Api MCP Server

MCP server for API testing. 35 tools: HTTP, assertions, flows, OpenAPI, collections.

Local serverstdioTypeScript

What is the Api MCP server?

MCP server for API testing. 35 tools: HTTP, assertions, flows, OpenAPI, collections. The api mcp server wraps that behind the Model Context Protocol, so an assistant can use it through 3 defined tools rather than through you.

What it actually does

The most complete MCP server for API testing. Period.

Its toolset

Everything the assistant can do here goes through one of these:

  • Assertions — The Assertions tool exposed by this server
  • Collections — The Collections tool exposed by this server
  • Environments — Environments hold your variables — BASE_URL, tokens, API keys — and keep them separated by context. The system has three core concepts:

Adding it to your client

@cocaxcode/api-testing-mcp on npm is all you need. Most clients run it directly, so configuration is a few lines and a restart.

Configuration

You will need 3 environment variables: TOKEN, API_TESTING_DIR, BASE_URL. The server will not start without them, which is usually why the tools fail to appear on a first run. Keep credentials in your client's env block or a secrets manager rather than in a file you might commit.

When to reach for it

This sits in the developer tooling group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. Api's toolset — Assertions, Collections, Environments — is a fair guide to whether it matches your workflow. It is maintained by cocaxcode; worth a glance at recent repository activity before you build anything load-bearing on it.

We check each listing at SyncDev against the project's documentation before it goes live — if something here drifts out of date, it is a bug worth reporting.

Caveats

  • It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
  • Missing credentials fail quietly in some clients — if no tools show up, check the environment block first.
  • MCP clients confirm each tool call by default. Leave that on until you have watched what the api mcp server does with a few real requests.

Available tools

ToolWhat it does
AssertionsThe Assertions tool exposed by this server.
CollectionsThe Collections tool exposed by this server.
EnvironmentsEnvironments hold your variables — BASE_URL, tokens, API keys — and keep them separated by context. The system has three core concepts:

How to install the Api MCP server

{
  "mcpServers": {
    "api-testing": {
      "command": "npx",
      "args": ["-y", "@cocaxcode/api-testing-mcp"],
      "env": {
        "TOKEN": "your-value",
        "API_TESTING_DIR": "your-value",
        "BASE_URL": "your-value"
      }
    }
  }
}

Add to claude_desktop_config.json, then restart Claude Desktop.

Configuration

VariableDescriptionRequired
TOKENCredential the server authenticates with.Yes
API_TESTING_DIRFilesystem location the server is allowed to use.Optional
BASE_URLEndpoint or connection string the server talks to.Yes

Example prompts to try

  • Use Api to Assertions.
  • Use Api to Collections.
  • Use Api to Environments.

Frequently asked questions

It connects Api to MCP-compatible AI assistants such as Claude and Cursor, exposing 3 tools (Assertions, Collections, Environments) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with Api directly.