diff --git a/_includes/head.html b/_includes/head.html
index 62bd767..22d987a 100644
--- a/_includes/head.html
+++ b/_includes/head.html
@@ -6,6 +6,29 @@
     <meta name="description"
           content='{% if page.excerpt %}{{ page.excerpt | strip_html | strip | truncatewords: 75 }}{% elsif page.description %}{{ page.description }}{% else %}{{ site.description }}{% endif %}'>
 
+    <meta property="og:site_name" content="{{ site.title }}">
+    {% if page.title %}
+        <meta property="og:title" content="{{ page.title }}">
+        <meta property="og:type" content="article">
+        <meta property="og:description" content="{{ page.excerpt | strip_html }}"/>
+    {% else %}
+        <meta property="og:title" content="{{ site.title }}">
+        <meta property="og:type" content="website">
+        <meta property="og:description" content="{{ site.description }}">
+    {% endif %}
+    {% if page.date %}
+        <meta property="article:published_time" content="{{ page.date | date_to_xmlschema }}">
+    {% endif %}
+    <meta property="og:url" content="{{ site.url }}{{ page.url }}" />
+    {% if page.tags %}
+        <meta itemprop="keywords" content="{{ page.tags | join: ',' }}" />
+        {% for tag in page.tags %}
+            <meta property="article:tag" content="{{ tag }}">
+        {% endfor %}
+    {% endif %}
+    {% if author %}
+        <meta property="article:author" content="{{ author.name }}" />
+    {% endif %}
     {% asset main.css %}
     {% asset fa-svg-with-js.css %}
     <link rel="canonical" href="{{ page.url | replace:'index.html','' | prepend: site.baseurl | prepend: site.url }}">
diff --git a/_layouts/post.html b/_layouts/post.html
index 72bb15b..94b82c9 100644
--- a/_layouts/post.html
+++ b/_layouts/post.html
@@ -1,6 +1,11 @@
 ---
 layout: default
 ---
+{% if page.date_modified %}
+{% assign modified = page.date_modified %}
+{% else %}
+{% assign modified = page.date %}
+{% endif %}
 <article class="post" itemscope itemtype="http://schema.org/BlogPosting">
 
     <header class="post-header">
@@ -10,6 +15,7 @@ layout: default
             <time datetime="{{ page.date | date_to_xmlschema }}" itemprop="datePublished">
                 {{ page.date | date: "%b %-d, %Y" }}
             </time>
+            <meta content="{{ modified | date_to_xmlschema }}" itemprop="dateModified" />
             {% if page.author %} • <span class="far fa-user"></span>
                 <span itemprop="author" itemscope itemtype="http://schema.org/Person">
                 <span itemprop="name">{{ page.author }}</span>