> ## Documentation Index > Fetch the complete documentation index at: https://docs.simpleemailapi.dev/llms.txt > Use this file to discover all available pages before exploring further. # Send an email. > Send an email. ## OpenAPI ````yaml api-reference/openapi.json post /v1.EmailService/SendEmail openapi: 3.1.0 info: title: SimpleEmailAPI description: >- The SimpleEmailAPI is a type-safe email API for sending transactional emails with real-time event streaming. Built on Connect RPC for maximum type safety and developer experience. contact: name: SimpleEmailAPI Support url: https://simpleemailapi.dev email: support@simpleemailapi.dev version: 1.0.0 servers: - url: https://api.simpleemailapi.dev description: Production security: - BearerAuth: [] tags: - name: v1.DomainService description: |- DomainService handles sending domains. To send emails with good deliverability, you need to: 1. Add a domain (AddDomain) 2. Configure the DNS records we give you 3. Verify the layout (VerifyDomain) - name: v1.EmailService description: >- EmailService is the core service for sending emails and listening to events. It provides a simple, stateless API designed for developer happiness. paths: /v1.EmailService/SendEmail: post: tags: - v1.EmailService summary: Send an email. description: Send an email. operationId: v1.EmailService.SendEmail parameters: - name: Connect-Protocol-Version in: header required: true schema: $ref: '#/components/schemas/connect-protocol-version' - name: Connect-Timeout-Ms in: header schema: $ref: '#/components/schemas/connect-timeout-header' requestBody: content: application/json: schema: $ref: '#/components/schemas/v1.SendEmailRequest' required: true responses: '200': description: Success content: application/json: schema: $ref: '#/components/schemas/v1.SendEmailResponse' default: description: Error content: application/json: schema: $ref: '#/components/schemas/connect.error' components: schemas: connect-protocol-version: type: number title: Connect-Protocol-Version enum: - 1 description: Define the version of the Connect protocol const: 1 connect-timeout-header: type: number title: Connect-Timeout-Ms description: Define the timeout, in ms v1.SendEmailRequest: type: object properties: from: type: string title: from description: >- Verified sender email address (e.g., "notifications@yourdomain.com"). to: type: array items: type: string title: to description: Primary recipients. cc: type: array items: type: string title: cc description: Carbon copy recipients. bcc: type: array items: type: string title: bcc description: Blind carbon copy recipients. subject: type: string title: subject description: Email subject line. body: type: string title: body description: Plain text content. Always recommended for better deliverability. html: type: string title: html description: HTML content. metadata: type: object title: metadata additionalProperties: type: string title: value description: >- Custom metadata to track this email. These values are returned in webhooks and events. scheduledAt: $ref: '#/components/schemas/google.protobuf.Timestamp' title: scheduled_at description: Schedule this email for a future time (UTC). attachments: type: array items: $ref: '#/components/schemas/v1.Attachment' title: attachments description: File attachments. inReplyTo: type: string title: in_reply_to description: >- Message-ID of the email to reply to. Setting this automatically handles threading headers (In-Reply-To, References). references: type: array items: type: string title: references description: >- Explicit threading references. Usually not needed if `in_reply_to` is set. replyTo: type: string title: reply_to description: |- Reply to a previous email using its email_id (from our response). Automatically resolves to the correct Message-ID for threading headers. For advanced use, you can still use in_reply_to with raw Message-IDs. title: SendEmailRequest additionalProperties: false description: Request to send an email. v1.SendEmailResponse: type: object properties: id: type: string title: id description: >- Unique email ID. Use this to track events and for reply_to in future emails. status: $ref: '#/components/schemas/v1.EmailStatus' title: status description: >- Status is always QUEUED. Listen to webhooks/events for delivery status. statusMessage: type: string title: status_message description: Human-readable description of the status. title: SendEmailResponse additionalProperties: false description: Response after sending an email. connect.error: type: object properties: code: type: string examples: - not_found enum: - canceled - unknown - invalid_argument - deadline_exceeded - not_found - already_exists - permission_denied - resource_exhausted - failed_precondition - aborted - out_of_range - unimplemented - internal - unavailable - data_loss - unauthenticated description: >- The status code, which should be an enum value of [google.rpc.Code][google.rpc.Code]. message: type: string description: >- A developer-facing error message, which should be in English. Any user-facing error message should be localized and sent in the [google.rpc.Status.details][google.rpc.Status.details] field, or localized by the client. details: type: array items: $ref: '#/components/schemas/connect.error_details.Any' description: >- A list of messages that carry the error details. There is no limit on the number of messages. title: Connect Error additionalProperties: true description: >- Error type returned by Connect: https://connectrpc.com/docs/go/errors/#http-representation google.protobuf.Timestamp: type: string examples: - '2023-01-15T01:30:15.01Z' - '2024-12-25T12:00:00Z' format: date-time description: >- A