Send Email

Last modified: August 4, 2026

Introduction

The Send Email activity allows you to send an email directly from a microflow. Within a single activity, you configure the following:

  • Email server connection
  • Authentication method
  • Sender and recipients
  • Message content
  • Attachments

You can also test the connection and send a test email from Studio Pro while your app is running without having to trigger the microflow.

Each Send Email activity holds its own connection and message configuration. Connection settings are not shared automatically between activities. To reuse the same server settings across multiple activities, store them in Constants and reference those constants from each activity. See the Connection section below for more information.

Properties

Double-click the Send Email activity to open its dialog box. The dialog box is organized into the following tabs:

  • General – configure the sender, the security method, and the server connection
  • Message – configure the recipients, custom headers, message body, and attachment
  • Test Email – send a test email to verify your configuration

General Tab

The General tab configures how Studio Pro connects and authenticates to the email (SMTP) server, and which address the email is sent from.

Sender's Details

Email ID (From)

The From address is the email address the email is sent from. You can type a value directly, or click Edit to define the value using a microflow expression.

Security Method

The Security method section determines how the connection authenticates to the email server. The connection uses basic authentication.

Username

The Username property is the username used to authenticate to the email server.

Password

The Password property is the password used to authenticate to the email server.

Connection

The Connection field configures how Studio Pro reaches the email server.

Email Protocol

The Email Protocol property is the protocol used to send email. This property is read-only.

Default value: SMTP

Security Type

The Security Type property is the transport security used for the connection: None, SSL, or TLS.

Default value: TLS

Check Server Identity

The Check Server Identity option defines whether to verify the server's identity (certificate). This option is only enabled when Security Type is set to SSL.

Default value: No

Timeout (ms)

The connection timeout (in milliseconds).

Default value: 20000

Server Host

The Server Host property is the address of the email (SMTP) server.

Server Port

The Server Port property is the port of the email (SMTP) server.

Test Connection

Click Test Connection to verify the configured connection and authentication settings are valid.

Message Tab

The Message tab configures the recipients, custom headers, message content, and attachment.

Receiver's Details

Configure the recipients in the table by selecting a row and clicking Edit (or double-clicking the row). Each value is defined using a microflow expression.

To

The To field is the primary recipient (or recipients) of the email.

Cc

The Cc field is the carbon-copy recipient (or recipients) of the email.

Bcc

The Bcc field is the blind carbon-copy recipient (or recipients) of the email.

Custom Headers

The Custom headers section allows you to add custom email headers. Use the toolbar to manage headers:

  • Add – add a new custom header
  • Edit – edit the selected custom header
  • Delete – remove the selected custom header

Name

The Name property is the name of the header. This can only contain letters, digits, and hyphens, and cannot be empty.

Value

The Value property is the value of the header. It cannot be empty or contain line breaks.

Message Body

The following fields can be defined either as plain text or as a string template. A string template is fixed text with {1}, {2}, … placeholders whose values are of type microflow expression and come from parameter expressions evaluated against the surrounding microflow. For example:

Subject: "Order {1} confirmed"
  {1} → $Order/OrderNumber

Body:    "Hi {1}, your order ships on {2}."
  {1} → $Order/Customer/FirstName
  {2} → formatDateTime($Order/ShipDate, 'yyyy-MM-dd')

Subject

The Subject property is the subject line of the email.

Message Body (Plain Text)

The Message Body (Plain Text) property is the plain-text version of the email body.

Message Body (HTML)

The Message Body (HTML) property is the HTML version of the email body.

Attachment

In the Attachment section, select a microflow variable to attach to the email.

Variable

Only variables of type System.FileDocument, List of System.FileDocument, or their specializations can be attached. The variable must exist in the microflow's scope before the Send Email activity (the file must already have been retrieved or created earlier in the flow).

Test Email Tab

The Test Email tab allows you to send a test email to verify your configuration from Studio Pro without triggering the microflow.

Test Email Details

Use Template for Test Email

When Use Template for Test Email is selected, the subject and body fields use the string templates configured on the Message tab. Because template placeholders reference microflow variables that are not available while testing, click the Edit icon next to each field to provide test values for the template parameters.

When not selected, you can enter the subject and body directly.

To

The To property is the recipient of the test email.

Subject

The Subject property is the subject line of the test email.

Message Body (Plain Text)

The Message Body (Plain Text) property is the plain-text version of the test email body.

Message Body (HTML)

The Message Body (HTML) property is the HTML version of the test email body.

Send Test Email

Click Send Test Email to send the test email using the current configuration. A message indicates whether the test email was sent successfully.

Error Handling

Sending emails can fail at runtime for reasons outside your app's control, such as:

  • The email server is unreachable
  • The connection times out
  • Authentication is rejected
  • A recipient address is invalid

When this happens, the Send Email activity raises and logs an error.

Handle these failures by configuring an error handler on the activity. This lets you, for example, log the failure, notify the user, or retry through an alternative path instead of letting the whole microflow fail. Because email delivery depends on external systems, wrapping the Send Email activity in error handling is strongly recommended for production apps.

Before Going to Production

Review the following before you deploy to a production app.

Authentication and Credentials

  • This version of the activity supports basic authentication (username and password) only. Confirm your email provider permits SMTP basic authentication (Google Workspace and Microsoft 365 disable it by default) or use a provider that does.
  • Do not hard-code credentials in the microflow model. Supply them through per-environment constants so secrets (the password in particular) are not stored in the app model or version control.

Email Deliverability (SPF, DKIM, and DMARC)

The sending domain must be configured correctly at the DNS level for your emails to be accepted and not marked as spam.

  • SPF – authorizes which servers may send emails for your domain
  • DKIM – cryptographically signs your messages so recipients can verify they were not altered
  • DMARC – tells receiving servers how to handle messages that fail SPF or DKIM checks

If these records are missing or misconfigured, receiving servers may reject your messages or route them to spam, even when the activity reports that the email was sent successfully. Set these up with your email provider and domain administrator before going live.

Read More