Sobmit Docs

Email trigger

The Email trigger gives a saved flow its own email address. Send an email to it — body, inline images and attachments included — and a run starts automatically with the email as its input.

The address

Every flow’s address is its public id on your receiving domain:

<shortId>@<domain>

The <shortId> is the flow’s public short id (the same one in its shareable URL), and the domain is the configured inbound domain (e.g. app.sobm.it). Enable or disable the trigger — and read the address — in the flow’s Email trigger panel in the sidebar.

The address is a credential: anyone who knows it can start (and spend credit on) the flow. Disable it to revoke that ability.

The run input

When an email arrives, the flow starts with a { kind: "email", … } payload:

{
  "kind": "email",
  "messageId": "<abc@example.com>",
  "from": "Alice <alice@example.com>",
  "fromEmail": "alice@example.com",
  "to": ["<shortId>@<domain>"],
  "cc": [],
  "subject": "Hello",
  "text": "Plain body",
  "html": "<p>HTML body</p>",
  "headers": { "…": "…" },
  "attachments": [
    {
      "name": "photo.png",
      "mime": "image/png",
      "kind": "image",
      "content": "data:image/png;base64,…"
    }
  ]
}

Images and PDFs in the email are available to an Agent as vision/document inputs, and to the Upload File, Transcribe Audio and Embed Data nodes.

Replying to the sender

The sender’s bare address is available as {input.fromEmail}. To send an answer back, wire the flow into an Email node and set its recipient to:

{input.fromEmail}

This resolves at run time, so a flow that starts with an email can respond to whoever wrote it — for example an Email trigger → Agent → Email chain that answers the incoming message.

Reliability & security

  • Emails are de-duplicated, so a re-delivery never starts a second (paid) run.
  • Each flow is rate-limited — a leaked address cannot flood runs.
  • The webhook is authenticated by Resend’s signature before anything runs.

Related

  • Email node — sending mail (including the reply).
  • Webhooks — trigger a flow over HTTP instead.
  • Schedules — run on a timer instead of a mail.