Gakuu - Learn Real Japanese

Gakku has a wide variety of reading materials in real Japanese (as opposed to textbook Japanese), from beginner right up to above JLPT N1 level.

You have to pay a subscription fee to get full lessons, but there are some free articles and you can also read the start of all articles by clicking on them, (see this article as an example: there’s actually a lot of free text on this one). So, you can actually get a lot out of this website for free.