CronWatch MCP server

CronWatch

Cron and scheduled-job monitoring that lives inside your app. Wrap a job once; CronWatch records every run in a database you already have and tells you when a run is missed, fails, gets stuck, runs slow, goes over budget, or quietly does nothing. No server to run, no account to make. MIT.

Site and docs: cronwatch.dev

// lib/cronwatch.ts
import { cronwatch } from "@cronwatch/sdk";
import { sqlite } from "@cronwatch/sdk/sqlite";
import { slack } from "@cronwatch/sdk/slack";

export const cw = cronwatch({
  store: sqlite({ path: "./data/cronwatch.db" }),
  alerts: [slack({ webhookUrl: process.env.SLACK_WEBHOOK_URL! })],
});

export const nightlyReport = cw.job("nightly-report", {
  schedule: "0 2 * * *", timezone: "UTC", grace: "15m", expect: "Report written",
});

// app/api/cron/nightly-report/route.ts: checks Authorization: Bearer CRON_SECRET
import { nightlyReport } from "@/lib/cronwatch";

export const GET = nightlyReport.handler(async (job) => {
  const report = await buildReport();
  job.log("Report written:", report.path);
  job.metric("cost", report.usdCost);
});

// app/cronwatch/[[...path]]/route.ts: a dashboard and JSON API behind CRONWATCH_TOKEN
import { cw } from "@/lib/cronwatch";

export const { GET, POST, DELETE } = cw.routes();

Packages

Package	What
@cronwatch/sdk	the library for Node, Cloudflare Workers, Deno, and Bun: jobs, runs, checks, stores (memory, SQLite, Postgres, D1), pg_cron jobs read from Postgres, alerts (Slack, Discord, webhook, email, SMS, error trackers), dashboard and API, adapters for Node servers, optional Claude triage
cronwatch gem	the Ruby port for Ruby and Rails apps: ActiveRecord store, ActiveJob and Sidekiq integration, schedules read from Solid Queue or sidekiq-cron, pg_cron jobs, the same alert channels, a check job, the dashboard as a Rack app. Same rules, alerts, and stored rows as the SDK
cronwatch-sdk for Python	the Python port for Python apps: the memory, SQLite, and Postgres stores, the same alert channels and Claude triage, pg_cron jobs, the dashboard as a WSGI and ASGI app, Django, Celery and beat, APScheduler, async jobs, and handler() for platform crons and AWS Lambda
cronwatch/cronwatch for PHP	the PHP port for PHP apps: the memory, SQLite, MySQL (and MariaDB), and Postgres stores, sharing tables with the SDK byte for byte, the same alert channels and Claude triage, pg_cron jobs, vendor/bin/cronwatch check, the dashboard (a bare script or PSR-15), handler() for platform crons, Laravel and Symfony integrations, a WordPress plugin, a Drupal module (drupal/cronwatch), and a Craft CMS plugin (cronwatch/craft) (its DESIGN.md)
cronwatch.dev/go	the Go port for Go apps: jobs, runs, and checks with context throughout and safe across goroutines, the memory store and a database/sql store for SQLite, Postgres, MySQL, and MariaDB over the app's own driver, sharing tables with the SDK byte for byte, the same alert channels and Claude triage, pg_cron jobs, the dashboard and job.Handler as http.Handlers, an AWS Lambda adapter, and modules of their own for robfig/cron, gocron, River, and Asynq (its DESIGN.md)
cronwatch crate	the Rust port for Rust services, on tokio: jobs, runs, and checks, safe across tasks, the memory store and cronwatch-sqlx for SQLite, Postgres, MySQL, and MariaDB over the app's own sqlx pool, sharing tables with the SDK byte for byte, the same alert channels and Claude triage, pg_cron jobs, the dashboard and handler() framework-free with tower and axum adapters (and so AWS Lambda through lambda_http), a blocking client, and crates of their own for tokio-cron-scheduler and apalis (its DESIGN.md)
cronwatch on Hex	the Elixir port for Elixir and Erlang services: an instance in the app's supervision tree, jobs run in the calling process and recorded when it dies, the memory store and an Ecto store for SQLite, Postgres, MySQL, and MariaDB over the app's own repo, sharing tables with the SDK byte for byte, the same alert channels and Claude triage over OTP's own sockets, pg_cron jobs, the dashboard and a job's handler as Plugs for a Phoenix router, telemetry events, a release's crontab check, and integrations for Oban and Quantum (its DESIGN.md)
dev.cronwatch:cronwatch for Java	the Java port for services on the JVM: jobs run in the calling thread and safe across platform and virtual threads, the current run carried across threads, a shutdown hook that records runs a stopping JVM leaves open, the memory store and a JDBC store for SQLite, Postgres, MySQL, and MariaDB over the app's own DataSource, sharing tables with the SDK byte for byte, the same alert channels and Claude triage over the JDK's own HTTP client, pg_cron jobs, the dashboard and a job's handler framework-free with adapters for the JDK's server, servlet containers (cronwatch-servlet), and Spring MVC and WebFlux, CronwatchCli for a crontab's check, a Spring Boot starter that watches every @Scheduled method (ShedLock included), and modules of their own for Quartz and JobRunr (its DESIGN.md)
Cronwatch on NuGet	the .NET port for .NET services: jobs run in the caller's flow and safe across threads and tasks, the current run carried across awaits, a process-exit hook that records runs a stopping process leaves open, the memory store and an ADO.NET store for SQLite, Postgres, MySQL, and MariaDB over the app's own DbDataSource, sharing tables with the SDK byte for byte, the same alert channels and Claude triage over HttpClient, pg_cron jobs, the dashboard and a job's handler framework-free with an ASP.NET Core adapter (Cronwatch.AspNetCore), the client in the Generic Host with hosted jobs on a cron (Cronwatch.Hosting), CronwatchCli for a crontab's check, Native AOT support, and packages of their own for Hangfire and Quartz.NET (its DESIGN.md)
@cronwatch/mcp	an MCP server so Claude Code, Cursor, and other agents can list jobs, read failures, run a check, and silence alerts
skills/cronwatch	an agent skill for Claude Code, Codex, Cursor, and others: how to add monitoring to a job and how to investigate a failure. npx skills add cronwatchdev/cronwatch installs it (on skills.sh)

