Upload an attachment

POST/v1/attachments

Uploads an attachment. Reference the returned att_id from message parts.

Requirements

The request body is the raw bytes: no multipart, no JSON wrapper.
content-type declares the attachment’s MIME type; x-filename declares its name.
Maximum 100,000,000 bytes (100 MB). Larger payloads return HTTP 413 too_large. An empty body returns HTTP 400 code 1017.
No Idempotency-Key: the server neither requires nor consults one here.

Behavior

Uploads are idempotent over your brand and the bytes: the att_id is derived from them, so re-uploading a file you already hold returns the same id and stores nothing twice. A retry is free and needs no key.
The stored mime and name stay the first upload’s, and the response reports the stored values: a later upload declaring a different content-type gets the original back. To change a stored type, upload altered bytes, which are a different attachment.
Attachments are scoped to your brand. Another brand uploading the identical file gets a different id and its own copy.

Header ParametersExpand Collapse

"x-filename": optional string

Body ParametersExpand Collapse

body: unknown

ReturnsExpand Collapse

id: string

Attachment id (att_…) to reference from parts.

mime: string

The STORED MIME type: the same value GET /v1/attachments/{att} reports, not an echo of the request header. It is your content-type when you sent one, application/octet-stream when you did not, and on a duplicate upload it is the type the FIRST upload of these bytes declared.

size: number

Stored size in bytes.

formatint64

Upload an attachment

curl https://messages.api.linqapp.com/v1/attachments \
    -H 'Content-Type: */*' \
    -H "Authorization: Bearer $LINQ_AMB_API_KEY" \
    -d '{}'

{
  "id": "att_1a3f77",
  "mime": "image/png",
  "size": 20481
}

Returns Examples

{
  "id": "att_1a3f77",
  "mime": "image/png",
  "size": 20481
}