[REST API] 400 Invalid Request Format when calling /operation/createpdf with valid assetID

Hi everyone,

I'm currently integrating Adobe PDF Services REST API (without SDK) in a Node.js server.

Everything works fine until the final conversion step.

Here’s my full sequence:

1)Token (IMS)
POST https://ims-na1.adobelogin.com/ims/token/v3
→ Works, I get a valid access token.

2) Asset Upload (HTML or ZIP)
POST https://pdf-services.adobe.io/assets
→ Works, returns a valid assetID (e.g., urn:aaid:AS:UE1:xxxx).

3) Conversion to PDF
POST https://pdf-services.adobe.io/operation/createpdf
Headers:

Body (latest attempt):

→ ❌ Always returns:

I’ve confirmed:

- The token is valid (no 401).

- The asset upload works perfectly.

- The same request with SDK v3.x works when a private key is available.

My questions:

- Is /operation/createpdf currently usable with standard REST OAuth2 credentials (client_id + secret)?

- Has the JSON structure changed since 2024 (the public documentation still shows the old schema)?

- Is there any updated schema or example for REST (non-SDK) workflows for HTML → PDF?

Thanks a lot in advance — I’ve tried every combination of headers and MIME types, so any internal example or confirmation would help clarify if this route is still open for REST developers.

I probably missed something...