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Security

· 12 checks — HTTP headers, CSP, TLS handshake, and cookie hygiene rolled into one auditable list.
SCORE
76
GRADE
C
FIX
3
REVIEW
4
PASS
5
INFO
0
Checks
12
5 PASS 4 REVIEW 3 FIX
D
Security Headers
Action
5 of 10 headers properly configured
FIX
5 of 10 headers properly configured
Critical::
HSTS header is missing
Strict-Transport-Security forces browsers to use HTTPS, preventing downgrade attacks. Add the header with a max-age of at least 1 year.
Expected: max-age=31536000; includeSubDomains
Info::
X-Content-Type-Options is properly configured
Got: nosniff
Warning::
X-Frame-Options header is missing
This header prevents clickjacking by controlling who can embed your page in a frame. Set it to DENY or SAMEORIGIN.
Expected: DENY
Info::
Referrer-Policy is properly configured
Got: no-referrer-when-downgrade
Warning::
Permissions-Policy header is missing
Controls which browser features (camera, microphone, geolocation) are allowed. Set it to restrict unused features.
Expected: geolocation=(), camera=(), microphone=()
Info::
Content-Security-Policy is present
Got: frame-ancestors 'self' *.grammarly.com
Info::
Cross-Origin-Opener-Policy is set but not 'same-origin'
Got: same-origin-allow-popups Expected: same-origin
Warning::
Cross-Origin-Embedder-Policy header is missing
COEP prevents loading cross-origin resources without explicit permission. Required for SharedArrayBuffer and high-resolution timers.
Expected: require-corp
Info::
X-Powered-By header is not present
Info::
Server header is not present

Strict-Transport-Security forces browsers to use HTTPS, preventing downgrade attacks. Add the header with a max-age of at least 1 year.

Expected: max-age=31536000; includeSubDomains
Why this matters

Without HSTS, a network attacker can downgrade the very first connection to HTTP and steal the user's session.

Learn more ▾

HSTS tells browsers 'never speak HTTP to this domain again.' Without it, a network attacker (public WiFi, malicious ISP, hostile DNS) intercepts the first HTTP attempt and serves a downgraded version of your site. One header, big surface reduction.

Source: RFC 6797 / OWASP

This header prevents clickjacking by controlling who can embed your page in a frame. Set it to DENY or SAMEORIGIN.

Expected: DENY
Why this matters

Without frame protection, your site can be embedded in a hostile page and used for clickjacking.

Learn more ▾

Clickjacking overlays your site under a transparent malicious page so users click invisible buttons. Setting X-Frame-Options: DENY (or a modern frame-ancestors CSP directive) blocks the embedding entirely. There's almost never a legitimate reason to allow it.

Source: OWASP / MDN

Controls which browser features (camera, microphone, geolocation) are allowed. Set it to restrict unused features.

Expected: geolocation=(), camera=(), microphone=()
Why this matters

Permissions-Policy locks down browser APIs you don't use — without it, every page can request camera/mic/geolocation if XSS lands.

Learn more ▾

By default every page can request the camera, microphone, geolocation, payment APIs, and dozens more. Permissions-Policy turns off the ones you don't need so a future bug can't quietly start using them. It's a defense-in-depth header — one line, big surface reduction.

Source: MDN / W3C

COEP prevents loading cross-origin resources without explicit permission. Required for SharedArrayBuffer and high-resolution timers.

Expected: require-corp
Why this matters

COEP enforces that all embedded resources opt-in to cross-origin embedding — required for cross-origin isolation features.

Learn more ▾

Cross-Origin-Embedder-Policy: require-corp ensures every embedded resource (script, iframe, image) explicitly allows being loaded cross-origin. Combined with COOP, this enables the cross-origin-isolated context that unlocks SharedArrayBuffer, high-resolution timers, and other powerful APIs.

Source: MDN / web.dev

Expected: same-origin
Why this matters

COOP is set to a less-restrictive value (same-origin-allow-popups or unsafe-none) — partial isolation only.

Learn more ▾

COOP: same-origin is the strictest level. same-origin-allow-popups allows authenticated popup windows back to your origin. unsafe-none is the legacy default (effectively off). Pick the strictest level your app's popup flows tolerate.

