CSP Evaluator API

API ID 14379

Finds the weak points in a website Content Security Policy that undermine script-injection protection. Returns one graded JSON report with a verdict, grade and stable issue codes.

API Documentation

Endpoints

Request
Fetches the page once, collects Content-Security-Policy and Content-Security-Policy-Report-Only response headers and meta tag policies, evaluates each policy against W3C CSP Level 3 and returns a verdict, a script protection level, a grade and issues. A static assessment of the policy text, not proof that a site is safe or vulnerable. Follows up to 5 redirects and reads the first 1 MB with a 10 second timeout. Results are cached for 15 minutes and fresh 1 bypasses the cache. A value without a scheme such as example.com is treated as https.
Endpoint ID: 36041
GET https://zylalabs.com/api/14379/csp+evaluator+api/36041/evaluate+the+content+security+policy+of+a+website
INPUT PARAMETERS

Evaluate the Content Security Policy of a website — Endpoint Features

Object Description
url Required Page to check, for example https example.com. Aliases u, uri, link, target, site, website, domain and host are also accepted, case-insensitive.
fresh Optional Set to 1 to bypass the result cache.

Free test requests remaining: 3 of 3.


INPUT PARAMETERS

url
fresh
API EXAMPLE RESPONSE
JSON
{
    "url": "https://example.com/",
    "finalUrl": "https://example.com/",
    "statusCode": 200,
    "enforced": false,
    "verdict": "no_csp",
    "scriptProtection": "none",
    "grade": "F",
    "score": 40,
    "summary": {
        "errors": 1,
        "warnings": 0,
        "infos": 0
    },
    "policies": [],
    "issues": [
        {
            "severity": "error",
            "code": "csp_missing",
            "message": "No Content-Security-Policy header and no <meta http-equiv=\"Content-Security-Policy\"> tag was found, so the browser applies no CSP and nothing limits where scripts load from. Basis: W3C Content Security Policy Level 3, \"Content-Security-Policy header\".",
            "docs": "https://www.w3.org/TR/CSP3/#csp-header"
        }
    ],
    "metaPolicies": 0,
    "cached": false,
    "checkedAt": "2026-10-21T15:38:39.223Z",
    "note": "Evaluates the Content Security Policy that the page declares in its HTTP response headers (Content-Security-Policy and Content-Security-Policy-Report-Only) and in <meta http-equiv> tags in the HTML head, using the W3C Content Security Policy Level 3 rules. The page is fetched with this API's own user agent, so a site that serves different headers to other clients can look different to real browsers. Policies set by scripts at runtime are not seen. Findings are static analysis of the policy text: they do not prove that a page is exploitable or safe, and a clean report is not a security guarantee."
}
Evaluate the Content Security Policy of a website — CODE SNIPPETS

curl --location --request GET 'https://zylalabs.com/api/14379/csp+evaluator+api/36041/evaluate+the+content+security+policy+of+a+website?url=https://example.com' --header 'Authorization: Bearer YOUR_API_KEY' 


    

API Access Key & Authentication

After signing up, every developer is assigned a personal API access key, a unique combination of letters and digits provided to access to our API endpoint. To authenticate with the CSP Evaluator API simply include your bearer token in the Authorization header.

Headers
Header Description
Authorization Required Should be Bearer access_key. See "Your API Access Key" above when you are subscribed.

No long-term commitment. Upgrade, downgrade, or cancel anytime. Free Trial includes up to 50 requests.

Starts at
$10,000/Year


  • Custom Volume
  • Custom Rate Limit
  • Specialized Customer Support
  • Real-Time API Monitoring

Overview

Finds the weak points in a website Content Security Policy that undermine script-injection protection. Returns one graded JSON report with a verdict, grade and stable issue codes.

CSP Evaluator API FAQs

The Content Security Policy of a web page, read from the response headers and from meta tags in the HTML head. It returns a verdict, a script protection level, a grade, the parsed policies and coded issues, each linked to the W3C CSP Level 3 section it is based on.

No. It is a static assessment of the policy text. A clean report is not a security guarantee, and policies that scripts add at runtime are not seen.

Strict means scripts are guarded by nonces or hashes, allowlist means only a host allowlist guards them, none means no effective script protection and unknown means it could not be determined, for example because the page returned an error status.

Yes. A bare domain such as example.com is treated as https. Parameter aliases such as u, link, target and site are accepted as well.

Yes. Results are cached for 15 minutes. Add the fresh parameter set to 1 to bypass the cache, for example right after you change your policy.

General FAQs

To obtain your API key, first sign in to your account and navigate to the API you want to use. From the API's Pricing section, choose a plan and complete the subscription process. Once subscribed, return to the API page and you will see your API Access Key displayed at the top of the documentation page. You can use this key to authenticate your requests.

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