Connectors

Communication, Email & Calendar

SMTP

Standard email sending protocol: deliver messages through any mail server
SMTP specificationAPI checked August 16, 2026
Signs in with
Connection details
Runs on
Cloud or On-Prem Worker
Operations
3
Ready-made triggers
0

Connect SMTP

  1. In Neblex open Connect › Connections and click New Connection.
  2. Search for SMTP and give the connection a clear name.
  3. Fill in the fields. Secret values are encrypted and never shown again.
  4. Click Test, then Create Connection.
If the system is only reachable inside your network, choose an On-Prem Worker under Test from and run the flow on that Worker. See On-Prem Workers.
FieldWhat to enter
Connection setupRequired
HostRequired
PortOptionalExample: 587
UsernameOptional
AuthenticationRequiredOAuth mode uses the username as the mailbox identity and the secret field as a short-lived access token.
Password or access tokenOptionalSecret
Require STARTTLSOptionalTurning this off sends traffic and credentials without transport encryption. Use plaintext only for a customer-controlled endpoint that explicitly requires it.
Connection stringRequiredSecretPaste smtp:// with tls=required or tls=opportunistic, or smtps:// for implicit TLS. Append auth=oauth2 to use the password field as an XOAUTH2 access token.

Use it in a flow

  1. Open a flow, open the node library and search for SMTP.
  2. Drag it onto the canvas and choose an Operation and your connection.
  3. Map the operation's fields from earlier steps, or click Map with Matt.
  4. Use Test this step to see what it returns, then save.

To start a flow from SMTP without a ready-made trigger: a Poll for changes trigger can check one of its list operations on a schedule and pass on only what is new; if SMTP can send webhooks, a Webhook trigger receives them at its own URL.

Operations

3 operations in 2 groups. Each one is a step you can add to a flow.

Connection1
Test connectionpingConnect, negotiate EHLO, authenticate when configured, and issue NOOP without sending mail.
Message2
Send a raw messagesendRawSubmit prebuilt RFC 5322/MIME bytes with an explicit SMTP envelope.
Send an emailsendSubmit a bounded RFC 5322/MIME message with plain and HTML alternatives, envelope control, threading headers, and multiple regular or inline attachments.