Rich text
For the note on an invoice or the body of a reminder — enough formatting to be useful, and no more. No editor library is bundled, so there is nothing extra to license or to keep up to date.
The editor
select some text and use the bar
Thank you for your business. This invoice covers bookkeeping for September and the quarter-end review.
Payment is due within 30 days. Our bank details are on the last page; please quote the invoice number so the payment is matched automatically.
What comes out
the markup, so you can see what would be stored
Type here, then format a word.
Being straight about this one
This editor is built on document.execCommand. That API is marked deprecated, and it is still the only formatting command every one of the five browsers Coffer targets implements — every small editor in this category is built the same way, whether or not it says so.
Because of that, all of it goes through one apply() function in src/js/coffer.js. If you would rather run a full editor, replace that one function and the toolbar keeps working.
Whatever you use, sanitise on the server. A contenteditable region can be pasted into, and anything it produces is untrusted the moment it leaves the page.