API Overview

Accurate Append offers a straightforward RESTful API that exposes our proven, low-level data append and verify services for use by developers familiar with HTTP requests...

Welcome to the Accurate Append API, a RESTful resource that allows developers to leverage our full suite of append and verify services in real time, directly inside their own applications. Our API exposes the same core functionality that powers Accurate Append's Batch Phone Append, Email Append, and Demographic Append (and Verification) solutions.

The API is implemented as a library of simple GET requests. Each call passes a single contact record, and our service returns enhanced, verified contact data in JSON format. That means it's a snap to integrate our services with your current applications. What's more, it's a user-friendly learning curve, which means even less-experienced developers can get up to speed quickly.

Key Features and Benefits

  • Take Control of your Valuable Contact Data
    Update and verify customer, prospect, and lead contact data in real time.
  • Get Started Quickly
    Write simple HTTPs requests that even inexperienced developers can start using right away.
  • Simple GET Requests
    GET is the only the method you use to fully exploit the API.
  • JSON Data
    New contact data, errors, and metadata are always returned as standard JSON.
  • Secure
    Send your authentication string with every call. No session management is required.
  • Free Trial
    Try it now for free: Click to get your trial authentication key...

The simplicity of the interface and our straightforward documentation will help you get up to speed quickly.

Get a Free Trial license key

You can evaluate the API directly, with a full-featured trial that includes up to 500 calls free for 30 days. Click here to obtain a trial license key – no credit card required.

Already have a license key? Let's start using the API...

Using the API

The GET requests used to access each 'service' need only comply with a few simple rules. The specific inputs, outputs, return values, and error codes for each endpoint are detailed in the API Reference.

The Basics

Each GET request is a single 'atomic' query that passes and returns data for just one contact at a time. That approach maintains a simplicity and transparency that frees you to build your custom logic on top of it, with loose coupling between modules – you retain control of business logic layers without having to worry about compatibility issues from hidden logic 'under the hood'.


Authentication is required with every GET request. A simple key string is used to authenticate with our server, and must be included in every GET request. There's no session management to worry about because each request is a simple query, usually for only a single contact subject.

Header Settings

In the request header, the "content-type" must be set to "application/json". If not set properly, you'll get an HTTP 400 Bad Request response. Note that many client libraries and GUI tools include this header automatically, but please consult the documentation for your library or client tool.

URL Format

Be sure to only use "%20" as the word delimitter within argument strings. Avoid using underscore or dash which may cause parsing errors or affect match rates.

For instance, "123 Elm Street" would be passed as "123%20Elm%20Street".

Quickstart - Make Your First API Call

For each API end-point the basic format for the request string is:

GET https://api.accurateappend.com/Services/V2/{SERVICE PATH}/{LIC KEY} /?KEY1=VAL1&KEY2=VAL2&KEY3=VAL3...

Ready to try a quick test call?

If you have your API key, a good first function to try is Reverse Email Append. Reverse Email Append finds and returns contact information based on the email address you pass it. That will confirm connectivity with our server, whether or not it finds information to return.

The endpoint to use for Reverse Email Append is:

GET https://api.accurateappend.com/Services/V2/ReverseEmail/{LIC KEY} /?emailaddress={EMAIL}

It's simple -- the only required input parameter is an email address.

For example, to query the Reverse Email Append function with these parameters:

Notice, we include the license key string with every call:

GET https://api.accurateappend.com/Services/V2/ReverseEmail/84296d8b-d8ff-45cc-99cf-be865be7f35/[email protected]


You should get a return code of '200', along with some JSON metadata. If you got another error, doublecheck the GET string for syntax, email format, and correct end-point.

Now that you have a sample query string to build on, you can replace the path in this URL with the path for any other function listed in the API reference, and add parameters as appropriate.

API Reference Page

The API Reference page on this site contains information about each specific operation and includes samples to get you up and running quickly.

Building More Complex Applications

While the API exposes the same powerful, low-level queries that power our "Batch" services, they don't include some of the higher level logic that wraps our turnkey append and verify products.

The advantage of this architecture is that you get simple, maintainable, understandable building blocks that handle the core query functionality, while retaining control of any additional code layers and business logic that you choose to develop on top of the core queries.

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