Understanding wp-comments-post.php: How WordPress Handles Comment Submissions

WordPress uses a dedicated script named wp-comments-post.php to process the data submitted from the site's comment forms. When a user fills in their name, email, and comment and submits, the browser sends a POST request to this file. The script validates the data, checks that commenting is allowed on the post, creates a new comment in the database, and then redirects the user back to the post with a status indicator.

What is wp-comments-post.php?

WordPress ships this file in the core to act as the endpoint for the comment form submission. The form on a post or page typically points to site url /wp-comments-post.php, rather than a page you create. The script coordinates input handling and delegates the actual storage to core comment functions. It relies on WordPress bootstrapping to load all plugins and theme code and to trigger appropriate action hooks.

How WordPress processes a comment submission

When a user submits a comment, WordPress follows a sequence of checks and actions:

• It collects data from the form, including author, email, url, the comment text, the post ID, and optional comment parent data.
• It sanitizes and validates the inputs to ensure required fields are present and the email looks valid.
• It verifies that commenting is open for the target post and that the user has permission to comment if applicable.
• If the commenter is not logged in, WordPress may require name and email and can use cookies to remember the commenter for future visits.
• It runs anti spam and moderation checks, which can involve plugins like Akismet and built in moderation rules.
• The comment is inserted into the database via WordPress core comment handling functions, which determine whether the comment is immediately approved or placed in a moderation queue.
• After insertion, WordPress triggers a set of hooks such as commentpost and wpnewcomment, and may redirect the user back to the post with a status indicator (for example commentsubmitted or comment_pending).

Security and spam considerations

Anti spam and moderation

WordPress supports moderation by default for new commenters or when settings require it. Plugins like Akismet can screen comments for spam, and site owners can enable stricter moderation for all comments or for comments from non-logged-in users. Adding a honeypot field or CAPTCHA can also deter automated bots.

Data validation and privacy

Input data is sanitized to prevent harmful content from being stored or displayed. Only required fields are collected for non logged-in users, and WordPress cookies may be used to remember commenters locally. Always ensure your privacy and data handling practices align with applicable laws and your site policy.

Common issues and troubleshooting

• Comments not appearing on a post: check if comments are closed for the post or if the comment is awaiting moderation.
• Posts returning an error or blank page after submission: a plugin or theme conflict can interfere with the submission flow; try disabling plugins or switching themes briefly to identify the culprit.
• Duplicate submissions or missing comments: caching or unusual redirects can cause multiple submissions; review your caching and redirect rules.
• Not receiving moderation emails: ensure your site’s email settings are correct and that comment moderation is enabled for new commenters.

Best practices for managing comments

• Keep WordPress and all plugins up to date to minimize security risks in the comment handling flow.
• Use moderation as a default, especially for first-time commenters, to reduce spam.
• Deploy anti spam measures such as Akismet or a vetted captcha/honeypot solution.
• Minimize required fields in the comment form to reduce friction while collecting essential information.
• Regularly review and back up your comments as part of your site maintenance routine.
• Consider blocking or moderating abusive language and implementing clear comment policies to maintain a healthy discussion space.