What does an address verification API do?

An address verification API checks an address against USPS data and returns a result your code can act on: a standardized, deliverable address, a suggested fix for a near-match, or an error. Pelcro's API also appends ZIP+4 and Carrier Route codes.

Can I validate addresses in real time at sign-up?

Yes. Call the API from your front-end or the Pelcro JS SDK as a subscriber types, so a bad address is caught and corrected before the account is created.

Does the API work server-side for batch cleansing?

Yes. Call it server-side to cleanse and enrich addresses across your workflows, for example before an export to a mail house.

What does the API return for a bad address?

For a near-match it returns a suggested standardized fix; for an address it cannot validate it returns an error with troubleshooting detail, so you can prompt the user or flag the record.

Does the API standardize addresses to USPS format?

Yes. Responses are standardized to USPS Publication 28, so you store a consistent, corrected address rather than the raw input.

Is the address verification API CASS certified?

Yes. The API runs on the same CASS-certified engine as the rest of Pelcro's address verification, so addresses it validates qualify your mail for USPS automation discounts.

USPS address verification · API

Address verification API

Call Pelcro to validate an address from your front-end sign-up flow, or cleanse and enrich addresses server-side. Every check returns a standardized address, a deliverability status and USPS codes.

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Already trusted by leading publishers worldwide

Case study

How the API works

Try the address verification API

Pick a call. See the request you send and the JSON Pelcro returns, including the standardized address and USPS codes.

1SendPOST an address to Pelcro from your front-end or your server.
2ValidatePelcro parses, standardizes and DPV-checks it against USPS data.
3ReturnYou get back the standardized address, a status, and ZIP+4 and Carrier Route.
4HandleAccept the match, apply a suggested fix, or surface the error to the user.

POST /v1/addresses/verify

{ "line1": "123 e main apt4",
  "city": "springfield", "state": "il" }

200 OK

{ "status": "deliverable",
  "line1": "123 E MAIN ST APT 4",
  "zip4": "62701-2234", "dpv": true }

Illustrative. Example request and response, not live API output.

Who it's for

Developers adding address validation to a sign-up or checkout flow
Engineering teams cleansing addresses across back-end workflows
Product teams that want fewer bad addresses at the source

Features

What it does

Front-end and server-side: Validate at the point of entry, or cleanse and enrich addresses server-side across your workflows.
One clear response: Every check returns a standardized address, a suggested fix for a near-match, or an error with detail.
Standardized, not just pass/fail: Responses are parsed and standardized to USPS Publication 28, so you can store the corrected address.
Deliverability and enrichment: Responses carry DPV status plus ZIP+4, Delivery Point, Carrier Route and eLOT codes.
Built into the Pelcro SDK: Validate from the Pelcro JS SDK on your sign-up form, or call the API directly from your server.
CASS-certified underneath: The same CASS-certified engine powers the API, so results qualify your mail for automation discounts.

Last updated November 8, 2026

FAQ

Frequently asked questions

What does an address verification API do?: An address verification API checks an address against USPS data and returns a result your code can act on: a standardized, deliverable address, a suggested fix for a near-match, or an error. Pelcro's API also appends ZIP+4 and Carrier Route codes. See USPS address verification
Can I validate addresses in real time at sign-up?: Yes. Call the API from your front-end or the Pelcro JS SDK as a subscriber types, so a bad address is caught and corrected before the account is created.
Does the API work server-side for batch cleansing?: Yes. Call it server-side to cleanse and enrich addresses across your workflows, for example before an export to a mail house.
What does the API return for a bad address?: For a near-match it returns a suggested standardized fix; for an address it cannot validate it returns an error with troubleshooting detail, so you can prompt the user or flag the record.
Does the API standardize addresses to USPS format?: Yes. Responses are standardized to USPS Publication 28, so you store a consistent, corrected address rather than the raw input.
Is the address verification API CASS certified?: Yes. The API runs on the same CASS-certified engine as the rest of Pelcro's address verification, so addresses it validates qualify your mail for USPS automation discounts. See CASS certified verification

Get started

Add address verification to your flow

Validate and enrich addresses from your front-end or server-side with one API.

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