Set-Cookie Analyzer API

API ID 14204

Check the cookies a site sets, per redirect hop and in JSON, for missing Secure/HttpOnly/SameSite flags and RFC violations, from CI or a script. Each cookie is reported with its attributes, Host-/

API Documentation

Endpoints

Request
Fetches the URL, follows up to 5 redirects hop by hop and analyzes every Set-Cookie header from every hop. Results are cached for 6 hours and the fresh parameter bypasses the cache. A value without a scheme such as example.com is treated as https.
Endpoint ID: 35259
GET https://zylalabs.com/api/14204/set-cookie+analyzer+api/35259/analyze+the+set-cookie+headers+of+a+url
INPUT PARAMETERS

Free test requests remaining: 3 of 3.


INPUT PARAMETERS

This endpoint does not require any input parameters.

API EXAMPLE RESPONSE
JSON
{
    "url": "https://github.com/",
    "finalUrl": "https://github.com/",
    "statusCode": 200,
    "redirectChain": [
        {
            "url": "https://github.com/",
            "statusCode": 200,
            "cookieCount": 3
        }
    ],
    "cookieCount": 3,
    "grade": "A+",
    "score": 99,
    "summary": {
        "errors": 0,
        "warnings": 0,
        "infos": 3
    },
    "cookies": [
        {
            "name": "_gh_sess",
            "valueLength": 354,
            "valuePreview": "55D…",
            "attributes": {
                "domain": null,
                "path": "/",
                "expires": null,
                "maxAge": null,
                "secure": true,
                "httpOnly": true,
                "sameSite": "Lax",
                "partitioned": false,
                "priority": null
            },
            "prefix": null,
            "lifetime": {
                "type": "session",
                "seconds": null,
                "source": null
            },
            "deletion": false,
            "sizeBytes": 362,
            "issues": [],
            "score": 100,
            "grade": "A+",
            "setBy": {
                "hop": 1,
                "url": "https://github.com/",
                "statusCode": 200
            }
        },
        {
            "name": "_octo",
            "valueLength": 27,
            "valuePreview": "GH1…",
            "attributes": {
                "domain": ".github.com",
                "path": "/",
                "expires": "2027-10-12T16:56:41.000Z",
                "maxAge": null,
                "secure": true,
                "httpOnly": false,
                "sameSite": "Lax",
                "partitioned": false,
                "priority": null
            },
            "prefix": null,
            "lifetime": {
                "type": "persistent",
                "seconds": 31536000,
                "source": "expires"
            },
            "deletion": false,
            "sizeBytes": 32,
            "issues": [
                {
                    "severity": "info",
                    "code": "domain_leading_dot",
                    "message": "A leading dot in Domain is ignored by modern browsers (RFC 6265 section 5.2.3); it can be removed."
                },
                {
                    "severity": "info",
                    "code": "httponly_missing",
                    "message": "The cookie has no HttpOnly attribute, so scripts can read it. Fine if JavaScript needs it; otherwise add HttpOnly."
                }
            ],
            "score": 98,
            "grade": "A+",
            "setBy": {
                "hop": 1,
                "url": "https://github.com/",
                "statusCode": 200
            }
        },
        {
            "name": "logged_in",
            "valueLength": 2,
            "valuePreview": "…",
            "attributes": {
                "domain": ".github.com",
                "path": "/",
                "expires": "2027-10-12T16:56:41.000Z",
                "maxAge": null,
                "secure": true,
                "httpOnly": true,
                "sameSite": "Lax",
                "partitioned": false,
                "priority": null
            },
            "prefix": null,
            "lifetime": {
                "type": "persistent",
                "seconds": 31536000,
                "source": "expires"
            },
            "deletion": false,
            "sizeBytes": 11,
            "issues": [
                {
                    "severity": "info",
                    "code": "domain_leading_dot",
                    "message": "A leading dot in Domain is ignored by modern browsers (RFC 6265 section 5.2.3); it can be removed."
                }
            ],
            "score": 99,
            "grade": "A+",
            "setBy": {
                "hop": 1,
                "url": "https://github.com/",
                "statusCode": 200
            }
        }
    ],
    "cached": false,
    "checkedAt": "2026-10-12T16:56:41.406Z"
}
Analyze the Set-Cookie headers of a URL — CODE SNIPPETS

curl --location --request GET 'https://zylalabs.com/api/14204/set-cookie+analyzer+api/35259/analyze+the+set-cookie+headers+of+a+url' --header 'Authorization: Bearer YOUR_API_KEY' 


    
Request
Parses Set-Cookie headers you provide and makes no outbound request. Provide either headers as a raw header block with one Set-Cookie per line, other header lines are ignored, or setCookie as an array. Max 50 cookies, 8 KB each.
Endpoint ID: 35260
POST https://zylalabs.com/api/14204/set-cookie+analyzer+api/35260/analyze+pasted+set-cookie+header+text+offline
INPUT PARAMETERS

Analyze pasted Set-Cookie header text offline — Endpoint Features

Object Description
Request Body Required Json

Free test requests remaining: 3 of 3.


