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POST /v1/verify/address free No key needed Verify

Parse, standardize (USPS Pub 28 / CASS)

Parse, standardize (USPS Pub 28 / CASS), and evaluate deliverability of international postal addresses

POST

Request

  • x-api-key: <your-api-key>
  • Content-Type: application/json

Response 

{
  "deliverabilityCode": "DELIVERABLE",
  "deliverabilityScore": 0,
  "standardizedAddress": {
    "addressLine1": "Powstańców Śląskich 5/212, 53-332 Wrocław",
    "addressLine2": "Powstańców Śląskich 5/212, 53-332 Wrocław",
    "city": "Wrocław",
    "countryCode": "PL",
    "countryName": "Poland",
    "postalCode": "53-332",
    "singleLineFormatted": "PL61 1090 1014 0000 0712 1981 2874",
    "state": "<state>"
  },
  "status": "success",
  "tokensDeducted": 1,
  "validationResult": {
    "isPostalCodeValid": true,
    "missingFields": [
      "<missing field>"
    ],
    "postalCodeFormat": "json",
    "warnings": []
  }
}
The response below is a mock built from the endpoint's own schema — no request leaves this page. Edit the body, press Send, read the shape you will get back. Run it for real in the dashboard →

What it does

Parse, standardize (USPS Pub 28 / CASS), and evaluate deliverability of international postal addresses

Request

Body

FieldTypeRequiredDescription
addressLine1stringnoPrimary street address line
addressLine2stringnoSecondary address line (Apt, Suite, Unit, etc.)
citystringnoCity, town, or municipality
countryCodestringnoISO 3166-1 Alpha-2 country code (default: US)
postalCodestringnoPostal or ZIP code
rawAddressstringnoOptional single-line address string to auto-parse if structured fields are omitted
statestringnoState, province, or region

Example request

{
  "addressLine1": "Powstańców Śląskich 5/212, 53-332 Wrocław",
  "addressLine2": "Powstańców Śląskich 5/212, 53-332 Wrocław",
  "city": "Wrocław",
  "countryCode": "US",
  "postalCode": "53-332",
  "rawAddress": "Powstańców Śląskich 5/212, 53-332 Wrocław",
  "state": "<state>"
}

Response

FieldTypeDescription
deliverabilityCodeenumOne of: DELIVERABLE, PARTIALLY_DELIVERABLE, UNDELIVERABLE.
deliverabilityScoreinteger
standardizedAddressobject
  ↳ addressLine1string
  ↳ addressLine2string
  ↳ citystring
  ↳ countryCodestring
  ↳ countryNamestring
  ↳ postalCodestring
  ↳ singleLineFormattedstring
  ↳ statestring
statusstring
tokensDeductedinteger
validationResultobject
  ↳ isPostalCodeValidboolean
  ↳ missingFieldsarray<string>
  ↳ postalCodeFormatstring
  ↳ warningsarray<string>

Example response

{
  "deliverabilityCode": "DELIVERABLE",
  "deliverabilityScore": 0,
  "standardizedAddress": {
    "addressLine1": "Powstańców Śląskich 5/212, 53-332 Wrocław",
    "addressLine2": "Powstańców Śląskich 5/212, 53-332 Wrocław",
    "city": "Wrocław",
    "countryCode": "PL",
    "countryName": "Poland",
    "postalCode": "53-332",
    "singleLineFormatted": "PL61 1090 1014 0000 0712 1981 2874",
    "state": "<state>"
  },
  "status": "success",
  "tokensDeducted": 1,
  "validationResult": {
    "isPostalCodeValid": true,
    "missingFields": [
      "<missing field>"
    ],
    "postalCodeFormat": "json",
    "warnings": []
  }
}

Errors

Every error answers with the same envelope: an HTTP status, a machine code and a sentence.

400The body or a parameter failed validation. The details array names the field.
401No key, a revoked key or a wrong header. Send x-api-key.
402The wallet cannot cover this call. Top up or wait for the monthly grant.
404The resource does not exist, or it is not yours. Both answer identically and cost nothing.
429Over the per-minute quota of your tier. Back off and retry.
5xxUpstream refused or timed out. The call is not billed.

