Development of phasor measurement units (PMUs) and wide-area measurement systems in power systems has enabled transmission system operators to monitor and assess the performance of their grids in real-time. In this study, a new practical method is proposed and prototyped for real-time monitoring of transient and short-term voltage stability using synchrophasor data obtained from PMUs. In the previous related studies, methods for detecting rotor angle and voltage instabilities were presented regardless of how they can be implemented and exploited in real settings. In this study, the authors present a framework considering practical concerns, such as noise of measurements and software requirements. The well-known Lyapunov exponent (LE) concept is used in the heart of the authors’ methodology. Their methodology uses time-series data obtained from PMUs for calculating LEs, and by averaging the latest data packages received in the control centre, the performance of their framework is significantly improved under noisy measurements. As the framework is mission-critical, they considered a suitable architecture merged with a flexible human–computer interaction with the goals of increasing security, reliability, resilience, robustness, and efficiency. Simulation results demonstrate the capability of their framework in fast and accurate assessment of short-term stability using the IEEE 9-bus and 69-bus test systems.