Use case
Secure Payment Portals & Checkout Pages
Ensure your payment pages can't be tampered with and that every script running on them is legitimate, monitored and controlled. Protect user credit card details from e-skimming, magecart, and more.
Ensure your payment pages can't be tampered with and that every script running on them is legitimate, monitored and controlled. Protect user credit card details from e-skimming, magecart, and more.
Bad actors inject or infiltrate a client-side script on your site to carry out attacks:
Listening to which keys are pressed while on the webpage. This is a rather common legacy script behaviour present in many client-side scripts. A browser would not block this by default. Legacy unsafe script behaviours are rarely prevented by browsers to offer compatibility with old websites but at the expense of security. By using cside, we give you back control.
Upon completing a form, hijacking the outbound fetch. Sensitive card details or personal information is siphoned out to a third party domain.
Rendering an identical looking iframe over the payment card field. After the user enters the credit card data, the form would fail with a retry message and disappear. Revealing the real payment page.
Trusted third parties (analytics, chatbots, …) can be compromised and used to exfiltrate sensitive data from your own payment pages. NPM dependencies can inject malicious first party scripts, even bypassing any supply chain security solutions you use.
If scripts are not monitored with integrity verified, you fall short of PCI DSS requirements 6.4.3 and 11.6.1. Misconfigured or malicious scripts can violate your data privacy policies and lead to GDPR violations.
Depending on the attack, compromised payment pages will see a severe cart abandonment spike and payment failures. You may be fined by card brands or acquiring banks for non compliance, usually translating into much higher fees.
Leading companies trust cside
Built for security teams who need visibility inside the browser, cside delivers proven defense against modern client-side attacks while supporting PCI DSS and GDPR compliance. Your trusted partner for securing the last mile of the web.
GDPR 
SOC 2 
PCI DSS FAQ
Frequently Asked Questions
We apply behavioral analysis to every script running in the browser. If a script attempts to read sensitive input fields (like credit card numbers), access form data, or send it to an unknown or unapproved domain, cside blocks it instantly and alerts your team.
No. cside loads asynchronously and is optimized for production environments. It wraps script execution without introducing latency or blocking rendering. In many cases we improve performance by caching static scripts.