"how do i find all youtube video ids in a string using a regex?" Answer’s


A YouTube video URL may be encountered in a variety of formats:

  • latest short format: http://youtu.be/NLqAF9hrVbY
  • iframe: http://www.youtube.com/embed/NLqAF9hrVbY
  • iframe (secure): https://www.youtube.com/embed/NLqAF9hrVbY
  • object param: http://www.youtube.com/v/NLqAF9hrVbY?fs=1&hl=en_US
  • object embed: http://www.youtube.com/v/NLqAF9hrVbY?fs=1&hl=en_US
  • watch: http://www.youtube.com/watch?v=NLqAF9hrVbY
  • users: http://www.youtube.com/user/Scobleizer#p/u/1/1p3vcRhsYGo
  • ytscreeningroom: http://www.youtube.com/ytscreeningroom?v=NRHVzbJVx8I
  • any/thing/goes!: http://www.youtube.com/sandalsResorts#p/c/54B8C800269D7C1B/2/PPS-8DMrAn4
  • any/subdomain/too: http://gdata.youtube.com/feeds/api/videos/NLqAF9hrVbY
  • more params: http://www.youtube.com/watch?v=spDj54kf-vY&feature=g-vrec
  • query may have dot: http://www.youtube.com/watch?v=spDj54kf-vY&feature=youtu.be
  • nocookie domain: http://www.youtube-nocookie.com

Here is a PHP function with a commented regex that matches each of these URL forms and converts them to links (if they are not links already):

// Linkify youtube URLs which are not already links.
function linkifyYouTubeURLs($text) {
    $text = preg_replace('~(?#!js YouTubeId Rev:20160125_1800)
        # Match non-linked youtube URL in the wild. (Rev:20130823)
        https?://          # Required scheme. Either http or https.
        (?:[0-9A-Z-]+.)?  # Optional subdomain.
        (?:                # Group host alternatives.
          youtu.be/       # Either youtu.be,
        | youtube          # or youtube.com or
          (?:-nocookie)?   # youtube-nocookie.com
          .com            # followed by
          S*?             # Allow anything up to VIDEO_ID,
          [^ws-]         # but char before ID is non-ID char.
        )                  # End host alternatives.
        ([w-]{11})        # $1: VIDEO_ID is exactly 11 chars.
        (?=[^w-]|$)       # Assert next char is non-ID or EOS.
        (?!                # Assert URL is not pre-linked.
          [?=&+%w.-]*     # Allow URL (query) remainder.
          (?:              # Group pre-linked alternatives.
            ['"][^<>]*>   # Either inside a start tag,
          | </a>           # or inside <a> element text contents.
          )                # End recognized pre-linked alts.
        )                  # End negative lookahead assertion.
        [?=&+%w.-]*       # Consume any URL (query) remainder.
        ~ix', '<a href="http://www.youtube.com/watch?v=$1">YouTube link: $1</a>',
    return $text;

; // End $YouTubeId.

And here is a JavaScript version with the exact same regex (with comments removed):

// Linkify youtube URLs which are not already links.
function linkifyYouTubeURLs(text) {
    var re = /https?://(?:[0-9A-Z-]+.)?(?:youtu.be/|youtube(?:-nocookie)?.comS*?[^ws-])([w-]{11})(?=[^w-]|$)(?![?=&+%w.-]*(?:['"][^<>]*>|</a>))[?=&+%w.-]*/ig;
    return text.replace(re,
        '<a href="http://www.youtube.com/watch?v=$1">YouTube link: $1</a>');


  • The VIDEO_ID portion of the URL is captured in the one and only capture group: $1.
  • If you know that your text does not contain any pre-linked URLs, you can safely remove the negative lookahead assertion which tests for this condition (The assertion beginning with the comment: "Assert URL is not pre-linked.") This will speed up the regex somewhat.
  • The replace string can be modified to suit. The one provided above simply creates a link to the generic "http://www.youtube.com/watch?v=VIDEO_ID" style URL and sets the link text to: "YouTube link: VIDEO_ID".

Edit 2011-07-05: Added - hyphen to ID char class

Edit 2011-07-17: Fixed regex to consume any remaining part (e.g. query) of URL following YouTube ID. Added 'i' ignore-case modifier. Renamed function to camelCase. Improved pre-linked lookahead test.

Edit 2011-07-27: Added new "user" and "ytscreeningroom" formats of YouTube URLs.

Edit 2011-08-02: Simplified/generalized to handle new "any/thing/goes" YouTube URLs.

Edit 2011-08-25: Several modifications:

  • Added a Javascript version of: linkifyYouTubeURLs() function.
  • Previous version had the scheme (HTTP protocol) part optional and thus would match invalid URLs. Made the scheme part required.
  • Previous version used the b word boundary anchor around the VIDEO_ID. However, this will not work if the VIDEO_ID begins or ends with a - dash. Fixed so that it handles this condition.
  • Changed the VIDEO_ID expression so that it must be exactly 11 characters long.
  • The previous version failed to exclude pre-linked URLs if they had a query string following the VIDEO_ID. Improved the negative lookahead assertion to fix this.
  • Added + and % to character class matching query string.
  • Changed PHP version regex delimiter from: % to a: ~.
  • Added a "Notes" section with some handy notes.

Edit 2011-10-12: YouTube URL host part may now have any subdomain (not just www.).

Edit 2012-05-01: The consume URL section may now allow for '-'.

Edit 2013-08-23: Added additional format provided by @Mei. (The query part may have a . dot.

Edit 2013-11-30: Added additional format provided by @CRONUS: youtube-nocookie.com.

Edit 2016-01-25: Fixed regex to handle error case provided by CRONUS.

Wednesday, March 31, 2021
answered 10 Months ago
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