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Postal Data API for AI agents

Postal Data API validates and looks up postal codes, locations, and regional metadata across more than 240 countries. Developers use it to clean and verify address data. Connect it once through Arc0, and your agent, or Claude, ChatGPT and Cursor, can use it through one MCP endpoint, limited to what each user approved.

Connect Postal Data APISee the 6 actions ↓
Developer toolsAPI keyMCP + RESTpostaldata.io
AUDIT LOG · POSTAL DATA APIPOLICY: acme-support
09:41:07 · claude · u_8f2read
postal_data_api.search_postal_codes_by_city
Search Postal Codes by City✓ allowed · 212ms
09:41:08 · claude · u_8f2read
postal_data_api.lookup_postal_code
Look Up Postal Code✓ allowed · 164ms
EVERY POSTAL DATA API CALL, ON THE RECORD
01 · USE CASES

What agents do in Postal Data API.

01

Validate a postal code

Check whether a postal code entered by a customer is valid before saving an order.

02

Look up a postal code's location

Retrieve city and region metadata for a postal code to auto-fill an address form.

03

Bulk validate postal codes

Validate a batch of postal codes in a customer list before a mailing campaign.

02 · ACTIONS

6 Postal Data API actions, graded by risk.

Every Postal Data API action is tagged read, write or destructive, so one policy covers the whole app and new actions inherit the right default.

read

6

Look things up. Allowed by default.

  • postal_data_api.get_api_information
    Get API Information
  • postal_data_api.get_postal_code_metadata
    Get Postal Code Metadata
  • postal_data_api.search_postal_codes_by_city
    Search Postal Codes by City
  • postal_data_api.lookup_postal_code
    Look Up Postal Code
  • postal_data_api.validate_postal_code
    Validate Postal Code
  • postal_data_api.validate_postal_codes_bulk
    Validate Postal Codes in Bulk

write

0

Create and change things. Allow, or ask the user first.

  • No write actions.

destructive

0

Delete, cancel or archive. Ask first, or deny outright.

  • No destructive actions.
03 · HOW IT WORKS

Postal Data API in three steps.

  1. 01Your users connect Postal Data APIThey add their Postal Data API api key on Arc0 Connect, under your brand. It goes straight into the vault.
  2. 02You set the rulesReads run, and writes like “updates” can wait for the user to approve.
  3. 03Any agent can actYour agent calls Postal Data API through the Arc0 SDK or MCP, and so can Claude, ChatGPT and Cursor. Every call lands on the audit log.
POLICY.TS
await arc0.policies.set('postal_data_api', {
  read: 'allow',
  write: 'ask',        
  destructive: 'deny',  
})

# Claude Code: the same connection, one URL
$ claude mcp add --transport http arc0 \
    https://mcp.arc0.ai/u/u_8f2
04 · AUTH AND DATA

How Postal Data API connects.

Users add their Postal Data API api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.

The same Postal Data API connection serves your agent over MCP and your own backend over REST and the proxy, so a user connects once. How Arc0 handles credentials →

AUTH
API key
CREDENTIALS
Per-tenant encrypted vault
MODEL SEES
Results only, never credentials
AUDIT LOG
Every call, on every plan
05 · WORKS WITH

Use Postal Data API from any agent.

Claude
ChatGPT
Cursor
Codex
VS Code
OpenAI Agents SDK
Claude Agent SDK
Vercel AI SDK
Mastra
LangGraph
06 · RELATED

More developer tools apps.

GitHub896 actionsSupabase129 actions0CodeKit8 actionsAbly25 actionsAbstract3 actionsAddressfinder17 actionsAddresszen2 actionsAlchemy36 actions
ALL DEVELOPER TOOLS APPS →
07 · FAQ

Postal Data API and Arc0, answered.

Q01

Can I use Postal Data API with Claude, ChatGPT or Cursor?

Yes. Connect Postal Data API to Arc0 once, then add your Arc0 MCP URL to Claude, ChatGPT, Cursor, Claude Code or any other remote-MCP client. Each assistant only gets the Postal Data API actions you allow.

Q02

How do users connect Postal Data API?

Users add their Postal Data API api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.

Q03

Which Postal Data API actions can my agent take?

6 in total: 6 read, 0 write and 0 destructive. Your policies decide which of them each agent may call.

Q04

Can I make my agent read-only in Postal Data API?

Yes. Allow read actions and deny writes in the Postal Data API policy. Your agent can still look things up, and any write it attempts is blocked and logged.

Q05

Can my own backend call Postal Data API too?

Yes. The same Postal Data API connection is available over REST and through the Arc0 proxy, so your product and your agent share one connection per user.

Get started

Plug Postal Data API into your agent.

Your users connect Postal Data API once, under your brand. Your agent gets 6 actions behind your policies, with every call on the record.

Connect Postal Data APIBrowse all apps →

Free to build · MCP + REST · Audit log on every plan