Timestamp represents a point in time independent of any time zone or local calendar, encoded as a count of seconds and fractions of seconds at nanosecond resolution. The count is relative to an epoch at UTC midnight on January 1, 1970, in the proleptic Gregorian calendar which extends the Gregorian calendar backwards to year one. All minutes are 60 seconds long. Leap seconds are "smeared" so that no leap second table is needed for interpretation, using a [24-hour linear smear](https://developers.google.com/time/smear). The range is from 0001-01-01T00:00:00Z to 9999-12-31T23:59:59.999999999Z. By restricting to that range, we ensure that we can convert to and from [RFC 3339](https://www.ietf.org/rfc/rfc3339.txt) date strings. # Examples Example 1: Compute Timestamp from POSIX `time()`. Timestamp timestamp; timestamp.set_seconds(time(NULL)); timestamp.set_nanos(0); Example 2: Compute Timestamp from POSIX `gettimeofday()`. struct timeval tv; gettimeofday(&tv, NULL); Timestamp timestamp; timestamp.set_seconds(tv.tv_sec); timestamp.set_nanos(tv.tv_usec * 1000); Example 3: Compute Timestamp from Win32 `GetSystemTimeAsFileTime()`. FILETIME ft; GetSystemTimeAsFileTime(&ft); UINT64 ticks = (((UINT64)ft.dwHighDateTime) << 32) | ft.dwLowDateTime; // A Windows tick is 100 nanoseconds. Windows epoch 1601-01-01T00:00:00Z // is 11644473600 seconds before Unix epoch 1970-01-01T00:00:00Z. Timestamp timestamp; timestamp.set_seconds((INT64) ((ticks / 10000000) - 11644473600LL)); timestamp.set_nanos((INT32) ((ticks % 10000000) * 100)); Example 4: Compute Timestamp from Java `System.currentTimeMillis()`. long millis = System.currentTimeMillis(); Timestamp timestamp = Timestamp.newBuilder().setSeconds(millis / 1000) .setNanos((int) ((millis % 1000) * 1000000)).build(); Example 5: Compute Timestamp from Java `Instant.now()`. Instant now = Instant.now(); Timestamp timestamp = Timestamp.newBuilder().setSeconds(now.getEpochSecond()) .setNanos(now.getNano()).build(); Example 6: Compute Timestamp from current time in Python. timestamp = Timestamp() timestamp.GetCurrentTime() # JSON Mapping In JSON format, the Timestamp type is encoded as a string in the [RFC 3339](https://www.ietf.org/rfc/rfc3339.txt) format. That is, the format is "{year}-{month}-{day}T{hour}:{min}:{sec}[.{frac_sec}]Z" where {year} is always expressed using four digits while {month}, {day}, {hour}, {min}, and {sec} are zero-padded to two digits each. The fractional seconds, which can go up to 9 digits (i.e. up to 1 nanosecond resolution), are optional. The "Z" suffix indicates the timezone ("UTC"); the timezone is required. A proto3 JSON serializer should always use UTC (as indicated by "Z") when printing the Timestamp type and a proto3 JSON parser should be able to accept both UTC and other timezones (as indicated by an offset). For example, "2017-01-15T01:30:15.01Z" encodes 15.01 seconds past 01:30 UTC on January 15, 2017. In JavaScript, one can convert a Date object to this format using the standard [toISOString()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toISOString) method. In Python, a standard `datetime.datetime` object can be converted to this format using [`strftime`](https://docs.python.org/2/library/time.html#time.strftime) with the time format spec '%Y-%m-%dT%H:%M:%S.%fZ'. Likewise, in Java, one can use the Joda Time's [`ISODateTimeFormat.dateTime()`]( http://joda-time.sourceforge.net/apidocs/org/joda/time/format/ISODateTimeFormat.html#dateTime() ) to obtain a formatter capable of generating timestamps in this format. v1.Attachment: type: object allOf: - properties: filename: type: string title: filename description: Name of the file (e.g., "invoice.pdf"). contentType: type: string title: content_type description: MIME type (e.g., "application/pdf"). - oneOf: - properties: base64Content: type: string title: base64_content description: Base64-encoded file content. title: base64_content required: - base64Content - properties: url: type: string title: url description: Publicly accessible URL to download the file from. title: url required: - url title: Attachment additionalProperties: false description: A file attachment. v1.EmailStatus: type: string title: EmailStatus enum: - EMAIL_STATUS_UNSPECIFIED - EMAIL_STATUS_QUEUED - EMAIL_STATUS_PROCESSING - EMAIL_STATUS_SENT - EMAIL_STATUS_FAILED description: Represents the current status of an email delivery. connect.error_details.Any: type: object properties: type: type: string description: >- A URL that acts as a globally unique identifier for the type of the serialized message. For example: `type.googleapis.com/google.rpc.ErrorInfo`. This is used to determine the schema of the data in the `value` field and is the discriminator for the `debug` field. value: type: string format: binary description: >- The Protobuf message, serialized as bytes and base64-encoded. The specific message type is identified by the `type` field. debug: oneOf: - type: object title: Any additionalProperties: true description: Detailed error information. discriminator: propertyName: type title: Debug description: >- Deserialized error detail payload. The 'type' field indicates the schema. This field is for easier debugging and should not be relied upon for application logic. additionalProperties: true description: >- Contains an arbitrary serialized message along with a @type that describes the type of the serialized message, with an additional debug field for ConnectRPC error details. securitySchemes: BearerAuth: type: http description: >- API key authentication. Get your API key from the SimpleEmailAPI dashboard and include it in the Authorization header as: Bearer sea_live_xxxxx scheme: bearer ````