MCPJam

MCPJam is a local development client that lets engineers test and debug MCP servers and ChatGPT apps by inspecting JSON‑RPC traffic, tracing tool calls, and previewing responsive UI layouts. It provides built‑in OAuth debugging, per‑turn latency and token metrics, and enterprise features such as SSO/SAML, RBAC, and audit logs for secure, compliant testing.

Updated 2 months ago

Funding

Funding not disclosed

Funding rounds are not available yet.

Founders

Founder details are not available yet.

Product

Problem

Developers of MCP servers and ChatGPT apps often lack a unified environment to test tool calls, UI rendering, and authentication flows, leading to hidden bugs, inconsistent user experiences, and costly iteration cycles before deployment.

Solution

MCPJam provides a local development client that lets engineers inspect JSON‑RPC requests, trace tool calls, and preview rendered UI for both MCP and ChatGPT apps without needing public endpoints or external subscriptions. The platform logs every agent step, token exchange, and redirect, offering full per‑turn visibility with latency and token metrics. Integrated UI previews can be toggled between mobile, tablet, and desktop layouts, and styled for ChatGPT or Claude. A built‑in OAuth debugger validates protocol conformance across multiple spec versions and client registration methods. Developers can share, mock, and collaborate on app views, while enterprise customers gain SSO/SAML, RBAC, audit logs, and custom compliance options.

Target Audience

Primary users are developers and engineering teams building MCP servers, ChatGPT apps, or agentic workflows, as well as enterprise organizations that require secure, compliant testing environments.

Features

Inspector view showing complete JSON‑RPC traffic, tool calls, arguments, responses, and errors
Visual OAuth debugger that logs each redirect, token exchange, and scope grant with spec‑level validation
UI preview panel with responsive rendering for desktop, tablet, and mobile, supporting both ChatGPT and Claude styling
Apps builder that emulates ChatGPT and MCP Apps locally, eliminating the need for public tunnels or subscriptions
Project organization and sharing features for collaborative testing and mock data scenarios
Open source SDK and logger integration for custom tooling and CI/CD pipelines
Enterprise controls including SSO/SAML, role‑based access, audit‑log retention, and customizable data processing agreements