Proton Mail
proton.me
Encrypted mailbox where the provider cannot read the contents of your messages
element.io
End-to-end encrypted group chat in a browser tab, on the open Matrix network.
A full chat client — rooms, threads, voice and video calls, file sharing — running in the page against the decentralised Matrix protocol, with end-to-end encryption on by default for private rooms. Because the protocol is open you can use the public matrix.org server, someone else's, or your own, and still talk to everyone. It is the realistic browser answer to 'a team chat nobody has to install'.
Questions
Free to use, but you have to register before it will do the job. Encryption key management is the rough edge — lose your recovery key on a new device and old messages stay permanently unreadable.
Yes. Element sends your input to its own servers to process it. That is fine for public material; for anything containing personal data, use one of the on-device tools instead.
Encryption key management is the rough edge — lose your recovery key on a new device and old messages stay permanently unreadable.
Alternatives
Same category or same task, ordered by how closely they overlap.
proton.me
Encrypted mailbox where the provider cannot read the contents of your messages
formspree.io
Gives a static site's contact form somewhere to POST that emails you the answers
toolbox.googleapps.com
Paste raw email headers and see every hop, the delay at each, and the auth results
mail-tester.com
Send one email to the address it gives you and get a spam score out of ten
mailerlite.com
Sends a newsletter to a small list on a free tier that does not expire
mailinator.com
Any address at mailinator.com already has an inbox you can read without signing up