MailStream vs PostGrid Address Verification
MailStream
mailstream.app
PostGrid Address Verification
postgrid.comSide by side
| Figure | MailStream | PostGrid Address Verification |
|---|---|---|
| Price from | — | $18/mo |
| Free plan | — | — |
| Free trial | — | Yes |
| Open source | — | — |
| Web | Yes | Yes |
| API | Yes | Yes |
| Self-hosted | — | Yes |
| Plans published | 0 | 6 |
| Spec score · Direct Mail Automation Software | 7.3 (#18) | 7.8 (#11) |
| Integrations | The integrations page describes Planning Center as available and lists several others, including Shopify, Zapier, Make, and n8n, as coming soon. | The international service names Salesforce, Stripe, Dynamics 365, Shopify, and Zapier as integrations for address verification workflows. |
| Intended users | The about page describes MailStream as physical-mail infrastructure for AI agents, agencies, SaaS teams, and business operators. | The product page describes offerings for developers using APIs and SDKs, operations and data teams using a no-code dashboard, and enterprises needing SLA-backed uptime and dedicated support. |
| Support | The security page says MailStream will share SOC 2 reports, complete security questionnaires, and arrange calls with its security team. | The international product page advertises native SDKs, free sandbox testing, detailed API documentation, and a 99.9% uptime SLA. |
Plans
PostGrid Address Verification
- Standard Essential$18 a month
- Standard Business$40 a month
- International Essential$70 a month
- Standard Growth$200 a month
- International Business$360 a month
- Standard EnterprisePriced on request
In their own words
MailStream
MailStream provides a self-serve platform, REST API, and MCP server for sending physical postcards and letters domestically. Postcards are offered in 4×6, 6×9, and 6×11 inch sizes, while letters use HTML templates or uploaded PDFs in white #10 double-window envelopes. A browser HTML and CSS editor supports personalized designs, reusable templates, and print proofs. Variable fields can add names, offer codes, QR links, account numbers, and balances. MailStream says it CASS-verifies addresses before printing and flags invalid or incomplete entries. USPS Intelligent Mail barcodes expose status through the dashboard, API, or webhooks. Printing and USPS handoff are listed at 1 to 2 business days, for campaigns targeting 10 to 100,000 addresses. Integrations include Shopify, Zapier, Make, n8n, and HTTP tools. The hosted MCP server lists 27 tools. A free plan is available; paid access starts at $99/mo. Security features include TLS 1.2 or higher, AES-256 at-rest encryption, annual SOC 2 Type 2 audits, and HIPAA handling with BAAs.
PostGrid Address Verification
PostGrid Address Verification checks, autocompletes, standardizes, and enriches addresses for delivery across the U.S., Canada, and 245+ countries and territories. It accepts structured fields, single-line freeform text, or incomplete entries and verifies against postal data in real time. Its international service supports CSV batches of up to one million addresses and can add geographic coordinates with rooftop-level accuracy. It supports non-Latin scripts including Chinese, Arabic, Japanese, and Korean, with conversion to standardized Roman scripts. Named integrations include Salesforce, Stripe, Dynamics 365, Shopify, and Zapier. Options include APIs and SDKs, a no-code dashboard, and self-hosting. Each verification, autocomplete, or standardization request counts as a lookup; monthly plans impose allowances and additional lookup charges beyond them. Standard Essential costs $18 a month billed yearly and includes 2,000 U.S. and Canada lookups monthly, with additional lookups at $0.02 each. Test API keys and 500 free lookup credits are available; a separate bulk verification service page describes 100 free lookups. The product page lists security and compliance provisions including HIPAA, PIPEDA, GDPR, SOC 2 Type 2, and PCI-DSS.