apiverve_pdfpagenumbers

https://github.com/apiverve/pdfpagenumbers-API

PDF Page Numbers stamps a page number on every page of a PDF, uploaded or fetched from a URL, and returns a download link to the numbered file. Choose the corner or edge and the font size. Paid plans can also set a label format such as Page 3 of 12, the starting number, and skip a cover page.