An Advanced Look at US Autocomplete Pro API

WEBINAR RECAP: We hosted a webinar talking about Smarty’s US Autocomplete Pro API and how it differs from other autocomplete tools in reliability, accuracy, & customizability.
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June 28, 2022

US Autocomplete Pro API Webinar Recap Graphic

Improving address form completion rates—whether in a shopping cart, request for quote, or other form—can be a sinch if you’re using an address autocomplete tool. Not sure what that is? When you see an address line on a form and think “oh shoot this is going to take a minute” and then it fills it in after only a few keystrokes, that’s address autocomplete.

And no, not all address autocomplete tools are created equal.

Some check against their own address database only that is not frequently maintained. Some are only checked against the United States Postal Service database so they do not include non-postal addresses. And most do not have any sort of customization options when it comes to utilizing their APIs.

Smarty’s US Autocomplete Pro API checks against our incredibly large database of over 160 million USPS addresses in addition to over 15 million non-postal addresses, and it is highly customizable.

Customizing For Geolocation

One typical use for US Autocomplete is to assist an end user entering in their own address. In this case, you likely want to provide suggestions that are close to the user's location. The Geolocation feature, which is turned on by default, does just that. It uses data which maps the user's IP address to a city or surrounding area. It then places their city and state into the prefer_cities field.

Customizing For Preferences

Another use for Autocomplete is for call centers where you may want to prefer suggestions that are in specific cities, states or zipcodes. When set, these results will occupy the top percentage (prefer_ration) of the results.


  • prefer_cities=SEATTLE, REDMOND,WA; RENO, NV
  • prefer_states=CO; OK
  • prefer_zip_codes=84660; 90210&prefer_geolocation=none

Customizing With Include Filters

Sometimes you want to limit results to only specific cities, states or zipcodes. This is different from preferences that could provide suggestions outside your preference areas. Filters will only show suggestions that match the filter. Note that there are some keywords you can use for states that will filter on the 48 contiguous states (including DC) which exclude territories, Alaska and Hawaii. Or all states which exclude just the territories.

As with preferences, if you use the zipcode filter, you cannot use any other preference or filter.

Customizing With Exclude Filters

If you need to exclude specific states from your results, you can use this filter. It cannot be used with any other filter or the geolocation preference, but it works with other preference settings.

Customizing the Source

US Autocomplete Pro has included non-postal addresses for a little over 6 months. Non-postal addresses are those that USPS will not deliver to, but are valid physical addresses. By default, only postal addresses will be returned.

Set this to “all” if you want to return non-postal addresses also. You will know if a result is a non-postal address if it contains the source field with the value of “other”.

Customizing a Selected Secondary

This parameter gets it name from when a user selects an address to drill down on a particular secondary. This is the most complicated one of the options discussed in the webinar but I’ll do my best to summarize.

If the address submitted is an appartment building with 100 units, this will dictate how many of those units there are, and if the user can drill down to an exact unit. You can learn more about it in the recording below beginning at 18:40.

View the Webinar Recording

This is just a brief overview of what was covered. You can view the full 26 minute video below.


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