Formula book entries?
 

For alchemist especially, how do we track which formulas we know?

Go to the Gear tab, click the + sign next to Gear, and scroll down to the bottom to find Formulas.

It would be nice if you could add Formulas directly to your Formula Book, but for now they're represented as separate "items" in your Gear list.

For now, click on the formula book and use the Notes section at the bottom of its customize form to record your formulas. Proper handling that can track exactly what you have a formula for and hopefully flag that in the purchase lists, handle the very wide variety of bonus formulas that each allow a narrow set of formulas to choose from (like the various bonus formulas an alchemist gets, or the formulas from learning snare crafting) is a large project that we haven't had a chance to implement yet.