API reference

Create upload URL

Mint a signed upload URL for an asset

POST/api/v2/assets/{asset}:createUploadUrl

Authentication WLT-Api-Key

Create an upload URL for a single untyped object, upload the exact content type and length, then complete the asset. Read the guide.

Path parameters

assetstringrequired

Request body

application/jsonRequired

Body of an :createUploadUrl request.

content_length is the wire-format string the API contract requires (JSON's large-integer limitation); the validator parses it to an int so handlers can pass it to the service layer untouched.

contentTypestringrequired

contentLengthintegerrequired

Expected upload size in bytes, serialized on the wire as a string. Capped at 1 GiB.

Rangevalue <= 1073741824

Responses

`200`

Successful Response

application/json

Upload ticket for a project-owned Asset.

uploadUrlstringrequired

Short-lived upload URL. Send the bytes here without the World Labs API key.

methodstringrequired

HTTP verb to use for the upload, e.g. PUT.

expiresAtstringrequired

When this upload grant expires; create a new one after.

Formatdate-time

headersobject

Headers the client MUST include on the upload request.

`422`

Validation Error

application/json

detailarray<ValidationError>

Request example

cURL

curl --request POST \  --url 'https://api.atlas-beta.worldlabs.ai/api/v2/assets/asset_01jexample000000000000000:createUploadUrl' \  --header "WLT-Api-Key: $WLT_API_KEY" \  --header 'Content-Type: application/json' \  --data '{  "contentType": "image/png",  "contentLength": 1}'

Response example200 · JSON

1{2  "uploadUrl": "https://example.com/image.png",3  "method": "string",4  "expiresAt": "2026-09-14T20:00:00Z",5  "headers": {}6}