OpenTelemetry is a versatile specification used for sending telemetry data to various observability backends, offering vendor-agnostic capabilities beneficial for monitoring Next.js applications. This guide provides a comprehensive overview of integrating OpenTelemetry with Next.js, detailing the processes for setting up tracing, logging, and metrics. The integration involves using the @vercel/otel package for simplified configuration, although setting up from scratch with the OpenTelemetry SDK offers more control. Next.js provides built-in spans for automatic tracing, exception tracking, and a simplified setup, while verbose logging can enhance data granularity. The guide outlines how to capture exceptions, export metrics, and utilize custom logging, emphasizing the importance of connecting automatic spans with custom ones for effective monitoring. Additionally, it touches on the benefits of integrating OpenTelemetry with platforms like Highlight.io for improved troubleshooting capabilities, enabling the visualization of response times, error rates, and detailed error reports for performance optimization and enhanced user experience.