Real-time communication (RTC) applications require low packet delay and loss while maintaining a stable throughput. WebRTC, a widely used framework, relies on Google Congestion Control (GCC). Meanwhile, newer methods like L4S (Low Latency, Low Loss, Scalable Throughput) provide opportunities with early congestion signaling. In this work, we extend client-side WebRTC to support L4S by adding ECN-based rate control and ECN feedback handling. Our results show that L4S improves real-time performance while remaining compatible with current WebRTC infrastructure.