To receive a free API key (which is per-IP) you should send us your server's IP and the full URL of the page where 3W1 SEO API will be implemented. The page must contain a note like: This tool is using <a href="http://3w1.eu/api">3W1 SEO API</a>. - it may be translated into other languages or extended, but the link must remain intact.
API Features List
http://api.3w1.eu/pagerank/?key=YOUR_KEY&url=THE_URL Returns the PageRank of THE_URL (integer from 0 to 10).
http://api.3w1.eu/predicted-pagerank/?key=YOUR_KEY&url=THE_URL Returns the predicted PageRank of THE_URL (integer from 0 to 10, can be sometimes slow [up to about 6 sec.]).
http://api.3w1.eu/whois/?key=YOUR_KEY&domain=THE_DOMAIN Returns the WHOIS records of THE_DOMAIN (string, up to 1 MB [limit]).
http://api.3w1.eu/http-headers/?key=YOUR_KEY&url=THE_URL Returns the HTTP headers of THE_URL (string, up to 1 MB [limit]).
All values are being returned as UTF-8 text/plain with a standard HTTP headers produced by Apache/2.