You can request a dungeon with a set of specific tags via the url parameter "tags" :
https://watabou.github.io/one-page-dungeon/?seed=177003564&tags=backdoor,chaotic....
It is also possible to make the browser download a map (as png/svg/json) right after it's generated:
https://watabou.github.io/one-page-dungeon/?seed=1143801683&export=png
Since it's a purely client-side application, there is no real api to work with it.