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Data collection (deprecated)
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.. important::

    Legacy Telemetry collection APIs are now deprecated.
    Please use Glean instead.

There are different APIs and formats to collect data in Firefox, all suiting different use cases.

In general, we aim to submit data in a common format where possible. This has several advantages; from common code and tooling to sharing analysis know-how.

In cases where this isn't possible and more flexibility is needed, we can submit custom pings or consider adding different data formats to existing pings.

*Note:* Every new data collection must go through a `data collection review <https://wiki.mozilla.org/Firefox/Data_Collection>`_.

The current data collection possibilities include:

* :doc:`scalars` allow recording of a single value (string, boolean, a number)
* :doc:`histograms` can efficiently record multiple data points
* ``environment`` data records information about the system and settings a session occurs in
* :doc:`events` can record richer data on individual occurrences of specific actions
* :doc:`Measuring elapsed time <measuring-time>`
* :doc:`Custom pings <custom-pings>`
* :doc:`Experiment annotations <experiments>`
* :doc:`WebExtension API <webextension-api>` can be used in privileged webextensions
* :doc:`User Interactions <user-interactions>` allow annotating hang report pings with information on what the user was interacting with at the time

.. toctree::
   :maxdepth: 2
   :titlesonly:
   :hidden:
   :glob:

   scalars
   histograms
   events
   measuring-time
   custom-pings
   experiments
   *

Browser Usage Telemetry
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For more information, see :ref:`browserusagetelemetry`.

Version History
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- Firefox 61: Stopped reporting Telemetry Log items (`bug 1443614 <https://bugzilla.mozilla.org/show_bug.cgi?id=1443614>`_).
