AgentCourier

AgentCourier provides a REST‑based email service designed for AI agents, automation scripts, and developers who need programmatic inbound and outbound messaging. An inbox is created with a single POST request, returning a unique address on a shared domain in milliseconds, and messages can be sent to that address from any email client or API. The service returns full email objects, including subject, sender, body, attachments, and threading information, and supports searching, filtering, and labeling of messages.

The API also offers outbound capabilities: agents can send, reply, reply‑all, and forward emails, with idempotent sends and support for attachments up to 10 MB, while dangerous file types are blocked automatically. Real‑time webhook notifications are available for received, sent, and rejected messages, secured with HMAC‑SHA256 signatures. Custom domain usage is supported through DNS verification, SPF, DKIM, and DMARC compliance.

All interactions are performed via simple HTTP calls without requiring IMAP, POP3, or a graphical interface, making it straightforward to integrate email handling into language‑model workflows, automation pipelines, or other software that needs to treat email as a programmable resource.