How popular is decoupled Drupal?

Decoupled Drupal has been an increasingly visible topic at Drupal events and on the web for several years now. But what is the percentage of decoupled Drupal sites out of all Drupal sites?

Unfortunately there is no way to get hard numbers at the moment. It also looks as if there have been no user surveys about decoupled Drupal usage so far.

One way to estimate the number of decoupled sites is to look at the usage statistics of modules commonly used on decoupled sites. So I thought I would do that.

(All figures are from 15 April 2018.)

Number of Drupal sites:

• Drupal 8: 226,908 sites
• Drupal 7: 895,343 sites
• Drupal 8 and 7 total: 1,122,251 sites.

To get a better overall picture let’s first look at the the most popular modules:

• Drupal 8: Token, installed on 102,563 sites (45.2 % of all Drupal 8 sites)
• Drupal 7: Chaos tool suite (ctools), installed on 795,261 sites (88.8 % of all Drupal 7 sites).

The difference between the most popular module on Drupal 8 and Drupal 7 is huge! This is probably because Drupal 8 core provides much more functionality out of the box.

Now let’s look at the modules used for decoupled Drupal. For Drupal 8 I have selected the REST UI module and for Drupal 7 the Services module:

• Drupal 8: REST UI, installed on 8,404 sites (3.7 % of all Drupal 8 sites)
• Drupal 7: Services, installed on 43,081 sites (4.8 % of all Drupal 7 sites)
• Drupal 8 and 7: REST UI + Services, installed on 51,485 sites (4.6 % of all Drupal 8 and 7 sites).

Finally let’s look at graphs of usage over time, starting with Services:

We can see that usage grew steadily until early 2016, when it stabilised at the current level. Probably something to do with Drupal 8 being released at that time.

And then the graph for REST UI:

We can see a steady and steep rise in usage right from the time Drupal 8 was released.

These figures and graphs seem to confirm that decoupled Drupal is rapidly gaining popularity, although Drupal 8 usage still has not reached Drupal 7 level (see update below). It will be interesting to see for how long this rate of increase in usage will continue.

Update 26 April 2018: It has been suggested that the JSON API module should be included in the figures for Drupal 8, and this is indeed a good suggestion. JSON API is used in decoupled Drupal distributions like Contenta and Reservoir, and there should be very little overlap in REST UI and JSON API usage.

• Drupal 8: JSON API, installed on 6,341 sites (2.8 % of all Drupal 8 sites)
• Drupal 8: REST UI + JSON API, installed on 14,745 sites (6.5 % of all Drupal 8 sites)
• Drupal 8 and 7: REST UI + JSON API + Services, installed on 57,826 sites (5.2 % of all Drupal 8 and 7 sites).

Usage graph for JSON API:

This looks very similar to REST UI, with a steady and steep rise in usage.