Hands down, this is one of the best apps I've ever used on Android. Absolutely amazing, something I've wanted for ages.
Type Machine, from the developer of just as brilliant Clipper, saves everything you type in all apps automatically, so that web form that ate your comment can go take a hike now.
It filters everything per-app, and you can even replay what you wrote using a timeline character by character.
You can set ignored apps in the settings, so you can, for example, disable your SMS app from being "spied on" by the app.
You can also schedule an automatic cleanup of the data (disabled, 1, 2, ..., 7 days).
Finally, you can require a PIN to unlock the app.
This is the app of the year for me.https://play.google.com/store/apps/details?id=fi.rojekti.typemachine