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calibreapp.com

https://calibreapp.com· First analyzed 14 May 2026· Updated 14 May 2026
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calibreapp.com
Desktop screenshot of calibreapp.com
Mobile screenshot of calibreapp.com
Mobile

Sponsored

Hosting Provider

Amazon Web Services (AWS)
aws.amazon.com

IP Address

13.249.228.72

Site Location

🇫🇷 Francevia ip

Server Location

🇫🇷 Paris, France

ASN

AS16509

Organization

AWS CloudFront (GLOBAL)

Server

Cloudflare

CDN

Cloudflare

WAF

Cloudflare

Nameservers

ns1.dnsimple-edge.com.ns2.dnsimple-edge.net.ns3.dnsimple-edge.io.ns4.dnsimple-edge.org.

Performance

100

Core Web Vitals

Weight

First Contentful Paint
485 ms10%
Speed Index
630 ms10%
Largest Contentful Paint
—25%
Total Blocking Time
0.0 ms30%
Cumulative Layout Shift
0.00025%
1.3 MB
52 requests

Image Optimization

Lazy LoadWebPResponsive
0–49
50–89
90–100

Architecture Stack

Monolithic
⚙️ SSR
Frontend
Framework
Svelte
Infrastructure
Platform
AWS CloudFront
CDN
Cloudflare

Technology Stack

6 Technologies Detected

Analytics

2
Fathom AnalyticsFathom

Frameworks

1
Svelte

Meta Frameworks

1
SvelteKit

CSS Frameworks

1
Tailwind CSS

CDN

1
Cloudflare

SEO Analysis

A82/100
24
4
0
Meta Tags15/15
Content10/12
Headings8/8
Technical22/25
E-E-A-T2/7
Images6/7
Links5/5
URL5/5
Social3/5
Freshness0/4
Mobile3/4
Indexability3/3
C
calibreapp.comcalibreapp.com

Calibre: Web Performance Monitoring for Every Team

Calibre combines real user monitoring, Google CrUX data, and synthetic page speed tests so your team always knows where performance stands and what to fix.

Title Length50 chars

Recommended: 50-60 chars (~310px / 580px)

Description Length155 chars

Recommended: 120-160 chars

Issues (0)

    4 issues found

    Upgrade to view details

    Crawlability

    Sitemap

    Type: standard

    355 URLs

    robots.txt

    15 rules

    Sitemap reference found

    Local SEO

    Local Search Readiness

    15/100
    Poor
    4 13

    This site doesn't appear to be a local business. Local SEO signals are optional for non-local websites.

    Sponsored

    AI & LLM Readiness

    D54/100
    Bot Access
    17/25
    Machine Read.
    14/25
    Schema Data
    7/25
    Citation
    16/25

    AI Bot Access

    10/14 accessible
    AI Search
    OAI-SearchBot
    PerplexityBot
    Claude-SearchBot
    Gemini-Deep-Research
    DuckAssistBot
    Training
    GPTBot
    ClaudeBot
    Google-Extended
    Meta-ExternalAgent
    Bytespiderinfo
    Amazonbot
    Applebot-Extended
    CCBotinfo
    Fetch
    ChatGPT-User

    Machine Readability

    llms.txtvalid
    llms-full.txt
    Semantic HTML
    Heading Hierarchy
    nav
    Text ratio:4%
    Words:932
    Token eff.:Optimal
    Depth:1/5

    Structured Data

    3 JSON-LD
    Organization×1.1WebSiteSearchAction
    sameAs entity links

    Citation Readiness

    Opening Summary24w
    Descriptive Headingsavg 4.1w
    Canonical URL
    Open Graph3/3
    Twitter Card0/3
    Language Tag
    Publish Date
    Author Info
    Lists
    Tables
    TL;DR / Summary
    About Page Link
    Recommendations (9)
    AI readiness recommendation preview...
    Upgrade to view recommendations

