Email validation API

Email address validation

Postcoder checks and validates email addresses in real-time as soon as they're typed into your form. Block incorrect or fraudulent signups, and capture real and deliverable email addresses from genuine customers.

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- Result Valid email address
- Valid
- Score 100
- Email address ada@example.com

Trusted by leading organisations worldwide

Real-time validation

Email validation API

Postcoder email validation performs multiple checks to confirm whether an email address can receive email.

Checks syntax with RFC 5322 email standard
Performs real-time queries on mail servers
Verifies SMTP connections are accepted
Flags spam sources and catch-all domains
Finds potential typos and suggests corrections

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GET /pcw/PCW45-12345-12345-1234X/email/ada%40example.com?format=json
----
{
	"state": "Success",
	"valid": true,
	"score": "100",
	"processtime": "10",
}

Checkout

Let's start with your email address so we can save your checkout

ada@example.com

Continue

"1 in 3 people give a fake email address at least some of the time."
Source: Verve Research

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Validate, clean, deliver

Unlock efficiency with Postcoder email validation

Validate email addresses in real-time
Postcoder instantly checks if email addresses are valid and able to receive messages.
```
{
	...
	"state": "Success",
	"valid": true,
	"score": "100",
	...
}
```
Highlight mispellings
Postcoder suggests alternative spellings for well-known email domains.
Email
josmith100@gmaail.com
Did you mean josmith100@gmail.com
{ ... "state": "Domain Does Not Exist", "valid": false, "alternative": "josmith100@gmail.com", ... }
Detect disposable emails
Postcoder flags disposable email addresses (DEAs) and catch-all domains.
```
{
	...
	"state": "Domain is Well Known DEA",
	"valid": true,
	"score": "0",
	...
}
```

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Elevate customer experiences

Enhance your customer relationships with email validation

Reduce bogus accounts
Eliminate fake, invalid or temporary email addresses from being used to create bogus accounts.
Minimise funnel leaks
Avoid losing leads or customers at registration due to accidental typos in their email address.
Stay connected
Ensure your customers get the emails they want from you by validating their email address.

Improve checkout times
Don't make your customers type their email address twice. Validation helps them complete your form faster.
Increase email deliverability
Enhance your sender reputation and improve deliverability rates by eliminating hard bounces.
Reduce support overhead
Decrease admin time spent following up with customers who missed your important email.

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Global scale

Email validation at scale

Postcoder delivers the scale you need for global commerce. It provides lightning quick responses and supreme reliability wherever your customers are based.

0.3s
transaction time
99.99_%
API uptime

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90-day mean transaction time to 9 April 2025 was 340ms.

Highly rated by customers

An award-winning API with top-tier performance, easy admin and great support

Customers love Postcoder according to independent user reviews on the world's most trusted software marketplace. Start a free trial and find out what you've been missing.

Simple, straightforward and easy to integrate

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100% developer-friendly

An optimised developer experience

Get up and running with email validation in minutes using the quick start guide, sample code and API docs.

Allows validation time to be customised
Works with a single API call
Includes free multi-channel support

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email.js

email.py

email.php

email.cs

// Prepare request URL
let url = `https://ws.postcoder.com/pcw/${key}/email/${user_email}`;

// Return JSON ♥
url += `?format=json`;

// Tag request for easy reporting
url += `&identifier=signup_form`;

GET /pcw/PCW45-12345-12345-1234X/email/ada%40example.com?format=json&identifier=signup_form


----
{
	"state": "Success",
	"valid": true,
	"score": "100",
	"processtime": "10"
}

Simplified admin

Buy credits, check usage and configure security with ease

Use the feature-rich admin area to set up and manage your account. It is natively mobile and desktop-friendly so whether you're updating a setting on the go or doing a deep-dive at your desk, it will be the same seamless experience. It supports dark mode too.

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Powerful customer stories

Postcoder is trusted by over 9,000 organisations of all sizes

Postcoder helps organisations in the UK and worldwide achieve measurable improvements in their form conversions and data quality. After integrating Postcoder, many of them report increased onboarding numbers, faster form completion, and a surge in quality leads. Postcoder captures contact details you can rely on.

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