# Postmark [09 agent-services](https://www.agentlist.io/categories/agent-services)/[Postmark](https://www.agentlist.io/ai/postmark)/ACTIVE Postmark supplies transactional email delivery and inbound webhooks that turn incoming messages into structured JSON for an application. - [Messaging surface](https://www.agentlist.io/capabilities/messaging-infra) - [API-native](https://www.agentlist.io/capabilities/api-native) 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 ## Other agent services (19) [AgentMail AgentMail · agent-services api · cloud · Free: 3 inboxes / 3,000 emails per month; Developer: $20/month, 10 inboxes / 10,000 emails (checked October 12, 2026)](https://www.agentlist.io/systems/agentmail) [x402 Coinbase · agent-services api · local/cloud · Open protocol (free); settlement on-chain](https://www.agentlist.io/systems/x402) [Agent Payments Protocol Google · agent-services api · local/cloud · Open protocol (free)](https://www.agentlist.io/systems/ap2) [Skyfire Skyfire · agent-services api · cloud · Usage-based (verify)](https://www.agentlist.io/systems/skyfire) [Payman Payman · agent-services api · cloud · Usage-based (verify)](https://www.agentlist.io/systems/payman) [Nevermined Nevermined · agent-services api · cloud · Usage-based (verify)](https://www.agentlist.io/systems/nevermined) [AgentCard AgentCard · agent-services api/cli · cloud · Per-card funding; no subscription](https://www.agentlist.io/systems/agentcard) [Keycard Keycard · agent-services api · cloud · Usage-based (verify)](https://www.agentlist.io/systems/keycard) [Arcade Arcade · agent-services api · cloud · Free tier; usage-based (verify)](https://www.agentlist.io/systems/arcade) [Scalekit Scalekit · agent-services api · cloud · Free tier; usage-based (verify)](https://www.agentlist.io/systems/scalekit) [Composio Composio · agent-services api · local/cloud · Free tier; usage-based (verify)](https://www.agentlist.io/systems/composio) [E2B E2B · agent-services api · cloud · Hobby: usage-based; Pro $150/mo plus usage](https://www.agentlist.io/systems/e2b) [Browserbase Browserbase · agent-services api · cloud · Free tier; usage-based (verify)](https://www.agentlist.io/systems/browserbase) [Exa Exa · agent-services api · cloud · Free tier; per-request pricing](https://www.agentlist.io/systems/exa) [Mem0 Mem0 · agent-services api · local/cloud · Free OSS; cloud tiers (verify)](https://www.agentlist.io/systems/mem0) [OpenMail OpenMail · agent-services api · cloud · Free: 3 inboxes / 3,000 emails per month; Pro: €9/month plus usage, 10 inboxes / 10,000 emails (checked October 12, 2026)](https://www.agentlist.io/systems/openmail) [Nylas Nylas · agent-services api · cloud · Free tier; Essentials: $15/month, with separate Connect and Agent Accounts allowances (checked October 12, 2026)](https://www.agentlist.io/systems/nylas) [Resend Resend · agent-services api · cloud · Transactional Free: 3,000 emails/month, 100/day; Pro: $20/month for 50,000, plus overages. Counts sent and received mail; each To, Cc, and Bcc recipient counts separately (checked October 12, 2026)](https://www.agentlist.io/systems/resend) [Daytona Daytona · agent-services api/cli · cloud · Usage-based CPU, memory, and storage; introductory credits](https://www.agentlist.io/systems/daytona) 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. Spec sheet **Name**: Postmark **Vendor**: [Postmark](https://www.agentlist.io/ai/postmark) **Category**: [Agent services](https://www.agentlist.io/categories/agent-services) **Interfaces**: api **Hosting**: cloud **Pricing**: Free developer tier: 100 emails/month; Pro with inbound processing: $16.50/month at 10,000 emails (checked October 12, 2026) **Status**: actively maintained **Speaks**: - [Email (SMTP/IMAP)](https://www.agentlist.io/transports/email) - [Webhooks](https://www.agentlist.io/transports/webhooks) **Record ID**: `sys://postmark/postmark` **Verified**: [2026-10-12](https://www.agentlist.io/changelog) Before you choose - [Email for AI agents: AgentMail and four alternatives](https://www.agentlist.io/articles/email-for-ai-agents-agentmail-alternatives) Sources - [↗ postmarkapp.com](https://postmarkapp.com/) - [↗ postmarkapp.com/developer/webhooks/inbound-webhook](https://postmarkapp.com/developer/webhooks/inbound-webhook) - [↗ postmarkapp.com/developer/user-guide/inbound/sample-inbound-workflow](https://postmarkapp.com/developer/user-guide/inbound/sample-inbound-workflow) - [↗ postmarkapp.com/pricing](https://postmarkapp.com/pricing) Catalog entries are editorial records, not paid placements or endorsements. Pricing and status are approximate as of the verification date shown above. --- Source: [Postmark — AGENT-SVC by Postmark | agentlist.io](https://www.agentlist.io/systems/postmark). This is the public page rendered as Markdown; interactive controls require the website.