If you need more than a device ID, cside is a strong FingerprintJS alternative. It delivers high-accuracy device fingerprinting and adds AI agent detection, VPN and proxy flagging, incognito identification, and chargeback evidence export from a single script tag, with no separate bot detection product to integrate.
TL;DR: cside vs FingerprintJS
- FingerprintJS Pro is a well-engineered device identification library, but it returns only a device ID: no AI agent flag, no VPN or proxy signal, no incognito detection, no PCI DSS evidence, and no chargeback export. It is paid-only, from around $99/month.
- cside is a FingerprintJS alternative that keeps high-accuracy fingerprinting across incognito, VPN, and cookie-clearing, and adds AI agent detection, VPN and proxy flagging, incognito identification, and chargeback evidence export from one script tag. Free tier: 1,000 API calls per month, then $99/month self-serve.
- Only need a stable visitor ID: FingerprintJS Pro. Need a fraud verdict and evidence alongside the fingerprint: cside.
What FingerprintJS Pro does well
FingerprintJS Pro is a well-engineered device identification library. Its core fingerprinting is reliable, its developer documentation is thorough, and the SDK is straightforward to integrate across web and mobile. If you need a stable visitor ID that persists through cookie deletion, it does that job well.
The product has been around long enough to build a solid reputation among front-end teams. For pure device identification without fraud context, it is a reasonable choice.
So why do teams look for a FingerprintJS alternative? Usually because their threat model has expanded and FingerprintJS has not moved with it.
Where FingerprintJS stops short
FingerprintJS Pro produces a fingerprint. What it does not produce is a fraud verdict, a chargeback evidence packet, or a signal about whether the visitor is a human at all.
Specifically, it does not tell you:
- Whether the visitor is an AI agent (OpenAI Operator, Claude for Chrome, Playwright, Puppeteer, Selenium)
- Whether the connection is routing through a VPN or proxy
- Whether the session is incognito
- Whether the device and session data meets PCI DSS 4.0.1 Requirements 6.4.3 and 11.6.1
For teams dealing with account takeover, chargeback fraud, or bot-driven abuse, those gaps mean bolting on additional tools. That adds cost, integration work, and more vendor contracts to manage.
Device fingerprinting is the primary pre-authentication signal for stopping the credential-stuffing campaigns that drive account takeover at scale. Javelin Strategy & Research put US account takeover losses at $13.5 billion in 2025, up 18% year on year. A fingerprint alone does not close that gap; a fraud verdict does.
Feature comparison: cside vs FingerprintJS Pro
| Feature | cside | FingerprintJS Pro |
|---|---|---|
| Device ID accuracy | High, across incognito, VPN, and cookie-clearing | High (not published) |
| AI agent detection | Yes (Operator, Claude, Playwright, Puppeteer, Selenium) | No |
| VPN/proxy detection (TLS handshake fingerprint TLS) | Yes | No |
| Incognito detection | Yes | No |
| PCI DSS 4.0.1 evidence | Yes (Req 6.4.3 + 11.6.1) | No |
| Chargeback evidence export | Yes | No |
| Free tier | Yes (1,000 API calls/month, no card) | No |
| Paid pricing | $99/month (Business, self-serve) | From ~$99/month (paid-only) |
How cside builds a high-accuracy fingerprint
cside analyzes more than 100 browser signals per visit. The signals include canvas entropy, font rendering differences, WebGL fingerprint, screen metrics, timing patterns, and headless browser flags.
On top of standard browser attributes, cside layers TLS handshake fingerprint TLS fingerprinting. TLS handshake fingerprint captures how a device negotiates a TLS connection, a signal that persists even when the user rotates through multiple VPNs or clears cookies. That is how cside keeps fingerprint accuracy high across incognito sessions, VPN connections, and cookie-clearing behavior.
The fingerprint ID structure is compatible with the format FingerprintJS Pro returns, which matters for migration.
Pricing: how the two products compare
FingerprintJS Pro is paid-only. Its entry plan starts at around $99 per month for 20,000 API calls, and there is no free tier to evaluate the product first.
cside gives you 1,000 API calls per month free, with no credit card required. That is enough to evaluate fingerprinting quality on real traffic, test the AI agent detection, and confirm VPN signal behavior before you spend anything.
When you are ready to scale, the Business plan is $99 per month, self-serve, with pricing published on the pricing page. Enterprise pricing is available for high-volume needs.
The practical difference is simple: you can validate cside's fingerprint accuracy on your own users before you pay. With FingerprintJS Pro, you are paying from the first call.
Migrating from FingerprintJS
The migration path from FingerprintJS to cside is designed to be low friction. Here is what it looks like in practice.
Step 1: Remove the FingerprintJS script tag and add the cside script tag to your page head. Both are single-tag integrations.
Step 2: Update your API call. cside returns a stable device fingerprint ID in the same structural position your existing code expects, so you do not need to rewrite the logic that stores or queries the ID.
Step 3: Start using the extra signals cside returns. Alongside the fingerprint, cside returns a real-time verdict that flags AI-agent and automated sessions, VPN and proxy connections, and incognito mode. These signals are additive, so you can adopt them immediately or introduce risk logic gradually.
Most teams complete the swap in an afternoon and spend the rest of the sprint testing the new signals rather than debugging the integration. The cside API documentation covers the full response schema and code examples.
If you are running a PCI-scoped checkout or need chargeback evidence, the cside chargeback evidence export uses the same fingerprint ID as its identifier, so no additional device data collection is needed.
Who should switch
You should evaluate cside as a FingerprintJS alternative if any of the following apply:
- You are losing chargebacks because you cannot prove the fraudster used a specific device
- You are seeing AI agent activity on your login or checkout flows
- Your compliance team needs PCI DSS 4.0.1 evidence for script integrity monitoring
- You want a free tier to validate accuracy before committing budget
- You want one vendor covering device ID, bot signals, and fraud evidence instead of three
If all you need is a stable visitor ID with no fraud context, FingerprintJS Pro is a competent product. But most fraud teams need more than a fingerprint.
