It would be great to have a feature similar to message reactions in chat apps, for example, being able to quickly tap an icon (like 👍 or ❤️) to react to an email without writing a full reply.

Microsoft Outlook already includes this, and it’s great for acknowledging messages or quick feedback without having to write a full reply.

For Proton Mail users, the reaction could appear inline (e.g., “Recipient liked this email”).
For other email providers, Proton could send a short, automatically generated message such as:
“[Username] reacted to your email with 👍.”