    Sponsored

    Accessibility

    WCAG 2.1 Compliance

    Evaluates how accessible your website is for users with disabilities, based on WCAG 2.1 guidelines. Checks images, forms, keyboard navigation, ARIA roles, and color contrast.
    A+
    92/100
    17
    Passed
    1
    Critical
    0
    Warnings
    Images & Alt Text
    18/20
    Checks if images have descriptive alt text for screen readers and visually impaired users.
    Semantic Structure
    20/20
    Evaluates proper use of HTML5 semantic elements (header, nav, main, footer) and heading hierarchy.
    Forms & Inputs
    15/15
    Verifies form fields have labels, error messages are clear, and inputs are properly associated.
    Color & Contrast
    15/15
    Tests text-to-background color contrast ratios against WCAG AA/AAA minimum requirements.
    Keyboard & Focus
    15/15
    Ensures all interactive elements are reachable and operable via keyboard (tab, enter, escape).
    ARIA & Roles
    9/15
    Checks correct use of WAI-ARIA attributes (roles, states, properties) for assistive technologies.

    Carbon Footprint

    SWDM v4 · Eco-Score

    Carbon emissions estimated using the Sustainable Web Design Model v4 (SWDM v4). Factors in data center, network, and device energy across new and returning visitors. Grade thresholds based on HTTP Archive percentiles.
    81/100
    B
    136 mg
    CO₂e / view
    1.3 MB
    Page Weight
    70%
    Cleaner Than
    New Visitor
    155 mg
    vs
    Returning (cached)
    78 mg
    Annual (10K/mo)
    16.3 kg
    Emission Segments
    Data Center
    7 mg
    Network
    40 mg
    Device
    89 mg
    Resource Breakdown
    JavaScript
    78.5 KB
    Images
    357.8 KB
    CSS
    119.7 KB
    Fonts
    39.9 KB
    HTML
    27.5 KB
    Other
    720.5 KB
    Green Hosting Verified
    Amazon Web Services (AWS)
    Provider Match
    B

    Security Score

    71%Good
    Static / Informational

    HTTPS

    WAF

    216d

    Certificate Details

    Type

    Domain Validated (DV)

    Certificate Authority

    Amazon

    Key Algorithm

    RSA (2048 bit)

    Signature

    SHA-256 with RSA

    TLS Version

    TLSv1.3

    HTTP Protocol

    HTTP/2+H3

    Valid From

    18.11.2025

    Valid Until

    16.12.2026

    OCSP Stapling

    Enabled

    Subject Alternative Names (2)

    calibreapp.comwww.calibreapp.com

    SHA-256 Fingerprint

    56:04:2D:F0:89:2B:9F:E9:B7:03:0C:17:06:6D:CF:3C:DD:5F:DD:DE...

    Recommendations

    Security recommendation preview

    Upgrade to view recommendations
    Upgrade to view header details

    HTTP Headers

    Developer Console

    age
    768
    alt-svc
    h3=":443"; ma=86400
    cache-control
    🟡 0s(public, max-age=0, s-maxage=3600, stale-while-revalidate=60)
    cf-cache-status
    DYNAMIC
    cf-ray🇺🇸 Washington DC
    9fb8ebbc3adad708-IAD
    content-encoding
    📦 Gzip(gzip)
    Good Warning Issue

    Email Infrastructure

    Google Workspace

    Score

    95

    SPF
    DKIM
    DMARC

    DMARC Policy

    Reject (Strictest)

    MX Records (5)

    aspmx.l.google.com
    alt4.aspmx.l.google.com
    alt3.aspmx.l.google.com
    alt2.aspmx.l.google.com

