Sends a WhatsApp message built from a message template to one recipient. Name the template, optionally pick its language variant, and fill its placeholders in `components`; Bird selects the sender number from the template's category, so the request carries no sender field. Templates are the only supported content type: a request without `template` is rejected with a `422`. Browse what you can send with [List available message templates](/docs/api/reference/list-whats-app-templates). The `202` response is the accepted message, echoing the resolved template and language; it is not a delivery confirmation. Follow delivery with [Get a WhatsApp message](/docs/api/reference/get-whats-app-message), the per-message timeline from [List events for a WhatsApp message](/docs/api/reference/list-whats-app-message-events), or `whatsapp.*` webhook events. A template name or language the catalogue does not stock, parameter values that do not match the template's declared placeholders, and a recipient that is not a valid phone number each return a `422`. The message recipient's phone number in E.164 format (for example `+31612345678`). A value that is not a valid phone number returns a `422` `WhatsAppInvalidRecipient`. The template to send. Bird selects the sender number from the template's category, so there is no sender field on this request. Templates are the only supported content type today: a request without one is rejected with a `422`. The template to send, by its name (for example `bird_otp`). Language code of the template variant to send (for example `en` or `pt_BR`). May be omitted when the template has a single language; when it is stocked in several, omitting the language returns a `422` that names the available codes. The accepted message echoes the resolved language. The values that fill the template's placeholders: one entry per content block that has placeholders, each carrying its `parameters` in `{{n}}` order. Parameter counts must match the template's declared placeholders exactly, or the send returns a `422` `WhatsAppTemplateParameterMismatch`. Which part of the template this fills in: `body` for the main text, `button` for a button's variable, `header` for the header. Bird manages header values itself, so a `header` entry supplied on a send is ignored. Possible values (may grow over time): `header`, `body`, `button` The values that fill this part's placeholders, in `{{n}}` placeholder order. The kind of value this parameter carries. `text` is the only kind today. The value substituted into the placeholder, as a plain string. For named-parameter templates: the placeholder this value fills (for example `first_name`). Omit for positional templates. Structured `{name, value}` labels for filtering. Tags become first-class query dimensions: filter the list endpoint by tag name. Maximum 20 tags per send. Use tags for low-cardinality dimensions (`category`, `experiment_variant`). For arbitrary structured context you do not need as a filter dimension, use `metadata` instead. Tag name. ASCII letters, digits, underscore, and hyphen only. Case-sensitive. Maximum 32 characters. Tag value. ASCII letters, digits, underscore, and hyphen only. Case-sensitive. Maximum 64 characters. Arbitrary JSON object stored on the message and returned on API reads. Maximum 2 KB serialized. Use metadata for per-send context like internal IDs and foreign keys. For low-cardinality filterable labels, use `tags` instead. ID of the message (`wam_`-prefixed), assigned when the send is accepted. Pass it as `message_id` to the get-message and list-events endpoints. Whether the message was sent by the business (`outbound`) or received from the contact (`inbound`). Possible values: `outbound`, `inbound` Sender of the message. On outbound messages, the business number it was sent from; on inbound, the WhatsApp contact. Phone number in E.164 format, when known. Business-scoped user ID, Meta's identifier for the WhatsApp user. Present only on the WhatsApp-user side of the message. Recipient of the message. On outbound messages, the WhatsApp contact; on inbound, the business number. Phone number in E.164 format, when known. Business-scoped user ID, Meta's identifier for the WhatsApp user. Present only on the WhatsApp-user side of the message. The template the message was sent from. For authentication templates the filled-in values are not returned. The template's stable handle (for example `bird_otp`). Content classification applied to messages sent from this template. The language code of the template variant that was sent (for example `en`). The values that filled the template's placeholders. Empty for an authentication template, whose content is never returned. Which part of the template this fills in: `body` for the main text, `button` for a button's variable, `header` for the header. Bird manages header values itself, so a `header` entry supplied on a send is ignored. Possible values (may grow over time): `header`, `body`, `button` The values that fill this part's placeholders, in `{{n}}` placeholder order. The kind of value this parameter carries. `text` is the only kind today. The value substituted into the placeholder, as a plain string. For named-parameter templates: the placeholder this value fills (for example `first_name`). Omit for positional templates. Failure detail for a message that did not reach the recipient. Present only when the message failed. Failure reason, uniform whether the failure happened internally or was reported by the WhatsApp network. `insufficient_balance`: the workspace could not afford the send. `price_not_found`: no price was configured for this destination/template combination. `internal_error`: an unexpected Bird-side failure. `undeliverable`: the recipient could not be reached (for example not on WhatsApp, or the number is invalid). `service_window_expired`: the 24-hour customer care window has closed and a free-form message cannot be sent; send a template instead. `rate_limited`: the send was throttled. `recipient_suppressed`: the recipient is on the workspace's suppression list; the message was rejected before sending. Open enum: new codes may be added over time, so treat any unrecognized value as a future code rather than an error. Possible values (may grow over time): `insufficient_balance`, `price_not_found`, `internal_error`, `undeliverable`, `service_window_expired`, `rate_limited`, `recipient_suppressed` Human-readable explanation of the failure. Raw error code from the WhatsApp Cloud API, when available, for low-level debugging. When the failure occurred. When the message was accepted for delivery. When the message was handed to the WhatsApp network. Null until then. When delivery was confirmed. Null until then. When the message was read by the recipient. Null until then. Structured `{name, value}` filter labels applied to this message. Tag name. ASCII letters, digits, underscore, and hyphen only. Case-sensitive. Maximum 32 characters. Tag value. ASCII letters, digits, underscore, and hyphen only. Case-sensitive. Maximum 64 characters. Arbitrary JSON metadata stored on the message.