TL;DR: cside vs F5 Client-Side Defense
- F5 Client-Side Defense monitors browser-side JavaScript and integrates with F5's WAF and bot management. The integration is the appeal. Forensic depth depends on what F5 surfaces, and pricing is enterprise-gated.
- cside runs on any CDN with no F5 dependency, in 100% of real user sessions with no sampling. Every script is downloaded for server-side analysis and raw attack code is preserved as QSA evidence. Public pricing, free tier.
- Committed to the F5 stack: F5. Want CDN-agnostic deployment, full session coverage, and QSA-grade evidence at a published price: cside.
What is F5 Client-Side Defense?
F5 Distributed Cloud Client-Side Defense protects against browser-side attacks, Magecart, formjacking, digital skimming, and PII harvesting. The underlying signal and obfuscation technology came from F5's roughly $1B acquisition of Shape Security, which closed in January 2020; CSD as a named capability was introduced in June 2022. It targets large enterprises in financial services, government, telco, retail, and travel that already run F5 infrastructure.
F5's enterprise footprint and balance sheet are genuine strengths. Where CSD gets harder to justify is when client-side security is the only thing you need and you aren't already an F5 shop.
How F5 Client-Side Defense works
Per F5's own technical documentation, CSD injects a browser-side JavaScript agent that observes other scripts after they execute, sends telemetry to F5's cloud Analysis Service where machine learning risk-scores the activity, and surfaces alerts in a dashboard. Mitigation is a human "one-click" block of the malicious exfiltration calls. Scripts reach and run in the browser before CSD acts, and CSD's value is tied to deploying through F5's platform.
How cside goes further
cside is a dedicated client-side security product, not a module inside a WAAP suite, and it doesn't care what infrastructure you run. It deploys as a single first-party script with no DNS changes.
Rather than risk-scoring activity after the fact, cside monitors what each script actually does in the real browser and performs AI-driven analysis on the script's content. That gives you a concrete view of behavior, and, critically, an immutable forensic record of every payload, so when an auditor or incident-response team asks what happened, you have the actual code and a timeline rather than a score.
cside also adds a dedicated fingerprinting product with device fingerprinting, bot detection, and AI agent detection, publishes a public status page at status.cside.com and trust portal at trust.cside.com, and offers a QSA-validated PCI dashboard and public pricing you can evaluate today.
Try cside before you buy. cside has a free plan, so you can sign up, deploy, and explore the platform yourself, with no sales calls or procurement process. And our support team is one message away whenever you need a hand.
Sign up or book a demo to get started.
Related resources
Founder and CEO of cside. Previously a product manager on Cloudflare Page Shield (now Cloudflare Client-Side Security). Co-chair of the W3C Anti-Fraud Community Group and a Forbes 30 Under 30 honoree. Building accessible security against client-side attacks, web security is not an enterprise-only problem.
