Send a Single Email

post

https://api.in.kaleyra.io/v2/{sid}/email/messages

Send one email payload to one or more recipients (To/CC/BCC). Attachments supported; total payload ≤ 20 MB.

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Path Params

sid

string

required

Kaleyra Account SID (e.g., HXAP16XXXXXX97IN).

Body Params

Email payload for single email sending.

from

string

required

Sender email address; domain must be whitelisted on your account.

from_name

string

Display name shown to recipients.

string

required

Comma-separated list of recipients (max 50 addresses).

string

Comma-separated CC recipients (max 50 addresses).

bcc

string

Comma-separated BCC recipients (max 50 addresses).

subject

string

Email subject. When using templates, the API subject overrides the template subject if present.

tag

string

Category/label for the email (for reporting/segmentation).

type

string

enum

Email type; defaults to MKT if omitted.

Allowed:

priority

integer

Send priority (implementation-specific; higher values may be processed first).

html_body

string

HTML content of the message (≤ ~5 MB). Preferred for tracking.

html_content

string

Plain-text body companion to html_body (e.g. multipart/alternative text part). Distinct from text_body in some integrations.

text_body

string

Plain text content (≤ ~5 MB). Used by clients that don’t support HTML.

reply_to

string

Reply-to address to receive responses.

dynamic_content

boolean

Set true to enable params substitution in subject/body (use {{key}} placeholders).

params

object

Key-value pairs for dynamic substitution (≤ 20 keys; key ≤ 20 chars; value ≤ 4000 chars).

attachments

array of objects

Attach files in JSON requests by absolute URL or Base64 content. For local file uploads, use multipart/form-data with repeated file fields. Overall email (text + html + attachments) ≤ 20 MB.

attachments

callback_profile_id

string

Callback profile ID configured for webhook notifications.

ref

string

Optional contextual reference (e.g., campaign name).

ref1

string

Optional contextual reference (e.g., customer ID).

ref2

string

Optional contextual reference.

ref3

string

Optional third contextual reference (e.g. segment or batch id).

template_id

string

Template ID to use; API fields override template fields where present.

template_name

string

Name of a saved template to use (alternative to template_id). API fields override template fields where present.

webhook_id

string

Optional webhook identifier if supported on your account.

metadata

object

Free-form metadata echoed in logs/callbacks (if enabled).

Headers

api-key

string

required

API Key generated by kaleyra.io. Example - Ac4XXXXX21f

content-type

string

enum

Defaults to application/json

Generated from available request content types

Allowed:

Responses

202Request accepted; messages queued for delivery.

400Bad Request - validation error.

401Unauthorized - incorrect SID or API key.

413Payload Too Large - overall request exceeded limits (e.g., attachments + bodies > 20 MB).

500Internal Server Error