What API can I use to get FAA NOTAMS or will this one I found work? I am not sure if this is the correct place to ask this because it has to do with APIs with XML/JSON/SOAP, but it also has to do with aviation.

I am in dire need to find an API associated with the FAA to get NOTAMs for areas and airports. NOTAMs are Notices to Airmen, and it will be a useful feature in a service I am creating.

I have done extensive searching for a NOTAMs API, but I cannot find anything except this:
https://notams.aim.faa.gov/notamWFS/

However, this website requires registration which is just a broken link. Any suggestions on how to use this?

Do you know of any other NOTAM APIs available?
Also, if possible, do you know of a weather API which has the same information included in an ATIS/AWOS reporting station?

I was able to find working APIs for US regulations and general weather (not specific enough) and pilot information, but I cannot find any for specific weather or NOTAMs.

EDIT: A friend of mine was able to click the registration button, and it didn't give him an error. He sent me the link and I am now trying to register on the site I found.
As @GdD mentioned in the comments, there is an API for NOTAMs here: https://www.icao.int/safety/iStars/Pages/notams.aspx

You also asked for metars, which you can get from here:
http://tgftp.nws.noaa.gov/data/observations/metar/cycles/${TIME}Z.TXT where ${TIME} is the hour of the Zulu time you are interest in, wrapped between 0 and 23 (eg. 16)