Flow 2: Fingerprint Endpoint

This is the standard Kasada implementation where the browser makes a background request to the /fp (fingerprint) endpoint. This flow applies to most Kasada-protected websites.

Overview

Unlike Flow 1, you may be able to access the homepage initially. Kasada is triggered when the browser makes a GET request to:

/149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/fp

This request returns a 429 status code with the Kasada challenge. After solving it, you'll receive tokens and cookies that must be included in subsequent requests to protected endpoints.

Step 1: Request the /fp Endpoint

Make a GET request to the fingerprint endpoint with query parameter x-kpsdk-v:

https://www.example.com/149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/fp?x-kpsdk-v=j-xxx

The response will be a 429 status code with HTML that looks like this:

<!DOCTYPE html>
<html>
<head></head>
<body>
<script>window.KPSDK={};KPSDK.now=typeof performance!=='undefined'&&performance.now?performance.now.bind(performance):Date.now.bind(Date);KPSDK.start=KPSDK.now();</script>
<script src="/149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/ips.js?tkrm_alpekz_s1.3=0ZhprgzXdlDhhn0esTCQPfWjA2AeaGW50gpHSJVGSjRUPSrKJRQmsSZjTK8HhAmopVcLq2dfwum0SJmpM0Kz5j2DupTTI4OB1PLl7lkhhJIVFAKsCsEoeL4hVm2tQjyFkyPUu42RgZ0dutvGd2xxDbpRLCWjV9MlMysNPzGvUTyg8CBX&x-kpsdk-im=AAIHh6ySRFXhFWAJcYSdsr-BStey6j5sKkK9HXfcJJ2BnB2_eCdWiiJjVu0OEOBEhsIFyZ4CgRIcu6EDyMf-WS88HRSC8PKJm2lZpq0ZTummEHy855H_HBuLSiiUmGQSiPUbJ74rXDFbWw"></script>
</body>
</html>

Step 2: Parse the Script Path

Extract the script path from the HTML response. The script URL will look like:

/149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/ips.js?...

You can parse this using our SDKs:

scriptPath, err := kasada.ParseScriptPath(reader)
if err != nil {
    // Handle the error
}
// scriptPath will look like: /149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/ips.js?...

Step 3: Fetch the ips.js Script

Make a GET request to the script path you parsed. Make sure to:

Use the full URL: https://www.example.com{scriptPath}
Match browser headers exactly
Maintain the same header order as Chrome
Set referer to the /fp URL

Save the JavaScript response body as you'll need it for the next step.

Step 4: Generate Payload via API

Use the Hyper Solutions API to generate the payload and headers needed for the /tl request. Refer to the Kasada and the SDK documentation for accurate fields.

payload, headers, err := session.GenerateKasadaPayload(ctx, &hyper.KasadaPayloadInput{
    // Fields
})
if err != nil {
    // Handle the error
}
// payload and headers are ready for the /tl request

import { KasadaPayloadInput, generateKasadaPayload } from 'hyper-sdk-js';

const result = await generateKasadaPayload(session, new KasadaPayloadInput(
    // kasada payload input fields
));

const payload = result.payload;
const headers = result.headers;

The payload returned by the API is base64-encoded. You must decode it before posting to /tl.

Step 5: POST to /tl Endpoint

POST the decoded payload to the /tl endpoint:

https://www.example.com/149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/tl

Critical requirements:

Content-Type must be application/octet-stream
Include all headers returned by the API (x-kpsdk-im, x-kpsdk-ct, x-kpsdk-dt)
Match browser header order exactly
POST the decoded (binary) payload
Set referer to the /fp URL

Step 6: Parse /tl Response

A successful response will return 200 status code with:

Response body:

{
    "reload": true
}

Critical response headers to save:

x-kpsdk-ct: Token that must be included in subsequent requests to protected endpoints
x-kpsdk-st: Timestamp value needed for generating POW (x-kpsdk-cd) headers
set-cookie: Kasada cookies (e.g., tkrm_alpekz_s1.3, tkrm_alpekz_s1.3-ssn)

Example response headers:

x-kpsdk-ct: 02Rrkf95YyBbq2lGyws6SFVp...
x-kpsdk-st: 1759149934586
set-cookie: tkrm_alpekz_s1.3=02Rrkf95YyBbq2lGyws6SFVp...; Max-Age=86400; Path=/; HttpOnly
set-cookie: tkrm_alpekz_s1.3-ssn=02Rrkf95YyBbq2lGyws6SFVp...; Max-Age=86400; Path=/; HttpOnly; Secure; SameSite=None

Store these values in your session:

Update your cookie jar with the Set-Cookie headers
Save x-kpsdk-st for future POW generation
Save x-kpsdk-ct as you'll need to include it in request headers to protected endpoints

Step 7: Making Requests to Protected Endpoints

Now you can make requests to protected endpoints with the Kasada tokens. Observe what headers the browser includes and match them exactly.

