As API's go this one is pretty weak, but it's how you can interact with this tool using your application or site. It's not much, but until I get around to releasing the code (I just need to scrub it and then I'll set it free) It's all there is. You are welcome to use the code below and interact with the tool, but if you're going to scrape the site, please give me a link. If you just place a form like the example below, no link is needed, but it would be appreciated.
If you include this tool in your site or application, please let me know and I'll assign you an identifier so I can keep track of how it's being used (I'm just curious to see how it's implemented).
To interact with this tool, just pass "url" using POST or GET to http://seopen/seopen-tools/header-checker.php where "url" is the url you want to check headers for. For example, the url http://seopen.com/seopen-tools/header-checker.php?url=http://www.webmasterworld.com will check the headers for http://www.webmasterworld.com. The code below illustrates how you could use this tool on your site.
<div style="background:grey; text-align:center; padding:5;"><form action="http://seopen.com/seopen-tools/header-checker.php" method="post">Check Server Headers: <input name="url" type="text" value="" title="Enter the URL" size="40"> <input type="submit" value="Show Headers" title="View Server Headers"></form>
<a href="http://seopen.com/">Free SEO Tools</a></div>
Enjoy. Let me know if you have any suggestions or requests.