Understanding mailable, shippable, and deliverable addresses

When it comes to address validation and logistics, the terms “mailable,” “shippable,” and “deliverable” often get tossed around interchangeably—but they aren’t the same thing. Understanding these terms is crucial for optimizing delivery processes, reducing costs, and improving customer satisfaction.
Let’s pull out your magnifying glass to more closely examine what each term means, how they differ, and how businesses can use that knowledge and address data to fine-tune your business and shipping strategies.
US address verification | International address verification | Bulk address validation |
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Zooming out, we'll cover:
- What is a shippable address?
- What is a mailable address?
- What is a deliverable address?
- Smarty's approach to address validation
- Why this matters for your business
Zooming in again, let's get started.
What is a shippable address?
A shippable address includes all shipping services. If an address is shippable, the title talks about whether an address can accept packages via common carriers such as USPS, FedEx, UPS, DHL, Amazon, or regional or private couriers.
Shippable addresses mean that something can be shipped to that address because it’s a complete address that contains a delivery point.
Key considerations:
- Broader criteria: Shippable addresses include those that USPS may not serve, such as rural addresses accessible only by private carriers.
- Business rules: Some carriers have specific restrictions. For example, FedEx and UPS typically won’t deliver to PO boxes.
- Flexibility: If USPS can’t handle the delivery, businesses can use alternative carriers for shippable items.

Example:
While a residential address in a remote area might not be serviced by the USPS, FedEx could deliver a package there, making it shippable.
What is a mailable address?
A mailable address refers to one that can be used to send mail via the U.S. Postal Service (USPS). Before adding any address to its database, the USPS will:
- Verify that the address in question is a full address
- Ensure that the address is CASS-certified
- Check for delivery point validation, aka deliverable (more on that later)
Let's check for understanding.
Most addresses can be considered shippable (even if the USPS does not serve them. We call these elusive addresses non-postals or non-USPS addresses.) Fewer addresses can be called mailable because not all addresses are included in the USPS database.
All mailable addresses are shippable, but only some shippable addresses (the ones in the USPS database) are also considered mailable.
Jess? Ok, bring that magnifying glass a little bit closer.
What is a deliverable address?
A deliverable address is the most nuanced and customer-specific concept of the 3, but we’ll try to make it simple.
The idea hinges on how businesses and organizations define deliverability based on their own rules and the metadata they receive about an address. Sometimes, customers of ours can feel frustrated because they just want us to tell them if an address is deliverable, but the idea is not so simple.
For example, consider a Chia pet company. (For those of you who don’t know what that is, we have two questions? 1) Do you live under a rock? And 2) Here’s a picture for you…

