Update, April 2026: JF Website Monitor is now live at jfwebsitemonitor.com. The free tier is available with no credit card required. Read on for the original launch post — and see the What's Shipped section below for everything added since January.
I'm thrilled to announce the launch of a project I've been working on for the past few months: JF Website Monitor. This isn't just another uptime checker; it's a comprehensive monitoring solution designed for developers, agencies, and online businesses who need to know not only if their site is online, but if it's working correctly.
The Problem with "Uptime"
Traditional uptime monitors are great for one thing: telling you if your server is responding. But what if your site is online, but the content has been replaced with a malicious script? What if a botched deployment breaks the layout on mobile devices? Most monitoring tools would still report "100% Uptime."
This is the problem I set out to solve with JF Website Monitor. I wanted a tool that could answer the question: "Is my website really okay?"
"Your website can be 'up' and still be completely broken. True monitoring is about ensuring correctness, not just availability."
What Makes JF Website Monitor Different?
JF Website Monitor combines three key areas of monitoring into one simple-to-use platform:
1. Real-Time Uptime Monitoring
Of course, we start with the basics. With checks as fast as every 15 seconds from multiple geographic locations, you'll be the first to know if your site goes down. Track response times, get detailed performance metrics, and receive instant alerts via email, SMS, or webhook.
2. Content Change Detection
This is where JF Website Monitor really shines. We take regular HTML snapshots of your pages and compare them. If anything changes—from a single line of text to a full-blown defacement—you get an alert. Our side-by-side diff viewer shows you exactly what changed, so you can quickly identify unauthorized modifications or accidental deletions.
3. SLA Compliance and Reporting
For agencies and freelancers, proving that you're meeting your Service Level Agreements (SLAs) is crucial. JF Website Monitor provides detailed, exportable PDF reports of uptime and performance. You can filter logs by date and status to create comprehensive documentation for clients.
Key Features at a Glance
✅ Core Features
- Global Uptime Monitoring: Checks from multiple locations.
- Content Change 'Diff' Alerts: Get notified of any HTML changes.
- Performance Tracking: Monitor response times and identify bottlenecks.
- SLA Reporting: Exportable PDF reports for clients.
- Instant Multi-Channel Alerts: Email, SMS, Slack, and webhooks.
🎯 Perfect For
- Digital Agencies: Monitor all your client sites in one place.
- E-commerce Stores: Ensure your checkout process is always working.
- Developers: Get peace of mind that your deployments are solid.
- Businesses: Protect your brand from defacement and silent outages.
Try it Yourself
JF Website Monitor is live. The free tier covers monitoring for multiple sites with no credit card required — sign up and have your first site monitored in under two minutes.
I'm incredibly proud of how this project has turned out, and I believe it solves a real problem that many of us in the web industry face. The goal is to provide actionable insights, reduce alert fatigue, and give you confidence that your online presence is secure and reliable.
What's Shipped Since Launch
Since the January 2026 launch, several significant features have landed. Here's what's new:
Puppeteer-Powered Content Change Detection
Content change detection now uses a headless Chromium instance (via Puppeteer) to render pages with JavaScript execution before taking snapshots. Static HTTP fetches miss dynamic content; the Puppeteer approach sees what your users actually see. CSS selector targeting lets you watch specific elements — a product price, a stock status badge, a shipping estimate — rather than the entire page. Changes below a configurable 5% threshold are ignored to prevent alert fatigue from cosmetic shifts. See the full technical deep-dive for implementation details.
SLA Compliance Reporting
The SLA reporting dashboard generates exportable PDF reports showing uptime percentage, incident counts, mean time to recovery, and P95 response times for any date range. Agencies can share these directly with clients as proof of SLA adherence. See the SLA reporting post for a walkthrough.
Self-Hosting Option
JF Website Monitor can now be self-hosted for teams that need monitoring data to stay within their own infrastructure. Docker Compose setup, environment variable configuration, and Postgres migration steps are documented in the self-hosting guide.
Alert Channels
Beyond email, alerts now route to Telegram (via bot message) and custom webhooks. The webhook payload is a structured JSON object that plugs directly into Slack, PagerDuty, or any other alert management system.