Grammar
Grammar & Resources, University of Texas at AustinExtensive description of the grammar.
A deep dive into the Persian grammar, compiled by the Department of Middle Eastern Studies at the The University of Austin, Texas. While I feel the material at times could be organized and presented a little better, it is a very exhaustive walkthrough of all the grammatical structures.
The websites also features high-quality audio pronouncations throughout, as well as some video content designed for learners.
DasturVery academic discussion of the Persian grammar
Navid Fazel's resource is so extensive, it really deserves to be published as a book. But it also clearly targets people with a background in linguistics. It is full of specialist terminology, and spends a lot of effort on categorizing and classifying.
I would think that someone starting to learn the language would very quickly feel lost, but for those more advanced seeking a reference, this will come in handy.
Unfortunately, on occasion the right-to-left text on the page does not interact correctly with the English left-to-right text, which can be annoying.
Ali Jahanshiri's Personal WebsiteVerb conjugator and concise, but extensive grammar resource.
A real gem. In addition to many other things, this contains one of the most concise, well-organized guides to Persian grammar you'll find, and a verb conjugator that works with both Persian script as well as roman transcription.
It was a great help to me when I was coding the grammar-parser of Farsi.school, and also my inspiration to start the page you are reading right now.
Ali is taking Bitcoin-donations, and if you find is site useful, I encourage you to support him.