Data Enrichment & Validation

For What and for Whom Is Open-Source Address Validation?

October 15, 2020
Inkit Team

If you are looking for open-source address validation, we must disappoint you from the start. Since address verification requires access to confidential and authoritative databases, there is no genuinely open-source address validation tool. The USPS, which is the holder of the US citizens’ address data, just cannot make such details public. This would let attackers easily compromise address information and result in regular data breaches.

Yet the open-source address validation limitations don’t mean that you cannot add verification capabilities to your software. USPS and third-party providers offer a bunch of address validation APIs for ZIP code lookup, global address standardization, verification, and other tasks. You can either use them instead of open-source address validation solutions or subscribe to mail automation software that supports validation as a part of its functionality.

To find out more about open-source address validation and the alternative options, keep reading our article about:

  • What is open-source address validation, who needs, and why
  • Why is open-source address validation not suitable for USPS addresses?
  • Address validation APIs as an open-source address validation alternative: Types and options
  • Inkit’s address validation tool for real-time address verification

What Is Open-Source Address Validation, Who Needs It, and Why?

An open-source address validation tool is an address scrubber the source code of which is public. Thus, anyone can access this code, read it, and make changes. Public availability improves the code quality and eliminates bugs but may also harm the security of the published solution.

Note. When it comes to open-source address validation, it’s important to distinguish between open-source and free. Many people mix up these notions. While open-source address validation is not quite possible, you can find free solutions for verifying addresses. So make sure you know what you’re looking for before starting the search.

Who needs address validation tools, and what for?

Address validation tools are essential for every company and organization that processes customer address data. Usually, these are governmental bodies, financial institutions, utilities, healthcare providers, and all kinds of enterprises delivering messages for marketing and business purposes. Address validation tools can bring such an organization a range of measurable benefits:

  • Increased customer database quality
  • Optimized return rates thanks to more accurate mailings
  • Cost-effective and improved return on investment
  • Partially automated marketing fulfillment achieved through the integration of address validation tools with mailing systems
  • Regulatory compliance

Why is open-source address validation not suitable for USPS addresses?

To understand why you should not rush with open-source address validation, we offer you to answer a simple question. Why do you need an address validation tool in the first place?

You probably want to enhance street addresses’ accuracy, eliminate invalid records, and reduce return rates. Or in other words, you seek reliability.

Open-source address validation cannot give you that. Although such solutions are cheaper than paid validation APIs, they are much less secure. The United States Postal Service will never put the address data at risk by making it accessible through open-source address validation tools.

Instead, the USPS and other software providers offer APIs. You can connect them with your database or CRM to safely validate thousands of street addresses. Everything happens automatically and takes minimum effort.

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Address Validation APIs as an Open-Source Address Validation Alternative: Types and Options

An address validation API is a piece of computing interface that checks street addresses on an analyzed list against a reliable database. Once it discovers an error, like incorrect postal code or house numbers, an alternative version is provided. The address validation API can be either integrated with your internal systems or built into a website. It significantly speeds up data verification and improves the accuracy of commercial and promotional mailings. Address validation APIs can be offered both free of charge and have paid versions.

In this article, we’d divide address validation APIs into two broad categories: USPS-powered and third-party. Below are the main options to choose from.

USPS-Powered Address Validation APIs

The United States Postal Service manages the database with street addresses for the whole country. The agency is always the first to learn any address updates and process change of address requests. Therefore, the USPS database is rightly considered the most reliable source of correct addresses.


The USPS makes its database accessible to mailers and other companies through an address validation API. The Address/Standardization “Verify” API allows you to correct errors, add missing information, and enrich ZIP codes with a +4 extension. “Verify” address validation API supports only five lookups per transaction, and its performance also leaves a lot to be desired. Besides, the USPS doesn’t provide an international address validation API, so your international mailings’ accuracy is likely to suffer.

When to opt for USPS-powered address validation APIs:

The USPS address validation tools can do well if data verification is not critical for your business operations. It’s also suitable when your mailings don’t have to meet tight deadlines and if the mail volume is low. Overall, USPS address validation tools and APIs can meet basic needs. If you expected something more sophisticated, consider third-party address validation APIs.

Third-Party Address Validation APIs

Fortunately, the USPS is ready to share its valuable data. To determine who is eligible for this, the agency uses CASS certification. CASS certified third-party companies could access USPS official databases to create alternative address validation tools and APIs. Inkit is one of such web services. It provides APIs for address verification and autocompletion to scan your database and detect errors based on the latest information from the USPS. The real-time address verification feature automatically checks your mailing lists to detect any inconsistencies.

When to opt for third-party address validation APIs:

Choose third-party address validation tools if direct mail is one of your key communication channels, and you want every mailing to reach the delivery point. Such software relies on USPS data but provides a more convenient and rich functionality than the USPS address validation tools. The integration is also more straightforward.

Apart from address validation APIs, there are also solutions for address standardization, ZIP code enrichment, geocoding, and address autocomplete. These APIs can help you learn additional details about your customers to improve targeting.

map geocoding

Inkit’s Address Validation Tool for Real-Time Address Verification

We’ve already mentioned Inkit’s address validation API as an effective alternative to the USPS solutions. If address verification isn’t the only feature you need, subscribe to Inkit’s platform.

Inkit is a full-fledged solution for 100% mail printing and delivery automation. It supports variable data printing, and, most importantly, smoothly integrates with hundreds of business and marketing solutions. Subscribing to Inkit, you get access to the platform that can connect several tools within one system. This enables you to collect data from multiple sources in a single database, automatically standardize data entries, and validate them in real-time. Address verification happens as a part of a more comprehensive automated data fulfillment process and doesn’t require micro-management.

This way, in addition to address verification, Inkit optimizes many other mail-related processes in your company and benefits its performance.

To test how it works or access Inkit’s address validation API, contact our sales team.

Start verifying addresses today
Don't waste time and money dealing with lost shipments that never made it to your customers.
Start for free