Anti-Dupe Plugin for MyBB
MYBB
PLUGIN
free
Catches the duplicate reply MyBB's own guard lets through — without blocking legitimate posts.
MyBB already stops the exact same message being posted twice in one thread. It does not catch the version where the member changes the subject line — and that is the one that slips past.
Anti-Dupe adds the missing checks:
• Matches identical replies in a thread even when the subject changed.
• Thread comparisons require the same forum, the same subject and the same message, so different threads with the same text are untouched.
• Normalises line endings only — case and meaningful code whitespace are preserved, so pasted code is compared fairly.
• Compares up to 50 recent own submissions over three minutes, under a per-member named lock, so a double-click cannot race itself.
It supplements the core guard rather than claiming to replace it, and it is stateless: no settings, no custom tables.
Anti-Dupe adds the missing checks:
• Matches identical replies in a thread even when the subject changed.
• Thread comparisons require the same forum, the same subject and the same message, so different threads with the same text are untouched.
• Normalises line endings only — case and meaningful code whitespace are preserved, so pasted code is compared fairly.
• Compares up to 50 recent own submissions over three minutes, under a per-member named lock, so a double-click cannot race itself.
It supplements the core guard rather than claiming to replace it, and it is stateless: no settings, no custom tables.
What's included
- Decides at post time whether a reply repeats something already in the thread, and stops it before it is stored.
- Fuzzy matching on the post body, so a copy with a different link or a word swapped still counts as a duplicate.
- Runs from the post datahandler — it works for quick reply, full reply and any other route that saves a post.
- No settings page and no tables: nothing to configure, nothing to clean up when you remove it.
At a glance
| Platform | MyBB plugin |
|---|---|
| Latest version | v2.0.0 |
| Download size | 16.2 KB |
| Released | 24 Oct 2026 |
| Downloads | 0 |
| Access | Free — sign in to download |
| Database | none — no tables created |
| Template change | none |
| Settings | none — nothing to configure |
| Hooks | datahandler_post_validate_post, datahandler_post_validate_thread |
| Files | 6 in the archive |
Requirements
- MyBB 1.8.x — the series this release is built for (1.8.38 for the ones we re-tested).
- PHP 7.4 or newer (8.x is fine).
Checksum
Verify your download before you upload it to your board.
da93a5000ac2101894842fdbb769b9100367890dc3fe7a7a660be5ea8e2e9772Install it
1. Copy inc/plugins/dfantidupe.php into your board's inc/plugins/ folder.
2. Admin CP -> Configuration -> Plugins -> DF Anti-Dupe -> Install & Activate.
3. Nothing to configure: the check runs on new replies and posts, in front of the core duplicate guard.
4. To remove it: Deactivate, then Uninstall. There are no settings and no custom tables.
2. Admin CP -> Configuration -> Plugins -> DF Anti-Dupe -> Install & Activate.
3. Nothing to configure: the check runs on new replies and posts, in front of the core duplicate guard.
4. To remove it: Deactivate, then Uninstall. There are no settings and no custom tables.
Questions people ask
Does it create database tables?
No. It reads what the platform already stores, so there is nothing to migrate or clean up.
Does it edit templates or core files?
No. It runs from hooks, so no core file is modified.
How do I check the file I downloaded?
Every release page prints a SHA-256 checksum. Hash the archive locally and compare — if the two differ, the download is damaged, not the release.
How are updates delivered?
Each version is its own release on this page with a changelog, and the older archive stays available. Install the new one over the old one; your settings and data stay where they are.
All releases
| Version | Released | Size | Downloads | Changelog |
|---|---|---|---|---|
| v2.0.0 latest | 24 Oct 2026 | 16.2 KB | 0 | - Rebuilt as a versioned 2.0.0 release. - Subject-changed duplicate replies now caught. - Same-forum/same-subject/same-message requirement added to reduce false holds. - Per-member named lock around the comparison window. |
Ratings & reviews
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