How to use the Email plugin

Send email from flows and trigger flows from incoming email using standard SMTP and IMAP connections.

Authentication

Set host, port, username, and password on each task, or apply them globally with plugin defaults to avoid repetition. Store credentials in secrets. Control encryption via transportStrategy: the default SMTPS uses implicit TLS on port 465; set it to SMTP_TLS for STARTTLS on port 587; or SMTP for unencrypted connections.

Tasks

MailSend sends an email as a step within a flow — set to, subject, and htmlTextContent (or plainTextContent for plain-text only). Use it for ad hoc notifications and alerts where you control the message body.

MailExecution sends a structured execution summary including status, duration, and an execution link, and is designed to be used with a Flow trigger in a dedicated monitoring namespace that watches other namespaces for failures — the same pattern as SlackExecution.

For inbound email, MailReceivedTrigger polls an IMAP inbox on a schedule and starts one execution per batch of new messages; RealTimeTrigger starts one execution per message as it arrives. Use MailReceivedTrigger for controlled batch processing and RealTimeTrigger when you need low-latency response to incoming email.

Both triggers store each attachment in Kestra's internal storage and expose its URI so it can be passed to downstream tasks: {{ trigger.latestEmail.attachments[0].uri }} on MailReceivedTrigger, {{ trigger.attachments[0].uri }} on RealTimeTrigger. If an attachment fails to store, its metadata (filename, contentType, size) is still returned with a null uri.