Reply to a conversation

POST /api/v1/conversations/conv_e0829641-…/reply
Authorization: Bearer ta_live_…
Content-Type: application/json
Idempotency-Key: reply-7f3a91

{ "text": "Yes — it left our warehouse this morning. Tracking: AB123456." }

{ "ok": true }

Only for a number with External Agents turned on. {id} is the conversationId from the message.received webhook.

Body

Send exactly one of these. Two in one call are refused, so a customer never gets two messages when you meant one.

string

Up to 4,096 characters. Only while the customer’s 24-hour window is open.

object

A file WhatsApp fetches from your link. Only while the window is open.

Field
`type`	`image`, `video`, `audio` or `file`
`url`	A public `https://` link, up to 2,048 characters
`caption`	Shown under an image or video. Optional
`filename`	What a document is called on the customer’s phone. Optional

WhatsApp’s own size and format limits apply.

string

A published WhatsApp form, by the name it has on the Forms page — "Delivery address" — or { "name": "…" }. It must belong to the agent the number is assigned to. Only while the window is open.

object

An approved template. Works after the window has closed too.

Field
`name`	The template’s name
`language`	e.g. `en`. Optional — the oldest approved language is used
`variables`	The body’s `{{1}}`, `{{2}}`… in order
`buttonVariables`	A link button’s placeholder, when it has one
`headerMediaUrl`	The header’s image, video or document, when it has one

It must be approved on this conversation’s number. The same checks as Send a message apply, including opt-outs for marketing templates.

Idempotency

Send an Idempotency-Key header, as on every endpoint that sends. A retry with the same key gets the first answer back and sends nothing. A 502 releases the key, so the same retry can succeed.

Errors

Status	Why
`400`	No kind, more than one kind, or a field that is not valid
`404`	The conversation is not in your workspace, or the template or form does not exist
`409`	External Agents is off for this number · a teammate has taken the conversation over · the 24-hour window has closed (send a template) · the template is not approved or is for another number · the customer opted out · the number is disconnected
`429`	Too many requests. Wait and retry
`502`	WhatsApp refused the message. Retry with the same key

Every error body is { "error": "…" } in plain words. See errors.

Pricing

Each message is charged at 10% of Meta’s rate, and Meta bills your WhatsApp account for its own fee. See External Agents.

​Body

​Idempotency

​Errors

​Pricing

Body

Idempotency

Errors

Pricing