Developer tools Firefox add-ons

Tools for developers: inspectors, API clients, formatters, debuggers and terminals. 2,406 live add-ons carry the topic.

Tags come from each listing's name, category and description, read in English: a listing written in another language is tagged only where it uses the English words.

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  1. Ghelper

    by ghelper · updated 2024-08-05

    This is a browser plugin for developers, cross-border workers, and research institutes to secure and speed Internet surfing.

    Social & Communication v2.7.10
    Daily users 2,946 +255 wk
    Rating 4.4 164 ratings
    Growth · week +9.8% weekly avg over 10 days

  2. REST Client APIsHub↗

    by Abdul Qadir · updated 2020-05-31

    A Modern and simple API testing tool!

    Web Development v2.5
    Daily users 2,830 +72 wk
    Rating 3.8 17 ratings
    Growth · week +2.6% weekly avg over 10 days

  3. JSON Viewer Pro↗

    by bIONArAq · updated 2024-01-24

    JSON Viewer lets you visualize a JSON in your browser.

    Web Development v1.0.1
    Daily users 1,056 +21 wk
    Rating 4.3 3 ratings
    Growth · week +2.0% weekly avg over 10 days

  4. Vue.js devtools↗

    by Vue.js · updated 2025-06-11

    DevTools extension for debugging Vue.js applications.

    Web Development v7.7.7
    Daily users 54,589 +838 wk
    Rating 4.7 617 ratings
    Growth · week +1.6% weekly avg over 10 days

  5. Mobile DevTools↗

    by surv · updated 2025-09-02

    A firefox add-on to get developper tools using eruda on your phone.

    Web Development v1.0.0
    Daily users 1,264 +19 wk
    Rating 2.8 6 ratings
    Growth · week +1.5% weekly avg over 10 days

  6. Octotree - GitHub code tree↗

    by Team Octotree · updated 2026-10-04

    GitHub on steroids

    Web Development v9.3.2
    Daily users 2,334 +34 wk
    Rating 4.8 239 ratings
    Growth · week +1.5% weekly avg over 10 days

  7. XML Viewer Plus↗

    by Francesco De Stefano · updated 2019-06-17

    A powerful XML Viewer, supports text/regex and jQuery/CSS, XPath selectors

    Web Development v1.2.6
    Daily users 3,783 +54 wk
    Rating 3.2 20 ratings
    Growth · week +1.5% weekly avg over 10 days

  8. Cross Domain - CORS↗

    by Mai Tan · updated 2020-01-05

    Cross Domain will help you to deal with cross domain - CORS problem. This is a small tool will helpful for web developer and related domain that face with cross domain issue.

    Web Development v0.2.2
    Daily users 1,061 +15 wk
    Rating 2.7 28 ratings
    Growth · week +1.4% weekly avg over 10 days

  9. DevTools Media Panel↗

    by Karolien Koorts · updated 2019-05-24

    DevTools panel that displays technical details about media elements and webrtc on the current page; intended primarily for web developers to understand media playback issues on their sites, and for us

    Web Development v2.6
    Daily users 1,583 +21 wk
    Rating 4.3 42 ratings
    Growth · week +1.4% weekly avg over 10 days

  10. Odoo Debug↗

    by Martin T. · updated 2019-07-02

    Toggle debug mode of an Odoo webpage. - Click for debug. - Double click for debug with Assets. - Use ctrl + . for keyboard shortcut Source code: https://github.com/pga-odoo/OdooDebug Emoji art suppl

    Web Development v4.0
    Daily users 8,358 +103 wk
    Rating 4.9 8 ratings
    Growth · week +1.3% weekly avg over 10 days

    Unrated listings show no rating rather than zero — the store renders 0 out of 5 for never-rated items, and storing that as 0.0 would drag every category average down. Blank install counts are equally real: themes never show a count, and many small extensions don't either. Delisted listings are excluded from these views but retained in the database.