Matomo Browser Injector

Fit the need I was looking for so long. Basically it is allowing you to copy/paste within a website you don't know about the Piwik tracking code. As a result you can get within your own Piwik installation a foretaste of how the data are pushed. The expert mode allows you to push extra lines of code such as custom dimensions, heartbeat functions, e-commerce... The perfect plugin for testing Piwik.