List of all WordPress functions (Categorized)

~1000 WordPress PHP Functions, by learning all of them you can say you are master in WP Development.

• cat_is_ancestor_of
• get_all_category_ids (deprecated)
• get_ancestors
• get_cat_ID
• get_cat_name
• get_categories
• get_category
• get_category_by_path
• get_category_by_slug
• get_the_category_by_ID
• get_the_category_list
• get_category_link
• get_category_parents
• get_the_category
• single_cat_title
• in_category
• is_category
• the_category
• wp_category_checklist
• wp_dropdown_categories
• wp_list_categories

• wp_create_category
• wp_delete_category
• wp_insert_category

• get_tag
• get_tag_link
• get_tags
• get_the_tag_list
• get_the_tags
• has_tag
• is_tag
• the_tags
• single_tag_title
• tag_description
• wp_generate_tag_cloud
• wp_tag_cloud

• get_object_taxonomies
• get_edit_term_link
• get_taxonomy
• get_taxonomies
• get_term
• get_the_term_list
• get_term_by
• the_terms
• get_the_terms
• get_term_children
• get_term_link
• get_terms
• is_taxonomy (deprecated)
• is_tax
• is_taxonomy_hierarchical
• is_term (deprecated)
• taxonomy_exists
• term_exists
• register_taxonomy
• register_taxonomy_for_object_type
• wp_get_object_terms
• wp_remove_object_terms
• wp_set_object_terms
• wp_insert_term
• wp_update_term
• wp_delete_term
• wp_terms_checklist

• get_adjacent_post
• get_boundary_post
• get_children
• get_extended
• get_next_post
• get_next_posts_link
• next_posts_link
• get_permalink
• the_permalink
• get_the_excerpt
• the_excerpt
• get_the_post_thumbnail
• get_post
• get_post_field
• get_post_ancestors
• get_post_mime_type
• get_post_status
• get_post_format
• set_post_format
• get_edit_post_link
• get_delete_post_link
• get_previous_post
• get_previous_posts_link
• previous_posts_link
• get_posts
• have_posts
• is_post (deprecated)
• is_single
• is_sticky
• get_the_ID
• the_ID
• the_post
• wp_get_recent_posts
• wp_get_single_post (deprecated)
• has_post_thumbnail
• has_excerpt
• has_post_format

• register_post_status

• register_post_type
• is_post_type_archive
• post_type_archive_title
• add_post_type_support
• remove_post_type_support
• post_type_supports
• set_post_type
• post_type_exists
• get_post_type
• get_post_types
• get_post_type_archive_link
• get_post_type_object
• get_post_type_capabilities
• get_post_type_labels
• is_post_type_hierarchical

• wp_delete_post
• wp_insert_post
• wp_publish_post
• wp_trash_post
• wp_update_post

• get_all_page_ids
• get_ancestors
• get_page (deprecated)
• get_page_link
• get_page_by_path
• get_page_by_title
• get_page_children
• get_page_hierarchy
• get_page_uri
• get_pages
• is_page
• page_uri_index (method of class WP_Rewrite)
• wp_link_pages
• wp_list_pages
• wp_page_menu
• wp_dropdown_pages

• add_post_meta
• delete_post_meta
• get_post_custom
• get_post_custom_keys
• get_post_custom_values
• get_post_meta
• update_post_meta
• register_meta

• get_attached_file
• image_resize (deprecated)
• image_edit_before_change (ported to WP_Image_Editor object)
• is_attachment
• is_local_attachment
• set_post_thumbnail
• update_attached_file
• wp_attachment_is_image
• wp_create_thumbnail (deprecated)
• wp_insert_attachment
• wp_delete_attachment
• wp_get_attachment_image
• wp_get_attachment_link
• wp_get_attachment_image_src
• wp_get_attachment_metadata
• wp_get_attachment_thumb_file
• wp_get_attachment_thumb_url
• wp_get_attachment_url
• wp_check_for_changed_slugs
• wp_count_posts
• wp_get_mime_types
• wp_mime_type_icon
• wp_generate_attachment_metadata
• wp_prepare_attachment_for_js
• wp_update_attachment_metadata

• get_bookmark
• get_bookmarks
• wp_list_bookmarks

• wp_get_post_categories
• wp_set_post_categories
• wp_get_post_tags
• wp_set_post_tags
• wp_get_post_terms
• wp_set_post_terms
• wp_count_terms
• has_term
• is_object_in_term

