OPEN SOURCE INFRASTRUCTURE

Every website is leaking visibility.

No black boxes. No gated reports. Paste any public URL and inspect 16 on-page SEO checks with exact code evidence and free DIY fixes.

16 Heuristics

0 Logins / Paywalls

100% Evidence-Based

edge-diagnostic-v0.2.0

STANDBY

Want to test the reporting engine first?

THE OBSERVATORY METHODOLOGY

How the engine inspects without crawling blind.

STAGE 01

DETECT

Cloudflare DNS-over-HTTPS checks A/AAAA records and rejects private or reserved addresses. DNS checks alone do not guarantee protection against rebinding.

DNS_DOH_SHIELD: ACTIVE

STAGE 02

ANALYZE

Streaming HTMLRewriter extracts metadata in real time: page title, meta description, heading hierarchy (H1-H6), canonical target, and image alt ratios within strict 450 KB limits.

HTML_REWRITER: 450KB_CAP

STAGE 03

UNDERSTAND

Extracted signals are evaluated using 16 on-page heuristics. Findings show their evidence and distinguish confirmed observations from checks we could not verify.

HEURISTIC_TAXONOMY: 16_RULES

STAGE 04

IMPROVE

Every finding surfaces example code snippets and a downloadable plain-text DIY checklist so website owners can repair their markup freely and immediately.

DIY_CHECKLIST: UNGATED

edge-inspect://worker-sandbox.internal

DEMO · STAGE: DETECT

DOH_RESOLVE target.domain.com -> 104.21.48.192 [PUBLIC_OK]

TLS_HANDSHAKE Illustrative connection — not a live TLS measurement

HTTP_GET / HTTP/1.1 -> 200 OK (Content-Type: text/html)

DNS_PREFLIGHT DNS TTL: 300s (Exceeds 0s threshold)

SHIELD_STATUS Connection approved for edge streaming.

<head>

<title>Sample Page — High Precision</title> [30 chars - OPTIMAL]

</head>

<body>

<h1>Primary Topic Target</h1> [H1 Count: 1 - VALID]

<img src="hero.webp" alt="Detailed caption"> [Alt present]

✓

Page Title Length 30 characters. Within Google 15–65 display window.

PASS

Meta Description Short (38 chars). Recommended 50–170 for snippet CTR.

OPPORTUNITY

✓

Heading Structure Single H1, sequential H2/H3 hierarchy. No level skips.

PASS

RECOMMENDED CODE FIX ZERO_PAYWALL

<!-- Optimized Snippet Preview -->
<meta name="description"
      content="High-fidelity website diagnostic suite for technical SEO. Zero login, open infrastructure.">

1. Update head template in CMS or repo

2. Deploy and re-run instant scan

THE MANIFESTO

Honest tools for the open web.

The SEO industry is built on fear, inflated keyword metrics, and forced subscriptions. NexusOpen SEO is our contribution to a transparent developer ecosystem. We inspect raw public markup, explain what we find in plain English, and provide the exact code required to fix it.

Pronab Chakraborty — Nexus World

Sarwar Jahan — Nexus World