Installing

Language	Install	Docs
TypeScript and Node	npm install @cronwatch/sdk, and the driver for a store (below)	Getting started
Ruby and Rails	bundle add cronwatch, then bin/rails generate cronwatch:install and bin/rails db:migrate in a Rails app (Ruby 3.2 or newer; Rails 7.2, 8.0, and 8.1)	Rails, Ruby, its README
Python	pip install cronwatch-sdk	Python, its README
PHP	composer require cronwatch/cronwatch	PHP, its README
WordPress	CronWatch in the plugin directory: search for it under Plugins, Add New Plugin, or wp plugin install cronwatch --activate	WordPress
Drupal	composer require drupal/cronwatch, then drush pm:install cronwatch	Drupal, drupal.org
Craft CMS	composer require cronwatch/craft, then php craft plugin/install cronwatch, or from the Plugin Store	Craft CMS
Go	go get cronwatch.dev/go, and go get cronwatch.dev/go/robfigcron (or /gocron, /river, /asynq) for a scheduler	Go, Go schedulers, its README
Rust	cargo add cronwatch --features alerts, cargo add cronwatch-sqlx --features postgres (or sqlite, mysql), cargo add sqlx --no-default-features --features runtime-tokio,postgres, and cargo add tokio --features macros,rt-multi-thread; cronwatch-tokio-cron-scheduler or cronwatch-apalis for a scheduler	Rust, Rust schedulers, its README
Elixir	{:cronwatch, "~> 0.14"} in mix.exs, with the app's Ecto adapter for the SQL store; Oban and Quantum are watched with no other package	Elixir, Elixir schedulers, its README
Java	dev.cronwatch:cronwatch (Java 21 or newer), or dev.cronwatch:cronwatch-spring-boot-starter in a Spring Boot app; cronwatch-servlet, cronwatch-quartz, and cronwatch-jobrunr beside it at the same version, with the app's JDBC driver for the SQL store	Java, Java schedulers, its README
.NET	dotnet add package Cronwatch (.NET 10 or newer), Cronwatch.Hosting in a Generic Host app or Cronwatch.AspNetCore in an ASP.NET Core app; Cronwatch.Hangfire and Cronwatch.Quartz beside it at the same version, with the app's ADO.NET driver for the SQL store	.NET, .NET schedulers, its README

The SDK depends only on croner. The core, the D1 store, the pg_cron source, and every alert channel use only fetch and Web Crypto, so they run on Node 22 or newer, Cloudflare Workers, Deno, and Bun; the SQLite and Postgres stores and @cronwatch/sdk/node need Node. Each driver is an optional peer, installed only when you use its entry point:

Entry point	Install
@cronwatch/sdk/sqlite	better-sqlite3 (and @types/better-sqlite3 for TypeScript)
@cronwatch/sdk/postgres	pg (and @types/pg for TypeScript)
@cronwatch/sdk/anthropic	@anthropic-ai/sdk 0.115 up to (not including) 0.129
@cronwatch/sdk/pg-cron	nothing: it queries through the pg Pool (or anything with query()) you pass it
@cronwatch/sdk/d1, /node, and the channels (/slack, /discord, /webhook, /resend, /postmark, /sendgrid, /mailgun, /ses, /twilio, /sentry, /honeybadger, /datadog, /rollbar, /bugsnag, /newrelic)	nothing

The store entry points' type declarations refer to the driver's types, so a TypeScript project using them without @types/better-sqlite3 or @types/pg fails with TS7016 unless skipLibCheck is on. The package ships ESM and CommonJS, each with its own types.

One library, nine languages

Every language's package follows the same design: each writes the same tables and sends the same alerts, so a Rails app, a Go service, and a Node worker can share one database and one dashboard. All of them are tested against the same recorded cases, so a job behaves the same whichever language runs it. Each package's README and its page on cronwatch.dev have the examples for its language and its schedulers.

Stability

From 1.0 every package follows semantic versioning, one version for all of them. Stability says what a 1.x release promises (the documented API, the stored data, the JSON API, the webhook, settings and environment variable names, documented behaviour) and what it does not; Environment variables lists every variable each library reads; Deprecations lists every deprecated name with its replacement. What changed in each release is in CHANGELOG.md.

Why a library and not a service

A hosted monitor gives you an observer that is alive when your job is not. That is real, and it is the one thing a library cannot do: if your whole app is down, nothing inside it can alert (pair it with any uptime monitor for that case). Everything else, from a job that never fires to one that costs three times what it should, is caught from within, with your run history in your own database and nothing to sign up for.

Contributing

Bugs, ideas, and questions are welcome in the issue tracker. CONTRIBUTING.md covers working on CronWatch itself: each language's tests, releases, and the site.

License

MIT, see LICENSE.