Enrique Fueyo Ramírez, Co-founder and CTO of Lang.ai, shares how his team instrumented performance monitoring for GraphQL resolvers using Sentry. They used Apollo to connect the frontend and backend, and created a custom plugin to intercept resolver lifecycles, starting and finishing spans for each request. The plugin allows them to monitor performance without adding explicit start/stop code to their functions, providing fine-grained information on individual transactions and distributed tracing capabilities.