> ## Documentation Index > Fetch the complete documentation index at: https://docs.mailglyph.com/llms.txt > Use this file to discover all available pages before exploring further. # Send transactional email > Send a transactional email via the public API. Automatically creates/updates contacts. ## OpenAPI ````yaml openapi.json POST /v1/send openapi: 3.0.3 info: title: MailGlyph API description: >- Email platform API for transactional emails, campaigns, and marketing automation version: 1.0.0 contact: name: MailGlyph Support url: https://mailglyph.com servers: - url: https://api.mailglyph.com description: Production server security: - ApiKeyAuth: [] tags: - name: Public API description: Public API endpoints for sending emails and tracking events - name: Events description: Event ingestion and querying - name: Contacts description: Contact management operations - name: Templates description: Email template management - name: Campaigns description: Email campaign management - name: Segments description: Audience segmentation - name: Workflows description: Workflow automation paths: /v1/send: post: tags: - Public API summary: Send transactional email description: >- Send a transactional email via the public API. Automatically creates/updates contacts. operationId: sendEmail requestBody: required: true content: application/json: schema: type: object required: - to - from properties: to: oneOf: - type: string format: email description: Simple email address - type: object required: - email properties: name: type: string description: Recipient display name email: type: string format: email description: Recipient email address description: Recipient with name and email - type: array maxItems: 50 items: oneOf: - type: string format: email - type: object required: - email properties: name: type: string description: Recipient display name email: type: string format: email description: Recipient email address description: >- Array of recipients (strings or objects), maximum 50 recipients description: >- Recipient email(s). Can be a string, an object with {name, email}, or an array of either. Maximum 50 recipients per request. subject: type: string description: Email subject (required if no template) body: type: string description: Email body HTML (required if no template) text: type: string description: >- The plain text version of the message. If not provided, the `body` will be used to generate a plain text version. You can opt out of this behavior by setting value to an empty string. template: type: string description: >- Template ID to use for this email. When provided, uses the template's subject, body, from, and reply-to settings. You can override these by explicitly providing subject, body, from, or reply fields in the request. Template variables are populated from the data field. from: oneOf: - type: string description: >- Sender as plain email or address string (e.g., "hello@example.com" or "My App <hello@example.com>") - type: object required: - email properties: name: type: string description: Sender display name email: type: string format: email description: Sender email address description: Sender with name and email description: >- Sender email address (requires verified domain). Required unless using a template that has a 'from' address configured. Can be a string (e.g., "hello@example.com" or "My App <hello@example.com>") or an object with {name, email} (e.g., {name: "My App", email: "hello@example.com"}). name: type: string description: Sender display name (alternative to using from.name) subscribed: type: boolean description: >- Whether recipient is subscribed to marketing emails. Defaults to false for transactional emails. default: false data: description: >- Optional template variables. Choose `Empty object` if you do not want to send any example preset keys. oneOf: - type: object title: Example object description: >- Optional common keys. You can still add additional custom key/value pairs. properties: resetLink: type: string description: Reset or action URL used in templates example: https://example.com/reset/abc123 example: resetLink: https://example.com/reset/abc123 additionalProperties: true - type: object title: Empty object description: >- No preset keys. Add any custom key/value pairs as needed. additionalProperties: true headers: type: object additionalProperties: type: string description: Custom email headers reply: type: string format: email description: Reply-to address attachments: type: array description: Email attachments (max 10 attachments, 10MB total) maxItems: 10 items: type: object required: - filename - content - contentType properties: filename: type: string maxLength: 255 description: Attachment filename content: type: string description: Base64 encoded file content contentType: type: string maxLength: 255 description: MIME type (e.g., application/pdf, image/png) examples: Simple transactional email: summary: Simple transactional email value: to: user@example.com from: My Company subject: Password Reset Request body: >-

Reset Your Password

Click the link to reset: {{resetLink}}

data: resetLink: https://example.com/reset/abc123 Email with recipient and sender names: summary: Email with recipient and sender names value: to: name: Jane Doe email: jane@example.com from: name: My Company email: hello@mycompany.com subject: Welcome to Our Service body:

Welcome {{name}}!

We're glad to have you.

data: name: Jane Email with sender address string: summary: Email with sender address string value: to: jane@example.com from: My Company subject: Welcome body:

Welcome!

Thanks for joining.

Multiple recipients with names: summary: Multiple recipients with names value: to: - name: Jane Doe email: jane@example.com - name: John Smith email: john@example.com from: name: Newsletter email: news@mycompany.com subject: Monthly Update body:

Hello {{name}}!

Using a template: summary: Using a template description: >- Send email using a template. Provide the template ID and any data for template variables. The template's subject, body, from address, and reply-to will be used automatically. value: to: user@example.com template: clx123abc456 data: firstName: John lastName: Doe resetCode: value: ABC123 persistent: false Using template with overrides: summary: Using template with overrides description: >- You can override template values by providing subject, body, from, or reply fields. This example overrides the template's subject line. value: to: user@example.com template: clx123abc456 subject: Custom Subject Override data: firstName: Jane 'Marketing email (set subscribed: true)': summary: 'Marketing email (set subscribed: true)' value: to: user@example.com subject: Weekly Newsletter body:

This Week's Updates

subscribed: true Email with PDF attachment: summary: Email with PDF attachment value: to: user@example.com subject: Your Invoice body: >-

Invoice Attached

Please find your invoice attached.

attachments: - filename: invoice.pdf content: JVBERi0xLjQKJeLjz9MKMSAwIG9iago8PC9UeXBlL... contentType: application/pdf responses: '200': description: Email queued successfully content: application/json: schema: type: object properties: success: type: boolean data: type: object properties: emails: type: array items: type: object properties: contact: type: object properties: id: type: string email: type: string email: type: string description: >- MailGlyph email record ID. Use this to correlate webhook events (included as 'emailId' in event payload data) with your send requests. timestamp: type: string format: date-time example: success: true data: emails: - contact: id: cnt_abc123 email: user@example.com email: ac32f08e-c6b9-45d3-9824-a73dff1e3bbf timestamp: '2025-01-15T10:30:00.000Z' '400': description: Bad request content: application/json: schema: $ref: '#/components/schemas/Error' '401': description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/Error' components: schemas: Error: type: object properties: code: type: integer error: type: string message: type: string time: type: integer securitySchemes: ApiKeyAuth: type: http scheme: bearer bearerFormat: API Key description: >- API Key authentication. **Secret keys (sk_*)** are required for all endpoints except `/v1/track`. **Public keys (pk_*)** only work with the `/v1/track` endpoint for client-side event tracking. Workspaces can have multiple active keys, and sender-domain operations enforce per-key domain scope when configured. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.