Postcards that print and ship in 24 hours.
Trigger a single API call, upload a CSV, or let an AI agent handle it. Every postcard is printed full-bleed on premium card stock and handed to USPS the same day.
Formats
Three sizes. One API.
Choose the size that fits your campaign or let your code decide dynamically. Every size prints on Premium 100# Gloss Cover stock.
4×6" Postcards
Classic for thank-you notes, reminders, and promotions. Fits mailboxes and qualifies for low USPS rates.
Capabilities
Everything you need to send postcards at scale.
- Full-bleed printing
- Edge-to-edge color on both sides. No white borders, no compromises. Your design prints exactly as you see it in the proof.
- Variable data personalization
- Merge recipient names, offer codes, QR links, or any dynamic field into your design. Every piece can be unique without slowing production.
- API or UI, your call
- Send one piece via the dashboard or a million via REST API. Both paths share the same print pipeline and the same 24-hour SLA.
- Delivery tracking
- Every postcard gets an Intelligent Mail barcode. Track printing, handoff to USPS, in-transit scans, and confirmed delivery via API or webhooks.
- Proof before you print
- Preview a pixel-perfect PDF proof of every postcard before it hits the press. Approve manually or auto-approve for high-volume sends.
- Built-in address verification
- Addresses are CASS-verified before printing. Invalid or incomplete addresses are flagged so you never waste postage on undeliverable mail.
Printing
Personalization
Integration
Tracking
Quality
Deliverability
- 24hr
- Print-to-ship turnaround
- 3
- Postcard sizes available
- 100#
- Premium Gloss Cover
- 100%
- Pieces tracked via USPS
- We are the manufacturer
- No middlemen or delays. Your mail goes directly from our floor to USPS, with quality checks.
- HITRUST-certified facility
- Your data runs in a HITRUST-certified environment with enterprise security and compliance.
- 25+ years of expertise
- Twenty-five years in direct mail, starting with an early online printer in 1998. We've tackled every edge case.
- Real-time USPS tracking
- Track Intelligent Mail barcodes. Know when printed, in transit, and delivered via dashboard, API, or webhooks.
Use cases
From one-off sends to autonomous campaigns.
- E-commerce thank-yous
- Trigger a branded postcard after every purchase. Customers who receive physical follow-ups have 25-40% higher repeat purchase rates than email-only cohorts.
- Win-back campaigns
- Re-engage lapsed customers with a personalized offer delivered to their mailbox. Physical mail gets opened at 5-9x the rate of marketing email.
- Event invitations
- Send save-the-dates, conference invites, or grand opening announcements that recipients actually pin to the fridge.
- AI-agent triggered sends
- Connect MailStream's MCP server to Claude, GPT, or any compatible agent and let it decide when a postcard is the right move, autonomously.
What everyone is saying
Trusted by professionals.
We replaced three vendors with MailStream and finally got full visibility from print to delivery. Tracking every piece in real time changed how we measure direct mail.
Daniel H.
VP of Growth, Northbridge Labs
The HTML design tool is a game changer. We design, personalize, and send without ever leaving the platform. No more emailing PDF proofs back and forth.
Olivia W.
Director of Lifecycle, Trailmark
We integrated the API in a day and had automated compliance notices running by the end of the week. The HITRUST certification made our security team very happy.
Ethan K.
Engineering Lead, Lattice Health
Join agencies, SaaS teams, and operators using MailStream to automate direct mail at scale without manual vendors or guesswork.