It was 2:47 AM when my phone buzzed. Another client. Another "THE SITE IS DOWN!!!" message with seventeen exclamation points.

I dragged myself out of bed, opened my laptop, and began the ritual every developer who’s supported a production site knows too well:

• Is the domain expired? Check DNS...
• Is the SSL certificate valid? Open another tab...
• Is the server responding? Ping, ping, ping...
• Is it a regional issue? Fire up a VPN...
• Is the CDN working? Yet another tool...

15 minutes and 8 browser tabs later, I discovered someone forgot to renew the SSL certificate. It had expired 4 hours ago.

This happened way more than I’d like to admit.

The Pattern I Noticed

After years of supporting websites—from small business sites to e-commerce platforms—I realized something:

The problem was never finding the issue. It was the time spent eliminating what WASN’T the issue.

When a site goes down, there are maybe 15-20 common culprits:

• Domain/SSL expired
• DNS misconfigured
• Server unreachable
• CDN issues
• Security headers missing
• Robots.txt blocking everything
• Mixed content warnings
• Response time tanked
• ...and so on

Each requires a different tool. Different interfaces. Some need logins. Some are painfully slow. Some output data that requires a decade of experience to interpret.

I wanted one button that runs ALL of these checks and tells me exactly what’s broken.

So I built it: SiteCenter Site Check

Why Existing Tools Frustrated Me

Most only test one thing. SSL checker here, DNS lookup there, performance test somewhere else. That’s why you end up with 8 tabs at 3 AM.

They don’t prioritize. Here’s 50 metrics—good luck figuring out which one is actually killing your site right now.

They’re built for SEO, not debugging. Cool, I got a score of 73. But why is the site down?

What It Actually Checks

One scan covers:

• SSL certificate validity + chain issues
• DNS resolution from multiple global locations
• Domain expiration status
• Security headers (HSTS, CSP, X-Frame-Options, etc.)
• Response time & availability from 30+ regions
• Robots.txt configuration
• Sitemap accessibility
• Mixed content detection

Everything you’d normally check across a dozen tools—done in seconds.

It’s free. No signup.

Why Free?

I’ve been on the receiving end of too many panic calls. If you’re a dev, freelancer, or agency owner managing websites—you deserve a tool that respects your time.

Try it: https://sitecenter.app/pub/siteCheck/

No signup. No credit card. Paste URL, get results.

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If You Want Ongoing Monitoring

The free tool is great for on-demand debugging, but if you want to catch issues before clients do, I also built a full monitoring platform at SiteCenter.app:

• Monitoring of domains, sites, servers, pages, backlinks, applications, etc.
• Checks every 30 seconds from 10+ regions
• SSL & domain expiration alerts (30/14/7/1 days out)
• Notifications via email, Telegram, etc.
• Client-facing status dashboards

But seriously — start with the free checker. If it saves you one 3 AM session, it’s done its job.

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I’m improving this tool and would love to hear your feedback. What checks would you add? What would make your debugging life easier? Drop your suggestions in the comments — I read every one.