ESPConnect

Use Hoppscotch to send REST, GraphQL, WebSocket, and other API requests from the web app, desktop client, or CLI. Collections, environments, scripts, and response tests turn one-off calls into repeatable workflows, while data can remain in a local session, sync through the hosted service, or run on a self-hosted deployment.

Langfuse helps teams instrument LLM applications so they can inspect traces, sessions, retrieval steps, prompts, scores, and evaluations in one place. It also supports prompt versioning, datasets, playground experiments, and integrations with common SDKs and frameworks. You can use the hosted service or self-host with Docker Compose or Kubernetes. Self-hosted instances send basic usage telemetry by default, but it excludes raw traces and can be disabled.

MCP Inspector connects to servers over stdio, SSE, or Streamable HTTP and lets developers inspect tools, resources, prompts, and responses in a browser UI. Its CLI supports scripted checks and continuous integration, and server configurations can be exported for other clients. Because the local proxy can spawn processes and connect to specified servers, it should not be exposed to untrusted networks.

Reactotron is a desktop debugger for React and React Native applications on macOS, Linux, and Windows. It can display application state, API requests and responses, logs, global errors, and quick performance benchmarks, while also subscribing to or replacing selected state. The integration is added as a development dependency and is not included in production builds.