Code

curl -X POST 'https://app.castomapi.com/v1/verify/address' \
  -H 'x-api-key: <your-api-key>' \
  -H 'Content-Type: application/json' \
  -d '{"addressLine1": "Powstańców Śląskich 5/212, 53-332 Wrocław", "addressLine2": "Powstańców Śląskich 5/212, 53-332 Wrocław", "city": "Wrocław", "countryCode": "US", "postalCode": "53-332", "rawAddress": "Powstańców Śląskich 5/212, 53-332 Wrocław", "state": "<state>"}'
const res = await fetch('https://app.castomapi.com/v1/verify/address', {
  method: 'POST',
  headers: { 'x-api-key': '<your-api-key>', 'Content-Type': 'application/json' },
  body: JSON.stringify({"addressLine1": "Powstańców Śląskich 5/212, 53-332 Wrocław", "addressLine2": "Powstańców Śląskich 5/212, 53-332 Wrocław", "city": "Wrocław", "countryCode": "US", "postalCode": "53-332", "rawAddress": "Powstańców Śląskich 5/212, 53-332 Wrocław", "state": "<state>"})
});
const data = await res.json();
console.log(data);
import { request } from 'node:https';

// Node 18+ has fetch built in
const res = await fetch('https://app.castomapi.com/v1/verify/address', {
  method: 'POST',
  headers: { 'x-api-key': '<your-api-key>', 'Content-Type': 'application/json' },
  body: JSON.stringify({"addressLine1": "Powstańców Śląskich 5/212, 53-332 Wrocław", "addressLine2": "Powstańców Śląskich 5/212, 53-332 Wrocław", "city": "Wrocław", "countryCode": "US", "postalCode": "53-332", "rawAddress": "Powstańców Śląskich 5/212, 53-332 Wrocław", "state": "<state>"})
});
const data = await res.json();
console.log(data);
import requests

res = requests.post(
    'https://app.castomapi.com/v1/verify/address',
    headers={'x-api-key': '<your-api-key>'},
    json={"addressLine1": "Powstańców Śląskich 5/212, 53-332 Wrocław", "addressLine2": "Powstańców Śląskich 5/212, 53-332 Wrocław", "city": "Wrocław", "countryCode": "US", "postalCode": "53-332", "rawAddress": "Powstańców Śląskich 5/212, 53-332 Wrocław", "state": "<state>"},
    timeout=30,
)
print(res.json())
<?php
$ch = curl_init('https://app.castomapi.com/v1/verify/address');
curl_setopt_array($ch, [
    CURLOPT_CUSTOMREQUEST => 'POST',
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => ['x-api-key: <your-api-key>', 'Content-Type: application/json'],
    CURLOPT_POSTFIELDS => json_encode(['addressLine1' => 'Powstańców Śląskich 5/212, 53-332 Wrocław', 'addressLine2' => 'Powstańców Śląskich 5/212, 53-332 Wrocław', 'city' => 'Wrocław', 'countryCode' => 'US', 'postalCode' => '53-332', 'rawAddress' => 'Powstańców Śląskich 5/212, 53-332 Wrocław', 'state' => '<state>']),
]);
$data = json_decode(curl_exec($ch), true);
print_r($data);

Cost and limits

This operation needs no API key and costs nothing: called without a key it answers 200 and deducts zero tokens, up to 10 requests a minute per IP address.

Rate limits per minute

No key10
Free60
Pro300
Enterprise1200

Docs → Pricing

Questions

What does Parse, standardize (USPS Pub 28 / CASS) cost?

This operation needs no API key and costs nothing: called without a key it answers 200 and deducts zero tokens, up to 10 requests a minute per IP address.

How do I authenticate?

Send your key in the x-api-key header. One key covers every metered endpoint; there is nothing to enable per endpoint.

Can I send an Authorization: Bearer token instead?

Not for a metered endpoint — those take the x-api-key header and nothing else. Bearer tokens belong to the account side: the dashboard and account APIs accept a JWT session, and castomapi-auth issues those through a standard OAuth2 handshake, with authorization code, client credentials and refresh grants. The auth service page covers it.

What are the limits?

10 requests a minute per IP with no key at all, 60 a minute on the free tier, 300 on Pro, 1200 on Enterprise. Above the no-key tier the quota is per account, across every endpoint.

OpenAPI: https://app.castomapi.com/docs/json