Source: MDN COOP

F
Subresource Integrity
Action
0 of 29 external resources have SRI
FIX
0 of 29 external resources have SRI
Warning::
External script from d34r8q7sht0t9k.cloudfront.net lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://d34r8q7sht0t9k.cloudfront.net/tag.js
Warning::
External script from www.googletagmanager.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://www.googletagmanager.com/gtag/js?id=G-CBK9K2ZWWE&l=dataLayerAt1333&cx=c&gtm=4e64f0
Warning::
External script from www.googletagmanager.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://www.googletagmanager.com/gtag/js?id=DC-11910764&l=dataLayerAt1333&cx=c&gtm=4e64f0
Warning::
External script from www.googletagmanager.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://www.googletagmanager.com/gtag/js?id=DC-10353179&l=dataLayerAt1333&cx=c&gtm=4e64f0
Warning::
External script from www.googletagmanager.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://www.googletagmanager.com/gtag/js?id=DC-10353176&l=dataLayerAt1333&cx=c&gtm=4e64f0
Warning::
External script from www.googletagmanager.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://www.googletagmanager.com/gtag/js?id=AW-956476927&l=dataLayerAt1333&cx=c&gtm=4e64f0
Warning::
External script from www.google-analytics.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://www.google-analytics.com/plugins/ua/ecommerce.js
Warning::
External script from www.googletagmanager.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://www.googletagmanager.com/gtm.js?id=GTM-NQ3XB9&l=dataLayerAt1333
Warning::
External script from www.google-analytics.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: //www.google-analytics.com/analytics.js
Warning::
External link from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/css/21a09db180a1580a.css
Warning::
External link from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/css/3540ba9e956cf59a.css
Warning::
External link from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/css/7566b533fcf855c8.css
Warning::
External script from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/chunks/polyfills-42372ed130431b0a.js
Warning::
External script from accounts.google.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://accounts.google.com/gsi/client
Warning::
External script from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/web-heartbeat/latest/index.js
Warning::
External script from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/chunks/125.9370fe004c6de1c5.js
Warning::
External script from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/chunks/webpack-0b3db51c0ac885df.js
Warning::
External script from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/chunks/framework-18871a3a7164e80f.js
Warning::
External script from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/chunks/main-a1ca2a318bff5472.js
Warning::
External script from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/chunks/pages/_app-0059e1bcc1031fec.js
Warning::
External script from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/chunks/cb702229-59bc8fe8570d0ac7.js
Warning::
External script from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/chunks/1a192442-e4e5b1da91b22ec4.js
Warning::
External script from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/chunks/516-effdeff0fc841817.js
Warning::
External script from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/chunks/17-e2c0c030cf58c736.js
Warning::
External script from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/chunks/pages/render-18b58af021878656.js
Warning::
External script from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/xJlU194TA9XLS801IftgH/_buildManifest.js
Warning::
External script from static-web.grammarly.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://static-web.grammarly.com/cms/master/_next/static/xJlU194TA9XLS801IftgH/_ssgManifest.js
Warning::
External link from accounts.google.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://accounts.google.com/gsi/style
Warning::
External script from transcend-cdn.com lacks integrity attribute
Without SRI, if this CDN is compromised, attackers could inject malicious code.
Got: https://transcend-cdn.com/cm/1c1f8e90-47d0-4bba-a1a2-472d59b002a2/airgap.js
SRI Coverage 0 / 29 of external resources have integrity hashes
TagDomainIntegrity
<script>d34r8q7sht0t9k.cloudfront.net✗ Missing
<script>www.googletagmanager.com✗ Missing
<script>www.googletagmanager.com✗ Missing
<script>www.googletagmanager.com✗ Missing
<script>www.googletagmanager.com✗ Missing
<script>www.googletagmanager.com✗ Missing
<script>www.google-analytics.com✗ Missing
<script>www.googletagmanager.com✗ Missing
<script>www.google-analytics.com✗ Missing
<link>static-web.grammarly.com✗ Missing
<link>static-web.grammarly.com✗ Missing
<link>static-web.grammarly.com✗ Missing
<script>static-web.grammarly.com✗ Missing
<script>accounts.google.com✗ Missing
<script>static-web.grammarly.com✗ Missing
<script>static-web.grammarly.com✗ Missing
<script>static-web.grammarly.com✗ Missing
<script>static-web.grammarly.com✗ Missing
<script>static-web.grammarly.com✗ Missing
<script>static-web.grammarly.com✗ Missing
<script>static-web.grammarly.com✗ Missing
<script>static-web.grammarly.com✗ Missing
<script>static-web.grammarly.com✗ Missing
<script>static-web.grammarly.com✗ Missing
<script>static-web.grammarly.com✗ Missing
<script>static-web.grammarly.com✗ Missing
<script>static-web.grammarly.com✗ Missing
<link>accounts.google.com✗ Missing
<script>transcend-cdn.com✗ Missing
D
Permissions-Policy
Action
No header set
FIX
No header set
Warning::
No Permissions-Policy header
Consider adding a Permissions-Policy header to restrict browser feature access from embedded content.

