Agent mail providers
Understand API-first inbox services for agents, evaluate permissions and event handling, and keep untrusted email from becoming instructions.
Reviewed
An agent mail provider gives software an inbox and operations for sending, receiving, and handling conversation threads. Some products are hosted APIs, not mail-server software you can install. Evaluate the actual deployment model before treating an “agent mail server” as self-hostable infrastructure.
Compare integration models
| Model | Suitable when | Check carefully |
|---|---|---|
| API-first agent inbox service | An agent needs a dedicated identity and programmatic inbox operations | Inbox creation, credential scope, message access, events, retention, and quotas |
| Existing mailbox API | An agent must work within an organization’s existing mailbox system | OAuth/admin approval, least-privilege access, tenant policy, and subscription renewal |
| Inbound webhook plus send API | Your application controls message handling and agent execution | Signature checks, durable queues, deduplication, thread handling, and outgoing-action approval |
| Self-hosted mail infrastructure | You require control over transport or storage | All host/security responsibilities plus the application layer that exposes tools to the agent |
AgentMail’s introduction describes a hosted API-first provider with programmatic inboxes and event delivery. MailKite exposes email tools through its agent integration and provides application receiving/sending APIs. The right choice depends on the workflow and access boundary, not the presence of “AI” in a product description.
Treat messages as untrusted input
Email senders control subjects, bodies, links, and attachments. None of that content should override your agent’s system instructions, grant access to credentials, authorize a payment, or approve a sensitive external action.
- Verify incoming events before handing their content to an agent.
- Store accepted work durably and deduplicate deliveries before triggering side effects.
- Scope credentials and tools to the inbox and operations the agent actually needs.
- Require human approval for consequential actions; a sentence in an incoming message is not authorization.
- Decide how long message content and attachments are retained and who can inspect them.
Build a first workflow
For the supported MailKite path, use Connect your agent. For provider comparisons and application walkthroughs, open the main guide’s Agent email section. Those pages have the main guide’s menu; this guide’s provider-specific submenus will grow only as researched articles are published.
Server-specific MailKite SDK integrations are planned separately. There are no implied package downloads or zero-configuration promises here: domain verification, credentials, and permission checks still apply to the current integration.