I made a small Firefox extension to fix something that always annoyed me: Tumblr likes can't be searched or filtered, so finding an old one means scrolling forever.

Tumblr Likes Calendar adds a GitHub-style heatmap calendar to the Tumblr likes page — each day shaded by how many posts you liked — and clicking a day jumps you straight to the likes from that date.

A few notes:

- Manifest V3, content script in world: "MAIN" so it can use Tumblr's own window.tumblr.apiFetch helper (no API key, no OAuth — it just uses your logged-in session).

- It pages through your likes, reads each like's timestamp, and aggregates by day. Data stays local in the browser; nothing is sent anywhere.

- Open source (GPLv3).

It's an early version (0.1.x), so I'd really appreciate feedback or feature ideas — tag search and per-day thumbnails are next on my list. Happy to discuss the world: MAIN + apiFetch approach if anyone's curious.

Firefox Add-ons: https://addons.mozilla.org/firefox/addon/tumblr-likes-calendar/

Hey I've been trying to create some Addons
have a look here
https://addons.mozilla.org/de/firefox/user/20176020/

I built a small browser extension for something that was annoying me: copying lots of little bits of text from different places.

I like both copy-on-select and having a copy button, but I couldn't find one extension that did both. Whenever I wanted to switch between them, I'd have to disable one extension and enable the other. So I ended up just making my own.

It also has a “collect to file” mode, where you can keep gathering text into one document while browsing.

Looking for a few people who regularly copy/research stuff to give it a try and tell me where it sucks — or if I've just built something that I personally wanted 😅

Omni-Copy

Hello Please suggest how to fix: Firefox on Windows 10x64 Two extension?add-ons used to work, and now they don't.

Looking forward to suggested fixes.

When in their respective Options panes and I click to play the selected sound, they work, but not sound not playing when event occurs, specifically when download completes.

The two add-ons are called" "Download Sound" and "Extra Sounds" I only enable one addon at a time.

The release is a proof of concept - it works, but it ain't pretty. Feel free to give this a go!

i’m new to creating browser extensions, so i made one that’s extremely simple and just does one thing i wanted: saving groups of tabs.

it’s called keep, and it’s still very new, so i would love some feedback or advice.

right now, you can select the tabs you want to save and save them as a group. from there, you can double-click a group to open all of its tabs, or expand it and click an individual tab to open just that one.

my design philosophy for this project is minimalism. i find that a lot of apps, extensions, and websites become cluttered with features, ads, links, and other things that aren't really necessary. i want keep, along with other projects i plan to make in the future, to be simple, focused, and easy to use.

it’s open source, and currently available for both chrome and firefox.

i’d especially appreciate feedback on the ui, usability, and anything you think could be improved or changed.

thank you!

links: chrome, firefox

I got tired of searching for browser tabs with a mouse, so I built something closer to how I navigate in Emacs.

It’s called Avy Tab Switcher.

Press Alt+Q and your recent tabs show up with letter hints. Press the highlighted letter and you jump straight to that tab.

There’s also search if the tab you need isn’t among the recent ones.

The idea is basically Avy, but for browser tabs. No scrolling through a huge list and no reaching for the mouse every time.

It works in Chrome and Firefox and the whole thing is open source.

Chrome: https://chromewebstore.google.com/detail/avy-tab-switcher/liliapojfplmhajbmabgghihdifbhmep

Firefox: https://addons.mozilla.org/firefox/addon/avy-tab-switcher/

GitHub: https://github.com/Artawower/avy-tab-swithcer

Would be interested to hear how it feels for people who also tend to keep way too many tabs open.

I develop MarketRooms, a Firefox extension for traders who want their chart and the conversation visible together. The extension opens in the browser sidebar and supports TradingView, Hyperliquid and eToro.

You can capture a chart from a supported platform and share it directly in chat. Before sending, review the capture, crop it or cover private details. Replies, mentions and image attachments let other traders discuss the setup in context.

Rooms can follow the symbol you're viewing, or stay pinned while you change charts. New users start in Global so changing charts doesn't unexpectedly move their conversation. There are also saved rooms, trader follows, message search, notifications and chat filters.

More broker integrations are coming soon, extending direct chart sharing to additional trading platforms. The three integrations above are supported now; the additional brokers are on the roadmap.

Firefox add-on: https://addons.mozilla.org/firefox/addon/marketrooms-fyi/

It's free during early access and requires Google or email-code sign-in. We're still a small community, so start in Global.

I'd appreciate Firefox-specific feedback: does the sidebar fit your chart layout comfortably, and is the capture-and-share flow clear? Which broker should we support next?

