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mockd MCP Server

io.mockd/mockd

Multi-protocol API mock server: HTTP, GraphQL, gRPC, WebSocket, MQTT, SSE, SOAP—all in one binary.

What is the mockd MCP server?

The mockd MCP server is a multi-protocol API mock server that supports HTTP, GraphQL, gRPC, WebSocket, MQTT, SSE, and SOAP from a single CLI tool. It enables AI agents to create mocks, manage state, import specs, and verify contracts through 18 built-in MCP tools, integrating seamlessly with Claude Desktop, Cursor, and other MCP-compatible editors.

mockd is a single-binary mock server supporting seven protocols with zero dependencies. It lets you create stateful CRUD APIs, import OpenAPI/Postman/HAR specs, inject chaos and circuit breakers, record real traffic, and manage isolated workspaces. The built-in MCP server allows AI agents to automate mock creation and management without CLI interaction.

How to install mockd

Copy-paste configuration for popular MCP clients.

transport: stdio
Config generated by PluginBench — verify against the source before use.
~/Library/Application Support/Claude/claude_desktop_config.json
{
  "mcpServers": {
    "mockd": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "ghcr.io/getmockd/mockd",
        "mcp"
      ]
    }
  }
}

Tools & capabilities

Tools this server exposes to the agent.

  • Mock CRUD operations — Create, read, update, and delete mock endpoints and rules
  • Stateful resource management — Manage stateful tables and CRUD operations with seed data
  • Chaos injection — Apply chaos profiles, latency, errors, and circuit breakers
  • Request logging and verification — View and verify request logs and contract compliance
  • Import/export — Import OpenAPI, Postman, HAR, WireMock, WSDL, and cURL; export to multiple formats
  • Workspace management — Create and manage isolated mock environments
  • Protocol configuration — Configure HTTP, gRPC, GraphQL, WebSocket, MQTT, SSE, and SOAP endpoints

Use cases

  • Build a stateful digital twin of a real API (e.g., Stripe, Twilio) that passes real SDK tests
  • Rapidly prototype and test microservices across multiple protocols without backend implementation
  • Inject chaos and latency to test client resilience and error handling
  • Record real API traffic via proxy and replay as mocks for offline development
  • Share local mock environments with team members via cloud tunnel for collaborative testing

mockd MCP server FAQ

What is the mockd MCP server?

mockd is an MCP server that exposes 18 tools for creating and managing mocks across seven protocols (HTTP, GraphQL, gRPC, WebSocket, MQTT, SSE, SOAP). AI agents can use it to create mocks, manage state, import specs, and verify contracts without touching the CLI.

Is mockd free?

Yes. mockd is free and open-source under the Apache License 2.0, with unlimited requests and mock rules. A paid cloud tier for team collaboration is coming soon.

How do I install mockd in Cursor or Claude?

Add mockd to your MCP configuration: {"mcpServers": {"mockd": {"command": "mockd", "args": ["mcp"]}}}. It works in Claude Desktop, Cursor, Windsurf, and any MCP-compatible editor.

Does mockd require authentication or external services?

No. mockd works fully offline with no account required. It runs as a single binary with zero dependencies. Cloud features (persistent mocks, team management) are optional and coming soon.

Can I import existing API specs?

Yes. mockd supports OpenAPI 3.x/Swagger 2.0, Postman collections, HAR files, WireMock mappings, WSDL, and cURL commands. Use `mockd import <spec>` or the MCP tools to import.

What protocols does mockd support?

mockd supports HTTP/HTTPS, gRPC, GraphQL, WebSocket, MQTT, SSE, and SOAP—all from a single binary and unified CLI.

README (reference)

Source of truth, from the repository.

