wp_send_json_error( mixed $value = null, int $status_code = null, int $flags = 0 ): never
- Since
- 3.5.0, 4.1.0, 4.7.0, 5.6.0
- Source
wp-includes/functions.php:4663
Terminates an Ajax request by echoing a JSON object with success set to false and the optional $value under a data key, then exits. Pass a WP_Error object as $value and its error codes and messages are flattened into an array of code and message pairs before encoding. Because its return type is never, any code written after the call in the same function is unreachable, so use its counterpart wp_send_json_success for the happy path.
Description
If the $value parameter is a WP_Error object, the errors within the object are processed and output as an array of error codes and corresponding messages. All other types are output without further processing.
Compatibility
- WordPress
- since 5.6.0
- PHP
- 7.4–8.6-dev
- 6.7.7
- 6.8.8
- 6.9.7
- 7.0.4
- 7.1.0
Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.
Parameters
$valuemixedoptional- Data to encode as JSON, then print and die. Default null.Default:
null $status_codeintoptional- The HTTP status code to output. Default null.Default:
null $flagsintoptional- Options to be passed to json_encode(). Default 0.Default:
0
Return value
never
Code examples
Every example is editable and runs in a real WordPress booted in your browser by WordPress Playground. Press Run, then edit the code: clicking away re-runs it. Nothing is sent anywhere until you do.
Return WP_Error validation messages from an Ajax handler
A comment-submission Ajax callback rejects an empty, too-frequent comment by collecting the problems into a WP_Error before responding.
$comment_error = new WP_Error();
$comment_error->add( 'empty_content', 'Please enter a comment before submitting.' );
$comment_error->add( 'rate_limited', 'You are commenting too quickly, please wait a moment.' );
wp_send_json_error( $comment_error, 422 );Each error code in the WP_Error object can hold more than one message, and every message becomes its own entry in the output array.
Send a custom HTTP status code and pretty-printed JSON for a failed meta check
A quick-edit save handler for post 2 checks a 'stock' meta field that the baseline install never sets, so the numeric check always fails and the error path runs.
$post_id = 2;
$stock = get_post_meta( $post_id, 'stock', true );
if ( ! is_numeric( $stock ) ) {
wp_send_json_error(
array(
'post_id' => $post_id,
'field' => 'stock',
'message' => 'Stock quantity meta is missing or not numeric.',
),
422,
JSON_PRETTY_PRINT
);
}
echo 'Stock check passed.';The final echo never runs here because the empty 'stock' meta always fails the is_numeric() check and wp_send_json_error() ends the script.
Common problems and fixes · 4
- Why does my Ajax response have success: false but no data key at all?
- Why do I get an array of objects instead of one error message when I pass a WP_Error?
- Can I run any cleanup code right after calling wp_send_json_error()?
- Why do URLs or other strings in my JSON response come back with escaped slashes?
Why does my Ajax response have success: false but no data key at all?
Why do I get an array of objects instead of one error message when I pass a WP_Error?
Can I run any cleanup code right after calling wp_send_json_error()?
Why do URLs or other strings in my JSON response come back with escaped slashes?
Alternatives and related functions
wp_send_json_success- When the Ajax request succeeded and you want the same success/data JSON envelope with success set to true instead of false.
wp_send_json- When you need full control over the shape of the response array instead of the fixed success/data wrapper this function builds for you.
WP_Error- When you need to accumulate one or more coded validation or processing errors before handing them to wp_send_json_error() for flattening.
rest_ensure_response- When the failing endpoint is a REST API route rather than an admin-ajax.php handler, since REST responses use WP_REST_Response and WP_Error differently than admin-ajax JSON.
Performance profile
How much work a call to wp_send_json_error() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Heavy
- Scaling
- Scales with input
- Instructions
- 12–24
- Plugin surface
- None
- Called by
- 50
Reads stored settings via get_option(), cached per request but not free on a cold cache.
The body loops, so the work grows with what you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 36.
Nothing here hands control to plugin code.
50 places in core call this, so the cost is paid more often than your own code shows.
What it touches
- hookthird-party callbacks
do_action()one call below wp_send_json_error() - optionoption read or write
get_option()one call below wp_send_json_error()
Further down the call graph this can also reach cache, serialize, query and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.
What one call costs · 2 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_send_json_error() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
!isset($value) | 12 | wp_send_json() |
isset($value) | 18–24 | is_wp_error(), wp_send_json() |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 36 instructions, 12–24 executed per call, 6 branches. The work does not change between versions.
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Uses · 2
- is_wp_error()Checks whether the given variable is a WordPress Error.
- wp_send_json()Sends a JSON response back to an Ajax request.
Used by · 50
- Custom_Background::ajax_background_add()Handles Ajax request for adding custom background context to an attachment.
- Custom_Image_Header::ajax_header_add()Given an attachment ID for a header image, updates its "last used" timestamp to now.
- Custom_Image_Header::ajax_header_crop()Gets attachment uploaded by Media Manager, crops it, then saves it as a new object. Returns JSON-encoded object details.
- Custom_Image_Header::ajax_header_remove()Given an attachment ID for a header image, unsets it as a user-uploaded header image for the active theme.