• add_meta_box
• remove_meta_box
• get_the_ID
• the_ID
• get_the_author
• the_author
• get_the_author_posts
• get_the_content
• the_content
• get_the_title
• the_title
• the_title_attribute
• wp_trim_excerpt
• wp_get_post_revision
• wp_get_post_revisions
• wp_is_post_revision
• paginate_links

• bloginfo_rss
• comment_author_rss
• comment_link
• comment_text_rss
• do_feed
• do_feed_atom
• do_feed_rdf
• do_feed_rss
• do_feed_rss2
• fetch_feed
• fetch_rss (deprecated)
• get_author_feed_link
• get_bloginfo_rss
• get_category_feed_link
• get_comment_link
• get_comment_author_rss
• get_post_comments_feed_link
• get_rss (deprecated)
• get_search_comments_feed_link
• get_search_feed_link
• get_the_category_rss
• get_the_title_rss
• permalink_single_rss (deprecated)
• post_comments_feed_link
• rss_enclosure
• the_title_rss
• the_category_rss
• the_content_rss (deprecated)
• the_excerpt_rss
• wp_rss (deprecated)

• add_cap
• add_role
• author_can
• current_user_can
• current_user_can_for_blog
• get_role
• get_super_admins
• is_super_admin
• map_meta_cap
• remove_cap
• remove_role
• user_can

• auth_redirect
• count_users
• count_user_posts
• count_many_users_posts
• email_exists
• get_currentuserinfo
• get_current_user_id
• get_profile (deprecated)
• get_user_by
• get_userdata
• get_usernumposts (deprecated)
• get_users
• set_current_user (deprecated)
• user_pass_ok (deprecated)
• wp_authenticate
• username_exists
• validate_username
• wp_dropdown_users
• wp_get_current_user
• wp_set_current_user
• wp_set_password
• get_author_posts_url
• get_the_modified_author
• is_multi_author

• add_user_meta
• delete_user_meta
• get_user_meta
• update_user_meta
• get_the_author_meta

• wp_create_user
• wp_delete_user
• wp_insert_user
• wp_update_user

• is_user_logged_in
• wp_login_form
• wp_signon
• wp_logout
• wp_loginout
• wp_logout_url

• wp_remote_get
• wp_remote_retrieve_body
• wp_get_http_headers
• wp_remote_fopen

• add_ping
• add_comment_meta
• check_comment
• comment_text
• comment_form
• comments_number
• discover_pingback_server_uri
• delete_comment_meta
• do_all_pings
• do_enclose
• do_trackbacks
• generic_ping
• get_approved_comments
• get_avatar
• get_comment
• get_comment_text
• get_comment_meta
• get_comments
• wp_list_comments
• get_enclosed
• get_lastcommentmodified
• get_pung
• get_to_ping
• have_comments
• get_comment_author
• is_trackback
• pingback
• privacy_ping_filter
• sanitize_comment_cookies
• trackback
• trackback_url
• trackback_url_list
• update_comment_meta
• weblog_ping
• wp_allow_comment
• wp_count_comments
• wp_delete_comment
• wp_filter_comment
• wp_get_comment_status
• wp_get_current_commenter
• wp_insert_comment
• wp_new_comment
• wp_set_comment_status
• wp_throttle_comment_flood
• wp_update_comment
• wp_update_comment_count
• wp_update_comment_count_now

• comment_class
• comment_ID
• comment_author
• comment_date
• comment_time
• get_comment_date
• get_comment_time

• paginate_comments_links
• previous_comments_link
• next_comments_link
• get_comment_pages_count

• has_filter
• add_filter
• apply_filters
• apply_filters_ref_array
• current_filter
• merge_filters
• remove_filter
• remove_all_filters

• has_action
• add_action
• do_action
• do_action_ref_array
• did_action
• remove_action
• remove_all_actions

• plugin_basename
• plugins_url
• get_plugin_data
• get_admin_page_title
• plugin_dir_path
• register_activation_hook
• register_deactivation_hook
• menu_page_url
• is_plugin_active
• is_plugin_active_for_network
• is_plugin_inactive
• is_plugin_page
• add_contextual_help (deprecated)
• get_plugins

• is_active_widget
• register_widget
• the_widget
• unregister_widget
• wp_add_dashboard_widget
• wp_convert_widget_settings
• wp_get_sidebars_widgets
• wp_get_widget_defaults
• wp_register_sidebar_widget
• wp_register_widget_control
• wp_set_sidebars_widgets
• wp_unregister_sidebar_widget
• wp_unregister_widget_control
• wp_widget_description

