validation for Auth0

The API. Your code sends POST /v1/email/validate with your API key as a Bearer token. One request can hold up to 100 addresses. Your code decides when to call it: when the email field loses focus, or when the form is submitted. If you were looking for a real time email validation API, this is the one to start with.

Zapier. Add the CampaignKit Validate Email action after your form's "new submission" trigger. Then use a Filter step, or Paths, to handle valid, risky and invalid addresses differently.

n8n. The CampaignKit community node has a Validate Email operation. Put it after a Webhook trigger that receives your form submissions, then filter on the result.

Auth0. A Pre User Registration Action calls the API before the user is created. If the address fails, the Action denies the sign-up and shows the person a message, including the suggested correction when there is one.

Only your own code can check an address while the person is still on the page. Zapier and n8n run after the form has been submitted, so use them to filter contacts before they reach your CRM or email list.

What to do with each result

Result What it means for your form What to do
valid No risk found Accept the address
risky The address may cause problems, for example a disposable or role address (info@, support@) Accept it and flag it, or ask for another address, depending on the form
invalid The address is undeliverable Ask the person to check the address

If an invalid result comes with a suggested correction, show it ("Did you mean john@gmail.com?") and let the person choose. Don't replace the address without asking: the suggestion is advice, and the person knows their own address.

How strict to be depends on the form. A free newsletter signup can accept risky addresses and flag them. A checkout or a trial signup may ask for a different address when it's disposable.

The request and response format, including the result fields, is in the email validation API reference.

If the check doesn't answer

Networks fail and services have outages, so decide in advance what your form does when the check doesn't come back. Our advice: set a timeout in your own code, and if it runs out, let the person through and check the address again later. Blocking a real sign-up because a check didn't answer costs you more than one unchecked address.

The Auth0 example works this way. It gives up after 5 seconds and lets the sign-up through.

The API returns a 429 error when you exceed the rate limit. Treat that the same way: accept the address and check it again later.

What real-time verification can't tell you

A valid result is a strong signal, not a promise of delivery:

  • Catch-all domains accept mail for any address, so a single mailbox can't be confirmed. The result carries a catch-all flag, and some of these addresses may still bounce. Our post on catch-all emails and whether to send to them helps you decide.
  • Some mail servers won't confirm a mailbox at all, so the address can't be fully verified.
  • A working address isn't proof of ownership. Someone can enter a real address that belongs to someone else. Add double opt-in, a confirmation email with a link, to make sure the owner wants your mail.

Real-time email verification pricing

CampaignKit is a pay-as-you-go service. You start with 200 free validations and no credit card. After that you buy credits in packs: there's no subscription, and credits never expire.

Each validated address uses one credit. If the same address appears twice in one request, it's charged once.

Pack size Price Cost per 1,000 emails
2,500 emails $6 $2.40
10,000 emails $15 $1.50
50,000 emails $75 $1.50
100,000 emails $120 $1.20
1,000,000 emails $429 $0.43

See all packs on the pricing page. Verifying more than 1,000,000 emails? Contact sales for custom pricing.

Related

Frequently asked questions

What is real-time email verification?
Real-time email verification, also called real-time email validation, checks an email address at the moment someone enters it in a signup, checkout or lead form, before it is saved. CampaignKit returns valid, risky or invalid for the address, plus a suggested correction when the address looks like a typo of a well-known email provider.
How is it different from bulk email verification?
Bulk verification checks a whole list in one job, usually weeks or months after the addresses were collected. Real-time verification checks each address as it comes in, while the person is still there to fix a typo or give another address. Most teams use both: real-time checks on their forms and a bulk clean before a big send.
Can I verify emails at signup without writing code?
Yes. The Zapier Validate Email action and the n8n Validate Email operation check each new form submission, so you can filter or branch before the contact reaches your CRM or list. They run after the form is submitted, though. To check the address while the person is still on the page, for example when they leave the email field, you need your own call to the API.
Will it slow down my form?
The check adds a request to your signup flow, so plan for it. Set a timeout in your own code, and if the check doesn't answer in time, accept the address and check it again later instead of blocking the sign-up. Our Auth0 example gives up after 5 seconds and lets the sign-up through.
Is there a real-time email verification API?
Yes. CampaignKit has a REST API: you send a POST request to the email validation endpoint with your API key as a Bearer token, and get a result for each address. One request can hold up to 100 addresses. The request and response format is in the email validation API reference.
Does it catch typos like gmai.com?
When an address looks like a misspelling of a well-known email provider's domain, such as gmai.com for gmail.com, the result includes a suggested correction. Treat it as advice: show it to the person and let them choose, rather than changing the address yourself. Not every typo gets a suggestion.
How much does real-time email verification cost?
Every new account gets 200 free validations, with no credit card. After that you buy credit packs, from $6 for 2,500 emails to $429 for 1,000,000 emails. Each validated address uses one credit, duplicates in the same request count once, credits never expire and there is no subscription.
How long does a verification result stay valid?
A result describes the address at the time it was checked. Mailboxes get closed and domains change, so an address that was valid at signup may bounce a year later. Check older addresses again before a big send, for example with a bulk verification of your list.

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