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Postmark

09 agent-services/Postmark/ACTIVE

Postmark supplies transactional email delivery and inbound webhooks that turn incoming messages into structured JSON for an application.

SEC.01

What it does

  • 01Transactional API and SMTP sending
  • 02Inbound message parsing
  • 03JSON payloads with attachments
  • 04Mailbox hashes for reply routing
  • 05Custom sending domains
SEC.02

Who it's for

A service that already sends transactional email and wants an agent to classify incoming replies or draft a response.

PRICING

Pricing

Free developer tier: 100 emails/month; Pro with inbound processing: $16.50/month at 10,000 emails (checked October 12, 2026). List prices as checked against the vendor's pricing page on 2026-10-12; plans change often, so confirm before deciding.

caveat · before you adopt

Inbound processing is listed on Pro and Platform plans; confirm the receiving allowance for your plan. Your application still owns conversation state, approvals, and agent behavior. Documentation reviewed October 12, 2026; no hands-on delivery benchmark.

ALT

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FAQ

Frequently asked

What is Postmark?

Postmark supplies transactional email delivery and inbound webhooks that turn incoming messages into structured JSON for an application.

Who is Postmark for?

A service that already sends transactional email and wants an agent to classify incoming replies or draft a response.

How much does Postmark cost?

Free developer tier: 100 emails/month; Pro with inbound processing: $16.50/month at 10,000 emails (checked October 12, 2026). List prices as checked against the vendor's pricing page on 2026-10-12; plans change often, so confirm before deciding.

Does Postmark run locally or in the cloud?

Postmark runs in the vendor's cloud. Its interfaces are an API or protocol.

What are alternatives to Postmark?

Other agent service entries in the catalog: AgentMail, x402, Agent Payments Protocol, Skyfire, Payman, Nevermined, AgentCard, Keycard, Arcade, Scalekit, Composio, E2B, Browserbase, Exa, Mem0, OpenMail, Nylas, Resend, Daytona. Different categories solve the same problem differently — see the Agent services category page for tradeoffs.

What should I know before adopting Postmark?

Inbound processing is listed on Pro and Platform plans; confirm the receiving allowance for your plan. Your application still owns conversation state, approvals, and agent behavior. Documentation reviewed October 12, 2026; no hands-on delivery benchmark.