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Complementos permitem que os respsonsáveis pelo desenvolvimento estedam e modifiquem a funcionalidade do Firefox. Estes são escritos utilizando as tecnologias da Web padrão - JavaScript, HTML e CSS - mais algumas API de JavaScript dedicadas. Entre outras coisas, umj complemento poderia:

  • Change the appearance or content of particular websites
  • Modify the Firefox user interface
  • Add new features to Firefox

Criar complementos

There are currently several toolsets for developing Firefox add-ons, but WebExtensions will become the standard by the end of 2017. The rest are expected to be deprecated over the same period of time.

Here you will find information about available options for developing add-ons, so you can make a decision on what’s best for you right now and in the future.

Criar um Novo Complemento

If you are writing a new add-on, we recommend you choose one of the following two methods. Until the transition to WebExtensions is complete, there will be pros and cons to each method. Please read through the options to decide which works best for you.

Migrar um Complemento Existente

There are changes coming to Firefox in the next year that will make browsing more reliable for users, and creating add-ons easier for developers. Your add-on may require updating to maintain its compatibility, but once this is done and the transition is complete, your add-on will be more interoperable, secure, and future-proof than ever.

We've created resources, migration paths, office hours, and more, to ensure you have the support you need to get through the transition.

To get started, use the add-on compatibility checker to see if your add-on will be affected.

Publicação de complementos, commonly known as "AMO," is Mozilla's official site for developers to list add-ons, and for users to discover them. By uploading your add-on to AMO, you can participate in our community of users and creators, and find an audience for your add-on.

You are not required to list your add-on on AMO, but starting with Firefox 40, your code must be signed by Mozilla or users won't be able to install it.

For an overview of the process of publishing your add-on, see Signing and distributing your add-on.

Outros tipos de complementos

Generally, when people speak of add-ons they're referring to extensions, but there are a few other add-on types that allow users to customize Firefox. Those add-ons include:

  • Lightweight themes are a simple way to provide limited customization for Firefox.
  • Mobile add-ons are add-ons for Firefox for Android. Note, though, that we intend to deprecate some of the technology underlying these APIs. In the future, WebExtensions will be fully supported on Firefox for Android.
  • Search engine plugins add new search engines to the browser's search bar.
  • Dicionários do utilizador são complementos que o deixam verificar a ortografia em diferentes idiomas.
  • Pacotes de idioma são complementos que o deixam ter mais idiomas disponíveis para a interface do utilizador do Firefox.


Pode utilizar as hiperligações abaixo para obetr ajuda, manter-se atualizado com as notícias relacionadas com os complementos, e dar-nos a sua opinião/comentário.

Fórum de complementos

Utilize o fórum de conversação sobre os complementos para discutir todos aspetos do desenvolvimento de complementos e obter ajuda.

Lista de Discusão

Use the dev-addons list to discuss development of the add-ons ecosystem, including the development of the WebExtensions system and of AMO:


If you're a fan of IRC, you can get in touch at:

  • #addons (discussion of the add-ons ecosystem)
  • #extdev (general discussion of add-on development)
  • #webextensions (discussion of WebExtensions in particular)