Use filter rest_{$this->post_type}_query to add the post meta support in WP Rest API.
Use below code snippet to add the post meta support for post type Post.
Syntax:
http://mysite.com/wp-json/wp/v2/post?meta_key=<meta-key>&meta_value=<meta-value>
How to use?
E.g. Get posts which post meta already-visited
value is true
.
http://mysite.com/wp-json/wp/v2/post?meta_key=already-visited&meta_value=true
Code Snippet: