Verifalia API documentation

Verifalia exposes a RESTful email validation API which is designed to have predictable, resource-oriented URLs and to use HTTP response codes to indicate API errors.

The Verifalia API uses built-in HTTP features, like HTTP authentication and HTTP verbs, which can be understood by off-the-shelf HTTP clients. The data interchange format for the Verifalia API is JSON (MIME content type application/json).

Base URLs

v1.2+ Verifalia provides two distinct endpoints for API consumption, with identical features and behavior, which are used to increase the service availability and speed. These endpoints, which are the base for all the URLs referenced in this documentation, are:

Most Verifalia official SDKs already implement an automatic retry, fail-safe logic, so you don't have to worry about picking one API endpoint or the other. If you are developing a custom API SDK, however, it is recommended that for each API request, the client picks a random endpoint and, in the event of failure, uses the next one and retries the original request.

Single base URL

While we recommend to apply an automatic retry logic to the distinct endpoints mentioned above, we also support a single API DNS record which points to the aforementioned API hosts, in a round-robin fashion. Thus, simpler client implementations which can't implement a full auto-retry logic (cURL, for example) may point to this single base URL instead:


Endpoints security

The Verifalia REST API is served over HTTPS only: to ensure data privacy, unencrypted HTTP is not supported. Also, our HTTPS endpoints require your web client to support Server Name Indication (SNI), a standard widespread extension to the TLS protocol which may be missing in some obsolete systems (most notably, in Microsoft Windows XP and lower version operating systems as well as in wget prior to version 1.14).


You authenticate to the Verifalia API by providing a sub-account SID and auth token, which are defined while creating a new sub-account from your subscription dashboard (API and sub-accounts pane). Authentication to the API occurs via HTTP Basic Auth, using the aforementioned sub-account SID as the username and the auth token as password: please be sure to keep your auth token secret.

Example, using CURL
curl -u MyAccountSid:MyAuthToken

HTTP status codes

The Verifalia API uses conventional HTTP status codes to indicate success or failure of a request. Here are the possible HTTP status codes which the API may return:

HTTP status code Meaning
200 Success. The API request completed without any error.
202 Accepted. The API request has been queued and will be completed as soon as possible by the system.
400 Bad request. Perhaps you are not sending a required parameter or not passing the information using JSON.
401 Unauthorized request. No valid Account SID or Auth token provided.
402 Payment required. Either the credit of your account is too low to process the validation request or the request would exceed the maximum number of monthly processable items.
404 Not found. The requested resource does not exist on the server.
406 Not acceptable. The requested resource is not available with respect to its current state.
410 Gone. The requested resource has been deleted and is no longer available on the server.
429 Too many requests. Returned when a request cannot be served due to the application's rate limit having been exhausted for the client.
5xx Server error. Verifalia failed to fulfill an apparently valid request.

Not a software developer?

Verifalia is a web-based email validation service which allows to upload and validate lists of email addresses with ease.

You don't need to be a software developer to use Verifalia! Just upload your list of email addresses and we will validate them for you, giving you back a detailed report.

Download the Verifalia SDK

To ease integrating Verifalia with your own software solutions, we are developing helper libraries that you can just download and plug where email validation is required. Validating an email address via Verifalia typically requires a couple of lines of code!

Microsoft .NET SDK

Free and open source helper library, C# language, VS 2015 solution, which allows to integrate Verifalia with other .NET 4.5 and higher solutions. Nuget package available!

Node.js SDK

Free and open source helper library which allows to integrate Verifalia with Node.js applications.


Free and open source helper library which allows to integrate Verifalia with PHP applications.

Ruby SDK

Free and open source helper library which allows to integrate Verifalia with Ruby applications.

Java SDK

Free and open source helper library which allows to integrate Verifalia with Java applications.