c/side vs @fastify/helmet: Side-by-Side Comparison (2026)

c/side: Client-side platform securing browser scripts, detecting fraud & ensuring PCI compliance. built by c/side. Core capabilities include Third-party script monitoring and inventory management, PCI DSS 4.0.1 compliance automation (requirements 6.4.3 and 11.6.1), Credit card skimming prevention..

@fastify/helmet: A Fastify plugin that implements HTTP security headers through a wrapper around the helmet library to protect web applications from common vulnerabilities..

Both serve the Runtime Application Self-Protection market but differ in approach, feature depth, and target audience.

c/side is developed by c/side. @fastify/helmet is open-source with 453 GitHub stars. Vendor maturity, funding stage, and team size can be important factors when evaluating long-term viability and support quality.

c/side and @fastify/helmet serve similar Runtime Application Self-Protection use cases: both are Runtime Application Self-Protection tools, both cover Web Security. Key differences: c/side is Commercial while @fastify/helmet is Free, @fastify/helmet is open-source. Review the feature comparison above to determine which fits your requirements.