• register_setting
• unregister_setting
• settings_fields
• do_settings_fields
• do_settings_sections
• add_settings_field
• add_settings_section
• add_settings_error
• get_settings_errors
• settings_errors

• add_shortcode
• do_shortcode
• do_shortcode_tag
• get_shortcode_regex
• remove_shortcode
• remove_all_shortcodes
• shortcode_atts
• shortcode_parse_atts
• strip_shortcodes

• comments_template
• get_footer
• get_header
• get_sidebar
• get_search_form

• add_custom_background (deprecated)
• add_custom_image_header (deprecated)
• add_image_size
• add_theme_support
• body_class
• current_theme_supports
• dynamic_sidebar
• get_404_template
• get_archive_template
• get_attachment_template
• get_author_template
• get_body_class
• get_category_template
• get_comments_popup_template
• get_current_theme
• get_date_template
• get_header_image
• get_header_textcolor
• get_home_template
• get_locale_stylesheet_uri
• get_page_template
• get_paged_template
• get_post_class
• get_query_template
• get_search_template
• get_single_template
• get_stylesheet
• get_stylesheet_directory
• get_stylesheet_directory_uri
• get_stylesheet_uri
• get_tag_template
• get_taxonomy_template
• get_template
• get_template_directory
• get_template_directory_uri
• get_theme_file_uri
• get_theme_file_path
• get_template_part
• get_theme (deprecated)
• wp_get_themes
• get_theme_data (deprecated)
• get_theme_support
• get_theme_mod
• get_theme_mods
• get_theme_root
• get_theme_roots
• get_theme_root_uri
• get_themes (deprecated)
• has_header_image
• header_image
• header_textcolor
• in_the_loop
• is_child_theme
• is_active_sidebar
• is_admin_bar_showing
• is_customize_preview
• is_dynamic_sidebar
• language_attributes
• load_template
• locale_stylesheet
• locate_template
• post_class
• preview_theme
• preview_theme_ob_filter
• preview_theme_ob_filter_callback
• register_nav_menu
• register_nav_menus
• get_registered_nav_menus
• wp_create_nav_menu
• register_sidebar
• register_sidebars
• register_theme_directory
• remove_theme_mod
• remove_theme_mods
• remove_theme_support
• require_if_theme_supports
• search_theme_directories
• set_theme_mod
• switch_theme
• validate_current_theme
• unregister_nav_menu
• unregister_sidebar
• wp_add_inline_style
• wp_clean_themes_cache
• wp_get_archives
• wp_get_nav_menu_items
• wp_get_theme
• wp_nav_menu
• wp_oembed_remove_provider
• wp_page_menu
• wp_title

• current_time
• date_i18n
• get_calendar
• get_date_from_gmt
• get_lastpostdate
• get_lastpostmodified
• get_day_link
• get_gmt_from_date
• get_month_link
• the_date
• get_the_date
• the_time
• get_the_time
• the_modified_time
• get_the_modified_time
• get_weekstartend
• get_year_link
• human_time_diff
• is_new_day
• iso8601_timezone_to_offset
• iso8601_to_datetime
• mysql2date

• is_serialized
• is_serialized_string
• maybe_serialize
• maybe_unserialize

• add_option
• add_site_option
• delete_option
• delete_site_option
• form_option
• get_alloptions (deprecated)
• get_site_option
• get_site_url
• get_admin_url
• get_user_option
• get_option
• update_option
• update_site_option
• update_user_option
• wp_load_alloptions

• set_transient()
• get_transient()
• delete_transient()
• set_site_transient()
• get_site_transient()
• delete_site_transient()

• add_menu_page
• remove_menu_page
• add_submenu_page
• remove_submenu_page
• add_object_page
• add_utility_page
• add_comments_page
• add_dashboard_page
• add_links_page
• add_management_page
• add_media_page
• add_options_page
• add_pages_page
• add_plugins_page
• add_posts_page
• add_theme_page
• add_users_page

• add_node
• remove_node
• add_group
• get_node
• get_nodes

• checked
• disabled
• selected
• submit_button
• get_submit_button

• check_admin_referer
• check_ajax_referer
• wp_create_nonce
• wp_explain_nonce (deprecated)
• wp_get_original_referer
• wp_get_referer
• wp_nonce_ays
• wp_nonce_field
• wp_nonce_url
• wp_original_referer_field
• wp_referer_field
• wp_send_json
• wp_send_json_error
• wp_send_json_success
• wp_verify_nonce

