We support A4, but will auto resize for countries like the US.
10 MB max. If you need larger files to be supported, please let us know.
If you need any more file types, please let us know.
If you need to convert a file to a PDF, it can be first passed to our uploads endpoint: /uploads?convert=post
This will return a URL to the converted pdf file that can be used in the /post/letters/send endpoint.
Our award-winning customer care team is here for you.Contact Support