Headers to include:

Kasada cookies (always required):
- Include all cookies from the /tl response in your Cookie header
x-kpsdk-ct header (if browser includes it):
- Use the value from the /tl response headers, or the one that was last returned from a protected endpoint.
- Some sites require this in the header, others only use cookies
x-kpsdk-cd header (if browser includes it):
- This is a POW (Proof of Work) that must be freshly generated for each request
- See the section below for how to generate it

Fetch Client Configuration (Optional - /mfc)

Some Kasada implementations require an additional step to fetch client configuration. If you observe the browser making a GET request to the /mfc endpoint, you'll need to include this step.

When to use /mfc

Check your browser's network logs. If you see a request to:

/149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/mfc

Then you need to perform this step after solving the initial challenge and before making requests to protected endpoints.

Requesting /mfc

Make a GET request to the /mfc endpoint:

https://www.example.com/149e9513-01fa-4fb0-aad4-566afd725d1b/2d206a39-8ed7-437e-a3be-862e0f06eea3/mfc

Important:

Include your Kasada cookies from the /tl response
Match browser headers and header order
The request should return a 200 status code

Parse /mfc Response Headers

The response will include these critical headers:

x-kpsdk-fc: Feature configuration value needed for POW generation on sites using /mfc
x-kpsdk-h: Header value that may be required on subsequent requests to protected endpoints

Example response headers:

x-kpsdk-fc: AH4kT...
x-kpsdk-h: 1-BwVlRFs

Store both values:

Save x-kpsdk-fc to use when generating POW (x-kpsdk-cd) headers
Save x-kpsdk-h and include it in requests to protected endpoints if the browser does

If your site doesn't use /mfc (you don't see it in browser logs), you can skip this step entirely and omit the fc parameter when generating POW.

Generating x-kpsdk-cd for Each Request

If the website requires the x-kpsdk-cd header on requests (check browser behavior), you must generate a fresh POW for each and every request. Never reuse POW values.

powPayload, err := session.GenerateKasadaPow(ctx, &hyper.KasadaPowInput{
    // POW challenge parameters
})
if err != nil {
    // Handle error
}

CRITICAL: The x-kpsdk-cd header must be regenerated for every single request. Reusing POW values will cause your requests to fail. Generate a new POW immediately before making each request.

When to Re-solve the Challenge

You may need to re-solve the Kasada challenge (repeat the entire flow) if:

Your Kasada cookies expire
You receive a 429 response on protected endpoints

To maintain long-running sessions:

Proactively refresh tokens before they expire
Handle 429 responses by triggering a new challenge solve

Summary

The complete flow:

✅ GET request to /fp endpoint → Receive 429 with block page
✅ Parse script path from HTML
✅ GET request to ips.js script
✅ Generate payload via Hyper Solutions API
✅ POST decoded payload to /tl endpoint
✅ Parse response headers and cookies
✅ Make requests to protected endpoints with:
- Kasada cookies (always)
- x-kpsdk-ct header (if browser uses it)
- x-kpsdk-cd header (if browser uses it - generate fresh for each request)

You have now successfully integrated Kasada's flow!

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Last updated 4 months ago

hashtagOverview

hashtagStep 1: Request the /fp Endpoint

hashtagStep 2: Parse the Script Path

hashtagStep 3: Fetch the ips.js Script

hashtagStep 4: Generate Payload via API

hashtagStep 5: POST to /tl Endpoint

hashtagStep 6: Parse /tl Response

hashtagStep 7: Making Requests to Protected Endpoints

hashtagHeaders to include:

hashtagFetch Client Configuration (Optional - /mfc)

hashtagWhen to use /mfc

hashtagRequesting /mfc

hashtagParse /mfc Response Headers

hashtagGenerating x-kpsdk-cd for Each Request

hashtagWhen to Re-solve the Challenge

hashtagSummary

Overview

Step 1: Request the /fp Endpoint

Step 2: Parse the Script Path

Step 3: Fetch the ips.js Script

Step 4: Generate Payload via API

Step 5: POST to /tl Endpoint

Step 6: Parse /tl Response

Step 7: Making Requests to Protected Endpoints

Headers to include:

Fetch Client Configuration (Optional - /mfc)

When to use /mfc

Requesting /mfc

Parse /mfc Response Headers

Generating x-kpsdk-cd for Each Request

When to Re-solve the Challenge

Summary