Install the QuickOSM plugin

• QGIS Plugins menu → Manage and Install Plugins…
• Search for QuickOSM and select it
• Install Plugin

Try a quick query

• Vector menu → QuickOSM -> QuickOSM
• In the key field enter amenity
• In the value field enter toilets
• Set the name of the town/village to London
• Run Query

The Overpass API takes a few seconds to respond, and after that you should get new point and polygon layers for the toilets of London! (nodes and ways in OpenStreetMap with the amenity=toilet tag on them)

QuickOSM allows you to work quickly with OSM data in QGIS thanks to Overpass API.

• Write some queries for you by providing a key/value
• Choose to run the query on an area or an extent
• Configure the query : which layers, which columns…
• Open a local OSM (.osm or .pbf) with a specific osmconf in QGIS
• Build some models with QGIS Processing

There are some useful tips, like automatic colours on lines (if the tag is present) or some actions (right-click in the attribute table) for each entities (edit in JOSM for instance).

Since QGIS 3.4, QuickOSM is available in the Processing modeler. Here some useful algorithms in an appropriate order:

• QuickOSM → Advanced, one of the Build query algorithms.
• File Tools → Download file.
• Modeler Tools → String concatenation. Useful to concatenate the downloaded filepath with
  • |layername=points
  • |layername=lines
  • |layername=multilinestrings
  • |layername=multipolygons
• QuickOSM → Open OSM file. Instead of the step above with the string concatenation.

Check a more detailed answer on stackexchange.

• Vector Table → Explode HStore field (QGIS ≥ 3.6)
• Vector Table → Feature filter

Since QGIS 3.6, you can export your Processing model as a Python script.

• QuickOSM is maintained only for a maintained QGIS version (LTR and stable release).
• Current test status master :

Etienne Trimaille : https://twitter.com/etrimaille