• xmlrpc_getpostcategory
• xmlrpc_getposttitle
• xmlrpc_removepostdata
• user_pass_ok (deprecated)

• __
• _x
• _n
• _nx
• _e
• _ex
• _ngettext (deprecated)
• esc_attr__
• esc_attr_e
• esc_html__
• esc_html_e
• get_locale
• load_default_textdomain
• load_plugin_textdomain
• load_muplugin_textdomain
• load_textdomain
• load_theme_textdomain
• is_rtl

• spawn_cron
• wp_clear_scheduled_hook
• wp_cron
• wp_get_schedule
• wp_get_schedules
• wp_next_scheduled
• wp_reschedule_event
• wp_schedule_event
• wp_schedule_single_event
• wp_unschedule_event

• comments_open
• has_nav_menu
• has_tag
• in_category
• is_404
• is_admin
• is_archive
• is_attachment
• is_author
• is_category
• is_comments_popup
• is_customize_preview
• is_date
• is_day
• is_feed
• is_front_page
• is_home
• is_month
• is_page
• is_page_template
• is_paged
• is_preview
• is_search
• is_single
• is_singular
• is_sticky
• is_tag
• is_tax
• is_time
• is_trackback
• is_year
• pings_open

• wp_dequeue_script
• wp_dequeue_style
• wp_deregister_script
• wp_deregister_style
• wp_enqueue_script
• wp_enqueue_style
• wp_localize_script
• wp_register_script
• wp_register_style
• wp_script_is
• wp_style_is
• sql
• get_tax_sql
• get_meta_sql
• get_posts_by_author_sql

• add_editor_style
• add_query_arg
• add_rewrite_rule
• admin_url
• bool_from_yn
• cache_javascript_headers
• capital_P_dangit
• clean_blog_cache
• content_url
• do_robots
• flush_rewrite_rules
• get_bloginfo
• get_num_queries
• get_post_stati
• get_post_statuses
• get_query_var
• home_url
• includes_url
• is_blog_installed
• is_main_site
• is_main_query
• is_multisite
• is_ssl
• is_wp_error
• log_app
• make_url_footnote (deprecated)
• network_admin_url
• network_home_url
• network_site_url
• nocache_headers
• plugin_dir_url
• query_posts
• remove_query_arg
• rewind_posts
• setup_postdata
• site_url
• status_header
• unzip_file
• validate_file
• validate_file_to_edit
• wp
• wp_cache_set
• wp_cache_get
• wp_cache_reset (deprecated)
• wp_check_filetype
• wp_clearcookie (deprecated)
• wp_die
• wp_editor
• wp_footer
• wp_get_cookie_login (deprecated)
• wp_get_image_editor
• wp_get_installed_translations
• wp_hash
• wp_handle_sideload
• wp_head
• wp_install_defaults
• wp_is_mobile
• wp_mail
• wp_mkdir_p
• wp_new_user_notification
• wp_password_change_notification
• wp_notify_moderator
• wp_notify_postauthor
• wp_parse_args
• wp_redirect
• wp_reset_postdata
• wp_reset_query
• wp_salt
• wp_safe_redirect
• wp_set_auth_cookie
• wp_strip_all_tags
• wp_upload_bits
• wp_upload_dir
• wp_list_pluck
• wp_text_diff
• post_submit_meta_box
• wp_max_upload_size

• confirm_delete_users
• is_user_member_of_blog
• wp_dashboard_quota
• admin_notice_feed (deprecated)
• avoid_blog_page_permalink_collision
• check_import_new_users
• check_upload_size
• choose_primary_blog
• display_space_usage
• fix_import_form_size
• format_code_lang
• get_site_allowed_themes (deprecated)
• grant_super_admin
• ms_deprecated_blogs_file (deprecated)
• mu_dropdown_languages
• new_user_email_admin_notice
• redirect_user_to_blog (deprecated)
• refresh_user_details
• revoke_super_admin
• secret_salt_warning
• send_confirmation_on_profile_email
• show_post_thumbnail_warning (deprecated)
• site_admin_notice
• sync_category_tag_slugs
• update_option_new_admin_email
• update_user_status
• upload_is_user_over_quote
• upload_space_setting
• wpmu_delete_blog
• wpmu_delete_user
• wpmu_get_blog_allowedthemes (deprecated)
• _admin_notice_multisite_activate_plugins_page (deprecated)

