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POST
/
v1
/
uploads
Initiate a resumable file upload
curl --request POST \
  --url https://api.example.com/v1/uploads \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "fileName": "<string>",
  "fileSize": 123,
  "contentType": "<string>"
}
'
{
  "uploadId": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "uploadUrl": "<string>",
  "maxChunkSize": 123,
  "correlationId": "3c90c3cc-0d44-4b50-8888-8dd25736052a"
}

Authorizations

​
Authorization
string
header
required

Clerk session JWT or Unkey API key passed as Bearer token

Headers

​
x-external-user-id
string

Optional. Identifies the end-user when authenticating with an API key. Ignored when authenticating with a Clerk JWT (the user ID is extracted from the token).

Example:

"user_abc123"

​
x-external-user-email
string<email>

Optional. Email of the external user, used for audit logging. Only applicable when authenticating with an API key.

Example:

"user@example.com"

Body

application/json
​
fileName
string
required

Original file name including extension

Minimum string length: 1
​
fileSize
integer
required

Total file size in bytes. Must not exceed the format-specific limit (e.g. 30 MB for PDF/images, 2 GB for video/audio, 10 MB for documents)

​
contentType
string
required

MIME type (e.g. application/pdf, image/png)

Minimum string length: 1

Response

Upload initiated — use uploadUrl to PUT file chunks

​
uploadId
string<uuid>
required

Server-generated upload identifier

​
uploadUrl
string
required

Relative URL for chunk uploads: PUT /v1/uploads/{uploadId}

​
maxChunkSize
integer
required

Maximum bytes per PUT chunk request (default 50 MB). Final chunk may be smaller.

​
correlationId
string<uuid>
required

Correlation ID for request tracing. Include in support requests.