MailStream
MailStream: A strong API-first choice for variable direct mail, with plans from free to enterprise. Ranked #5 of 28 in Direct Mail Automation Software by our editors (8.8/10); pricing: Free plan; best for API-first postcard and letter automation.
At a glance
- Editor score8.8 / 10
- PricingFree plan
- Best forAPI-first postcard and letter automation
- Free planYes
- Paid from$99/mo
- Personalization levelVariable
- Facts checked21 Sep 2026
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
Our verdict on MailStream
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.
Your product? Our editors can test MailStream in depth and publish a review, labelled as paid · from $149/mo →
MailStream pricing
All 3 MailStream plans and prices →
MailStream fact sheet
| Free plan | Yes |
|---|---|
| Paid from | $99/mo |
| Mail formats | 4×6, 6×9, and 6×11 postcards; 8.5×11 letters |
| Personalization level | Variable |
| API access | Yes |
| CRM connections | Planning Center, HubSpot, Salesforce, GoHighLevel, ActiveCampaign |
| Address verification | Yes |
| Delivery scope | Domestic |
| Deployment | Cloud |
| Platforms | Web |
| Support | Email, Docs |
| Built for | Solo, Small business, Mid-market, Enterprise (editorial estimate) |
| Integrations | 11 integrations: Planning Center, ServiceTitan, Shopify, Zapier, Make, HubSpot … See all → |
| Pricing | Free plan (source) |
| Website | mailstream.app |
| Facts checked | 21 Sep 2026 |
MailStream integrations
MailStream lists 11 integrations on its own site.
- Planning Center
- ServiceTitan
- Shopify
- Zapier
- Make
- HubSpot
- Salesforce
- GoHighLevel
- ActiveCampaign
- Klaviyo
- n8n
See all MailStream integrations →
Alternatives to MailStream
- Click2MailA broad direct-mail platform with free access, APIs, CRM workflows, and no monthly fees.9.3
- PostalyticsA CRM-connected direct mail platform with a free plan and advanced automation from $199/month.9.1
- thanks.ioA flexible direct mail platform for personalized multichannel campaigns and developer workflows.9.0
See all MailStream alternatives →
MailStream vs the competition
- MailStream vs Click2Mail
- MailStream vs Postalytics
- MailStream vs thanks.io
- MailStream vs Stannp
- MailStream vs DocuPost
- MailStream vs MailerBot
Compare MailStream with any tool side by side →
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The editor score above is our own research. What this page doesn't have yet is a reader's view — what you used MailStream for, what worked and what didn't. No stars are seeded and no review is paid for; an editor reads every one before it appears.
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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