RequestExpand all Send a single transactional or marketing email via REST API.
Simple API for sending emails with:
Automatic queuing and delivery Built-in tracking (opens & clicks) File attachments (PDF, ZIP, images, documents) Calendar invites (iCal/RFC 5545) Template variable support Custom headers Full bounce and complaint handling Requirements:
Verified sending domain Active customer account Valid API key Auto-domain selection: If you don't specify a domain, we'll automatically use your first verified domain.
Security View security details Bodyapplication/json required Sending domain (optional - auto-selects first verified domain if omitted)
Example: "mail.yourdomain.com"
From email address (defaults to noreply@domain)
Example: "hello@mail.yourdomain.com"
Example: "user@example.com"
Example: "support@yourdomain.com"
cc Array of strings (email) Example: ["manager@example.com"]
bcc Array of strings (email) BCC recipients (hidden from other recipients)
Example: ["archive@yourdomain.com"]
Example: "Welcome to our platform!"
Example: "<h1>Welcome!</h1><p>Thanks for signing up.</p>"
Plain text email body (fallback for non-HTML clients)
Example: "Welcome! Thanks for signing up."
Enable open tracking (default: account setting)
Example: true
Enable click tracking (default: account setting)
Example: true
headers object
Custom email headers for the message.
Use cases:
Add custom headers like X-Order-ID, X-User-ID Set Reply-To address Add tracking or reference headers Store structured data as JSON string Webhook support: Headers are included in webhook payloads alongside metadata.
Note: Headers are sent with the email and included in webhooks. Use metadata for data that should NOT be sent in the email.
Example: {"X-Campaign-ID":"campaign-123","X-User-ID":"user-456","Reply-To":"support@example.com"}
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Tag for organizing emails (for analytics, not routing)
Example: "welcome-series"
IP stream type for routing (default: shared)
transactional: High-priority emails (passwords, confirmations)broadcast: Marketing campaigns and newslettersshared: General purpose emails Enum "transactional" "broadcast" "shared"
Example: "transactional"
Custom metadata (stored in database, NOT sent in email).
Use cases:
Link emails to orders, users, or resources in your system Track campaign performance and ROI Store application-specific context Filter and analyze emails by custom attributes Pass through data to your webhook handlers Webhook support: Metadata is included in all webhook events (delivered, bounced, opened, clicked, complained, unsubscribed).
Difference from headers: Metadata is never sent in the email, while headers are included in the email message.
Example: {"user_id":"12345","order_id":"ord_789","campaign":"summer_sale","tier":"premium"}
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attachments Array of objects File attachments (PDF, ZIP, images, documents).
Important : Attachments are sent directly through SMTP without storing on server. Base64 encode your files and include them in the request.
Max per file: 10 MB (configurable) Max total size: 25 MB (including HTML) Supported: All file types Example: [{"filename":"invoice.pdf","content":"JVBERi0xLjQK...","contentType":"application/pdf"},{"filename":"report.csv","content":"TmFtZSxFbWFpbC...","contentType":"text/csv"}]
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iCal calendar event in RFC 5545 format for meeting invites.
Native calendar support - works with Gmail, Outlook, Apple Mail:
Gmail: Shows "Add to Calendar" button Outlook: Shows Accept/Decline/Tentative buttons Apple Mail: Shows "Add to Calendar" button Implementation : Sends as both text/calendar MIME alternative AND invite.ics attachment for maximum compatibility.
Important : Event is sent directly, not stored on server.
Example: "BEGIN:VCALENDAR\nVERSION:2.0\nPRODID:-//YourApp//Calendar//EN\nMETHOD:REQUEST\nCALSCALE:GREGORIAN\nBEGIN:VEVENT\nUID:meeting-123@yourdomain.com\nDTSTAMP:20250127T120000Z\nDTSTART:20250128T140000Z\nDTEND:20250128T150000Z\nSUMMARY:Team Meeting\nDESCRIPTION:Discuss Q1 goals\nLOCATION:Conference Room A\nORGANIZER;CN=Manager:mailto:manager@yourdomain.com\nATTENDEE;CN=Employee;RSVP=TRUE:mailto:employee@example.com\nSTATUS:CONFIRMED\nSEQUENCE:0\nBEGIN:VALARM\nTRIGGER:-PT15M\nACTION:DISPLAY\nDESCRIPTION:Reminder\nEND:VALARM\nEND:VEVENT\nEND:VCALENDAR\n"