REST API + MCP

Send individual US letters and postcards from your software.

Connect your application or AI agent to IRIS. Upload print-ready PDFs, get the mailing price, and submit one order after a person reviews it.

Create my API account Read the docs

Verify your email → buy mailing credits → create an API key.

From PDF to mailing status

  1. Upload

    Upload PDFs privately, then register immutable, account-bound documents.

  2. Quote

    Get the server-calculated price for the documents, addresses, and mailing options.

  3. Review

    Have a person approve the content, recipient, authority, intent, and price.

  4. Submit

    Send one mailing with a unique Idempotency-Key and enough credits.

  5. Status

    Read the mailing status and available tracking through REST or MCP.

Follow the integration workflow

Plan your integration

Use an account-bound API key from trusted server-side software. REST and MCP share the same mailing workflow.

Endpoint reference
PDF uploads
Up to 26 MiB (27,262,976 bytes) per PDF. Upload URLs expire after 10 minutes.
Letters
US Letter-size PDFs. Up to 60 single-sided or 120 double-sided pages. Certified Mail is limited to 6 sheets: 6 single-sided or 12 double-sided pages.
Postcards
4 × 6 or 6 × 9 inches. Separate one-page front and back PDFs, each using the required bleed dimensions in the docs.
Mailing credits
Prepaid $25, $100, or $500 packs. Credits pay exact mailing totals; they have no cash value and cannot be transferred.
Request limits
60 requests per minute per API key and 120 per minute per client IP address.

Individual mail. A person decides to send.

Send US letters, completed forms, and postcards. IRIS does not provide mailing lists, campaigns, batch personalization, EDDM, Marketing Mail, scheduling, QR-code generation, or international delivery.

Read the human-review requirements