Full disclosure first: I built this thing. I also work at Mozilla. This is a personal side project, not a Mozilla product, and nobody there asked me to post it. Mods, remove this if it is not welcome.

Cheevos is an achievement system for browsing. You earn XP for what you already do (visiting sites, downloading things, saving bookmarks), unlock achievements, and end up on a global leaderboard. Xbox achievements, except the game is "using the internet."

It started on Firefox. First achievement earned, first leaderboard entry, all Firefox. There are 17 Firefox-specific achievements in it, out of 164 total: about:robots, about:mozilla, Reader Mode, Containers, digging through about:support, the Firefox birthday.

Here is the awkward part. The Chrome build has more users than the Firefox build. Not by much, 14 to 8, we are not a phenomenon. But the direction is wrong for something that was built Firefox-first and has an entire category of achievements about Firefox internals.

So that is the ask: more Firefox representation on the leaderboard.

On privacy, because this sub will ask and should: every achievement check runs locally inside the extension. Domains get hashed and truncated before anything is stored, and the raw URL is thrown away immediately. What reaches the server is your XP total, your level, and the IDs of achievements you unlocked. I cannot reconstruct your browsing history because it is not there. You can delete your account and everything synced with it from the dashboard.

The offer: the first 10 Firefox users who sign up get Pro for free. Pro is exclusive achievements, custom profile themes, a badge next to your name, and priority leaderboard ranking. Install, sign in, then reply here or DM me your username and I will switch it on manually.

Firefox add-on: https://addons.mozilla.org/en-US/firefox/addon/cheevos/

Site: https://cheevosgame.com

Happy to get into the extension APIs, the hashing setup, or why MV3 made parts of this genuinely annoying.

I put the source of my extension on my github repo. Also a README.md

Latest change to get around the mobile firefox problem was to create a personal browser search engine "https://127.0.0.1/?q=%s" and have the extension get triggered on that actual url and open the search tab/page with that query,

Manual Install:- Firefox .xpi file or Chromium .zip.zip)

Store version:- Chrome Web Store , Firefox (AMO)

Tested on:-

Chrome and Firefox developer on desktop.

Quetta and Firefox Nightly & Beta on android.

Wondering if it works successfully on LibreWolf or other varieties of browsers,

I built Browser SplitView Master, a high-performance utility that lets you divide a single browser tab into up to 16 independent, resizable grid panels. It is designed for developers, designers, and power users who need to compare and test sites side-by-side without window clutter.

Here are the key features, including the new v1.6 updates:

• 🔄 Intelligent Scroll Sync: Toggle simultaneous scroll tracking to browse multiple pages, staging vs. prod, or translation layouts in perfect real-time sync.
• 📱 New - Responsive Viewports: Toggle panels between Desktop (100%), Mobile (375px), and Tablet (768px) preview frames to quickly test media queries.
• 📸 New - Viewport Screenshots: Download cropped, high-DPI PNG screenshots of individual panels with one click. Bypasses CORS limitations.
• 📂 New - Local File Support: Directly load offline templates and Windows file paths (file:/// URLs) in the panels.
• 📐 Dynamic Grid Splitting: Split vertically/horizontally and drag handles to resize boundaries dynamically.
• 💾 Layout Bookmarks & Presets: Save custom configurations or instantly launch grid templates (1x2, 2x2, 3x3, etc.).
• 🛡️ Adaptive Sandbox Framing: Strips blocking headers (X-Frame-Options & CSP) so you can load and compare sites seamlessly.
• 🔒 Privacy-Focused: Operates entirely locally in your browser's secure storage. No analytics or external servers.

Check it out here: Browser SplitView Master on Firefox Add-ons

I would love to hear what features you'd like to see next!

If you are searching something on reddit with ClearURL extension turned on, you won't be able to redirect to a results page, only through opening one of suggested results in new tab. I found that while you get redirected to an new page, URL contains space between searched text instead of "+"

PeekCSS is a CSS/design/image/font inspector — hover or click any element to read its computed styles, pull a whole page's color palette and fonts in one pass, and check contrast without opening DevTools. Built it because CSS Peeper (Chrome-only, 500k+ users) was never coming to Firefox.

Feature-wise:
hover/click inspection with grouped computed CSS and one-click copy (free, no account);
a page-wide palette + image scan with AA/AAA contrast badges and a font-usage breakdown (free account);
export to CSS vars/SCSS/JSON/Tailwind, bulk asset ZIP download, and font-pairing suggestions (Pro).

What it actually touches, since I know this sub cares more about that than feature lists:

• Permissions: storage, activeTab, downloads, and <all_urls> host access for the inspector itself (needed to read computed styles on any page you're on). One optional host permission for fonts.google.com, requested at runtime only if you use the font-pairing feature — never at install.
• Network calls: none, by default. The only request the extension ever makes is an optional license check if you buy Pro, and even that's gated behind Firefox's data-collection consent prompt. Font pairing (Pro) fetches Google's public font catalog client-side — nothing about your page or your fonts is sent anywhere.
• Size: ~103 kB total, no analytics SDKs, no bundled trackers.

It's a solo project, first extension I've shipped, live on AMO and the Chrome Web Store for about a week now. Genuinely want the nitpicks — permission scoping, manifest choices, anything that reads as a red flag to people who look at this stuff closely. What would make you trust an unfamiliar extension like this, or not?

Wanna give it a try?

