MCP Playground — Test MCP Servers Online Free

Overview

What is MCP Playground?

MCP Playground is a free, browser-based testing tool for the Model Context Protocol (MCP). Test MCP servers, clients, and tools directly in your browser without any installation or configuration.

Supports all core MCP features including tools, prompts, and resources. Connect to any remote server, browse capabilities, execute commands, and view real-time request/response logs.

Benefits

Why Use It for Testing?

Traditional MCP testing requires local setup, dependencies, and configuration. MCP Playground eliminates all of this — just enter a server URL and start testing.

Perfect for validating server implementations, testing tools before deployment, or exploring the MCP servers list. Works with any standard MCP server that supports remote connections.

Features

Key Features

Browser-Based

No software to install

Remote Servers

Connect via URL

Full Protocol

Tools, prompts, resources

Real-Time Logs

Live request/response

10000+ Servers

Official MCP Registry

Free & Open

No limits, no sign-up

Guide

How to Test MCP Servers

Navigate to the MCP server testing page

Enter your MCP server URL (add auth token if needed)

Click Connect to establish a connection

Browse tools, execute commands, view logs

AI Agents

Test MCP Servers with AI Models

A server that responds correctly can still be unusable by an agent — an ambiguous tool description or an under-specified schema only fails when a real model tries to call it. MCP Agent Studio connects your server to 60+ models — Claude, GPT-5, Gemini, DeepSeek, Grok, Qwen — and shows every tool call with its full JSON input and output.

Run the same prompt across up to four models at once to see which picks the right tool, or start from a pre-built agent template for GitHub, Stripe, Notion, Linear and more.

Evals

What Are MCP Evals?

An MCP eval answers a different question than a tester does: not “did the server respond?” but “can an agent actually accomplish something with it?” The suite is generated from your real tool schemas, so it tests exactly what a model would see.

Direct checks — output-schema conformance, JSON-RPC error codes, pagination, idempotency — are decided by code, not by a model. Agentic tasks are driven by one model and graded by another. You get a pass/fail report per tool, with evidence, that you can re-run after every change.

Frequently Asked Questions

What is the Model Context Protocol (MCP)?

MCP is an open standard, introduced by Anthropic in November 2024, that defines how AI applications connect to external tools and data. It replaces bespoke per-app integrations with one protocol: a server implements an integration once, and any MCP-compatible client — Claude, ChatGPT, Cursor, VS Code, a custom agent — can use it without changes. The protocol is transport-agnostic JSON-RPC 2.0 and is now maintained as an open specification with contributions from across the industry.

What is the difference between an MCP server, client and host?

The host is the AI application the user interacts with, such as Claude Desktop or an IDE. The client is the connector inside that host, and it holds exactly one connection to one server. The server is the program exposing capabilities — a GitHub server, a Postgres server, a filesystem server. One host runs many clients, each paired to a single server, which is why connecting a new integration never requires changing the model or the app.

What are MCP tools, resources and prompts?

They are the three things a server can expose, and they differ by who decides to use them. Tools are model-controlled: the model chooses to call them, and they can have side effects, like creating an issue or running a query. Resources are application-controlled: passive data the host attaches to context, such as a file or a database row, identified by URI. Prompts are user-controlled: templates a person deliberately invokes, usually surfaced as a slash command. Most servers ship only tools, which is why the other two are widely misunderstood.

What transports does MCP support?

Two are current. Stdio runs the server as a local subprocess communicating over standard input and output — it is the right choice when the server needs your filesystem, your kubeconfig or a database that is not reachable from the internet. Streamable HTTP is the remote transport, letting one hosted server serve many clients over a URL. The older HTTP+SSE transport was deprecated in the 2025-03-26 revision and is kept only for backward compatibility with existing deployments.

Which MCP specification version should I target?

The specification is revised by date rather than by semantic version. 2026-07-28 is the current revision, and 2025-11-25 is the widely deployed predecessor that most clients in the wild still speak. Well-behaved servers negotiate: they implement the newer revision and still accept legacy initialize handshakes from older clients. Version negotiation happens during initialize, so a mismatch shows up immediately as a failed connection rather than as subtly wrong behaviour later.

What are MCP sampling and elicitation?

Both reverse the usual direction of the conversation. Sampling lets a server ask the client to run an LLM completion on its behalf, so a server can use a model without holding an API key of its own. Elicitation lets a server pause mid-tool-call to ask the user a question — a confirmation before returning a secret, or a missing parameter. Many clients implement neither, so a server that depends on them can fail against an otherwise healthy client. The Everything reference server exists specifically to test these paths.

How do I test an MCP server?

Open the server tester, paste the server URL, add an auth token if the server needs one, and connect. You will see the tools, prompts and resources it advertises, and you can call any of them and read the raw JSON-RPC request and response. That confirms the server works. To find out whether an agent can actually use it, run it against a real model in Agent Studio — an ambiguous tool description only fails when a model tries to choose between it and something similar.

Can I test a local or stdio MCP server in the browser?

Not directly, because a browser cannot spawn a local subprocess or reach a process on your machine over stdio. The usual approach is a bridge such as supergateway or mcp-remote, which wraps the stdio server and exposes it over HTTP so any remote client can connect. Alternatively, expose it through a tunnel. Once it has a URL, it tests exactly like any hosted server.

Are MCP servers safe to connect to real accounts?

The credential is the security boundary — the protocol itself grants an agent whatever the token permits, and nothing in it prevents a destructive call. Use a scoped, read-only credential first and point it at staging or a replica. Two risks are specific to MCP: prompt injection, where text a server returns from a scraped page or an issue comment is written to look like an instruction to your agent, and tool poisoning, where a malicious server description manipulates the model. Keep servers that read the open web separate from servers that can write, deploy or spend.

Does MCP only work with Claude?

No. MCP started at Anthropic but is an open specification, and any model with tool calling can drive an MCP server — GPT, Gemini, Llama, Grok, Qwen and open-weight models all work. Reliability does vary: servers with many similarly named tools, or tasks needing several chained calls, separate strong models from weak ones quickly. That is worth measuring rather than assuming, which is why you can run the same server against 60+ models here and compare.

What MCP servers can I test here?

Any server reachable over a URL, including your own work in progress. The official registry indexes more than 10,000 public servers, and we publish in-depth guides to the most-used ones — GitHub, Postgres, Notion, Stripe, Firecrawl, Kubernetes and dozens more — covering the tools each exposes and the connection details you need. Mock servers are also available if you want to exercise a client against known-good behaviour, including deliberate error and edge-case responses.

Is MCP Playground free?

The testing tools are completely free with no sign-up, no credit card and no usage limits — the server tester, the client tester, the mock servers, the config generator and the security scanner. Agent Studio runs real models on your behalf, so it needs an account and runs on credits, and every new account starts with free credits.

More depth in the introduction to MCP, the MCP security guide, and awesome MCP servers.

Ready to test? Start testing MCP servers, run your server against an AI model, explore the server registry, or validate your client. The testing tools are free with no registration; Agent Studio gives you free credits on sign-up.