The complete technical specification for Web Credibility Score v2.0 — the AI-era website trust standard by Alert91.
Web Credibility Score (WCS) is a composite trust metric that measures how credible and trustworthy a website is — to AI systems, search engines, and human visitors. It is designed for the AI-era web, where content credibility signals increasingly determine whether your content appears in AI answers, AI Overviews, and generative search results.
WCS was created by Alert91 in 2026 as a response to a gap in existing metrics: Domain Authority (DA) and Domain Rating (DR) measure backlink profiles, not actual trustworthiness. A site can have high DA and still have no HTTPS, no privacy policy, and no legitimate business signals.
WCS measures what actually makes a website trustworthy — security posture, AI readiness, legal compliance, business legitimacy, accessibility, and operational reliability. It cannot be gamed with link-building.
WCS scores range from 0 to 100. Higher is better. Only sites scoring 80+ (Grade A or A+) are eligible to display the WCS Compliant badge.
WCS is a weighted composite of 7 sub-indices. Each index measures a distinct dimension of credibility:
Each index is scored 0–100 based on checks within that index. The final WCS is subject to Kill Switch caps (see Section 4).
Alert91 dashboard clients receive a more accurate WCS using 30 days of real monitoring data — uptime history, Core Web Vitals from CrUX, full security audits, and accessibility scans. The public WCS checker uses a live snapshot scan.
Measures how readable and citable your content is by AI systems like ChatGPT, Claude, Perplexity, and Google AI Overviews.
| Check | Weight | Why it matters |
|---|---|---|
| llms.txt file present | 15pt | Tells AI crawlers what to index |
| Structured data (Schema.org) | 20pt | Enables AI to understand your content type |
| Organization sameAs (3+ profiles) | 8pt | Anti-gaming — proves real social presence |
| AI crawlers not blocked | 10pt | GPTBot, ClaudeBot, PerplexityBot must be allowed |
| FAQ schema markup | 12pt | Enables direct answer extraction by AI |
| Question-format headings | 8pt | What/How/Why H2s improve AI citability |
| llms-full.txt present | 8pt | Extended AI knowledge base file |
| dateModified in schema | 7pt | Tells AI how fresh your content is |
Measures signals of a real, legitimate business operating online.
| Check | Weight |
|---|---|
| Domain age ≥ 1 year | 15pt |
| About page present | 10pt |
| Named author attribution | 8pt |
| Reviews / ratings schema | 12pt |
| Social profile links | 8pt |
| Phone number displayed | 10pt |
| Email address displayed | 8pt |
| Office address displayed | 10pt |
The highest-weighted index. Security is non-negotiable for credibility.
| Check | Weight |
|---|---|
| HTTPS / SSL active | 20pt |
| HSTS header | 10pt |
| Content Security Policy | 10pt |
| X-Frame-Options header | 8pt |
| SPF record configured | 8pt |
| DMARC record configured | 8pt |
| No malware detected | 15pt |
| No sensitive files exposed | 10pt |
| No dangerous ports open | 8pt |
| TLS version secure (1.2+) | 7pt |
| robots.txt present | 5pt |
Measures operational reliability and speed. Slow or unreliable sites lose credibility.
| Check | Weight |
|---|---|
| 30-day uptime ≥ 99% | 30pt |
| Avg response time < 800ms | 20pt |
| LCP ≤ 2.5s (Core Web Vitals) | 20pt |
| CLS ≤ 0.1 (Core Web Vitals) | 15pt |
| Mobile viewport configured | 15pt |
India-specific compliance signals including DPDP Act 2023 requirements.
| Check | Weight |
|---|---|
| Privacy Policy | 15pt |
| Terms & Conditions | 15pt |
| Cookie consent banner | 10pt |
| DPDP Act 2023 compliance | 10pt |
| Refund/cancellation policy | 10pt |
| GSTIN displayed (India) | 10pt |
| DPDP Grievance Officer named | 10pt |
| CIN/company registration | 5pt |
| FSSAI (food businesses) | 5pt |
WCAG 2.1 compliance signals. Accessible sites are more trustworthy and rank better.
| Check | Weight |
|---|---|
| HTML lang attribute set | 15pt |
| Page title present | 10pt |
| All images have alt text | 20pt |
| Skip navigation link | 10pt |
| ARIA landmark roles | 15pt |
| Form labels present | 20pt |
| Viewport meta tag | 10pt |
External reputation signals — the smallest weight because they're harder to control but still matter.
| Check | Weight |
|---|---|
| Google Safe Browsing clean | 30pt |
| External reviews present | 25pt |
| Social profiles verified | 25pt |
| Not blacklisted | 20pt |
Certain critical failures automatically cap the WCS regardless of other scores. These represent fundamental trust failures that no amount of good signals can compensate for.
Kill switches are applied after the base WCS is calculated. The cap is always the lower of the base score and the kill switch cap.
| Grade | Score Range | Label | Badge Eligible |
| A+ | 90–100 | Highly Credible | ✅ |
| A | 80–89 | Credible | ✅ |
| B | 70–79 | Generally Credible | ❌ |
| C | 55–69 | Needs Improvement | ❌ |
| D | 40–54 | Low Credibility | ❌ |
| F | 0–39 | Not Credible | ❌ |
The Confidence Score is a meta-metric that indicates how much real data was available to calculate the WCS. A snapshot scan has lower confidence than a dashboard audit with 30 days of monitoring data.
| Confidence Level | Data Sources Available |
|---|---|
| Very High | All: uptime history + CrUX + security audit + accessibility scan + domain age |
| High | 4 of 5 data sources |
| Medium | 2–3 data sources |
| Low | Only HTML snapshot available |
Trust Momentum shows how a site's WCS has changed over time. It compares the current WCS with the most recent audit from at least 1 day prior.
Example: WCS was 74/B on June 24. After implementing HTTPS headers and compliance pages, WCS improved to 90/A+ on June 27. Trust Momentum shows: ↑ +16pts in 3 days.
Trust Momentum directions: Improving ↑ (positive change), Declining ↓ (negative change), Stable → (no change).
WCS automatically detects the industry of a website and applies additional industry-specific checks. The ITS is a supplementary score (0–100) that does not affect the main WCS but provides targeted recommendations.
The WCS Compliant badge can only be displayed by websites scoring 80 or above (Grade A or A+). This threshold ensures the badge remains a meaningful trust signal.
To embed the badge on your website, add this code before your closing </footer> tag:
The badge links to verify.alert91.com/yourdomain.com where visitors can verify the score.
| WCS (Alert91) | DA (Moz) | DR (Ahrefs) | |
| Measures | Actual trustworthiness | Backlink profile | Backlink profile |
| Can be gamed? | No — technical signals | Yes — buy links | Yes — buy links |
| India signals | Yes (GSTIN, CIN, DPDP) | No | No |
| AI readiness | Yes (llms.txt, schema) | No | No |
| Security checks | Yes (11 checks) | No | No |
| Free to check | Yes | Limited | Limited |
The WCS public API returns the latest score for any domain that has been audited via Alert91.
Returns: wcs_score, grade, label, confidence, badge_eligible, trust_momentum, 7 index scores, audited_at.
Rate limit: 60 requests/hour. No authentication required.