URL Rewrite - Remove .html extension
This solution worked for me in the end:
<rule name="RedirectUserFriendlyURL1" stopProcessing="true">
<match url="^(.*)\.(.*)$" />
<conditions>
<add input="{REQUEST_METHOD}" pattern="^POST$" negate="true" />
</conditions>
<action type="Redirect" url="{R:1}" appendQueryString="false" />
</rule>
<rule name="RewriteUserFriendlyURL1" stopProcessing="true">
<match url="^(.*)$" />
<conditions>
<add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
<add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
</conditions>
<action type="Rewrite" url="{R:1}.(.*)" />
</rule>