This document summarizes the code history of WordPress from its founding in 2003 to the present. It discusses major releases, contributors, added features like post meta and plugins, tools used for development like Git and unit testing, and the future direction of new APIs. The timeline shows steady growth from a few early contributors to over 200 today, with major releases every 6-12 months adding significant new functionality that maintains backwards compatibility.

1. The code history
of WordPress
WordCamp Paris - 2014

2. Who I am?
• Marko Heijnen - @markoheijnen
• Working at 1&1 as their WordPress
specialist
• WordPress core contributor
• GlotPress core developer - @GlotPress
• Co author of WP_Image_Editor

3. Our timeline
• 2003 - WordPress was founded
• 2005 - WordPress 2.0 got released
• 2006 - I started to use WordPress
• 2010 - My first contribution to WordPress
• 2012 - Recent rockstar of 3.4
• 2013 - WordPress becomes 10
• 2013 - 3.8 was the 21 major release

4. January 17, 2014 at 08:07

5. The first couple of
years I missed

6. I would say the
golden years

7. It was founded by
Matt Mullenweg
Mike Little

8. It all started almost 11
years ago when Matt
wrote a blog post

10. The comment

11. And WordPress
was born

12. But what were the most
important changes that
happened in the code?

13. Post Meta
When was this added to WordPress?

14. 0.70
• WordPress had its first release as a fork of
b2 on May 27, 2003
• A lot of code cleanups to make it more
stable and faster
• Functions like texturize and manual excerpt
were added

15. 1.0 “Miles Davis”
• Search engine friendly
permalinks
• Multiple categories
January 3, 2004

16. 1.2 “Charles Mingus”
• Post meta
• New plugin architecture
• Encryption of password
• Localization
• Sub categories
• Thumbnail creation
May 22, 2004

17. The WordPress Plugin Repository
• On January 10, 2005 the WordPress Plugin
repository was announced
• It was then on WP-Plugins.org
• It was focused on Trac since it didn’t have a
user friendly front-end, yet

18. 1.5 “Billy Strayhorn”
• The basic template engine
was added
• Pages was added
February 17, 2005

19. 2.0 “Duke Ellington”
• AJAX functionality got added
• Capability API
• Inline uploading
• User level options
• Pluggable object cache
• Functions.php was added
• Nonces 2.0.3
December 31, 2005

20. 2.1 “Ella Fitzgerald”
• Autosave
• All queries got checked
• More AJAX
• Cron API
• WP_Error class was added
January 22, 2007

21. 2.2 “Stan Getz”
• Widgets API
• Started using jQuery
• PHPMailer got added
• Increased the inline
documentation
May 16, 2007

22. The first unit tests got
September 20, 2007

23. 2.3 “Dexter Gordon”
• Updating system
• Taxonomy API got added
• Canonical URLs
• $wpdb->prepare()
• Activation protection
• Restructure of wp-admin
folder
September 24, 2007

24. 2.5 “Michael Brecker”
• Shortcode API
• Multi-file upload with
March 29, 2008
progress bar
• EXIF extraction
• Search posts and pages
• Installing/updating plugins
22 contributors

25. 2.6 “McCoy Tyner”
• Post Revisions
• Full SSL support
• Theme previews
July 15, 2008
75 contributors

26. 2.7 “John Coltrane”
• HTTP API
• Uninstall a plugin
• Settings API
• wp_page_menu()
• Plugin installer
• WordPress upgrader
December 10, 2008
144 contributors

27. 2.8 “Chet Baker”
• New Widgets API
• HTTP API updates and fixes
• Search/Install themes
June 11, 2009

28. 2.9 “Carmen McRae”
• Built-in image editor
• Post thumbnails
• Basic post type support
• Meta data for comments
• oEmbed
December 18, 2009
140> contributors

29. 3.0 “Thelonious Monk”
• WordPress MU merged
• Custom menus
• Custom post type support
• Lots of other improvements
June 17, 2010
218 contributors

31. 3.1 “Django Reinhardt”
• Admin bar
• WP_User_Query
• Advanced queries
• List-type Admin Screens
February 23, 2011
180> contributors

32. 3.2 “George Gershwin”
• Moved to PHP 5 and MySQL 5
• Speed improvements
• WP_Meta_Query
July 4, 2011
133 contributors

33. 3.3 “Sonny Stitt”
• New editor API
• Post-slug-only permalinks
• is_main_query()
• WP_Screen
• Metadata API improvements
December 12, 2011
179 contributors

34. 3.4 “Grant Green”
• Theme customizer
• wp.* XML-RPC methods
• WP_Theme
June 13, 2012
183 contributors

35. More awareness for
out unit tests

36. 3.5 “Elvin Jones”
• WP_Image_Editor
• switch_to_blog()
• Underscore/Backbone
• WP_Comment_Query and
December 11, 2012
WP_User_Query excepting
meta queries
260 contributors

37. 3.5 “Elvin Jones”
• WP_Post
• Ordering by post__in
• AJAX support functions like
December 11, 2012
wp_send_json_success()
260 contributors

38. 3.6 “Oscar Peterson”
• Audio/Video support
• Better control for revisions
• has_shortcode()
• Heartbeat API
August 1, 2013
225 contributors

39. 3.7 “Count Basie”
• Automattic updates
• Stronger passwords
• Language packs
• Cleanup tickets
• Better documentation
• Improved Search
• Date queries
October 24, 2013
211 contributors

40. 3.8 “Charlie Parker”
• Heartbeat performance and
December 12, 2013
API improvements
• Nginx detection
• automatic_updates_complete
188 Contributors

41. A great progress
was made

42. Backwards compatibility

43. The market

44. PHP versions

45. Our tools
• Official GIT mirrors
• Grunt
• JSHint
• Unit testing PHP and JS
• Minification
• Sass

46. The future
• 2014 looks like a great year for new API
features like:
• WP API
• Media improvements
• Post Meta library
• More see: http://make.wordpress.org/
core/features-as-plugins/

47. WPCentral.io
• @WPCentralio
• Work in progress
• If you like to see this information back in a
interactive way
• Currently building the features like:
• Download & Version history
• Timeline of features

48. Questions?
@markoheijnen - http://markoheijnen.com