No Permissions-Policy header set.

Without this header, embedded iframes can request access to sensitive device features.

Suggested header
Permissions-Policy: camera=(), microphone=(), geolocation=(), payment=(), usb=()
B
Content Security Policy
2 of 10 CSP checks passed
REVIEW
2 of 10 CSP checks passed
Info::
Raw CSP policy
Got: frame-ancestors 'self' *.grammarly.com
Warning::
default-src directive is missing
default-src provides a fallback for other directives. Set it to restrict default resource loading.
Expected: default-src 'self'
Info::
No script-src or default-src to check for 'unsafe-inline'
Info::
No script-src or default-src to check for 'unsafe-eval'
Info::
No script-src or default-src to check for wildcard
Info::
object-src falls back to default-src
Warning::
base-uri directive is missing
Without base-uri, attackers can inject a <base> tag to hijack relative URLs. Set it to 'self' or 'none'.
Expected: base-uri 'self'
Info::
frame-ancestors directive is set
Got: frame-ancestors 'self' *.grammarly.com
Warning::
form-action directive is missing
form-action restricts where forms can submit data, preventing form hijacking.
Expected: form-action 'self'
Info::
upgrade-insecure-requests is not set
This directive upgrades HTTP resources to HTTPS automatically, preventing mixed content.
Expected: upgrade-insecure-requests

default-src provides a fallback for other directives. Set it to restrict default resource loading.

Expected: default-src 'self'
Why this matters

Security gaps expose your site and users to attacks, eroding trust.

Without base-uri, attackers can inject a <base> tag to hijack relative URLs. Set it to 'self' or 'none'.

Expected: base-uri 'self'
Why this matters

Missing base-uri in CSP leaves a base-tag injection attack path open even on otherwise strict policies.

Learn more ▾

A common omission: developers add CSP for script-src and frame-ancestors but forget base-uri. The result is a CSP that looks strict but lets an attacker rewrite every URL on the page via <base href>. Add `base-uri 'self'` to close the gap.

Source: MDN CSP

form-action restricts where forms can submit data, preventing form hijacking.

Expected: form-action 'self'
Why this matters

Security gaps expose your site and users to attacks, eroding trust.

This directive upgrades HTTP resources to HTTPS automatically, preventing mixed content.

Expected: upgrade-insecure-requests
Why this matters

Without upgrade-insecure-requests, any HTTP subresource link survives as a mixed-content warning instead of auto-upgrading.

Learn more ▾

Adding `upgrade-insecure-requests` to your CSP turns every http:// subresource fetch into https:// at the browser layer. One-line defense against accidental mixed content from legacy links or third-party widgets.

Source: MDN CSP

Parsed Policy

frame-ancestors 'self'*.grammarly.com
B
CORS Configuration
No CORS headers
REVIEW
No CORS headers
Info::
No CORS headers present — secure default
CORS Configuration ✓ Secure

No CORS headers detected.

Cross-origin requests are blocked by browser same-origin policy.

Origin reflection test

Some servers mirror the request Origin header, which can be exploited. Test manually:

curl -sI -H "Origin: https://evil.com" <url> | grep -i access-control
B
security.txt
Published with 1 contact(s)
REVIEW

