Use cases — 25+ real applications

Anywhere you want a low-cost, low-friction notification channel. “Webhook → JSON → phone push” beats “build your own dashboard or pay PagerDuty” for the vast majority of small-to-mid systems.

Infrastructure / DevOps

1. CI/CD notifications — GitHub Actions / GitLab CI / Jenkins post build pass/fail with commit + branch + author. PRs auto-pinged.
2. Deploy notifications — deploy.sh posts version + duration + diff link to #dev.
3. Cron job monitoring — wrap every cron in a shell helper that posts success/failure with exit code + last 50 log lines.
4. Server uptime monitoring — Prometheus/Alertmanager → Discord webhook (Alertmanager has native Discord support). Same for Grafana, Loki, Sentry, Datadog, Bugsnag.
5. SSL cert expiry warnings — daily cron checks openssl s_client on every domain, posts when <30 days remain.
6. Disk-full / OOM warnings — node_exporter alerts → Discord.
7. Container registry pushes — post when a new image lands so the team sees it.
8. Backup completion — pg_dump / restic backup posts size + duration + checksum.
9. Log error rate spikes — Loki/Splunk alert when error log lines per minute exceed baseline.
10. Kubernetes events — kubectl get events watcher posts pod crashes, OOMKills, image pull errors.

Application monitoring

1. API latency alerts — p99 > threshold for N minutes.
2. Database slow-query alerts — pg_stat_statements daily top-10 posted to #dev.
3. Background-job failures — Celery/Sidekiq/Resque dead-letter queue items posted as they land.
4. Cache hit-rate drop — Redis hit/miss ratio dipping below baseline = post.
5. Security alerts — failed-login bursts, IP geolocation anomalies, new admin role assignments.

Business / product events

1. New signup / churn — every new user (or only first-of-day, or only if revenue > $X) posted to #growth.
2. Payment events — Stripe webhook relay: every charge over $1k or every refund or every chargeback dispute.
3. High-value customer activity — VIP user logged in / hit a paywall / downgraded.
4. Trading / fintech alerts — order filled, position closed, daily P&L summary, risk limit breached (this repo was originally extracted from an algo trading system).
5. E-commerce stock alerts — low-inventory pings for SKUs under reorder threshold.
6. SaaS feature flag changes — every flag toggle posted so the team sees who flipped what.

Personal / hobby

1. IoT sensor alerts — temperature, humidity, water leak, door/window contact. ESPHome + Home Assistant → webhook.
2. Weather alerts — daily forecast at 7am, or only when severe weather alerts fire for your area.
3. Stock / crypto price triggers — when a watchlist symbol hits a target.
4. Sports scores — favorite team final score, or only goals/runs.
5. RSS / podcast new episodes — daemon polls feeds, posts new items.
6. GitHub mentions — daemon polls notifications.github.com, posts issues/PRs mentioning you.
7. Reminder bot — at-style scheduled posts (“send msg to #personal at 5pm tomorrow”).

Security / audit

1. Login from new IP — webhook from auth middleware on every new geolocation.
2. sudo log relay — /var/log/auth.log tail to #audit.
3. Webhook honeypot — fake admin endpoint that posts every attempt so you see who’s probing.
4. CSP violation reports — browser CSP report endpoint relays to #security.

ChatOps

1. Manual deploy approval — slash-command bot (or webhook + button) lets a human approve a deploy from their phone.
2. Slack-style status broadcasts — anyone on the team can post a “I’m taking the system down for 5 min” notice.

Anti-uses (where Discord webhooks are NOT enough)

• Critical wake-from-silent-mode alerts — iOS hardware silent mode blocks Discord push. Layer a real phone call (Twilio, CallMeBot WA call) or Pushover Pro for iOS Critical Alerts.
• High-volume metrics streaming — Discord is rate-limited at ~5/sec/webhook. Use Prometheus + Grafana for graphs, Discord only for state-change alerts.
• Long-term log archive — Discord history is unlimited but not designed for grep-style search at 10M+ messages. Pair with Loki/Elasticsearch.
• Two-way support chat with end users — Discord channels are for your team. Use Intercom/Crisp/Zendesk for customer chat.
• Compliance-regulated audit trail — Discord retention is up to Discord. For regulated industries, mirror to your own DB too.

Combine with other tools

Layer	Purpose	Examples
Discord (this repo)	Visual, threaded, searchable	Embed colours, channels, audit mirror
ntfy.sh	Free push with priority levels	P0 wake-up vibrate + banner
Pushover Pro	iOS Critical Alerts	Silent-mode override, ~$5/yr
CallMeBot / Twilio	Real phone call	Sleep-through-anything wake-up
WhatsApp (WeSender, Twilio WA, etc.)	Family-visible alerts	Wife/spouse also sees the alert
Email	Audit trail, regulatory	Long-term archive

A typical production stack: Discord for visual, ntfy or Pushover for phone wake, real phone call for P0 only. Total cost: $0–$10/year.

Next: production patterns.