MailStream review
A strong API-first choice for variable direct mail, with plans from free to enterprise.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
MailStream is a direct mail automation platform for sending postcards and letters through a web dashboard, REST API, webhooks, or AI-agent workflows. It is designed for developers, marketers, agencies, SaaS teams, e-commerce businesses, healthcare organizations, and financial-services teams that need automated physical mail. Supported formats include 4×6, 6×9, and 6×11 postcards, plus 8.5×11 letters. Variable-data personalization, proofing, reusable templates, address verification, USPS delivery tracking, and radius-based household targeting cover the core campaign workflow.
The pricing structure suits teams that want to start with usage-based sending. Free costs $0 per month and includes pay-only-for-what-you-send billing, the web app, API and AI agents, address verification, delivery tracking, unlimited lists, addresses and campaigns, and email support. Pro costs $99 per month and adds wholesale per-piece rates, webhooks, bulk address import, and priority support. Enterprise costs $499 per month and adds contracted volume rates, guaranteed response times and SLAs, white-label support, and a dedicated account manager. The paid tiers make the clearest case for teams with recurring volume or operational requirements beyond basic sending.
MailStream’s strongest fit is an automation-heavy stack. Integrations include Planning Center, ServiceTitan, Shopify, Zapier, Make, HubSpot, Salesforce, GoHighLevel, ActiveCampaign, Klaviyo, and n8n, while the REST API and event webhooks support custom workflows across print, shipping, delivery, and return events. The vendor states that it prints and hands mail to USPS within one to two business days, with current delivery focused on the US. Choose MailStream for API-led, personalized postcard and letter campaigns; consider another option if international delivery is central to the program.
MailStream pros and cons
- Where it wins
- REST API, webhooks, and AI-agent MCP server
- Variable-data personalization with reusable HTML/CSS templates
- Address verification, USPS tracking, and radius-based targeting
- Where it doesn't
- Delivery is currently focused on the US
- Priority support starts with the $99 Pro plan
- Enterprise features require a $499 monthly subscription
MailStream fact sheet, pricing and score →
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