Just another oembed service.
Calling the API
curl -H "Accept: application/json" https://oembedly.com/api.php?url=https%3A%2F%2Fyoutu.be%2FgfJVoF5ko1Y
{
"result": true,
"html": "<iframe width=\"480\" height=\"270\" src=\"https:\/\/www.youtube.com\/embed\/gfJVoF5ko1Y&feature=oembed\" frameborder=\"0\" allowfullscreen><\/iframe>"
}