Ok, the second one wasn’t a question. Moving along!
This chia pet company may have specific rules and regulations surrounding where they can ship to. They might not want to deliver their packages to PO boxes. Makes sense. That wacky-haired plant baby is sure to die in a stuffy box that’s likely only checked twice a month if that.
In this case if a customer requests that a chia pet be sent to PO Box, although the address is technically shippable, and maybe even mailable via USPS’s services, the chia pet company may still determine that this address is not deliverable.
This is where Smarty’s role becomes pivotal.
Smarty's approach to address validation
Smarty simplifies the complexity of address validation by matching submitted addresses to its exhaustive dataset of known U.S. addresses. Here’s how Smarty helps businesses:
- Matching accuracy: Smarty doesn’t judge whether an address is “valid”; instead, it finds the best possible match in its database.
- Metadata insights: Smarty provides details such as:
- DPV (Delivery Point Validation) match codes (e.g., active or inactive address)
- PO Box status
- Residential or commercial classification
- Vacant status
- Subunit information for high-occupancy buildings
- Etc. There are up to 55 points of metadata that could be included on any address run through US Address Verification.
- Client control: Deliverability decisions remain with the client, who can use Smarty’s metadata to apply their own business logic.
In a nutshell:
First, Smarty's role—Smarty determines if an address matches its comprehensive dataset, which includes postal and non-postal sources. Once a match is made, Smarty provides metadata about the address (e.g., is it residential, vacant, or a PO box).
Second, analyze the results—Results include lots of metadata such as “vacant,” “residential/commercial,” or “high-rise with subunits” empowers businesses to decide if an address meets their criteria for deliverability.
Smarty's results
If you're specifically interested in having an address that’s highly likely to be accepted by the USPS and be delivered to the place it needs to go, there are two specific columns/properties/metadata points to look at when you check an address with Smarty. Those two magical columns are "DPV Footnotes" and "Enhanced Match."
- DPV Footnotes - The DPV (or Delivery Point Validation) footnote code is the USPS's way of saying how accurate an address is. You can look up the full table of possible DPV footnote codes and see what you get. However, if you're looking for a shortcut, what you're looking for in a quality mailing address is "AABB" or "AABBCC."
- AABB means ZIP, state, city, street name, and primary number match.
- AABBCC means ZIP, state, city, street name, and primary number match, but secondary does not. A secondary is not required for delivery. It's a little risky to send to this type of address, but not as risky as the other codes.
- Enhanced Match - Smarty's enhanced matching allows for a more human-readable result when it comes to the mailing bit of an address. As long as you're using "enhanced" parameters when you call Smarty's API, you'll get these results. If you're using one of Smarty's plugins, you'll want to make sure that the "Match" is set to Enhanced. If you're using the API on its own, make sure you have a "match" parameter set to "enhanced_match." There are several result possibilities, but what you're hoping to get is "postal-match." There are other options that may be useful as well.
- non-postal-match - A match was found within additional, non-postal address data.
- postal-match - A match was found within postal address data.
Looking for these specific codes doesn't guarantee a 100% deliverable package, but it’ll drastically reduce your chances of getting returned mail. If you send to the "AABBCC" or "non-postal-match" addresses, there's a chance your mail will still be returned because there wasn't a suite listed and the postal worker can't figure out where to take it, or the address existed, but the USPS hasn't started sending mail trucks to it. However, because the endpoint of the USPS delivery process is a human being, your mail might still get it to its destination.
That human being might also cause you problems. If you send mail to a "postal-match" or "AABB" address, but that address has a really mean dog, there's a chance the postal worker will mark it as "undeliverable" and return it to you anyway.

Unfortunately, the return notes/reasons on a piece of mail don't always give super accurate information as to why mail is coming back. Imagine you're a postal worker, and you have to memorize all kinds of different return reason codes. If it were me, I'd just memorize my three most likely and use those every time. One could imagine that this would become a common practice among postal workers.
Finally, (this is the part where you come in), apply your organization’s logic to determine deliverability—Deliverability depends on the product or service and the business’s rules. For example, these use cases have specialized rules to determine deliverability:
- Alcohol cannot be shipped to Utah, regardless of address type, so if you sell these elixirs, you may need to work that into your own organizational logic to filter out Utah addresses.
- A perishable food company may choose not to deliver to PO boxes due to the product's shelf life.
- Pest control services may only care about residential addresses because marketing to commercial addresses may not have as much of an ROI impact, so they may build their logic out to sift through the RDI and ignore commercial ones.
- An e-commerce business shipping via USPS could potentially identify non-postal matches using Smarty. For such addresses, they either notify the customer that their address isn’t mailable via USPS, or the organization can choose a different carrier, avoiding costly and time-wasting returns for both parties.
Why this matters for your business
Understanding the distinctions between mailable, shippable, and deliverable addresses ensures that businesses:
- Avoid unnecessary shipping costs or returns.
- Use the right carriers for the job.
- Make data-informed decisions about address deliverability.
With Smarty, you gain a robust tool to validate addresses and access metadata that supports your unique operational needs. By leveraging this data, you can optimize logistics, reduce friction, and deliver a better experience for your customers.
Ready to take your address validation to the next level? Check out Smarty’s address solutions to ensure every shipment arrives where it needs to go—efficiently and accurately.
We’ll even let you try it out for free. Go ahead. Test us out.