Side by side
MailStream vs ZAP~POST
Both stand on direct mail automation software. Which one you can start free with, which one lets you read the code, and what each costs once you pay.
Free plan APIWeb
MailStream combines physical mail production with API and MCP-based automation, address checks, and USPS tracking. The free plan offers a way to start, while paid access begins at $99/mo.
Visit MailStream Free plan APIWeb
ZAP~POST combines triggered mail campaigns with personalization, data cleansing, and multiple integration options. Check country-specific mail details and contact the company for first-class pricing.
Visit ZAP~POSTThe facts
| MailStream | ZAP~POST | |
|---|---|---|
| Free plan | Yes | Yes |
| Open source | Not published | Not published |
| Runs on | API, Web | API, Web |
| Lowest paid plan | Not published | Free or on request |
| Plans published | None | 10 |
| Maker | Not published | Not published |
| Website | mailstream.app | zappost.com |
| On direct mail automation software | #8 of 28 | #12 of 28 |
MailStream: what it does well
- Supports postcards and letters through API and web
- Personalizes mail with variable fields
- CASS address checks flag incomplete entries
- USPS tracking appears in dashboard, API, or webhooks
- Free plan available
What to know first
- Delivery scope is domestic
- Paid access starts at $99/mo
ZAP~POST: what it does well
- Automates mail triggered by real-time events or customer actions
- Designs support custom fields and uploaded images
- Supports recipient-specific QR codes and tracking
- Validates recipient data and cleanses records
- Offers a one-off trial without a credit card
What to know first
- First-class pricing requires contacting the company
- Specifications, prices, and turnaround vary by country
- Trial guidance recommends at least 1,000 recipients
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