You can link to protonURL with the text box pre-filled to have the protonURL ready to be created. To do this, you just need to create a link like:
https://protonurl.ch?prefilled=TG9yZW0gaXBzdW0KZG9sb3Igc2l0IGFtZXQ=
The content of the "prefilled" field must be encoded in base64. Here is an example code in PHP:
<a href="https://protonurl.ch/?prefilled=<?php echo base64_encode("Login: my-login\nPassword: my-password"); ?>" target="_blank">Bouton</a>
You can also include the language to redirect the visitor directly to your language:
<a href="https://protonurl.ch/en?prefilled=<?php echo base64_encode("Login: my-login\nPassword: my-password"); ?>" target="_blank">Bouton</a>
Please note, this feature is intended for experienced users, use these pre-filled links with care, they should only be displayed to people who are already aware of the content or to whom this content is voluntarily sent, and not to the public. The "prefilled" content encoded via base64 is not encrypted, this encoding is used simply to facilitate the creation and sharing of the link.
We decline all responsibility in the event of misuse of our system.