Interactive testing environment for the CreepJS Fingerprinting API. Learn by doing - generate tokens, test endpoints, and explore integration patterns in real-time without writing any backend code.
The API Playground is a hands-on learning environment designed for developers who want to understand and test the CreepJS Fingerprinting API before integrating it into their applications. This interactive tool eliminates the need for backend setup during the exploration phase, allowing you to focus on understanding the API's capabilities and response structures.
Unlike traditional API documentation, the Playground provides immediate visual feedback and real browser fingerprint data. You can see exactly what information is collected, how it's structured, and what responses to expect - all within seconds of loading this page.
No backend infrastructure, authentication servers, or local development environment needed. Just open your browser and start testing.
Copy-paste ready code snippets in JavaScript, Python, cURL, and Go. All examples are pre-filled with your actual API token for immediate use.
Test API endpoints with your actual browser fingerprint. See live API responses and understand the data structure before writing production code.
Token Generation & Management
Understand how API tokens are created, formatted, and used for authentication. Learn about token security and rate limit associations.
Fingerprint Data Structure
Explore the complete fingerprint payload including confidence scores, timestamps, and collector outputs. See real data from your browser.
API Request & Response Patterns
Master the complete request/response cycle including headers, body format, error handling, and success criteria.
Integration Code Examples
Review production-ready code examples in multiple programming languages. Understand client-side vs server-side implementations.
Rate Limiting & Quotas
Learn how rate limits work, what happens when exceeded, and how to monitor your usage for production planning.
Error Handling Strategies
Understand different error types, HTTP status codes, and how to implement proper error handling in your applications.
Follow these steps to generate your API token and test your first fingerprint submission. The entire process takes less than 2 minutes.
Pro Tip: Keep this page open while reading the code examples. The interactive testing helps you understand API behavior before writing production code.
Enter your email to receive a free API token (1000 requests/day)
Use this token in the X-API-Token header for authentication
Send your browser's fingerprint data to the API
Response will appear here after testing...
Copy-paste ready code snippets in multiple languages
// Using fetch API
const fingerprint = await fetch('https://api.creepjs.org/v1/fingerprint', {
method: 'POST',
headers: {
'Content-Type': 'application/json',
'X-API-Token': 'YOUR_API_TOKEN'
},
body: JSON.stringify({
fingerprintId: 'abc123...',
data: { /* fingerprint data */ },
timestamp: Date.now(),
confidence: 0.95
})
});
const result = await fingerprint.json();
console.log(result);Never expose API tokens in client-side code or public repositories. Use environment variables on your backend server. For production applications, implement server-side proxy endpoints that handle token authentication internally.
Cache fingerprint results in localStorage or sessionStorage to avoid redundant API calls during the same browsing session. Set appropriate TTL (1-24 hours) based on your use case. This reduces API quota consumption and improves response times.
Always implement comprehensive error handling for network failures, rate limit exceeded (429), and invalid requests (400). Provide fallback behavior for when fingerprinting fails - never let API errors break your application flow.
For sensitive applications, collect fingerprints client-side but submit them via your backend server. This keeps tokens secure and allows you to add additional validation, logging, or business logic before hitting the CreepJS API.
Monitor your API usage through response headers (X-RateLimit-Remaining). Implement exponential backoff when approaching limits. For high-traffic applications, consider upgrading to Pro or Enterprise tiers before hitting daily quotas.
Always inform users about fingerprinting in your privacy policy. Provide opt-out mechanisms for users who don't want to be tracked. Ensure compliance with GDPR, CCPA, and other applicable data protection regulations.
Collect fingerprints during account registration and login. Flag suspicious activities when the same fingerprint attempts multiple accounts or when fingerprints change unexpectedly during a session.
Automated bots often have inconsistent or spoofed fingerprints. Check for lies detection flags, webdriver indicators, and headless browser signatures to identify automated traffic.
Improve visitor tracking accuracy in privacy-focused environments where cookies are blocked. Use fingerprints as a supplement to traditional analytics, not a replacement.
Maintain user sessions across cookie deletions or incognito mode. Fingerprints provide an additional layer of session continuity for enhanced user experience.
Ensure consistent experiment groups even when users clear cookies. Fingerprints help maintain test group assignment for more reliable A/B test results.
Enforce API or resource access limits based on device fingerprints rather than IP addresses. More effective against distributed attacks using proxy networks.
Your API token is missing, invalid, or expired.
Solution: Generate a new token using Step 1 above. Ensure you're including the token in the X-API-Token header. Tokens start with cfp_ prefix.
You've exceeded your daily request quota (1,000 for free tier).
Solution: Wait until the next day (resets at midnight UTC) or upgrade to Pro tier (100K requests/day). Implement caching to reduce API calls. Check response headers for X-RateLimit-Remaining.
Request body format is incorrect or missing required fields.
Solution: Ensure JSON is properly formatted. Required fields are fingerprintId, confidence, timestamp, and data. Check code examples above for correct structure.
Not enough distinguishing characteristics were collected.
Solution: This often occurs in privacy-focused browsers (Tor, Brave) or with anti-fingerprinting extensions. It's normal behavior. Consider combining fingerprints with other identification methods for critical use cases.
Fingerprint IDs are different on each visit for the same user.
Solution: Fingerprint stability varies by browser and user behavior. Browser updates, extension changes, or resolution changes will alter fingerprints. Use fingerprints as one signal among many, not the sole identifier. Consider monitoring fingerprint components to identify which attributes are causing instability.
Cross-origin requests are blocked by browser security policies.
Solution: CORS errors are expected when testing from localhost or unauthorized domains. For production, either add your domain to our CORS whitelist (contact support) or implement a backend proxy that adds proper CORS headers. Never expose API tokens in client-side code for production apps.
If you're experiencing issues not covered here, we're here to help:
Now that you've explored the Playground and understand how the API works, here's what to do next:
Deep dive into all API endpoints, SDK options, collector details, and integration best practices.
See all 24+ fingerprint collectors in action with real-time data from your browser.
Examine the open-source implementation on GitHub to understand collector logic and algorithms.
Ready for Production? Contact us at hello@creepjs.org to discuss Pro or Enterprise plans with higher rate limits, SLA guarantees, and dedicated support.