This project is no longer maintained, due to GGG removing quest reward and vendor reward data from the GGPK. Keeping this data up to date manually is not feasible for me.

Path of Exile Leveling Helper was a website hosted at cinnabarit.pythonanywhere.com (broken link)
where you could import a Path of Building code to list all contained skill gems,
in the order you would receive them while leveling through the game acts.