Minecraft Advancement Builder
Advancements are the closest thing vanilla has to a quest system. They chain into trees, show a toast when completed, and can hand out experience, unlock recipes or run a function. This builder writes the JSON and the /advancement grant line to fire it.
Advancements live inside a data pack. The data pack generator builds the folder if you do not have one.
Start from a preset
File
A root advancement starts its own tab in the advancements screen. Give it a parent instead and it becomes a step in that parent's tree.
Display
Trigger
Rewards
Unlocking a recipe here is how a custom recipe finally appears in the recipe book. That is the whole job of most vanilla advancements you never see.
Generated JSON
Save as
Grant it by hand
With the impossible trigger this is the only way it completes, which is exactly what you want when a quest step is finished by your own logic rather than by the world.