NeomMob

function wpb_after_post_content($content){
	if (is_single()) {
		if( in_category( 'ma_catégorie' ) ){
			$custom_content = "<h2>Ceci est mon super pied de page!</h2>";
			$content =   $content . $custom_content ;
		}
	}
	return $content;
}
add_filter( "the_content", "wpb_after_post_content" );

NeomMob

    "Layouts":[
        {
           "Name" : "Default",
           "Group" :"Basic",
           "Snippet": "# Fidele",
           "Classes": "titleandcolumns",
           "Dynamic": false,
           "DynamicPart" :"",
           "FixedParts": 1,
           "Template": "<div class=\"grid\"><div class=\"column\"> {@{content}@}</div></div>",