The URL/endpoints exposed by RESTBase should map accurately to how the routes will be processed by Proton internally. This is because edge caches will receive URLs of the form /{domain}/v1/page/pdf/ for proton and those need to be rewritten to match what Proton will do internally.
Below is a table of the end-points map
| RESTBase URL/endpoint (received on edge) | Rewrite for Proton |
| /{domain}/v1/page/pdf/{title} | /{domain}/v1/pdf/{title}/a4 |
| /{domain}/v1/page/pdf/{title}/{format} | /{domain}/v1/pdf/{title}/{format} |
| /{domain}/v1/page/pdf/{title}/{format}/{type} | /{domain}/v1/pdf/{title}/{format}/{type} |
NOTE: RESTBase will append the format (a4) to the URL if only a title is supplied but support for this is not yet in proton, see: https://gerrit.wikimedia.org/r/c/mediawiki/services/chromium-render/+/933885 (adding support).