    +1 more

    Domain Information

    calibreapp.com

    Domain Age
    12y 7m

    Created

    06.10.2013

    Expires

    06.10.2027

    Last Updated

    13.05.2026

    Registrar

    1API GmbH

    DNSSEC
    Not Enabled

    Privacy & Compliance

    Cookie Consent Banner
    Privacy Policy
    Terms of Service

    GDPR Indicators

    Privacy policy page linked

    Mobile Compatibility

    Viewport & Responsive Test

    Tests how well your website works on mobile devices. Checks viewport configuration, responsive layout, touch targets, font readability, and simulates rendering across different screen sizes.
    A
    81/100
    Mobile Friendly1 breakpoint
    Viewport Meta
    The viewport meta tag tells mobile browsers how to scale the page. Without it, mobile devices render at desktop width.
    Responsive Design
    Uses CSS media queries or flexible layouts to adapt content to different screen sizes automatically.
    Touch Icons
    Apple touch icons and favicons displayed when users add the site to their home screen on mobile devices.
    Readable Font Size
    Base font size should be at least 16px on mobile to ensure text is readable without zooming.
    Relative Units
    Using em, rem, %, or vw instead of fixed px values allows content to scale properly across screen sizes.
    No H-Scroll Risk
    No elements wider than the viewport that would cause horizontal scrolling on mobile devices.
    Tap Targets OK
    Interactive elements (buttons, links) are at least 48x48px with enough spacing to prevent accidental taps.
    No Fixed Widths
    No elements with fixed pixel widths that could overflow on smaller screens and break the layout.
    Viewport
    width=device-width, initial-scale=1

    Typography & Readability

    Calibre

    WCAG AA
    81/100
    Readability
    /30
    22/30

    16px · LH 1.50

    Hierarchy
    /20
    19/20

    4.38x ratio · ✓ H1→H6

    WCAG
    /25
    22/25

    4.67:1 min contrast

    Performance
    /25
    18/25

    1 font · 5 req

    Heading Font

    Calibre

    Sans70px

    Body Font

    Calibre

    Sans16px

    Contrast Ratio

    4.67:1

    WCAG AA (≥4.5:1)

    Reading Comfort

    ~37 CPL

    Narrow lines
    70px
    h1
    70px
    h2
    16px
    h3
    16px
    p

    ✅ Excellent readability: 16px body text is ideal for all devices.

    ✅ Optimal line spacing: 1.50 ratio (ideal range 1.4–1.6).

    ✅ WCAG AA contrast: All text meets 4.5:1 ratio (min 4.7:1).

    ✅ Perfect heading hierarchy: Sequential h1→h2→h3 with single H1 — ideal for SEO & accessibility.

    ✅ Strong hierarchy: Headlines are 4.4x larger than body text.

    ✅ Modern fluid typography: clamp() with rem units ensures zoom accessibility (WCAG 1.4.4).

    Buy on MyFontsFluid Type (rem)Flesch 53

    Color Palette

    9 unique colors
    2.48:1 Fail Light
    #ffffff
    Background· 85.50000000000001%
    #a1a4b0
    Secondary· 1.4%
    #3057f4
    Primary· 0%
    #1d2238
    Primary· 3%
    #2948c4
    Accent· 2%
    #bcc1cf
    Secondary· 1.5%
    #d8dce4
    Secondary· 1.3%
    #7e87aa
    Secondary· 1.1%

    Business & Marketing Stack

    1 Tools Detected

    Growing

    Behavior Analytics

    1
    Google AnalyticsFree

    User behavior and product analytics

    1

    Categories

    1

    Total Tools

    0

    Enterprise

    0

    Mid-Market

    Assessment: Growing marketing technology adoption

    Sponsored

    Scripts & Styles

    12 Resources

    2
    Scripts
    10
    Styles
    1
    Async
    1
    Defer

    Top Script Sources

    cdn-eu.usefathom.com(1)use.calibre.app(1)

    Website Identity

    Calibre

    Calibre

    Organization

    Web performance monitoring platform that helps teams track page speed, Core Web Vitals, and deliver fast user experiences.

    12 years old
    Location detected: 🇫🇷 Francevia ip
    1API GmbH📧 Google Workspaceen

    Social Profiles

    LinkedInGitHubBluesky

    Sponsored

    Last analyzed: 14 May 2026 at 22:19

    Historical Analysis & Change Tracking