• add_blog_option
• delete_blog_option
• get_blogaddress_by_domain
• get_blogaddress_by_id
• get_blogaddress_by_name
• get_blog_details
• get_blog_option
• get_blog_status
• get_id_from_blogname
• get_last_updated
• is_archived
• refresh_blog_details
• restore_current_blog
• switch_to_blog
• update_archived
• update_blog_details
• update_blog_option
• update_blog_status
• wpmu_update_blogs_date

• ms_cookie_constants
• ms_file_constants
• ms_subdomain_constants
• ms_upload_constants

• add_existing_user_to_blog
• add_new_user_to_blog
• add_user_to_blog
• check_upload_mimes
• create_empty_blog
• domain_exists
• filter_SSL
• fix_phpmailer_messageid
• force_ssl_content
• get_active_blog_for_user
• get_admin_users_for_domain
• get_blogs_of_user
• get_blog_count
• get_blog_id_from_url
• get_blog_permalink
• get_blog_post
• get_current_site
• get_dashboard_blog
• get_dirsize
• get_most_recent_post_of_user
• get_sitestats
• get_space_allowed
• get_space_used
• get_upload_space_available
• get_user_count
• get_user_id_from_string (deprecated)
• global_terms
• insert_blog
• install_blog
• install_blog_defaults
• is_blog_user (deprecated)
• is_email_address_unsafe
• is_upload_space_available
• is_user_option_local
• is_user_spammy
• maybe_add_existing_user_to_blog
• maybe_redirect_404
• newblog_notify_siteadmin
• newuser_notify_siteadmin
• recurse_dirsize
• redirect_mu_dashboard (not a function??)
• redirect_this_site
• remove_user_from_blog
• signup_nonce_check
• signup_nonce_fields
• update_blog_public
• update_posts_count
• upload_is_file_too_big
• upload_is_user_over_quota
• upload_size_limit_filter
• users_can_register_signup_filter
• welcome_user_msg_filter
• wordpressmu_wp_mail_from (not a function??)
• wp_get_sites
• wpmu_activate_signup
• wpmu_admin_redirect_add_updated_param (deprecated)
• wpmu_create_blog
• wpmu_create_user
• wpmu_log_new_registrations
• wpmu_signup_blog
• wpmu_signup_blog_notification
• wpmu_signup_user
• wpmu_signup_user_notification
• wpmu_validate_blog_signup
• wpmu_validate_user_signup
• wpmu_welcome_notification
• wpmu_welcome_user_notification
• get_current_site_name (deprecated)
• is_subdomain_install
• ms_not_installed
• ms_site_check
• wpmu_current_site (deprecated)

• absint
• add_magic_quotes
• addslashes_gpc
• antispambot
• attribute_escape (deprecated)
• backslashit
• balanceTags
• clean_pre
• clean_url (deprecated)
• convert_chars
• convert_smilies
• ent2ncr
• esc_attr
• esc_html
• esc_js
• esc_textarea
• esc_sql
• esc_url
• esc_url_raw
• force_balance_tags
• format_to_edit
• format_to_post (deprecated)
• funky_javascript_fix (deprecated)
• htmlentities2
• is_email
• js_escape (deprecated)
• make_clickable
• popuplinks
• remove_accents
• sanitize_email
• sanitize_file_name
• sanitize_html_class
• sanitize_key
• sanitize_mime_type
• sanitize_option
• sanitize_sql_orderby
• sanitize_text_field
• sanitize_title
• sanitize_title_for_query
• sanitize_title_with_dashes
• sanitize_user
• seems_utf8
• stripslashes_deep
• trailingslashit
• untrailingslashit
• urlencode_deep
• url_shorten
• utf8_uri_encode
• wpautop
• wptexturize
• wp_filter_kses
• wp_filter_post_kses
• wp_filter_nohtml_kses
• wp_iso_descrambler
• wp_kses
• wp_kses_array_lc
• wp_kses_attr
• wp_kses_bad_protocol
• wp_kses_bad_protocol_once
• wp_kses_bad_protocol_once2
• wp_kses_check_attr_val
• wp_kses_decode_entities
• wp_kses_hair
• wp_kses_hook
• wp_kses_html_error
• wp_kses_js_entities
• wp_kses_no_null
• wp_kses_normalize_entities
• wp_kses_normalize_entities2
• wp_kses_post
• wp_kses_split
• wp_kses_split2
• wp_kses_stripslashes
• wp_kses_version
• wp_make_link_relative
• wp_normalize_path
• wp_rel_nofollow
• wp_richedit_pre
• wp_specialchars
• wp_trim_words
• zeroise