<p align="center"> <a href="https://mockd.io"><img src="https://mockd.io/getmockd.svg" alt="mockd" width="200"></a> </p> <h3 align="center">One binary. Seven protocols. Zero dependencies.</h3> <p align="center"> Mock HTTP, gRPC, GraphQL, WebSocket, MQTT, SSE, and SOAP from a single CLI tool.<br> Import OpenAPI specs. Build digital twins. Let AI agents create mocks for you. </p> <p align="center"> <a href="https://github.com/getmockd/mockd/actions/workflows/ci.yaml"><img src="https://github.com/getmockd/mockd/actions/workflows/ci.yaml/badge.svg" alt="CI"></a> <a href="https://github.com/getmockd/mockd/releases"><img src="https://img.shields.io/github/v/release/getmockd/mockd?include_prereleases" alt="Release"></a> <a href="https://github.com/getmockd/mockd/stargazers"><img src="https://img.shields.io/github/stars/getmockd/mockd?style=social" alt="Stars"></a> <a href="https://go.dev"><img src="https://img.shields.io/badge/Go-1.25+-00ADD8?logo=go" alt="Go"></a> <a href="LICENSE"><img src="https://img.shields.io/badge/License-Apache%202.0-blue.svg" alt="License"></a> </p> <p align="center"> <a href="https://mockd.io">Website</a> &middot; <a href="https://docs.mockd.io">Docs</a> &middot; <a href="https://github.com/getmockd/mockd-samples">Samples</a> &middot; <a href="https://github.com/getmockd/mockd/blob/main/CONTRIBUTING.md">Contributing</a> </p> <p align="center"> <img src=".github/assets/demo.gif" alt="mockd demo" width="800"> </p>

Quick Start

# Install
curl -sSL https://get.mockd.io | sh

# Start + create a stateful CRUD API in one command
mockd start
mockd add http --path /api/users --stateful users

# It works immediately
curl -X POST localhost:4280/api/users -d '{"name":"Alice","email":"alice@test.com"}'
# → {"id":"a1b2c3","name":"Alice","email":"alice@test.com"}

curl localhost:4280/api/users
# → {"data":[{"id":"a1b2c3","name":"Alice","email":"alice@test.com"}],"meta":{"total":1}}
<details> <summary><strong>More install options</strong></summary>
brew install getmockd/tap/mockd                                          # Homebrew
docker run -p 4280:4280 -p 4290:4290 ghcr.io/getmockd/mockd:latest      # Docker
go install github.com/getmockd/mockd/cmd/mockd@latest                    # Go

Pre-built binaries for Linux, macOS, and Windows on the Releases page.

</details>

Why mockd?

Every other mock tool makes you choose: pick one protocol, install a runtime, bolt on extensions. mockd doesn't.

mockdWireMockMockoonPrismMockServerBeeceptorjson-server
Single binary, no runtime✅❌ JVM❌ Electron✅❌ JVM❌ SaaS❌ Node
All 9 protocols built-in✅🔌 ExtPartialHTTP onlyHTTP onlyPartialREST only
Chaos profiles + circuit breakers✅⚠️ Cloud❌❌❌❌❌
MCP server✅ local⚠️ Cloud❌❌❌⚠️ Cloud, Team+❌
Free + self-hostable, unlimited✅✅✅✅✅50 req/day✅

🔌 Ext = requires separate extension JAR • ⚠️ Cloud = only in paid/hosted tier

<details> <summary><strong>Full capability matrix</strong> (deployment, protocols, capabilities, imports/exports, pricing)</summary>

Deployment

mockdWireMockMockoonPrismMockServerBeeceptorjson-server
Native single binary✅ Go❌❌✅❌❌❌
Runtime requirednoneJVMElectron/Nodeoptional NodeJVMn/a (SaaS)Node
Docker image✅✅✅ CLI✅✅⚠️ Enterprise❌
Managed SaaS offeringroadmapWireMock CloudMockoon CloudStoplight❌✅❌

