The official website for So I’m a Spider, So What? announced that the anime adaptation will be released on January 2021. There will also be a two consecutive cours.
The anime was originally scheduled for 2020 but has been pushed back to 2021 due to COVID-19.
Yen Press describes the light novel as:
I used to be a normal high school girl but in the blink of an eye, I woke up in a place I’ve never seen before and-and I was reborn as a spider?! How could something that’s nothing more than a tiny spider (that’s me) possibly survive in literally the worst dungeon ever? Are there no rules? There should be some rules! Who the hell is responsible for this? SHOW YOUR FACE!
Source: So I’m a Spider, So What? official website