c/side

c/side (also written cside or c-side, and identified in one industry profile as Client-side Development, Inc.) sells a client-side security platform that gives organizations visibility into what executes inside a visitor's browser after a page has been delivered. Customers add a single script tag to the page head, after which the platform inventories every script execution, captures device fingerprints and behavioural signals across visitor sessions, and flags script changes, headless browsers, AI agents, VPN use and fraud signals. Alerts can be routed to Slack, Microsoft Teams, email or a webhook, and collected data can be exported as compliance reports, chargeback evidence packages, or feeds into existing fraud and SIEM tooling.

The product's core technical approach is a proxy that sits between the browser and third-party JavaScript, allowing each script payload to be inspected for behaviours such as keystroke logging, formjacking, digital skimming, crypto mining and unauthorized data exfiltration, and to be blocked, flagged for review, or allowed. Detection is paired with an AI engine; one industry profile describes a locally hosted, custom-tuned large language model that summarizes payload behaviour in plain English and is used to refine detections. Installation options include a script tag for site builders such as Webflow, and an NPM package recommended for React, Next.js and similar frameworks.

A second product line addresses compliance: the platform automates PCI DSS 4.0.1 requirements 6.4.3 (a justified inventory of scripts on payment pages) and 11.6.1 (continuous monitoring of headers and scripts for unauthorized change), producing reports the company describes as QSA-ready and VikingCloud-validated. The company also markets monitoring of privacy and consent leakage across third parties in relation to GDPR and CCPA.