Protocol support

mockdWireMock OSSMockoonPrismMockServerBeeceptorjson-server
REST / HTTP✅✅✅✅✅✅✅
gRPC✅🔌 Ext❌❌❌✅❌
GraphQL✅🔌 Ext❌❌❌✅❌
WebSocket✅🔌 Ext (beta)✅❌❌❌❌
MQTT✅❌❌❌❌❌❌
SSE✅❌❌❌❌❌❌
SOAP (WSDL)✅❌Partial❌Partial✅❌
mTLS✅✅Partial❌✅✅❌
OAuth flows✅❌❌❌❌❌❌

Capabilities

mockdWireMock OSSMockoonPrismMockServerBeeceptorjson-server
Stateful CRUD✅❌✅Partial❌✅✅
Multi-step stateful flows✅✅ ScenariosPartial❌Partial✅❌
Fault injection (delay, errors)✅✅✅❌✅✅❌
Chaos profiles✅⚠️ Cloud❌❌❌❌❌
Circuit breakers✅⚠️ Cloud❌❌❌❌❌
Bandwidth throttling✅❌❌❌❌roadmap❌
Admin REST API✅✅CLI only❌✅✅Partial
Built-in web dashboard✅⚠️ Cloud⚠️ Cloud❌✅ read-only✅❌
Native desktop GUI❌❌✅ Electron❌❌❌❌
MCP server✅ local⚠️ Cloud❌❌❌⚠️ Cloud Team+❌
Cloud tunnel sharing✅❌⚠️ Cloud❌❌✅❌

Import / export

mockdWireMock OSSMockoonPrismMockServerBeeceptorjson-server
OpenAPI import✅⚠️ Cloud✅✅✅✅❌
Postman import✅⚠️ Cloud❌✅❌❌❌
HAR import✅❌❌❌❌❌❌
WSDL import✅❌❌❌❌✅❌
cURL import✅❌❌❌❌❌❌
WireMock format import✅native❌❌❌❌❌
Mockoon format import✅❌native❌❌❌❌
HAR export✅✅❌❌✅✅❌

Free tier limits

RequestsMock rulesCost
mockdunlimitedunlimitedfree (Apache 2.0)
WireMock OSSunlimitedunlimitedfree (Apache 2.0)
Mockoon desktop / CLIunlimitedunlimitedfree (MIT)
Prismunlimitedunlimitedfree (Apache 2.0)
MockServerunlimitedunlimitedfree (Apache 2.0)
Beeceptor free tier50 / day / endpoint3$10/mo+ for more
json-serverunlimitedunlimitedfree (MIT)

Legend: ✅ built-in • 🔌 Ext = separate OSS extension • ⚠️ Cloud = only in paid / hosted tier • Partial = limited implementation • roadmap = on the project's stated roadmap, not yet shipped

Note on WireMock imports. The ⚠️ Cloud marks on OpenAPI and Postman import reflect first-party WireMock features. Community converters exist (e.g. openapi-to-wiremock, OpenAPI Generator targets) but are not bundled with the OSS standalone JAR.

</details>

Digital Twins

Import a real API spec, bind it to stateful tables, and get a mock that passes the real SDK:

# mockd.yaml — Stripe digital twin
version: "1.0"
imports:
  - path: stripe-openapi.yaml
    as: stripe
tables:
  - name: customers
    idStrategy: prefix
    idPrefix: "cus_"
    seedData:
      - { id: "cus_1", name: "Acme Corp", email: "billing@acme.com" }
extend:
  - { mock: stripe.GetCustomers, table: customers, action: list }
  - { mock: stripe.PostCustomers, table: customers, action: create }
  - { mock: stripe.GetCustomersCustomer, table: customers, action: get }
  - { mock: stripe.PostCustomersCustomer, table: customers, action: update }
  - { mock: stripe.DeleteCustomersCustomer, table: customers, action: delete }
mockd start -c mockd.yaml --no-auth
curl -X POST localhost:4280/v1/customers -d "name=Test&email=test@corp.com"
# → {"id":"cus_a1b2c3","object":"customer","name":"Test","email":"test@corp.com"}

Validated with real SDKs:

  • Stripe: 49/49 stripe-go SDK tests pass
  • Twilio: 13/13 twilio-go SDK tests pass
  • OpenAI: openai Python SDK verified (models, assistants, chat completions)

See mockd-samples for complete digital twin configs.

