Finding a quality address validation API

Address validation APIs | What to look for

There are two main qualities that will help you determine if an address validation API is a good one or not. The first is "Standardization", the process by which addresses are cleaned up and prepared for validation. The second is "Validation", where the addresses are actually checked for validity. We'll discuss each of these in turn.

(You can try the USPS & International Address Validation APIs from Smarty for free)

Address standardization requirements

• Good standardization: A validation API can't properly do its job—comparing addresses against an authorized list—unless it can also standardize the data, so that it follows the same format as the authorized list. So a good validation API will standardize addresses. A great address standardization API will do it well.
• Authoritative standards: A good validation API will get its data straight from the source: in the US, for example, that's the United States Postal Service.
• Accepts multiple input types: People use a variety of different systems to store their information, and most don't want to spend the manpower converting it to a different method or medium just so they can have the data processed. So a good validation API will accept multiple input types for address standardization, and then will do the work of putting it in the right format for the API.
• Accepts Dirty Data as well as Clean Data: Addresses submitted for validation can have a lot of problems. Sometimes things are misspelled. Sometimes information is missing. Sometimes ZIP Codes or cities are wrong, etc. Sometimes we forget that computers, unlike humans, can't intuit our meaning. But with good programming, they can come close. A good validation API is written so that it doesn't just take "clean" data for validation, it can also take "dirty" data and clean it up.

Validation requirements

• Authoritative: Similar to what's listed above, an address validation service is only as good as the source data they use to validate.
• Updated frequently: Even if the list is authoritative, if it's 50 years old, the addresses are pretty much useless. Address data can change a lot over a short period of time, so a good API is tied to a well-kept database.
• Graceful degradation: Good APIs will be able to scale down their output rather than cut it off outright. For example, watching a Youtube video is more enjoyable in HD, but the program wisely clocks down the output if bandwidth becomes a problem. First it scales down to lower quality outputs (720p, 480p, etc.). If that's still not enough, rather than show a grainy video, or failing altogether, it buffers. It gives the best output it can. With a validation API, it's the same way. The more information provided, the better. But the good ones can still offer you the best options for incomplete data, rather than offering nothing.
• Processes "batches": A batch is just shorthand for a large group of something. In this case, a long list of addresses. Some APIs, like the one on the USPS website, only processes one at a time. Not very efficient if you're a shipping business with 50,000 clients. A good address validation API will be able to process a large number (or "batch") of addresses all in one go, then return the information to you once it's finished. Speed of batch processing varies by provider, but the option to process batches is pretty crucial unto itself.
• Useful output: It probably sounds like a more generic API standard to have output in a format that's clear and useful, but hear us out. It's all fine and dandy when you only validate addresses one at a time, but when you process a batch as mentioned above, things get tricky. You need to be able to give them a huge list, and have the API understand it. Then you need it to work the other way around, with data coming back in a format that won't take days to sort through. Typically this involves exporting the list to a spreadsheet for you, but however the API does it, it needs to be as close to "plug-n-play" as possible.
• Comprehensive: In order for an address validation service to be useful it should include as many valid addresses as possible. Since the USPS only keeps records of addresses where they offer door service, there are still millions of valid addresses not included in the USPS data. Just because the USPS doesn't send a delivery personnel to an address doesn't make it any less real. Especially since shippers like FedEx and UPS still offer delivery to these addresses. The best address validation services start with the USPS data and then add addresses from additional high quality and authoritative sources.

What do I do now?

This list is a baseline. APIs that don't meet most of the requirements on this list are just not pumping out enough water to put out the fire, so to speak. There are attributes beyond this, as mentioned before, like speed, turnaround time, breadth of supplemental information etc. These things all become more applicable once individual needs are taken into account. But even if the API you're looking at has power windows and an attachment for making pasta, if it doesn't meet the standards above, it's not making the cut. If it can't do the basic, simple things well, how is it going to juggle all the fancy bells and whistles?

That's how you know you've got a good one. Simple first. Extravagant later.