DEV Community: Anton

I built a free tool that runs 15+ website diagnostic checks at once

Anton — Thu, 25 Dec 2025 10:19:20 +0000

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.

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.

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.

Quick way to check SSL Certificate

Anton — Mon, 18 Aug 2025 09:42:48 +0000

Quick SSL Certificate Check

Here's a super simple way to check your SSL certificate status instantly:

sitecenter.app/pub/sslExpireCheck

Just enter your URL and get:

External validation of your certificate
Exact days remaining until expiration
No installation or setup required

Level Up: Automated Monitoring

For production sites, manual checking isn't enough. That's where sitecenter.app comes in handy:

Continuous SSL certificate monitoring
Email alerts before expiration
Multiple sites dashboard
Prevent unexpected outages

Don't let expired certificates catch you off guard again. A few minutes of setup can save hours of downtime and frustrated users.

Share your experience of using this service below, I appreciate your opinion.

How to monitor your ssl certificates

Anton — Mon, 30 Jun 2025 13:52:28 +0000

Keeping a website healthy is a continuous game of “What could go wrong next?” — from an unnoticed certificate expiry to a midnight server hiccup. sitecenter.app shields you from those surprises with more than fifty automated checks that run on a schedule you control, sending instant alerts long before issues reach users. Below, you’ll see why SSL and uptime monitoring matter, what those 50 + probes cover, and how you can be up and running in minutes.

The hidden cost of being offline

Even short outages can drain budgets fast: industry surveys peg a single incident anywhere between $10 k and $1 M in lost revenue, depending on company size and digital dependence.

Beyond the direct hit to sales, downtime chips away at brand reputation and customer trust, making repeat incidents progressively more expensive to recover from.

SEO penalties for downtime

Search engines track availability, and extended or frequent outages drag rankings down. Maintaining at least 99.9 % uptime is now a baseline expectation rather than a bragging right.

The invisible SSL time bomb

When a certificate slips past its expiry date, modern browsers flash red-flag warnings that drive visitors away instantly.

The fallout isn’t limited to user fright: expired certificates expose sessions to risky ciphers and non-compliant chains, raising security audits and potentially blocking API integrations.

Certificate chains themselves evolve; a 2024 intermediate-switch announcement showed how an upstream change can break legacy devices overnight for sites that don’t keep track. Continuous certificate monitoring gives you days (or weeks) of notice to renew, re-issue, or swap chains safely.

Beyond “ping”: 50 + health checks in one dashboard

sitecenter.app bundles an extensive toolkit, grouped into categories you can toggle individually or enable en masse:

TLS & Certificates
Expiry countdown, weak-cipher scan, OCSP stapling, mixed-content detection
Availability HTTP/HTTPS status, keyword match, multi-region reachability, port-level TCP/UDP probes

DNS & Domain
SOA serial drift, DNSSEC validity, blacklist lookups, propagation lag

Performance
Core Web Vitals, First Byte, edge latency, Lighthouse trendlines (slow pages hurt conversions by 6 % +).

Security
Security-header audit, vulnerable path sweeps (.git, .env, installer leftovers), CMS fingerprinting
Infrastructure Server IP changes, hosting geo-drift, SSL chain symmetry
Workflow hooks Cron heartbeat, webhook echo, synthetic transaction flows

Regular intervals can be as tight as one minute, letting you catch blips before customers notice. Guidance on scheduling best-practice monitoring confirms that frequency is the key to early detection.

Three-step setup

Create an account (no credit card needed to start).
Add a target — enter a domain or IP; auto-discovery pulls DNS and current certificates.
Select checks & cadence — enable the full 50 + suite or pick only what you need; defaults are sensible, but every probe is tweakable.

A clean UI shows live status seconds after onboarding and historical charts within the first hour. Integrations pipe alerts into email, chat, webhooks, or incident-management platforms so the right people act fast.

Peace of mind, delivered

Prevent silent failures. Get notified days before a cert expires or when DNS drifts.
Protect revenue and SEO. Catch outages early and keep your ranking intact.
Simplify your stack. One service covers performance, security, and availability across the whole site.

You don’t need a dozen dashboards to watch over critical systems. With sitecenter.app, just sign in, flip a few switches, and rest easy knowing you’ll hear about problems before your visitors do.

Ready to safeguard your site? Start your first monitors today at sitecenter.app — it only takes a few minutes, and the next “what could go wrong” won’t catch you off guard.