Servers & devices
Cron jobs
Set up the background schedule Zender needs to actually dispatch scheduled messages, wake up devices, expire subscriptions, and clean up old files — none of which happen on their own without it.
Zender doesn't run any background process of its own. Everything time-based — dispatching scheduled messages, prompting devices and WhatsApp accounts to fetch their queued sends, expiring subscriptions, and clearing old files — only happens when something calls one of the endpoints below from outside the app, on a schedule you set up yourself. Without cron configured, none of it runs on its own, no matter how long the site is up.
Every job is called the same way: /cron/{endpoint}/{token}, where
{token} is your site's system token (see the Configuration page for
where that value lives). A wrong or missing token is rejected and nothing runs. A
super admin can see the exact command for every job below, pre-filled with your
site's real token, from Admin → Overview — the Cron
button there opens the same setup guide this page is describing.
Endpoints
| Endpoint | Purpose | Recommended interval |
|---|---|---|
sender |
Pushes an FCM wake-up to every device and WhatsApp account with messages waiting in their queue, so they fetch and send immediately instead of waiting for their next poll. | Every minute |
sms.scheduled |
Finds SMS scheduled sends whose time (or repeat interval) has arrived, builds the recipient list from pasted numbers and/or contact groups, and queues the actual messages for sending. | Every minute |
wa.scheduled |
The WhatsApp equivalent of sms.scheduled — resolves due
schedules, checks the target WhatsApp account is actually connected, and
queues the messages before asking the WhatsApp server to send them. |
Every minute |
subscription |
Warns subscribers by email 5 days before their package expires, and deletes (plus emails) subscriptions that have already expired. | Every 5–15 minutes |
cleaner |
Deletes WhatsApp received/sent media files older than the configured retention period, and asks every registered WhatsApp server to run the same garbage collection on its own stored files. | Once daily |
quota |
Resets usage quotas — see the warning below before scheduling this one. | See below |
quota is destructive and unconditional: every time this endpoint is hit,
it wipes usage counters for every user on the site at once, not just
whoever is due for a reset. Schedule it to match your site's actual reset cadence
(daily or monthly, set from the Settings screen under
Admin → Overview — the dashboard's cron setup guide shows you which one
applies) and nothing more often. Adding it to a per-minute crontab line like the
other jobs will reset every user's SMS/WhatsApp usage counters every minute.
Example crontab
Replace your-domain.com with your real site domain, prefixed with
whichever scheme (http or https) your site actually runs
under, and YOUR_SYSTEM_TOKEN with your real system token:
* * * * * curl -s "your-domain.com/cron/sender/YOUR_SYSTEM_TOKEN" > /dev/null
* * * * * curl -s "your-domain.com/cron/sms.scheduled/YOUR_SYSTEM_TOKEN" > /dev/null
* * * * * curl -s "your-domain.com/cron/wa.scheduled/YOUR_SYSTEM_TOKEN" > /dev/null
*/5 * * * * curl -s "your-domain.com/cron/subscription/YOUR_SYSTEM_TOKEN" > /dev/null
0 3 * * * curl -s "your-domain.com/cron/cleaner/YOUR_SYSTEM_TOKEN" > /dev/null
0 0 * * * curl -s "your-domain.com/cron/quota/YOUR_SYSTEM_TOKEN" > /dev/nullThe last line assumes Daily reset mode and runs at midnight; on
Monthly reset mode, move it to a monthly line (e.g.
0 0 1 * *) instead.