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Use PostGrid through Corsair: one client, typed API calls. PostGrid prints and mails physical mail on demand. Create a key under Settings in the dashboard and paste it in; it travels in the x-api-key header. A key created in test mode reads and writes test-mode data only, which is the right place to develop. What to know before you print:
  • An order spends money. letters.create, postcards.create and selfMailers.create print and post a physical item. There is no sandbox flag on the request: test mode is a property of the key.
  • Idempotency. Order creation accepts an Idempotency-Key header, and PostGrid honours it for 24 hours. The plugin generates one per call; pass idempotencyKey in the input to reuse it so a retried request returns the original order instead of printing a second one.
  • Cancelling. An order can be cancelled only while its status is ready. After that it is with the printer. For a send-as-soon-as-possible order that is roughly midnight Eastern on the following day.
  • Tracking. Every order carries status, from ready through printing and processed_for_delivery to completed or cancelled. Live mail bound for the US also gains imbStatus, the USPS stage, plus imbDate and imbZIPCode.
  • Paging is by offset. List routes take skip and limit and return totalCount; page while skip is below it by adding limit each time.
  • Addresses are corrected. A created contact may come back with a different address than it was sent, and addressStatus says whether it was verified, corrected or failed. On an order, a to or from contact given with an id is sent as that id alone, so skipVerification and forceVerifiedStatus take effect only on an inline contact (address fields, no id).
  • Webhooks. PostGrid can post delivery notifications to a URL you register in its dashboard, but this plugin does not handle inbound deliveries.
What you get:
  • 21 typed API operations

Setup

1

Install

2

Add the plugin

corsair.ts
With multiTenancy: true, scope calls with corsair.withTenant(id). See Quick start for KEK + Hub keys, and Multi-tenancy for account isolation.
3

Choose authentication

4

Connect a tenant

Mint a connect link and send the tenant to it. Hub hosts the page and delivers the result to your app — see Connect / OAuth.

Example API calls

List recent letters
Create a template with a merge variable
See the full list on the API page.

What’s next

API reference

Every postgrid.api.* operation with input and output types.

Connect / OAuth

createLink, Hub delivery, and tenant connect flows.

Use with agents

Expose this plugin’s operations as MCP tools.