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robotstxt-og/docs/OG-TWITTER-REFERENCE.md
Javier Casares f7702f2872 v1.0.0
2026-02-19 11:16:44 +00:00

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Open Graph & Twitter Cards — Reference

This document covers the Open Graph (OG) and Twitter Cards meta tag specifications relevant to this plugin, including which tags are mandatory, recommended, optional, and which this plugin outputs automatically.

Open Graph Protocol

Defined by Facebook/Meta. All OG tags use the property attribute.

Core Tags (og: namespace)

Property Type Required Notes
og:title string Required Title of the content. Used by all social crawlers.
og:type string Required Content type: website, article, video.movie, etc.
og:url URL Required Canonical URL of the page.
og:description string Recommended Short description (2–4 sentences). Max ~300 chars.
og:site_name string Recommended Name of the overall site (e.g. "My Blog").
og:locale string Recommended Locale in language_TERRITORY format (e.g. es_ES).
og:image URL Required (for cards) Must be JPEG or PNG for social crawler compatibility. Min 200×200 px. Recommended 1200×630 px.
og:image:secure_url URL Optional HTTPS version of og:image. Same value when the site is HTTPS-only.
og:image:type MIME type Recommended MIME type of the image (image/jpeg, image/png).
og:image:width integer Recommended Width in pixels. Avoids reflow in crawler previews.
og:image:height integer Recommended Height in pixels.
og:image:alt string Recommended Alt text for the image. Required for accessibility audits.

Article Tags (article: namespace)

Used when og:type = article. All are optional but recommended for news/blog content.

Property Type Notes
article:published_time ISO 8601 datetime Publication date (c format in PHP: get_the_date('c')).
article:modified_time ISO 8601 datetime Last modification date.
article:author URL Profile page of the author (Facebook profile URL). Often omitted.
article:section string Primary category or section (e.g. "Technology").
article:tag string Topic tags. Can be repeated once per tag.
article:expiration_time ISO 8601 datetime When the article expires (rarely used).

Video Tags (video: namespace)

For og:type = video.movie, video.episode, etc. Out of scope for this plugin.

Twitter Cards

Defined by X (formerly Twitter). Tags use the name attribute (not property).

Twitter falls back to og:* tags if the corresponding twitter:* tag is absent — except twitter:card, which is always required.

Card Types

Value Description
summary Small square image (minimum 144×144 px).
summary_large_image Large rectangular image (minimum 300×157 px, recommended 1200×628 px). Most common for blog/news content.
app Promotes a mobile app.
player Embeds a video/audio player.

Twitter Tags

Name Required Falls back to Notes
twitter:card Required — Must always be present. Without it, no Twitter Card is shown.
twitter:site Recommended — @username of the site's Twitter/X account.
twitter:creator Optional — @username of the content author.
twitter:title Recommended og:title Title of the content.
twitter:description Recommended og:description Description. Max 200 chars.
twitter:image Recommended og:image Must be JPEG, PNG, WebP, or GIF. Max 5 MB.
twitter:image:alt Recommended og:image:alt Alt text for the image. Max 420 chars.

What This Plugin Outputs

When no SEO plugin is active (direct injection)

The plugin outputs a complete set of OG and Twitter Card tags via wp_head (priority 5).

Open Graph tags

<!-- Core -->
<meta property="og:title" content="..." />
<meta property="og:type" content="article" />     <!-- or "website" -->
<meta property="og:url" content="..." />
<meta property="og:description" content="..." />  <!-- when available -->
<meta property="og:site_name" content="..." />
<meta property="og:locale" content="es_ES" />

<!-- Image (when a compatible image is resolved) -->
<meta property="og:image" content="https://...jpg" />
<meta property="og:image:secure_url" content="https://...jpg" />  <!-- HTTPS only -->
<meta property="og:image:width" content="1200" />
<meta property="og:image:height" content="630" />
<meta property="og:image:type" content="image/jpeg" />
<meta property="og:image:alt" content="..." />  <!-- when set in media library -->

<!-- Article-specific (og:type = article only) -->
<meta property="article:published_time" content="2026-02-18T00:00:00+00:00" />
<meta property="article:modified_time" content="2026-02-18T00:00:00+00:00" />
<meta property="article:section" content="Technology" />  <!-- primary category -->
<meta property="article:tag" content="WordPress" />       <!-- repeated per tag -->

Twitter Card tags

<meta name="twitter:card" content="summary_large_image" />
<meta name="twitter:site" content="@example" />  <!-- when configured in Settings -->
<meta name="twitter:image" content="https://...jpg" />  <!-- when image available -->

Twitter falls back to og:title, og:description, and og:image automatically, so those tags are not duplicated.

When Yoast SEO or RankMath is active

The plugin acts as a corrector only: it filters the image URL via the SEO plugin's filter hook, converting incompatible formats (AVIF/WebP) to JPEG/PNG. All other OG/Twitter tags are managed by the SEO plugin.

og:type Values Reference

Value When to use
website Default for homepages and most pages.
article Blog posts, news articles. This plugin uses this for is_singular('post').
profile User profile pages.
video.movie Movie pages.
video.episode TV episode pages.
music.song Song pages.
music.album Album pages.

Per-Post Overrides (Editor Meta Box)

The plugin adds an "Open Graph / Social Media" meta box to all post editors, allowing per-post overrides of:

Field OG Tag Fallback
Custom Title og:title Post title (get_the_title())
Custom Description og:description Post excerpt, or empty

These overrides are stored as post meta:

  • _og_title — custom OG title
  • _og_description — custom OG description

Context → og:type Mapping (this plugin)

WordPress context og:type
is_singular('post') article
is_singular('page') website
is_singular(other) website
is_front_page() / is_home() website
is_tax() / is_category() / is_tag() website

Image Compatibility

Social crawlers (Facebook, X, LinkedIn, WhatsApp, Telegram) generally require:

  • Format: JPEG or PNG (WebP partial support; AVIF not supported)
  • Minimum size: 200×200 px (Facebook requires 200×200 for summary)
  • Recommended: 1200×630 px for summary_large_image
  • Max file size: 8 MB (Facebook), 5 MB (Twitter)

This plugin's core function is to detect when a featured image is in an incompatible format (AVIF, WebP) and automatically serve a JPEG/PNG alternative via fallback resolution.

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