AI-Native (MCP)

mockd includes a built-in Model Context Protocol server with 18 tools. AI agents can create mocks, manage state, import specs, and verify contracts without touching the CLI:

{
  "mcpServers": {
    "mockd": { "command": "mockd", "args": ["mcp"] }
  }
}

Works in Claude Desktop, Cursor, Windsurf, and any MCP-compatible editor. Tools cover mock CRUD, stateful resources, chaos injection, request logs, verification, workspaces, and import/export.

Features

<details> <summary><strong>Multi-Protocol Mocking</strong> — 7 protocols, unified CLI</summary>
ProtocolPortExample
HTTP/HTTPS4280mockd add http --path /api/hello --body '{"msg":"hi"}'
gRPC50051mockd add grpc --proto svc.proto --service Greeter --rpc-method Greet
GraphQL4280mockd add graphql --path /graphql --operation hello
WebSocket4280mockd add websocket --path /ws --echo
MQTT1883mockd add mqtt --topic sensors/temp --payload '{"temp":72}'
SSE4280mockd add http --path /events --sse --sse-event 'data: hello'
SOAP4280mockd add soap --path /soap --operation GetWeather --response '<OK/>'
</details> <details> <summary><strong>Import & Export</strong> — OpenAPI, Postman, HAR, WireMock, cURL, WSDL</summary>
mockd import openapi.yaml           # OpenAPI 3.x / Swagger 2.0
mockd import collection.json        # Postman collections
mockd import recording.har          # HAR files
mockd import wiremock-mapping.json  # WireMock stubs
mockd import service.wsdl           # WSDL → SOAP mocks
mockd import "curl -X GET https://api.example.com/users"  # cURL commands
mockd export --format yaml > mocks.yaml
</details> <details> <summary><strong>Chaos Engineering</strong> — latency, errors, circuit breakers</summary>
mockd chaos apply flaky       # 30% error rate
mockd chaos apply slow-api    # 200-800ms latency
mockd chaos apply offline     # 100% 503 errors
mockd chaos disable
</details> <details> <summary><strong>Cloud Tunnel</strong> — share local mocks instantly</summary>
mockd tunnel
# → https://a1b2c3d4.tunnel.mockd.io → http://localhost:4280

All 7 protocols multiplexed through a single secure connection on port 443. Works behind NAT and firewalls.

</details> <details> <summary><strong>Workspaces</strong> — isolated mock environments</summary>
mockd workspace create -n "Payment API" --use
mockd import stripe-openapi.yaml
mockd workspace create -n "Comms API" --use
mockd import twilio-openapi.yaml
# Mocks, state, and logs are fully isolated per workspace
</details> <details> <summary><strong>Proxy Recording</strong> — record real traffic, replay as mocks</summary>
mockd proxy start --port 8888
# Configure your app to use http://localhost:8888 as proxy
# Traffic is recorded, then replay with:
mockd import recordings/session.json
</details> <details> <summary><strong>Web Dashboard</strong> — manage mocks visually</summary>

Release builds serve a web UI from the admin port (http://localhost:4290). VS Code-style editor, command palette, mock tree with folders, request log viewer, and near-miss debugging.

</details>

Mockd Cloud

mockd works fully offline with no account required. For teams that want shared environments:

  • Persistent cloud mocks — deploy mock environments your whole team can hit
  • Team management — shared workspaces with access controls
  • Cloud tunnels — authenticated tunnels with custom domains

Coming soon. Join the waitlist.

Documentation

Full guides, API reference, and config docs at docs.mockd.io.

Contributing

Contributions welcome! See CONTRIBUTING.md for setup.

License

Apache License 2.0 — free for commercial use.

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