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  1. [ Mozilla  ](/en-US/docs/Mozilla)
  2. [ Add-ons  ](/en-US/docs/Mozilla/Add-ons)
  3. [ Browser extensions  ](/en-US/docs/Mozilla/Add-ons/WebExtensions)

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##  In this article

  * Key resources 
  * Get started 
  * Concepts 
  * User interface 
  * How to 
  * Firefox workflow 
  * Reference 

  1. [ **Browser extensions** ](/en-US/docs/Mozilla/Add-ons/WebExtensions)
  2. Getting started 
    1. [ What are extensions? ](/en-US/docs/Mozilla/Add-ons/WebExtensions/What_are_WebExtensions)
    2. [ Your first extension ](/en-US/docs/Mozilla/Add-ons/WebExtensions/Your_first_WebExtension)
    3. [ Your second extension ](/en-US/docs/Mozilla/Add-ons/WebExtensions/Your_second_WebExtension)
    4. [ Anatomy of an extension ](/en-US/docs/Mozilla/Add-ons/WebExtensions/Anatomy_of_a_WebExtension)
    5. [ Example extensions ](/en-US/docs/Mozilla/Add-ons/WebExtensions/Examples)
    6. [ What next? ](/en-US/docs/Mozilla/Add-ons/WebExtensions/What_next_)
  3. Concepts 
    1. [ JavaScript APIs ](/en-US/docs/Mozilla/Add-ons/WebExtensions/API)
    2. [ Content scripts ](/en-US/docs/Mozilla/Add-ons/WebExtensions/Content_scripts)
    3. [ Background scripts ](/en-US/docs/Mozilla/Add-ons/WebExtensions/Background_scripts)
    4. [ Match patterns ](/en-US/docs/Mozilla/Add-ons/WebExtensions/Match_patterns)
    5. [ Work with files ](/en-US/docs/Mozilla/Add-ons/WebExtensions/Working_with_files)
    6. [ Internationalization ](/en-US/docs/Mozilla/Add-ons/WebExtensions/Internationalization)
    7. [ Content Security Policy ](/en-US/docs/Mozilla/Add-ons/WebExtensions/Content_Security_Policy)
    8. [ Native messaging ](/en-US/docs/Mozilla/Add-ons/WebExtensions/Native_messaging)
    9. [ Differenc