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mermaid.live

Online FlowChart & Diagrams Editor - Mermaid Live Editor

Last scanned Jul 27, 2026, 8:44 AM · 1 view

76

Overall score

Fair

Summary

Simplify documentation and avoid heavy tools. This website uses Svelte hosted on Fastly behind Fastly CDN. SEO is fair (65/100) and accessibility is excellent (90/100). Security scores fair (65/100) and performance excellent (90/100). Top issue: Meta description longer than 160 characters.

Simplify documentation and avoid heavy tools. Open source Visio Alternative. Commonly used for explaining your code! Mermaid is a simple markdown-like script language for generating charts from text via javascript.

United States
Hosted on Fastly

Top issues to fix

9 issues found · 3 high priority

  • Missing Strict-Transport-Security header

    Security

    Add HSTS so browsers always use HTTPS — this closes the protocol-downgrade attack window.

  • Missing Content-Security-Policy header

    Security

    Add a CSP to control which sources can run scripts — the strongest single defense against XSS.

  • No H1 heading found

    SEO

    Add exactly one H1 describing the page's main topic — it anchors the document outline for search engines and screen readers.

  • Missing X-Content-Type-Options header

    Security

    Add X-Content-Type-Options: nosniff to stop MIME-sniffing attacks.

  • Missing X-Frame-Options header

    Security

    Add X-Frame-Options (or a CSP frame-ancestors rule) to prevent clickjacking via hidden iframes.

  • Meta description longer than 160 characters

    SEO

    Trim the meta description to under 160 characters to avoid truncation in search results.

+3 more issues — details in the sections below.

65

SEO

5 issue(s) found

90

Performance

3 ms

65

Security

HTTPS & header checks

90

Accessibility

1 issue(s) found

Not enough scan history yet to show a trend — check back after this site has been re-scanned a few more times.

Organization

Company details published in this site's own structured data.

Simplify documentation and avoid heavy tools. Open source Visio Alternative. Commonly used for explaining your code! Mermaid is a simple markdown-like script language for generating charts from text via javascript.

Meta tags

Title
Online FlowChart & Diagrams Editor - Mermaid Live Editor
Description
Simplify documentation and avoid heavy tools. Open source Visio Alternative. Commonly used for explaining your code! Mermaid is a simple markdown-like script language for generating charts from text via javascript.
Canonical
Language
en
Charset
utf-8
Viewport
width=device-width, initial-scale=1
Robots meta
Manifest
https://mermaid.live/manifest.json

OpenGraph & Twitter Card

OpenGraph

og:title
og:description
og:type
og:url

Twitter Card

twitter:card
twitter:title
twitter:description

Technologies

Detected frameworks, languages, and tools.

Hosting & CDN

Hosting provider
Fastly
CDN provider
Fastly
IP address
185.199.108.153
ASN
AS54113 (FASTLY - Fastly, Inc., US)

DNS records

TypeValue
A
  • 185.199.108.153
  • 185.199.109.153
  • 185.199.111.153
  • 185.199.110.153
AAAA
  • 2606:50c0:8001::153
  • 2606:50c0:8000::153
  • 2606:50c0:8003::153
  • 2606:50c0:8002::153
MX
  • fwd2.porkbun.com
  • fwd1.porkbun.com
TXT
  • v=spf1 -all
  • google-site-verification=Aw_N4i2o7EndKs_mSATH68FphyvZ8sh0Q-Q7PADOalY
NS
  • dns1.p06.nsone.net
  • dns4.p06.nsone.net
  • dns2.p06.nsone.net
  • dns3.p06.nsone.net
CAA
CNAME
IPv6 supportYes

TLS / SSL certificate

Version
TLS 1.3
Issuer
Let's Encrypt
Subject
mermaid.live
Valid from
Jul 10, 2026
Valid to
Oct 8, 2026
Days until expiry
73
SAN domains
mermaid.live, www.mermaid.live

Security headers

  • Strict-Transport-SecurityMissing
  • Content-Security-PolicyMissing
  • X-Frame-OptionsMissing
  • X-Content-Type-OptionsMissing
  • Referrer-PolicyMissing
  • Permissions-PolicyMissing

Compression: gzip · 0 cookie(s) observed

Content & assets

Headings

H1 0 · H2 0 · H3 0

Links

2 internal · 5 external · 0 broken

Images

3 total · 0 missing alt

Scripts / Styles

2 scripts · 5 stylesheets

JS / CSS size

1.3 KB · 422 KB

Page size

3.5 KB

Robots.txt & Sitemap

robots.txt
Found
Disallow rules
0
sitemap.xml
Found
URLs in sitemap
1

SEO issues

  • Meta description longer than 160 characters
  • Missing canonical link
  • No H1 heading found
  • No structured data (JSON-LD) found
  • Missing OpenGraph tags

Accessibility issues

  • No H1 heading found

Scan details

Requested URL
https://mermaid.live
Final URL
https://mermaid.live
HTTP status
200
HTTP version
HTTP/2
Response time
3 ms
HTML size
3.5 KB
Redirect chain
https://mermaid.live

See something wrong on this report? Request a correction

Frequently asked questions

What technology does mermaid.live use?
mermaid.live is built with Svelte.
Is mermaid.live secure (HTTPS)?
Yes. mermaid.live uses TLS 1.3 with a certificate issued by Let's Encrypt, valid until Oct 8, 2026.
Who hosts mermaid.live?
mermaid.live is hosted on Fastly, behind Fastly CDN.
What is mermaid.live's SEO score?
mermaid.live scored 65/100 for SEO in the latest analysis (fair).
What is mermaid.live's overall website score?
mermaid.live has an overall SiteGraph score of 76/100, combining SEO, performance, security, and accessibility.