security.txt

Contact: security@grammarly.com
B
Transport Security
HTTP/3, HSTS, and TLS version analysis
REVIEW
HTTP/3, HSTS, and TLS version analysis
Info::
HTTP/3 (QUIC) not advertised
HTTP/3 eliminates head-of-line blocking. If your CDN supports it, consider enabling it.
Warning::
Missing Strict-Transport-Security header
HSTS tells browsers to only use HTTPS, preventing SSL stripping attacks.
Info::
TLS 1.3 in use (fastest handshake, 1-RTT)
A+
TLS & Certificates
TLS 1.3, 7 checks passed
PASS
TLS 1.3, 7 checks passed
Info::
TLS 1.3 is used
Got: TLS 1.3
Info::
Strong cipher suite is used
Got: TLS_AES_128_GCM_SHA256
Info::
HTTP/2 is not negotiated
HTTP/2 provides multiplexing and header compression for better performance.
Got: http/1.1
Info::
Certificate is valid (expires in 127 days)
Got: 2026-08-21T23:59:59Z
Info::
Certificate chain has 3 certificates
Info::
Certificate uses modern signature algorithm
Got: SHA256-RSA
Info::
Certificate covers 2 domain(s)
Got: www.grammarly.com, grammarly.com
Info::
Certificate is issued by a trusted CA
Got: CN=Amazon RSA 2048 M02,O=Amazon,C=US

HTTP/2 provides multiplexing and header compression for better performance.

Why this matters

HTTP/1.1 forces the browser to make sequential requests, multiplying latency on every page.

Learn more ▾

HTTP/2 (and HTTP/3) multiplex many requests over a single connection, eliminating head-of-line blocking. HTTP/1.1 forces the browser to either queue requests or open many parallel connections — both worse. Most modern web servers support HTTP/2 with one config line.

Source: MDN Web Docs

Connection
Protocol
TLS 1.3
Cipher Suite
TLS_AES_128_GCM_SHA256
HTTP Version
HTTP/1.1

Certificate Chain

Leaf Certificate
Subject CN=www.grammarly.comIssuer CN=Amazon RSA 2048 M02,O=Amazon,C=USValid 2025-07-23T00:00:00Z → 2026-08-21T23:59:59ZExpires in 127 days SANs www.grammarly.com, grammarly.comSignature SHA256-RSASerial 316b6347007b64e6f210e827de61381
Intermediate (CA Certificate)
Subject CN=Amazon RSA 2048 M02,O=Amazon,C=USIssuer CN=Amazon Root CA 1,O=Amazon,C=USValid 2022-08-23T22:25:30Z → 2030-08-23T22:25:30ZExpires in 1590 days Signature SHA256-RSASerial 773124a4bcbd44ec7b53beaf194842d3a0fa1
Intermediate (CA Certificate)
Subject CN=Amazon Root CA 1,O=Amazon,C=USIssuer CN=Starfield Services Root Certificate Authority - G2,O=Starfield Technologies\, Inc.,L=Scottsdale,ST=Arizona,C=USValid 2015-05-25T12:00:00Z → 2037-12-31T01:00:00ZExpires in 4276 days Signature SHA256-RSASerial 67f944a2a27cdf3fac2ae2b01f908eeb9c4c6
A+
Cookie Security
No cookies set — no cookie security risks
PASS
No cookies set — no cookie security risks
Info::
No cookies set — no cookie security risks

No cookies detected — no cookie security risks to report.

A+
JS Library Vulnerabilities
No known vulnerabilities
PASS
No known vulnerabilities
Info::
No known JavaScript library vulnerabilities detected

No known JavaScript library vulnerabilities detected.

A+
Information Leakage
No exposures
PASS
No exposures
Info::
security.txt is present — good practice
Info::
No sensitive files exposed

No sensitive files exposed — all paths returned 404.

PathStatusCategoryRisk
/.git/HEAD✓ Not foundVersion Control—
/.git/config✓ Not foundVersion Control—
/.svn/entries✓ Not foundVersion Control—
/.env✓ Not foundConfiguration—
/.env.local✓ Not foundConfiguration—
/.env.production✓ Not foundConfiguration—
/wp-config.php✓ Not foundConfiguration—
/.htaccess✓ Not foundConfiguration—
/phpinfo.php✓ Not foundDebug—
/server-status✓ Not foundDebug—
/server-info✓ Not foundDebug—
/.well-known/security.txt✗ ExposedSecurity PolicyInfo
A+
Email Security
DMARC: reject
PASS
DMARC: reject
Info::
DMARC policy is reject — strongest protection
DMARC
Policy reject — strongest protection Record v=DMARC1; p=reject; rua=mailto:dmarc@grammarly.com,mailto:dmarc_agg@dmarc.250ok.net,mailto:rujwa3ev@ag.dmarcian.com; ruf=mailto:dmarc_fr@dmarc.250ok.net; fo=1; pct=100; rf=afrf
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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