- WP_Customize_Manager::handle_changeset_trash_request()Handles request to trash a changeset.
- WP_Customize_Manager::handle_dismiss_autosave_or_lock_request()Deletes a given auto-draft changeset or the autosave revision for a given changeset or delete changeset lock.
- WP_Customize_Manager::handle_load_themes_request()Loads themes into the theme browsing/installation UI.
- WP_Customize_Manager::handle_override_changeset_lock_request()Removes changeset lock when take over request is sent via Ajax.
- WP_Customize_Manager::refresh_nonces()Refreshes nonces for the current preview.
- WP_Customize_Manager::save()Handles customize_save WP Ajax request to save/update a changeset.
- WP_Customize_Nav_Menus::ajax_insert_auto_draft_post()Ajax handler for adding a new auto-draft post.
- WP_Customize_Nav_Menus::ajax_load_available_items()Ajax handler for loading available menu items.
Show all 50
- WP_Customize_Nav_Menus::ajax_search_available_items()Ajax handler for searching available menu items.
- WP_Customize_Selective_Refresh::handle_render_partials_request()Handles the Ajax request to return the rendered partials for the requested placements.
- WP_Customize_Widgets::wp_ajax_update_widget()Updates widget settings asynchronously.
- WP_Plugin_Dependencies::check_plugin_dependencies_during_ajax()Checks plugin dependencies after a plugin is installed via AJAX.
- locate_block_template()Finds a block template with equal or higher specificity than a given PHP template file.
- wp_ajax_activate_plugin()Handles activating a plugin via AJAX.
- wp_ajax_crop_image()Handles cropping an image via AJAX.
- wp_ajax_delete_plugin()Handles deleting a plugin via AJAX.
- wp_ajax_delete_theme()Handles deleting a theme via AJAX.
- wp_ajax_destroy_sessions()Handles destroying multiple open sessions for a user via AJAX.
- wp_ajax_edit_theme_plugin_file()Handles editing a theme or plugin file via AJAX.
- wp_ajax_find_posts()Handles querying posts for the Find Posts modal via AJAX.
- wp_ajax_get_attachment()Handles getting an attachment via AJAX.
- wp_ajax_get_community_events()Handles Ajax requests for community events
- wp_ajax_get_revision_diffs()Handles getting revision diffs via AJAX.
- wp_ajax_health_check_background_updates()Handles site health checks on background updates via AJAX.
- wp_ajax_health_check_dotorg_communication()Handles site health checks on server communication via AJAX.
- wp_ajax_health_check_get_sizes()Handles site health check to get directories and database sizes via AJAX.
- wp_ajax_health_check_loopback_requests()Handles site health checks on loopback requests via AJAX.
- wp_ajax_health_check_site_status_result()Handles site health check to update the result status via AJAX.
- wp_ajax_heartbeat()Handles the Heartbeat API via AJAX.
- wp_ajax_image_editor()Handles image editing via AJAX.
- wp_ajax_install_plugin()Handles installing a plugin via AJAX.
- wp_ajax_install_theme()Handles installing a theme via AJAX.
- wp_ajax_media_create_image_subsizes()Handles creating missing image sub-sizes for just uploaded images via AJAX.
- wp_ajax_parse_embed()Applies [embed] Ajax handlers to a string.
- wp_ajax_parse_media_shortcode()
- wp_ajax_press_this_add_category()Ajax handler for creating new category from Press This.
- wp_ajax_press_this_save_post()Ajax handler for saving a post from Press This.
- wp_ajax_query_attachments()Handles querying attachments via AJAX.
- wp_ajax_query_themes()Handles getting themes from themes_api() via AJAX.
- wp_ajax_save_attachment()Handles updating attachment attributes via AJAX.
- wp_ajax_save_attachment_compat()Handles saving backward compatible attachment attributes via AJAX.
- wp_ajax_save_attachment_order()Handles saving the attachment order via AJAX.
- wp_ajax_save_user_color_scheme()Handles auto-saving the selected color scheme for a user's own profile via AJAX.
- wp_ajax_save_wporg_username()Handles saving the user's WordPress.org username via AJAX.
- wp_ajax_search_install_plugins()Handles searching plugins to install via AJAX.
- wp_ajax_search_plugins()Handles searching plugins via AJAX.
Source code
function wp_send_json_error( $value = null, $status_code = null, $flags = 0 ) { $response = array( 'success' => false ); if ( isset( $value ) ) { if ( is_wp_error( $value ) ) { $result = array(); foreach ( $value->errors as $code => $messages ) { foreach ( $messages as $message ) { $result[] = array( 'code' => $code, 'message' => $message, ); } } $response['data'] = $result; } else { $response['data'] = $value; } } wp_send_json( $response, $status_code, $flags );}Changelog
Introduced in 3.5.0. One change between 6.7.7 and 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
none to never.verified against source$flags parameter was added.from the docblock$status_code parameter was added.from the docblock$value parameter is now processed if a WP_Error object is passed in.from the docblockAbout this page
- Parsed data
- Generated from the wordpress-develop 7.1.0 tag, from
src/wp-includes/functions.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
- Something wrong on this page? Report it and it gets fixed in the next regeneration.