Blog · Messaging
Scheduled messages and alerts for Slack, Discord and WhatsApp
Messaging APIs ship send endpoints, not clocks. These posts cover the external cron shape for scheduled reminders and the failure alerts that hit your team chat the moment a job goes red.
About this topic
Messaging
WhatsApp Business has no scheduler. Meta Cloud API and Twilio WhatsApp both expose a send endpoint and leave the cadence to you, which is fine if you only send one message a day and bad if you run class reminders, daily digests, or review nudges across time zones. Slack, Discord, and Telegram are similar: the APIs are ready when you are, but nothing inside them tells you when you should send.
Crontap fills both halves. On the send side, it calls your /whatsapp-notification (or /slack-digest, or /telegram-recap) endpoint on a per-IANA cadence, so the 8am reminder lands at 8am in the user's local time even when DST shifts under it. On the alert side, connected Slack, Discord, Telegram, and email channels receive human-facing failure alerts. Generic success or failure webhooks stay under Integrations for machine callbacks. The WhatsApp Business reminders post walks the outbound shape; the native alert guides cover operational delivery.
Blog on Messaging
5 items- Product
Slack, Discord and Telegram alerts are here
Connect chat channels once, then route formatted schedule, uptime and heartbeat alerts with defaults, per-entity overrides and delivery tests.
- Guides
From raw JSON to a one-line Slack digest
Nobody opens raw JSON in Slack. After a scheduled HTTP run, Crontap's AI integration reads that run's response and forwards a one-sentence digest (or a 3-bullet status) to your channel. No formatter route, no deploy.
- Guides
Turn an RSS or changelog feed into a morning brief in Slack
Your reader app has 400 unread items you meant to read. Crontap's AI Integration fetches a feed on a daily schedule, condenses the newest items into five bullets, and posts the brief to Slack in your timezone, before standup.
- Guides
Build in public Twitter automation: daily devlog tweet from your GitHub commits
GitHub Actions cron drifts 30-60 minutes and auto-disables after 60 days no commits. Here is the indie-hacker pattern that pulls yesterday's commits, asks GPT for a tweet draft, and parks it in Typefully for tomorrow's 09:30 in your timezone, for about $0.02 a month.
- Guides
Scheduled WhatsApp Business reminders at scale
WhatsApp Business has no scheduler. Build a /whatsapp-notification endpoint, drive it from an external cron per timezone, and ship reminders, recaps, and review nudges without rebuilding a clock.
Related on Crontap
The same Messaging topic, from other angles.
FAQ
Common questions on Messaging
- Can I schedule a message directly from Crontap to Slack?
- Indirectly. Crontap calls a URL, so you point it at a Slack incoming webhook (or a small backend that calls chat.postMessage). For one-off scheduled messages it's fine. For richer formatting, a thin endpoint that builds the block payload is the cleaner shape.
- WhatsApp Business has a 24-hour message window. Doesn't that conflict with cron?
- It does for free-form messages. For scheduled reminders, you use approved message templates, which sit outside the 24-hour window. The WhatsApp Business post covers template selection and the exact send-endpoint shape.
- I want a Slack ping when a different schedule fails. How does that work?
- Connect Slack in notification settings, enable it in the Schedules defaults, or select it on one schedule with Choose channels. Generic webhook Integrations remain separate for machine callbacks.
More from Crontap
Topics across the site.
Every topic Crontap covers, in one row. Each one has its own page on the blog surface.
Ready to fix it?
Point Crontap at any URL. Pick any cron. Done.
WordPress, Shopify, Railway, Cloud Run, Vercel, HubSpot, Ghost, your own box. If it answers HTTP, Crontap can drive it on a clock you can read, in the timezone that actually matters, and page you when something breaks.
Free forever tier ・ No credit card required
/wp-cron.php?doing_wp_cron=1
Schedule
"every 5 minutes"
Next
in 23s