Email

The Email step (email.send-email) sends an email message over any SMTP server. Use it for transactional notifications, post-run reports, file delivery, or anything else where the destination is a mailbox.

It works with any SMTP provider — Gmail, Office 365, Postmark, SendGrid, Amazon SES, Mailgun, your own Postfix box, etc. Either pick an SMTP connection you’ve already configured, or paste credentials directly into the step.

Configuration

SMTP Connection

Field	Description
SMTP Connection	Pick a saved connection of type smtp. The connection holds the host, port, credentials, and default From address — the step injects them at runtime.

If you don’t have a connection set up, the step also accepts inline credentials via the credentials field (host, port, username, password, secure flag, optional default From). Connections are preferred — they keep the password out of the workflow JSON and let you swap providers without editing every step.

Email Configuration

Field	Description
To	Recipient email addresses (one or more). Supports template expressions — e.g. {{ initial.email }} or {{ fetch-customers.body.contacts }}.
CC	Carbon-copy recipients (optional)
BCC	Blind carbon-copy recipients (optional)
Reply To	Reply-to address (optional)
From	Sender address (optional — overrides the connection’s default From)
Subject	Subject line. Supports templates.
HTML Body	Email body as HTML. Supports templates.
Plain Text Body	Plain-text fallback for clients that don’t render HTML. At least one of HTML or Plain Text is required.

Attachments

Add files to the email by listing them under Attachments. Each attachment has:

Field	Description
File Content	The file’s content. Usually templated from a file step, e.g. {{ generate-report.file.content }}.
File Name	Filename including extension (e.g. invoice.pdf)
Encoding	utf-8 for text files (CSV, JSON, HTML), base64 for binary files (PDF, images, ZIPs)

A common pattern is to chain a file step into the email step:

Step 1 (file.generate-pdf): inline HTML → invoice.pdf
Step 2 (email.send-email):  attachments[0].content  = {{ generate-pdf.file.content }}
                            attachments[0].fileName = invoice-{{ initial.invoiceId }}.pdf
                            attachments[0].encoding = base64

Output

{{ send-email.sent }}                       // true if delivery succeeded
{{ send-email.email.messageId }}            // SMTP message ID returned by the server
{{ send-email.email.accepted }}             // array of accepted recipients
{{ send-email.email.rejected }}             // array of rejected recipients (partial failure)
{{ send-email.email.response }}             // raw SMTP response string
{{ send-email.error }}                      // error message (only when sent === false)
{{ send-email.errorCode }}                  // taxonomy error code (see below)

If some recipients are accepted and others are rejected, sent is still true but the step is flagged with an EMAIL_RECIPIENTS_REJECTED warning visible in $meta.operationalErrors and the $errors array.

Error handling

The Email step retries transient SMTP failures (connection failures, timeouts, 4xx SMTP responses, rate limits) with exponential backoff and fails fast on permanent ones (auth failure, invalid recipient, mailbox full, message rejected). Tune this in the step’s Error Handling panel.

On failure, errorCode is one of:

Code	Cause	Meaning
SMTP_CONNECTION_FAILED	transient	Could not reach the SMTP server (DNS / connection refused / reset)
SMTP_TIMEOUT	transient	SMTP session timed out
SMTP_SERVICE_UNAVAILABLE	transient	Server returned 421 — service temporarily unavailable
SMTP_MAILBOX_BUSY	transient	Server returned 450 / 451 — mailbox temporarily unavailable
SMTP_INSUFFICIENT_STORAGE	transient	Server returned 452 — temporary storage exhaustion
SMTP_RATE_LIMITED	transient	Server is throttling — too many connections / messages
SMTP_AUTH_FAILED	permanent	Authentication rejected (530 / 535) — credentials wrong, expired, or scoped out
SMTP_INVALID_RECIPIENT	permanent	Recipient rejected (550 / 551 / 553) — mailbox missing or domain invalid
SMTP_MAILBOX_FULL	permanent	Recipient mailbox is full (552)
SMTP_MESSAGE_REJECTED	permanent	Message rejected (554) — typically spam filter or content policy
SMTP_INVALID_COMMAND	permanent	SMTP protocol error (500–504) — usually a misconfigured transport
SMTP_POLICY_VIOLATION	permanent	Sender policy rejection (521 / 556) — server doesn’t accept mail from this origin
SMTP_INVALID_SENDER	permanent	Sender address rejected — check the From header and SPF/DMARC config
EMAIL_UNKNOWN_ERROR	unknown	Unclassified — retried by default

Plus the warning-level code:

Code	Meaning
EMAIL_RECIPIENTS_REJECTED	Some recipients were accepted, others rejected. The step succeeds but logs a warning.

See Error Handling → Which step types have taxonomies for how the taxonomy plugs into the retry policy and the Custom retry mode editor.

Tip

Pair the Email step with Continue on Error when an email failure shouldn’t halt the rest of the workflow — for example, an internal “we synced 12 leads” notification at the end of a pipeline should never block the pipeline itself.

Common patterns

Send a simple notification

SMTP Connection: postmark
To:              {{ initial.userEmail }}
Subject:         Your report is ready
HTML Body:       <p>Hi {{ initial.userName }}, your report finished processing.</p>

Send a generated PDF as an attachment

Step 1 (file.generate-pdf): inline HTML → report.pdf
Step 2 (email.send-email):
  To:                       {{ initial.recipientEmail }}
  Subject:                  Monthly report — {{ initial.month }}
  HTML Body:                <p>Your report is attached.</p>
  Attachments[0].content:   {{ generate-pdf.file.content }}
  Attachments[0].fileName:  report-{{ initial.month }}.pdf
  Attachments[0].encoding:  base64

Branch on delivery success

{% if send-email.sent %}
  Logged delivery for {{ send-email.email.messageId }}
{% else %}
  Failed: {{ send-email.errorCode }} — {{ send-email.error }}
{% endif %}