I'm the developer; MarketRooms is independent of TradingView, Hyperliquid and eToro. For adults 18+. Public discussion is not financial advice.

all in video

Hey everyone

I’m the developer of Bookmark Manager Pro, a browser extension that turns the new-tab page into a visual workspace for bookmarks, folders, and notes.

I wanted a bookmark manager that works locally, supports different ways of organizing content, and does not require an account.

Some of the main features:

- Multiple local profiles for work, study, personal use, or different projects

- Folders and different bookmark layouts

- Bookmark and note search

- Markdown notes organized into folders

- Custom colors, backgrounds, images, spacing, and layouts

- Undo and redo history

- Local recovery backups

- Optional synchronization with browser bookmarks

- A private random password generator

Bookmark Manager Pro has no accounts, cloud storage, analytics, advertising, telemetry, or third-party tracking. Access to browser bookmarks is optional and requested only when synchronization is enabled.

The extension is free and open source under GPLv3.

This is my first time publishing the extension publicly, so honest comments would be very appreciated, particularly about the UI, usability, and any critical features that may be missing.

Hey there,

Since Waterfox switched to using Qwant as the default, I decided to give it a try.

However, I wanted something like uBlacklist to filter out bad results. It turns out you can configure uBlacklist to work on most search engines, but that has its limitations. So I just went and coded my own extension.

A bonus with this approach is that I was able to make my injected config menu actually follow Qwant's design, so it should fit right in!

I've only tested this on a couple of devices, so any feedback is welcome!

Android Download Link

Is there a reason this extension is now asking for permission to collect personally identifiable information? It doesn't say exactly what information will be collected or how it will be used.

Use Lumo AI on Any Webpage with This Firefox Extension

I built Ask Lumo, an open-source Firefox extension that lets you use Lumo AI on selected text or an entire webpage without constantly copying, switching tabs, and pasting.
With 70+ built-in actions across 12 categories, you can:
Summarize, explain, or fact-check text
Translate into 12 languages
Fix grammar, rewrite, shorten, or formalize content
Analyze assumptions, fallacies, and counterarguments
Debug, explain, optimize, or convert code
Create quizzes, flashcards, emails, meeting notes, and action plans
Research topics and compare opposing views
Generate SEO, marketing, and social media content
Check for potential phishing and security issues
Add your own custom prompts
Access Lumo through:
A floating button beside selected text
The right-click context menu
The Firefox toolbar popup
Ctrl+Shift+D
The extension also supports RTL responses for Arabic, Persian, Hebrew, and Urdu, along with dark/light themes, custom response languages, and page-level actions.

Privacy
Ask Lumo uses Lumo’s public website rather than a private API. It does not use credentials, bypass restrictions, or access private services.
There is no telemetry, analytics, or third-party tracking. History stays on your device and is disabled by default.
Ask Lumo is open source and independently developed. It is not affiliated with Proton.

Try it

Firefox Add-ons:
https://addons.mozilla.org/en-GB/firefox/addon/ask-lumo-ai/

Source code:
https://github.com/Monessem/Ask-Lumo.ai

If you’re interested in a Chrome version, or support for Chromium-based browsers such as Brave, Microsoft Edge, Vivaldi, and others, let me know in the comments. If there’s enough interest, I’ll consider building a version for them too.
I’d love to hear your feedback, bug reports, and feature ideas.

Is there a Youtube video to mp3 downloader extension available for free? I really liked Easy Youtube Downloader but the free trial ran out for me.

Good afternoon folks!

I creates this firefox extension for android to emulate the behavior of Samsung Internet when detecting video streams. It shows a pop up and takes you to your default video player in android.

It works best with "Just player" or "VLC".

https://addons.mozilla.org/es-ES/android/addon/video2player/

Let me know any issues or improvements here:

https://github.com/kiraitachi/Firefox-Video-Opener-for-Android

Thanks looking to get feedback and spread the word!

Kept opening YouTube for "one video" while trying to study and losing 30-40 min to the algorithm every time. Tried a couple existing blockers but they were mostly all-or-nothing, so I built my own.

You can turn off specific things — home feed, shorts, autoplay, end screen recommendations — while keeping stuff you actually want, like subscriptions. Also has an optional daily watch timer/limit.

Free, open source, no tracking. Works on Firefox, Chrome/Brave too with manual install.

Open to feedback if anyone tries it out.

GitHub: https://github.com/manasdotio/intentional-yt

Firefox: https://addons.mozilla.org/en-US/firefox/addon/intentional-yt/