mockd

One binary. Seven protocols. Zero dependencies.

Mock HTTP, gRPC, GraphQL, WebSocket, MQTT, SSE, and SOAP from a single CLI tool.
Import OpenAPI specs. Build digital twins. Let AI agents create mocks for you.

Website · Docs · Samples · Contributing

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":"[email protected]"}'
# → {"id":"a1b2c3","name":"Alice","email":"[email protected]"}

curl localhost:4280/api/users
# → {"data":[{"id":"a1b2c3","name":"Alice","email":"[email protected]"}],"meta":{"total":1}}

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

Why mockd?

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

🔌 Ext = available via separate extension, not bundled. mockd includes everything in a single binary.

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: "[email protected]" }
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 protected]"
# → {"id":"cus_a1b2c3","object":"customer","name":"Test","email":"[email protected]"}

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

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

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

mockd tunnel
# → https://a1b2c3d4.tunnel.mockd.io → http://localhost:4280

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

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

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.