This article takes an honest look at the features of Jscrambler Web Page Integrity, another company focussing on client-side security.
Since you’re on the cside website, we acknowledge our bias. That said, we’ve built our case honestly and based our analysis on publicly available information, industry information, and our own or our customers' experiences.
If you want to verify these claims yourself, please navigate to their product page.
| Criteria | cside | Jscrambler | Why It Matters | What the Consequences Are |
|---|---|---|---|---|
| Approaches used | Active client-side detections + optional ability to proxy + scanner | Static client-side script | ||
| Real-time Protection | Attacks can occur between scans or in the excluded data when sampled | Delayed detection = active data breaches | ||
| Full Payload Analysis | Ensures deep visibility into malicious behaviors within script code itself | Threats go unnoticed unless the source is known on a threat feed | ||
| Dynamic Threat Detection | Identifies attacks that change based on user, time, or location | Missed detection of targeted attacks | ||
| DOM-Level Threat Detection | Tracks changes to the DOM and observes how scripts behave during runtime | Unable to identify sophisticated DOM-based attacks | ||
| 100% Historical Tracking & Forensics | Needed for incident response, auditing, and compliance | Needed for incident response, auditing, and compliance | ||
| Bypass Protection | Stops attackers from circumventing controls via DOM obfuscation or evasion | Stealthy threats continue undetected | ||
| Certainty the Script Seen by User is Monitored | Aligns analysis with what actually executes in the browser | Gaps between what's reviewed and what's actually executed | ||
| AI-driven Script Analysis | Detects novel or evolving threats through behavior modeling | Reliance on manual updates, threat feeds or rules = slow and error-prone detection | ||
| QSA validated PCI dash | The most reliable way to ensure a solution is PCI compliant is to conduct a thorough audit by an independent QSA | Without QSA validation, you rely entirely on marketing claims, which could result in failing an audit | ||
| SOC 2 Type II | Shows consistent operational security controls over time | Lacks verified security control validation, making it a risky vendor | ||
| PCI specific UI | An easy interface for quick script review and justification via one click or AI automation | Mundane tasks and manual research on what all the scripts do, which takes hours or days |
What is Jscrambler
Jscrambler is a cybersecurity tool that protects JavaScript code through obfuscation, runtime protection, and anti-tampering techniques.
How Jscrambler works
Jscrambler protects first-party JavaScript code by transforming it through obfuscation. This makes the code difficult to reverse-engineer or steal. It's main use is to protect companies scripts with sensitive logic in the frontend such as proprietary algorithms, licensing enforcement, or in-browser app logic. Be sure to debug your own script after obfuscation to see if it functions as normal.
LLM's are increasingly getting better at deobfuscation however. Our own product cside uses it in real-time to analyze even the most strong obfuscated scripts.
The “code locks” features allow developers to restrict where and when the code can run (e.g., on a specific domain or time window). It secures what’s already known (your own code), but it doesn’t track or analyze what other scripts are doing once the app is live.
Their runtime protections aim to detect tampering and debugging, but they are self-contained. These defenses can block execution if someone tries to interfere with the protected code, but they don’t extend to monitoring other scripts or the dynamic behavior of the full webpage.
This method most crucially places all detections in the browser, making an ideal sandbox for an attacker to develop an attack that circumvents their detection methods.
Not fully protected
One of the key issues with the Jscrambler client-side approach is that by design, they don't know what they don't catch. Any attack that successfully avoids their client-side hooks goes unseen and undetected making it much harder to improve detection capabilities and giving no ability to perform forensics.
In June of 2025, they publicly posted their product evaluation by OBS Global, a cybersecurity and digital transformation consulting firm. In there, they dissect their "iFrame Integrity" product, which focuses almost exclusively on blocking src and srcdoc modifications to iFrames.
In practice, attackers don’t necessarily need to touch the iframe. A script can just spread a div over the iframe with whatever they want.
So their "iFrame Integrity" product solves 1 very specific kind of attack. But the protection is full of holes, which can very easily be abused by the attacker.
For 3rd-party scripts, they use a Content Security Policy (CSP). This is a rules-based system which essentially trusts the source (domain). Should the source stay the same but the content changes, like in the biggest client-side attack of 2024 – Polyfill – a CSP won’t catch it.
We wrote an in depth article on Why CSP Doesn’t Work in regards to providing the best client-side security solution:
CSP operates on an allow-list model, which permits resources from trusted domains but cannot block individual scripts or resources from those domains.
How cside goes further
Cside primarily offers a hybrid proxy approach which sits in between the user session and the 3rd party service. It analyzes the served dependencies code in real-time before serving it to the user.
This allows us to not only spot advanced highly targeted attacks and alert on them, cside also makes it possible to block attacks before they touch the user's browser. It also checks the box for multiple compliance frameworks, including PCI DSS 4.0.1. We even provide deep forensics, including if an attacker bypasses our detections. Allowing you to more tightly scope the size of the incident us to make our detection capabilities better every day. No other vendor has this capability.
We believe this is the most secure way to monitor and protect your dependencies across your entire website. We've spent years in the client-side security space before we started cside, we've seen it all, this is the only way you can actually spot an attack.
Sign up or book a demo to get started.
