Send a trade message

POST /api/trades/:id/messages
Content-Type: multipart/form-data

User (buyer, seller or admin)

Form fields

Field	Type	Rules
content	text, optional	≤ 2,000 chars, trimmed
image	file, optional	JPEG, PNG or WebP by content; ≤ 5 MB

At least one is required.

curl -X POST "$API/api/trades/$TRADE/messages" \
  -H "Authorization: Bearer $TOKEN" \
  -F "content=Paid, receipt attached" \
  -F "image=@receipt.png"

Response 201

The created message (see list messages). A message:new event is emitted to the trade room.

Errors

Status	Code	Cause
400	BAD_REQUEST	Empty message, or file isn't a supported image
400	UPLOAD_ERROR	"Image must be 5 MB or smaller"
403	FORBIDDEN
409	CONFLICT	"Chat for this trade is closed" (24 h after the trade ended)