How to Build a Node.js Cron Job for Slack and Email Error Alerts

Developers lacking built-in alert routing in their error tracker can bridge the gap using a small Node.js polling worker run as a cron job. The worker periodically queries recent unresolved error groups, persists last-seen event IDs or timestamps to avoid duplicate alerts, and forwards only new items to destinations like Slack, Teams, or email. A key pitfall is silently swallowed HTTP 429 rate-limit errors, which can make a failing poller appear healthy; the fix is to treat 429 as a scheduling signal, honor Retry-After headers, and surface final failures explicitly. Because a polling worker cannot detect its own absence, a separate heartbeat or uptime monitor such as Healthchecks must be paired with it to catch cases where the cron job stops running entirely. The pattern is intentionally narrow, suited for simple channel-alert workflows rather than full on-call systems with escalation and retry policies.