Authentication

All API requests require an API key passed in the Authorization header.

Creating an API key

Log in to your dashboard
Click Create key and give it a name (e.g. “Production”, “My App”)
Copy the key immediately — it is only shown once

API keys look like this: tpc_aBcDeFgHiJkLmNoPqRsTuVwXyZ...

Using your API key

Include the key in the Authorization header as a Bearer token:

curl -X POST https://thepostalcompany.com/api/v1/letters \
  -H "Authorization: Bearer tpc_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{ ... }'

Revoking a key

Go to API Keys in the dashboard and click Revoke next to the key you want to disable. Revoked keys immediately stop working.

Error responses

Status	Meaning
`401`	Missing, invalid, or revoked API key

{
  "error": "Invalid or revoked API key"
}