📬 Postally Documentation

API quickstart: send your first postcard

Verify your email, send a test postcard with our hosted sample artwork, look at the rendered card, then go live with a Live key and prepaid credits.

What’s new in the API

Released API improvements, fixes, and compatibility notes.

Personalized Mail with unique postcard PDFs

Prepare 125–500 eligible unique postcards as one campaign: review every PDF, check the total quote, then submit with prepaid credits.

Plain-text Markdown for AI assistants and developers

API Reference

Complete API documentation — 70+ endpoints, authentication, schemas, and code examples.

Dashboard User Guide

Step-by-step guide for the web dashboard — sending postcards, managing recipients, campaigns, and billing.

Print House Integration Guide

Technical guide for production partners — SFTP specs, job format, status reporting, and quality requirements.

Security & Compliance Overview

Privacy law support (GDPR, PIPEDA, CCPA), where data is stored and who processes it, card payments handled by Stripe (we never see or store card numbers), and security architecture for PHI-aware data handling. Postally is not currently HIPAA-certified or SOC 2-audited.

Shopify Integration Guide

Step-by-step guide for integrating Shopify with Postally — abandoned cart recovery, order thank-you cards, and more.

Postcard Design Guide — 4×6

CAD-style anatomy for the 4×6 postcard: trim 4″×6″, bleed added outside trim (4.25″×6.25″ full), 3.75″×5.75″ safe zone, and mailing-side zone placements.

Postcard Design Guide — 5×7

CAD-style anatomy for the 5×7 postcard: trim 5″×7″, 5.25″×7.25″ full with bleed, 4.75″×6.75″ safe zone, and mailing-side zone placements.

Postcard Design Guide — 6×9

CAD-style anatomy for the 6×9 postcard: trim 6″×9″, 6.25″×9.25″ full with bleed, 5.75″×8.75″ safe zone, and mailing-side zone placements.

Postcard Design Guide — 6×11

CAD-style anatomy for the 6×11 postcard: trim 6″×11″, 6.25″×11.25″ full with bleed, 5.75″×10.75″ safe zone, and mailing-side zone placements.

Postcard Design Guide — 4×6 Classic Layout

CAD-style anatomy for the 4×6 postcard with the classic divided-back mailing side: 2.5″ receiver column on the right, return address at the top-left safe corner, and the same trim/bleed/safe geometry as the standard 4×6.

Postcard Design Guide — 5×7 Classic Layout

CAD-style anatomy for the 5×7 postcard with the classic divided-back mailing side: 2.9″ receiver column on the right, return address at the top-left safe corner, and the same trim/bleed/safe geometry as the standard 5×7.

Postcard Design Guide — 6×9 Classic Layout

CAD-style anatomy for the 6×9 postcard with the classic divided-back mailing side: 3.6″ receiver column on the right (per the Canada Post guideline), return address at the top-left safe corner, and the same trim/bleed/safe geometry as the standard 6×9.

Postcard Design Guide — 6×11 Classic Layout

CAD-style anatomy for the 6×11 postcard with the classic divided-back mailing side: 3.6″ receiver column on the right (per the Canada Post guideline), return address at the top-left safe corner, and the same trim/bleed/safe geometry as the standard 6×11.

Recipient List Template

Excel/CSV template with all supported recipient columns — name, address, return address, merge variables — plus a field reference sheet. Use as a starting point when preparing a recipient list for upload.