Email Authentication API

Email Authentication API

Verifies email syntax, domain and email delivery, with details about the address and domain.

About the API:  

The Email Authentication API designed to validate and assess the authenticity of email addresses, providing valuable information about their deliverability and security. By analyzing various aspects of email infrastructure and authentication mechanisms, this API provides a holistic approach to email validation, ensuring that only legitimate and trustworthy messages are processed and delivered.

First, the API performs a series of checks to verify the syntax of the email address. This initial validation step ensures that the email conforms to the standard format and structure required for proper communication. By confirming that the syntax is valid, the API helps to avoid errors and inaccuracies that can arise from incorrectly formatted email addresses.

Next, the API checks the domain associated with the email address. This includes verifying the existence and configuration of the domain, as well as checking for any issues that may affect email delivery. By validating the domain, the API helps ensure that emails sent from this domain are legitimate and trustworthy, which improves the overall security of email communications.

In addition, the API performs SMTP checks to verify the availability and functionality of the SMTP (Simple Mail Transfer Protocol) server associated with the domain. This involves establishing a connection to the SMTP server and verifying its responsiveness, ensuring that emails can be successfully sent and received using this server.

While the syntax, domain and SMTP checks may have passed successfully, the API also evaluates the authentication mechanisms implemented by the domain, including SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail). SPF allows domain owners to specify which servers are authorized to send emails on behalf of their domain, while DKIM adds digital signatures to emails to verify their authenticity. In this case, both SPF and DKIM checks have failed, indicating possible problems with email authentication for the domain.

In addition, the API evaluates the provisional deliverability of emails sent to the specified address. This evaluation takes into account several factors that can affect deliverability, such as server configuration, reputation and spam filtering. In this case, the provisional deliverability of the email has failed, suggesting the existence of potential obstacles that may hinder the successful delivery of emails to this address.

In summary, the Email Authentication API provides a comprehensive assessment of email addresses, covering syntax validation, domain verification, SMTP functionality, authentication mechanisms, deliverability assessment and overall quality score. Leveraging this API, companies and organizations can ensure the integrity and security of their email communications, reducing the risk of fraud, spam and deliverability issues.


What this API receives and what your API provides (input/output)?

It will receive a parameter and provide you with a JSON.


What are the most common uses cases of this API?

  1. User Registration: Validate email addresses entered by users during registration to ensure they are genuine and formatted correctly.

    Lead Generation: Verify email addresses collected from lead generation forms to ensure accuracy and increase the quality of leads.

    Marketing Campaigns: Clean email lists before launching marketing campaigns to improve deliverability and reduce bounce rates.

    Account Management: Authenticate email addresses associated with user accounts to prevent unauthorized access and ensure security.

    E-commerce Transactions: Confirm email addresses provided by customers during checkout to facilitate order processing and communication.


Are there any limitations to your plans?

Basic Plan: 5 requests per minute.

API Documentation


To use this endpoint you must indicate an email in the parameter.


Email Verifier - Endpoint Features
Object Description
email [Required]
Test Endpoint


                                                                                                                                                                                                                            {"originalEmail": "[email protected]", "normalizedEmail": "[email protected]", "domain": "", "localPart": "john", "isDisposable": false, "isValid": true, "isDeliverable": true, "isSmtpUtf8": false, "mx": [{"host": "", "priority": 5}, {"host": "", "priority": 10}, {"host": "", "priority": 20}, {"host": "", "priority": 30}, {"host": "", "priority": 40}], "message": "Valid email address.", "asciiEmail": "[email protected]", "asciiLocalPart": "john", "asciiDomain": ""}

Email Verifier - CODE SNIPPETS

curl --location --request GET '[email protected]' --header 'Authorization: Bearer YOUR_API_KEY' 


API Access Key & Authentication

After signing up, every developer is assigned a personal API access key, a unique combination of letters and digits provided to access to our API endpoint. To authenticate with the Email Authentication API REST API, simply include your bearer token in the Authorization header.


Header Description
Authorization [Required] Should be Bearer access_key. See "Your API Access Key" above when you are subscribed.

Simple Transparent Pricing

No long term commitments. One click upgrade/downgrade or cancellation. No questions asked.

🚀 Enterprise
Starts at
$ 10,000/Year

  • Custom Volume
  • Dedicated account manager
  • Service-level agreement (SLA)

Customer favorite features

  • ✔︎ Only Pay for Successful Requests
  • ✔︎ Free 7-Day Trial
  • ✔︎ Multi-Language Support
  • ✔︎ One API Key, All APIs.
  • ✔︎ Intuitive Dashboard
  • ✔︎ Comprehensive Error Handling
  • ✔︎ Developer-Friendly Docs
  • ✔︎ Postman Integration
  • ✔︎ Secure HTTPS Connections
  • ✔︎ Reliable Uptime

To use this API users must provide an email address.

