Data Flow

Browser -> GET /blog
  -> Magento Router (matches base path)
  -> Blog\Index Controller
     -> PostRepository::getList(page, perPage)
        -> WordPressCache::load('posts_page_1')
           [cache hit] -> return cached Post[]
           [cache miss] ->
             -> Client::getPosts(['page' => 1, '_embed' => true])
                -> GET /wp-json/wp/v2/posts?page=1&_embed=1
                -> HTTP response
             -> Post::fromApiResponse() for each post
             -> WordPressCache::save(Post[], 'posts_page_1', [WORDPRESS_POST])
             -> return Post[]
     -> Assign posts to Block/ViewModel
  -> Layout renders blog/index.phtml
  -> Response to browser

Browser -> GET /blog/my-post-slug
  -> Magento Router
     -> resolveRoute('my-post-slug') -> controller: post, action: view
  -> Post\View Controller
     -> PostRepository::getBySlug('my-post-slug')
        -> WordPressCache::load('post_slug_my-post-slug')
           [cache miss] ->
             -> Client::getPostBySlug('my-post-slug')
                -> GET /wp-json/wp/v2/posts?slug=my-post-slug&_embed=1
             -> Client::getSeoMeta($post->id)   [if SEO enabled]
                -> GET /wp-json/oc-bridge/v1/seo/42
             -> ContentProcessor::process($post->content)
             -> WordPressCache::save(Post, key, [WORDPRESS_POST, WORDPRESS_POST_42])
     -> SeoPlugin injects meta tags into page head
  -> Layout renders blog/post/view.phtml

WordPress (content saved)
  -> save_post hook fires
  -> OC_Bridge_Cache_Webhook::on_post_save()
  -> wp_remote_post() non-blocking POST to Magento

Magento -> POST /wordpress/webhook/cachepurge
  -> Webhook\CachePurge Controller
     -> read X-OC-Bridge-Signature header
     -> compute HMAC-SHA256(request body, api_key)
     -> hash_equals(computed, received)
        [fail] -> 401 response
        [pass] ->
          -> parse payload: object_type, object_id
          -> map object_type to cache tags
          -> Magento\Framework\App\Cache\TypeListInterface::invalidate(tags)
     -> 200 OK response