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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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Email address validation
    • Result Valid email address
    • Valid
    • Score 100
    • Email address ada@example.com
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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",
}
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Let's start with your email address so we can save your checkout
Email
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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Always on

Everything your business needs

Postcoder and its team of address and technology specialists meet the needs of high-demand applications and rapidly growing businesses.

  • ISO 9001 certified

    Built on quality management best practices you can trust.

  • Auto-scaling infrastructure

    Seamlessly handles enterprise volumes and traffic spikes.

  • PCI-DSS & GDPR compliant

    Designed for secure, privacy-first data handling.

  • 99.99%+ uptime

    Proven reliability to keep your integrations running smoothly.

  • 24/7 internal response team

    Our engineers are on standby 24/7 to respond to service disruptions.

  • Low-latency response times

    Fast, reliable API performance at all times, even under load.

  • Full API access & integrations

    Connect easily with your existing tech stack.

  • Real-time validation

    Email validation that checks syntax, mail servers and deliverability in real time.

  • Dedicated onboarding specialist

    Personalised setup and best-practice guidance.

  • Migration assistance included

    Smooth transition from legacy systems or providers.

  • Free multi-channel support

    Get help via chat, email or phone - at no extra cost.

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Highly rated by customers

Award-winning with top performance, easy admin and great support

Businesses rate Postcoder 4.7 stars out of 5 on the world's most trusted software marketplace.

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  • "Having a more simplified checkout page with the help of Postcoder has had two major benefits to our business. Faster checkouts by customers who haven't had to type in their full address, a much simpler customer journey and a major reduction in data errors; where we saw a big drop in incorrect details entered."
    Alex Woods Digital Marketing Executive / Victorian Plumbing
  • "We picked Postcoder because the API is simple to use and it supports many countries which we want to scale out to."
    David Annez Head of Engineering / loveholidays
  • "The reason we like Postcoder is that the rooftop lat/long coordinates have proven to be far more accurate than any other service and Postcoder has hugely increased our successful delivery rates."
    Laura Bailey E-commerce Product Manager / Pasta Evangelists
  • "Postcoder offers a seamless integration with our services. It is very popular with our customers."
    James Gutterson Commercial Manager / Signicat
  • "Postcoder has been great; there has been a noticeable quality increase in our campaigns. In some the pickup rate went from 30% to 60-70% and our appointment ratings for a campaign went from a 15% average to 40% for one client!"
    Daniel Jones IT Technician / Lead Pronto
  • "Postcoder is a single API that provides all the features we need... Rather than integrate several APIs, we only had to integrate one."
    Carl Horn Head of Digital Servicing & Customer Transformation / Capquest
  • "Postcoder ensures that all the address data, the mobile number and the email addresses that our customers give us are correct. It really speeds up the process for our customers."
    Julie Taylor Operations Director / Barrhead Travel