The Email Authentication API is a tool that verifies the authenticity and validity of email addresses by checking various authentication protocols.

There are different plans to suit all tastes, including a free trial for a small number of requests, but your rate is limited to avoid abuse of the service.

Zyla provides a wide range of integration methods for almost all programming languages. You can use these codes to integrate with your project as you need.

By verifying the integrity of email addresses, you can ensure that your contact database contains accurate and up-to-date information, which is crucial for effective communication and marketing campaigns.

Zyla API Hub is like a big store for APIs, where you can find thousands of them all in one place. We also offer dedicated support and real-time monitoring of all APIs. Once you sign up, you can pick and choose which APIs you want to use. Just remember, each API needs its own subscription. But if you subscribe to multiple ones, you'll use the same key for all of them, making things easier for you.

Prices are listed in USD (United States Dollar), EUR (Euro), CAD (Canadian Dollar), AUD (Australian Dollar), and GBP (British Pound). We accept all major debit and credit cards. Our payment system uses the latest security technology and is powered by Stripe, one of the world’s most reliable payment companies. If you have any trouble paying by card, just contact us at [email protected]

Additionally, if you already have an active subscription in any of these currencies (USD, EUR, CAD, AUD, GBP), that currency will remain for subsequent subscriptions. You can change the currency at any time as long as you don't have any active subscriptions.

The local currency shown on the pricing page is based on the country of your IP address and is provided for reference only. The actual prices are in USD (United States Dollar). When you make a payment, the charge will appear on your card statement in USD, even if you see the equivalent amount in your local currency on our website. This means you cannot pay directly with your local currency.

Occasionally, a bank may decline the charge due to its fraud protection settings. We suggest reaching out to your bank initially to check if they are blocking our charges. Also, you can access the Billing Portal and change the card associated to make the payment. If these does not work and you need further assistance, please contact our team at [email protected]

Prices are determined by a recurring monthly or yearly subscription, depending on the chosen plan.

API calls are deducted from your plan based on successful requests. Each plan comes with a specific number of calls that you can make per month. Only successful calls, indicated by a Status 200 response, will be counted against your total. This ensures that failed or incomplete requests do not impact your monthly quota.

Zyla API Hub works on a recurring monthly subscription system. Your billing cycle will start the day you purchase one of the paid plans, and it will renew the same day of the next month. So be aware to cancel your subscription beforehand if you want to avoid future charges.

To upgrade your current subscription plan, simply go to the pricing page of the API and select the plan you want to upgrade to. The upgrade will be instant, allowing you to immediately enjoy the features of the new plan. Please note that any remaining calls from your previous plan will not be carried over to the new plan, so be aware of this when upgrading. You will be charged the full amount of the new plan.

To check how many API calls you have left for the current month, look at the ‘X-Zyla-API-Calls-Monthly-Remaining’ header. For example, if your plan allows 1000 requests per month and you've used 100, this header will show 900.

To see the maximum number of API requests your plan allows, check the ‘X-Zyla-RateLimit-Limit’ header. For instance, if your plan includes 1000 requests per month, this header will display 1000.

The ‘X-Zyla-RateLimit-Reset’ header shows the number of seconds until your rate limit resets. This tells you when your request count will start fresh. For example, if it displays 3600, it means 3600 seconds are left until the limit resets.

Yes, you can cancel your plan anytime by going to your account and selecting the cancellation option on the Billing page. Please note that upgrades, downgrades, and cancellations take effect immediately. Additionally, upon cancellation, you will no longer have access to the service, even if you have remaining calls left in your quota.

You can contact us through our chat channel to receive immediate assistance. We are always online from 8 am to 5 pm (EST). If you reach us after that time, we will get back to you as soon as possible. Additionally, you can contact us via email at [email protected]

To let you experience our APIs without any commitment, we offer a 7-day free trial that allows you to make API calls at no cost during this period. Please note that you can only use this trial once, so make sure to use it with the API that interests you the most. Most of our APIs provide a free trial, but some may not support it.

After 7 days, you will be charged the full amount for the plan you were subscribed to during the trial. Therefore, it’s important to cancel before the trial period ends. Refund requests for forgetting to cancel on time are not accepted.

When you subscribe to an API trial, you can make only 25% of the calls allowed by that plan. For example, if the API plan offers 1000 calls, you can make only 250 during the trial. To access the full number of calls offered by the plan, you will need to subscribe to the full plan.

 Service Level
 Response Time


Related APIs