Initiate chunked upload
POST/:workspace/media/chunked/initiate
Step 1 of the chunked upload flow. Creates an upload session and returns the upload_uuid together with the chunk plan your client must follow (chunk_size and total_chunks).
How the chunk plan is calculated:
- If
total_sizeis not larger than the configured chunk size, the file is sent as a single chunk (chunk_sizeequalstotal_size,total_chunksis 1). - Otherwise the chunk size comes from your instance's
MIXPOST_CHUNKED_UPLOAD_SIZEsetting (default 10 MB) and is always clamped to between 10 MB and 64 MB. These bounds are fixed and cannot be configured. - An upload may use at most 1000 chunks, so for very large files the chunk size is increased as needed (still never above 64 MB) to keep the count within that limit.
Always use the returned chunk_size and total_chunks rather than computing your own.
The session belongs to the workspace it was opened in and to the user the token authenticates as. Every later step must be addressed to that same workspace with that same token — a session addressed from anywhere else is reported as not found.
Request
Responses
- 200
- 401
- 403
- 404
- 422
Upload session created.
The bearer token is missing, malformed, unknown, or expired.
The token is valid, but the user it belongs to may not perform this action:
- they are not a member of the
{workspace}in the path; or - their workspace role is too low for this endpoint (write routes require Admin or Member); or
- for
/panelendpoints, they are not a platform administrator.
The host application that Mixpost is installed into can also deny access to Mixpost as a whole, which produces the same response.
The {workspace} UUID in the path does not match any workspace.
Validation failed, or your workspace's media-upload limit denied the upload. A limit denial returns the usual errors.limit entry plus an extra top-level limit object describing the limit.