When to use strict vs enhanced matching in your address API

Updated December 11, 2025

Understanding strict mode

Strict mode is precisely what it sounds like—it rigorously validates addresses against the official USPS database, ensuring that only fully accurate, postal-verified addresses are accepted. This mode is typically used for operations requiring high precision, such as legal or financial document dispatch.

For example, if you enter a known address into Smarty's address tools with strict mode, you'll see that it processes and standardizes address data, rejecting any entry that doesn't perfectly match USPS records.

However, while most people use strict mode for its reliability in confirming that an address is recognized by the USPS, its rigidity creates problems.

Introduction to enhanced mode

Enhanced mode is better than strict mode because it uses fuzzy logic, machine learning, and generally more information to provide a holistic story for each address. This mode is designed to capture and validate addresses that might not be part of the USPS database. These are known as non-postal addresses and include things such as newer developments or rural locations.

Enhanced mode’s ability to handle non-postal addresses is a significant benefit. For instance, it can identify and validate non-postal addresses and correct common address mistakes, giving you workable information instead of just an unknown result.

Enhanced mode provides everything strict mode will, but with more information about why an address does or doesn’t match. Instead of giving a “yes/no” response, it may give a “yes, if” response or “no, because.”

You can play with the enhanced mode results on the US Street API demo page.

FAQ for enhanced mode

What are the main sources for non-postal addresses in Smarty’s database?
The sources for non-postal addresses include several proprietary datasets that Smarty™ has access to, which are part of our "secret sauce." For detailed information, you can reach out to an account executive.

If I want results only from USPS addresses, should I use enhanced mode and filter out non-postal matches, or stick with strict mode?
Using enhanced mode is recommended even if you require only USPS addresses. Enhanced mode's aggressive matching strategy means it can handle typographical errors and other common discrepancies better than strict mode. Results that are non-postal will be clearly indicated, allowing easy filtering while still benefiting from enhanced mode's robust matching capabilities.

How does enhanced mode handle inputs with significant errors or typos, especially in critical components like the street name or number?
Enhanced mode is designed to be more forgiving of errors, including significant misspellings. It uses sophisticated algorithms to interpret and correct errors where possible, differentiating it from strict mode, which requires exact matches. However, there are limits; if an input is too far off from any real address data, even enhanced mode may not be able to make a correct match.