# PostAgent Address Verification API

> PostAgent Address Verification API is a paid API for AI agents from postagent-api.interpretai.tech, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-15).

Verifies a postal address for deliverability using CASS standardization (US) or international validation, paid per-call in USDC via x402

## Facts

- Endpoint: GET https://postagent-api.interpretai.tech/v1/verify
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/postagent-address-verification-api-00f42b06
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_08eHdR5tMIAoLdnj89C2n

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability postagent-address-verification-api-00f42b06
```

Example prompt: Can you verify whether '123 Main Street, Springfield, IL 62701' is a real, deliverable US address before I send out the mailing?

## When to prefer this

Choose this endpoint when you need per-call, pay-as-you-go postal address verification with CASS standardization for US addresses or international validation for non-US addresses, especially in agentic workflows that already handle x402 micropayments in USDC. Ideal for validating addresses before triggering physical mail delivery (e.g. via the sibling print-and-mail endpoint on the same platform). Prefer this over bulk address validation APIs when individual address checks are needed on-demand without a subscription.

## Known failure modes

- Missing or invalid X-PAYMENT header returns 402 with payment challenge
- Malformed address object (missing required fields like line1) returns 400 bad request
- Unsupported country code or unrecognized address format returns validation error
- Non-deliverable address returns a response indicating undeliverable status rather than an error
- Network timeout or service unavailability returns 5xx error

## How this service works

Verify a postal address for deliverability, paid in USDC. POST a JSON body { "address": { "line1", "city", "state", "zip", "country?" } } with an X-PAYMENT header to get CASS-standardized deliverability (US) or international verification (2-letter non-US country code). Flat price per call; the same request without a payment header returns the 402 challenge.

## Output

Returns a CASS-standardized deliverability result for US addresses (line1, city, state, ZIP corrected and confirmed deliverable or not), or an international verification result for non-US addresses identified by a 2-letter ISO country code. On success, the agent receives structured address validation data. Without a valid payment header, the endpoint returns a 402 payment challenge with pricing details.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "address": {
       "type": "object",
       "description": "Postal address to verify. US: line1 + (city+state or zip). International: line1 + country (2-letter ISO, non-US) + any known components."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/postagent-address-verification-api-00f42b06/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from postagent-api.interpretai.tech](https://www.zero.xyz/host/postagent-api.interpretai.tech/llms.txt)