API guides
Work with PDF files and remote assets
Handle binary responses and use remotely loaded images safely.
Reviewed 2026-08-05 · PDFDesignAPI Engineering
Binary PDF responses
A successful synchronous generation response is PDF bytes. Stream or save the body and preserve the application/pdf content type.
Do not decode the PDF as text or include its contents in logs.
Remote image restrictions
Use publicly reachable HTTP or HTTPS asset URLs. The renderer blocks private, loopback, link-local, metadata, reserved, credentialed, unsupported, and unresolvable destinations.
Use stable assets with appropriate cache and access behavior; expiring URLs must remain valid for the complete render.
Fonts and glyphs
Verify that selected fonts contain every language and symbol required by the document. Test localized fixtures and all weights used by the template.