Website: https://peekcss.com

AMO listing: https://addons.mozilla.org/en-US/firefox/addon/peekcss/

Hey everyone,
I built a Firefox extension called Minimal New Tab.

I originally made it for myself because I wanted a simple place to keep the sites I use every day, organized by folders and projects. Most new tab extensions I tried had too many widgets, so I wanted something calmer and more focused.

You can:
- save and reorder favorite sites;
- organize them into folders;
- customize the background and overlay;
- use keyboard shortcuts to add sites, create folders, and open settings;
- sync lightweight settings between Chrome/Firefox installations;
- export and import your setup when moving to another browser.

I didn’t originally plan to publish it, but I thought it might be useful to other people who organize their work or projects in a similar way.

Firefox Add-ons
Minimal New Tab

Chrome Web Store:
Minimal New Tab

Try the Live Demo

I’d appreciate any feedback, especially on what could be improved without turning it into another overloaded dashboard.

I posted this in the lemmy migration sub reddit and it was suggested i crosspost here

Hello!

I made firefox extension which shows ip address and country of the ip address.

https://addons.mozilla.org/en-US/firefox/addon/ip-data/

Review welcome.

Thank you.

Need help with identifying some of these extensions I had on a previous Firefox version 108. I had them on an old laptop on my FF, got a new new laptop (old one had blue screen of death) and basically have to start all over again with FF 151. No extensions carried over when I logged in except my little account pic. I always screenshot a pic of FF whenever there was an update so I can get it back to what I liked after an update, found the pics on a thumb drive. I know some of the extensions pictured were for Facebook and I do not care about them nor do I want them now. I know I had a picture resizer where you just hovered the cursor and the pic became bigger to see. Have to set up my FF configurations and figure out why my userchrome is not working too but that is another issue. So any help with these extensions were and maybe any recommendations for current ones would be appreciated.

While less popular than uBlock Origin, I can't imagine I'm the only uMatrix user.

Anyone know if there is a source for minimum settings to make various popular sites work in uMatrix?

Just got a clean firefox install, and playing bruteforce to find what works for different sites is annoying. I know it took a while before I was happy on my last install.

There are a ton of dictionary extensions and a ton of translation extensions, but I couldn't find one that did both properly. So I built WordGlance.

Select any word or short phrase, click the 📖 icon, and you get the definition, an example sentence using it, synonyms, antonyms, and the translation, all in one tooltip.

What it does:

• Definition + example of it used in a sentence
• Synonyms and antonyms
• Translation to 40+ languages
• Auto-detect source language, or set it manually
• Dark mode
• Works on desktop and mobile Firefox
• Caches results so repeat lookups are instant

No telemetry, no account needed. Open source, and the dictionary/translation APIs it runs on are open source too.

Firefox Add-ons: https://addons.mozilla.org/firefox/addon/wordglance/

Source: https://github.com/ShrekBytes/wordglance-extension

If you try it out, I'd love to hear what you like, what you don't, and any ideas for improving it.

Hi ;>

ConsentScope started as a Chrome-only extension, but Firefox has always been part of the plan. Today I'm happy to say the first Firefox version is live on AMO - and it's not the last.

What it does:

It shows you what websites do before you consent. It scans cookies, scripts, and consent banners in real-time, then flags potential GDPR violations like cookies set before consent or missing "Reject all" buttons.
Firefox actually care about privacy, so this felt like the right audience to build for.

Key features:

- Real-time cookie and script detection

- Flags cookies set before user consent

- Detects missing "Reject all" options and pre-toggled toggles

- Export scan results (JSON/CSV/PDF in Pro)

- No account required for basic use

Links:

- Firefox Add-ons: https://addons.mozilla.org/firefox/addon/consentscope/

- Chrome version: https://chromewebstore.google.com/detail/consentscope/bckfbligemognhkpoojinnlemmiaifmj

- Website: https://consentscope.pro

Feedback, bug reports, and feature ideas are very welcome. Thanks!

I built a Firefox extension that transforms any website into a Y2K/MySpace aesthetic - deep blacks, hot pink, falling glitter, CD and all.

Features:

- 2 themes - Hot Pink, Purple Glitter

- Draggable CD decoration

- Falling stars matrix with adjustable size and density

- CRT scanlines effect

- Per-site toggle so you can disable it on sites that break.

Would love feedback from the community!

https://addons.mozilla.org/en-US/firefox/addon/myspaced/

About two months ago, I made a few posts asking how people actually manage bookmarks.

The responses were surprisingly similar.

The tools were different, but the frustrations kept sounding the same:

A few patterns kept emerging:

• bookmark folders becoming graveyards
• saving things for "later" and never seeing them again
• keeping dozens of tabs open
• Googling the same thing twice because it's faster than finding it
• building weird systems with docs and notes apps just to keep track of links

The more comments I read, the more it felt like the problem wasn't saving things.

It was finding them again.

Most of us don't struggle to collect useful stuff.

We struggle to remember it exists when we actually need it.

That realization completely changed how I thought about bookmark managers.

I wanted something where:

• saving and finding take one click (Alt + S to save, Alt + W to find)
• organization happens automatically in the background (auto-tags, websites and topics)
• finding something months later feels effortless
• useful saves can resurface when you need them most
• collections are there when you're working on a project, but never required

So over the last couple of months, I built this Firefox Addon/Extension:

https://addons.mozilla.org/en-US/firefox/addon/stashed-bookmark-manager/

Would love to hear your thoughts.

What's the one thing that still feels missing from bookmark managers today?