How Joomla Web Cron Works
Web Cron is a trigger for Joomla Scheduled Tasks
Joomla Scheduled Tasks stores and manages the individual jobs inside Joomla. Web Cron is one way to trigger Joomla's scheduler from outside the site. When Web Cron is enabled in Scheduled Tasks options, an external service can request Joomla's generated Webcron link so Joomla has an opportunity to process scheduled work.
Joomla protects the trigger with a hash
Joomla's Scheduled Tasks help documents that Web Cron is disabled by default and, when enabled, requires a hash to trigger the scheduler. Before the first save Joomla indicates that a key is required. After the configuration is saved, Joomla displays a Webcron link URL that can be copied for use by the external scheduler.
The external service supplies the timing
A web-cron provider or another trusted HTTP scheduler requests the generated URL at the interval you configure with that service. This is different from Lazy Scheduler, where normal site visitors provide trigger opportunities, and from server cron with Joomla CLI, where the server launches a command-line process.
Due tasks remain controlled by Joomla
Calling the Web Cron URL does not mean every scheduled task should run on every request. Individual Joomla tasks retain their enabled state, execution rule, priority, and task-specific parameters. The external request triggers the scheduler; Joomla determines which configured work is due.
Web Cron is useful when shell cron is unavailable
Some shared-hosting environments do not provide convenient command-line cron access. In those cases, Web Cron can provide an external trigger without relying on visitor traffic. When server cron and Joomla CLI are available, they may be preferable for jobs where command-line execution and predictable server-side triggering are operational priorities.
Treat the Web Cron URL as a credential
The generated URL contains the information Joomla uses to authorize the Web Cron trigger. Do not publish it, place it in public documentation, or expose it in screenshots. Give it only to the service or administrator that must trigger the scheduler, and regenerate or change the key if you believe it has been disclosed.
Verify the complete path
First manually test a safe Joomla scheduled task so you know the task itself works. Then configure the external service to request the Web Cron URL and confirm a later automatic execution using Last Run information or Execution History where available. This separates task failures from Web Cron delivery or authentication problems.
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