INPUT PARAMETERS

API EXAMPLE RESPONSE
JSON
{
    "cookieCount": 3,
    "grade": "D",
    "score": 66,
    "summary": {
        "errors": 2,
        "warnings": 4,
        "infos": 5
    },
    "assumptions": {
        "https": true,
        "host": null,
        "note": "Parsed offline. Secure checks assume the cookie was served over HTTPS (set \"https\": false to change); Domain checks run only when \"host\" is given."
    },
    "cookies": [
        {
            "name": "__Host-id",
            "valueLength": 1,
            "valuePreview": "…",
            "attributes": {
                "domain": "a.com",
                "path": null,
                "expires": null,
                "maxAge": null,
                "secure": false,
                "httpOnly": false,
                "sameSite": null,
                "partitioned": false,
                "priority": null
            },
            "prefix": "__Host-",
            "lifetime": {
                "type": "session",
                "seconds": null,
                "source": null
            },
            "deletion": false,
            "sizeBytes": 10,
            "issues": [
                {
                    "severity": "error",
                    "code": "host_prefix_violation",
                    "message": "A __Host- cookie requires the Secure attribute, Path=/, no Domain attribute (RFC 6265bis section 4.1.3.2); browsers reject it otherwise."
                },
                {
                    "severity": "warning",
                    "code": "secure_missing",
                    "message": "The cookie has no Secure attribute although it was served over HTTPS, so browsers may also send it over plain HTTP."
                },
                {
                    "severity": "info",
                    "code": "httponly_missing",
                    "message": "The cookie has no HttpOnly attribute, so scripts can read it. Fine if JavaScript needs it; otherwise add HttpOnly."
                },
                {
                    "severity": "info",
                    "code": "samesite_missing",
                    "message": "No SameSite attribute: browsers default to Lax (Chrome, Edge, Firefox in some modes). State the intent explicitly with SameSite=Lax, Strict or None."
                }
            ],
            "score": 63,
            "grade": "D"
        },
        {
            "name": "s",
            "valueLength": 1,
            "valuePreview": "…",
            "attributes": {
                "domain": null,
                "path": null,
                "expires": null,
                "maxAge": null,
                "secure": false,
                "httpOnly": false,
                "sameSite": "None",
                "partitioned": false,
                "priority": null
            },
            "prefix": null,
            "lifetime": {
                "type": "session",
                "seconds": null,
                "source": null
            },
            "deletion": false,
            "sizeBytes": 2,
            "issues": [
                {
                    "severity": "error",
                    "code": "samesite_none_requires_secure",
                    "message": "SameSite=None requires the Secure attribute; Chrome, Firefox and Safari reject the cookie otherwise (RFC 6265bis section 4.1.2.7)."
                },
                {
                    "severity": "warning",
                    "code": "secure_missing",
                    "message": "The cookie has no Secure attribute although it was served over HTTPS, so browsers may also send it over plain HTTP."
                },
                {
                    "severity": "info",
                    "code": "httponly_missing",
                    "message": "The cookie has no HttpOnly attribute, so scripts can read it. Fine if JavaScript needs it; otherwise add HttpOnly."
                }
            ],
            "score": 64,
            "grade": "D"
        },
        {
            "name": "t",
            "valueLength": 1,
            "valuePreview": "…",
            "attributes": {
                "domain": null,
                "path": null,
                "expires": null,
                "maxAge": 99999999,
                "secure": false,
                "httpOnly": false,
                "sameSite": null,
                "partitioned": false,
                "priority": null
            },
            "prefix": null,
            "lifetime": {
                "type": "persistent",
                "seconds": 99999999,
                "source": "max-age"
            },
            "deletion": false,
            "sizeBytes": 2,
            "issues": [
                {
                    "severity": "warning",
                    "code": "lifetime_exceeds_400_days",
                    "message": "The lifetime is about 1157 days; Chrome caps cookie lifetime at 400 days (RFC 6265bis section 5.5), so it will be truncated."
                },
                {
                    "severity": "warning",
                    "code": "secure_missing",
                    "message": "The cookie has no Secure attribute although it was served over HTTPS, so browsers may also send it over plain HTTP."
                },
                {
                    "severity": "info",
                    "code": "httponly_missing",
                    "message": "The cookie has no HttpOnly attribute, so scripts can read it. Fine if JavaScript needs it; otherwise add HttpOnly."
                },
                {
                    "severity": "info",
                    "code": "samesite_missing",
                    "message": "No SameSite attribute: browsers default to Lax (Chrome, Edge, Firefox in some modes). State the intent explicitly with SameSite=Lax, Strict or None."
                }
            ],
            "score": 78,
            "grade": "C"
        }
    ],
    "checkedAt": "2026-10-12T16:57:50.219Z"
}
Analyze pasted Set-Cookie header text offline — CODE SNIPPETS

