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FPScanner

Free#10 of 11 in Bot Detection and Mitigation Software

Self-hosted browser fingerprinting and bot detection library.

—Not yet scored
FPScanner— Visit FPScanner

At a glance

  • Editor score
    Not yet scored
  • Pricing
    Free plan
  • Best for
    Developers detecting browser automation in-house
  • Free plan
    Yes
  • Paid from
    None
  • Protected surfaces
    websites
  • Facts checked
    24 Sep 2026
  • Where it wins

    • Detects WebDriver, CDP, Playwright, Selenium and other automation signals
    • Cross-context validation spans pages, iframes and web workers
    • Fingerprint encryption, obfuscation and anti-replay protections are optional
  • Where it doesn't

    • Client-side detection does not include behavioral analysis
    • No dashboards, rule engines or managed mitigation service
    • Teams must deploy and operate the npm package themselves

Our verdict on FPScanner

FPScanner is an MIT-licensed, open-source JavaScript library for teams that want to detect browser automation on infrastructure they control. It runs client-side in web applications and supports self-hosted deployment. The library collects browser and automation signals, then creates a short-lived browser fingerprint with a JA4-inspired fsid identifier. Its intended audience is developers building bot checks directly into their own applications rather than buyers seeking a managed enforcement platform.

The detection layer covers WebDriver, CDP, Playwright, Selenium and other automation indicators. Cross-context validation compares signals from the main page, iframes and web workers, while timestamp and nonce checks help guard against replay. Teams can optionally encrypt fingerprint payloads with build-time key injection and apply JavaScript code obfuscation. Node.js and Python examples show how to decrypt and validate data server-side, making the package suitable for web stacks that can split collection in the browser from verification in backend code.

FPScanner’s narrow scope is also its main boundary. It focuses on client-side detection and does not provide behavioral detection, custom rules, dashboards or managed mitigation. Operating the npm package, client-side JavaScript and server-side validation remains the team’s responsibility, with documentation and community support as the listed channels. Choose FPScanner when you need open-source building blocks for in-house browser-automation detection and can design the surrounding response workflow. Look elsewhere if you need a hosted service, visual monitoring, behavioral analysis or centrally managed enforcement.

FPScanner pricing

Plans Free planFree Free to use — no paid tier required for the core job.
See plans on fpscanner.com

FPScanner fact sheet

Free planYes
Paid fromNone
Challenge typesNot verified
Protected surfaceswebsites
Behavioral detectionNo
Custom bot rulesNo
Deployment methodsself-hosted npm package; client-side JavaScript
Supported protocolsNot verified
DeploymentSelf-hosted
PlatformsWeb
SupportDocs, Community
Built forSolo, Small business, Mid-market (editorial estimate)
PricingFree plan
Websitefpscanner.com
Facts checked24 Sep 2026

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Reviewed by iTechGuides Editors · Editorial team · Updated Sep 2026

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