CronDeck - Cron Jobs & Uptime Monitoring
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CronDeck - Cron Jobs & Uptime Monitoring

📌 Overview

CronDeck is a cron-as-a-service platform for developers. You schedule HTTP requests with cron expressions, and every execution is recorded with its status, HTTP code, duration, response headers and response excerpt — so when a job fails you can see exactly why.

On top of scheduled jobs it adds uptime monitors, heartbeat checks, incidents and public status pages, with alerts by email and Slack.

👉 Try it live: crondeck.cc.cd

🚀 Features

Scheduled HTTP Jobs

  • Cron expressions with explicit IANA timezone selection (browser timezone detected by default).
  • Any method, custom headers, query params, request body, and auth configuration (stored encrypted).
  • Run now for manual execution, plus configurable per-job timeouts.
  • Full execution history with status, response code, duration, headers and body excerpt.

Monitoring & Alerts

  • Uptime monitors with response assertions.
  • Heartbeat checks that alert when a job stops pinging in.
  • TLS certificate expiry checks.
  • Failure alerts after N consecutive failures, auto-disable rules, and recovery notifications — by email and Slack.
  • Incidents and public status pages with optional custom domains and branding.

Platform

  • Google and GitHub sign-in, team members, and a REST API with API keys.
  • Free, Developer, and Pro plans with per-plan limits on jobs, monitors, status pages, history retention and minimum interval.

🔒 Security

A scheduler that fires arbitrary HTTP requests is an SSRF risk, so target URLs are validated before they are stored and again before they run:

  • HTTP and HTTPS only, no embedded credentials.
  • Local, private and reserved hostnames blocked; DNS resolved through DNS-over-HTTPS and private/reserved IPs rejected, including IPv4-mapped IPv6.
  • Restricted header names and values, request body size limits, and a 30-second outbound timeout.
  • No automatic redirect following, and capped capture of response headers and bodies.
  • Same-origin checks on browser mutations and per-user rate limits.

🏗️ Architecture

  • A single Hono app on Deno Deploy serves the dashboard, API and public pages.
  • A 1-minute Deno.cron tick finds due jobs, claims each with a short lock, runs them in concurrent batches of 25, records the execution, and computes the next run with croner.
  • The same tick checks overdue heartbeats, downgrades expired subscriptions, and purges deleted accounts.
  • State lives in SQLite on Turso (libSQL) — users, jobs, executions, monitors, status pages and subscriptions.
  • Status pages on managed subdomains and custom domains (e.g. status.yourbrand.com) are routed and cached by a Cloudflare Workers edge layer, with a Vercel Edge reverse proxy issuing SSL for customer domains.

🛠️ Tech Stack

  • Runtime: Deno, TypeScript
  • Web: Hono, server-rendered HTML UI
  • Scheduling: Deno.cron, croner
  • Database: SQLite (Turso / libSQL)
  • Edge: Cloudflare Workers (status pages), Vercel Edge (custom domains)
  • Deployment: Deno Deploy