curl --location --request POST 'https://zylalabs.com/api/14204/set-cookie+analyzer+api/35260/analyze+pasted+set-cookie+header+text+offline' --header 'Authorization: Bearer YOUR_API_KEY' 

--data-raw '{"headers":"Set-Cookie: __Host-id=1; Domain=a.com\nSet-Cookie: s=1; SameSite=None\nSet-Cookie: t=1; Max-Age=99999999"}'

    

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 Set-Cookie Analyzer 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

Check the cookies a site sets, per redirect hop and in JSON, for missing Secure/HttpOnly/SameSite flags and RFC violations, from CI or a script. Each cookie is reported with its attributes, __Host-/__Secure- prefix rules, lifetime and size, and the response carries coded issues plus an overall grade (A+ to F) and a score out of 100. Checks are based on RFC 6265 and the RFC 6265bis draft (SameSite=None needs Secure, prefix requirements, 400-day lifetime cap, 4096-byte limit) plus common best practices, such as flagging session-like cookie names that lack HttpOnly. The grade and score use our own formula; they describe cookie attributes only and are not a security audit of the site or a check of cookie-consent or privacy-law compliance. Redirects are followed hop by hop (up to 5) and cookies from every hop are analyzed. Full cookie values are never returned: only valueLength and a short masked valuePreview (at most the first 3 characters). A second endpoint parses Set-Cookie header text you paste in, offline, with no outbound request. Results reflect a single anonymous GET from our servers; cookies set by JavaScript, or only after login or consent, are not visible, and sites that block datacenter traffic may time out or show fewer cookies. Results for /v1/analyze are cached for 6 hours per URL; add fresh=1 to bypass the cache. Private-network targets are rejected.

Set-Cookie Analyzer API FAQs

The GET endpoint returns a JSON object containing cookie analysis results, including the final URL, status code, redirect chain, cookie count, grade, score, and detailed cookie attributes. The POST endpoint returns similar data but focuses on the provided Set-Cookie headers, including errors, warnings, and cookie attributes.

Key fields include `url`, `finalUrl`, `statusCode`, `cookieCount`, `grade`, `score`, and `cookies`. Each cookie object contains attributes like `name`, `valueLength`, `valuePreview`, and flags such as `secure`, `httpOnly`, and `sameSite`.

The returned data is in JSON format. The structure includes a top-level object with summary information and an array of cookie objects, each detailing attributes and compliance issues. For example, the `cookies` array contains individual cookie details like `name`, `valueLength`, and `attributes`.

The GET endpoint provides cookie attributes, compliance grades, and redirect analysis. The POST endpoint offers insights into the provided Set-Cookie headers, including errors and warnings related to cookie attributes and compliance with standards.

The response data is organized into a main object containing summary information and an array of cookies. Each cookie object includes its attributes and compliance status, allowing users to easily assess cookie security and adherence to standards.

The data is sourced from the HTTP responses received during the analysis of the specified URL or the provided Set-Cookie headers. The API follows RFC 6265 and best practices to evaluate cookie attributes and compliance.

Typical use cases include auditing cookie security for web applications, ensuring compliance with cookie standards, and identifying potential vulnerabilities in cookie configurations. Developers can integrate this analysis into CI/CD pipelines for automated checks.

Users can customize requests by specifying the `fresh` parameter in the GET endpoint to bypass cached results. In the POST endpoint, users can provide custom Set-Cookie headers in various formats, allowing for tailored analysis of specific cookies.

General FAQs

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