CronWatch records every run of your scheduled jobs in your own database and tells you when one is missed, fails, gets stuck, runs slow, or costs too much. It is a library, not a service, so there is no server to run and no account to make.
It supports TypeScript, Ruby, Python, PHP, Go, Rust, Elixir, Java, and .NET. Every alert includes the error and the last lines of output, and can be sent to the channels you choose. If you turn on triage with an Anthropic API key, the alert also carries a diagnosis.
You add it where the job lives, declare the schedule once, and keep the history in SQLite, Postgres, MySQL, or D1. It mounts inside your app, works with cron and common job frameworks, and includes a setup prompt you can paste into an AI coding agent to wire up every job.