New Tab Dedupe by 阳熙来

New Tab Dedupe checks for duplicates as soon as a new page starts requesting, keeping tab clutter under control. When it matches a loaded page, it closes the new tab and switches to the original; when it matches only an unloaded tab, it closes the old tab and keeps the new page.

🧩 The extension offers flexible allowlist and blocklist modes, so you can tailor deduplication to different situations.

• Allowlist mode (exclusions): Deduplication is enabled on every supported page by default except addresses on the list. Listed pages may be opened more than once; all other pages are deduplicated automatically
• Blocklist mode (active scope): Pages may be opened more than once by default, and deduplication is enabled only for addresses on the list. Only listed pages are deduplicated automatically
• Rule management: Enter one rule per line. Use a domain to match an entire site, or a full web address, local file address, or internal browser address to match pages whose addresses begin with it. Blank lines and duplicate entries are removed automatically when you save

✨ Extension features:

• Smart deduplication: Compares cleaned addresses and ignores common tracking parameters and page fragments, accurately recognizing the same page even when its links differ slightly
• New-tab handling: When a new page duplicates a loaded tab, the new tab is closed and the original is brought forward; when it only duplicates an unloaded tab, the old unloaded tab is closed and the new page stays open
• Scope isolation: Deduplication stays within the same browser window and Firefox container, so separate windows and containers do not affect one another
• Special-tab options: Choose separately whether fixed or pinned tabs, internal browser pages, and unloaded tabs take part in deduplication; fixed and pinned tabs are protected by default
• Internal browser pages: Use one setting to choose whether internal pages are checked; custom rules take precedence over this setting
• Local file support: Recognizes local files opened more than once, with rules to choose which files and folders are deduplicated or allowed to repeat
• Notices: Closing a duplicate tab does not add a new browser-history entry; after processing, a notice appears at the lower right of the page
• Immediate updates: Changing modes, editing rules, or changing special-tab options immediately checks applicable open tabs again using the new settings
• Settings sync: Deduplication modes, rules, special-tab options, and interface language can sync between devices through your Firefox account
• Startup check: Restored tabs are checked automatically when the browser starts, clearing duplicate pages left over from the previous session
• WeChat optimization: WeChat Official Account article links receive dedicated handling, so the same article is recognized even when shared from different sources
• Multilingual interface: The settings page can follow the browser language automatically or let you choose manually from 13 languages and regional variants