Multi-protocol API mock server: HTTP, GraphQL, gRPC, WebSocket, MQTT, SSE, SOAP.
# 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}}
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.
Every other mock tool makes you choose: pick one protocol, install a runtime, bolt on extensions. mockd doesn't.
| mockd | WireMock | Mockoon | json-server | Prism | MockServer | |
|---|---|---|---|---|---|---|
| Single binary, no runtime | :white_check_mark: | :x: JVM | :x: Node | :x: Node | :x: Node | :x: JVM |
| HTTP + gRPC + GraphQL + WS | :white_check_mark: | 🔌 Ext | :x: | :x: | :x: | Partial |
| MQTT + SSE + SOAP + OAuth | :white_check_mark: | :x: | :x: | :x: | :x: | :x: |
| Stateful CRUD | :white_check_mark: | :x: | :white_check_mark: | :white_check_mark: | :x: | :x: |
| Import OpenAPI/Postman/HAR | :white_check_mark: | :white_check_mark: | :white_check_mark: | :x: | :white_check_mark: | :white_check_mark: |
| Chaos engineering | :white_check_mark: | :white_check_mark: | :x: | :x: | :x: | :x: |
| MCP server (AI-native) | :white_check_mark: | :x: | :x: | :x: | :x: | :x: |
| Cloud tunnel sharing | :white_check_mark: | :x: | :white_check_mark: | :x: | :x: | :x: |
| Built-in web dashboard | :white_check_mark: | :x: | :white_check_mark: | :x: | :x: | :x: |
🔌 Ext = available via separate extension, not bundled. mockd includes everything in a single binary.
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-go SDK tests passtwilio-go SDK tests passopenai Python SDK verified (models, assistants, chat completions)See mockd-samples for complete digital twin configs.
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.
| Protocol | Port | Example |
|---|---|---|
| HTTP/HTTPS | 4280 | mockd add http --path /api/hello --body '{"msg":"hi"}' |
| gRPC | 50051 | mockd add grpc --proto svc.proto --service Greeter --rpc-method Greet |
| GraphQL | 4280 | mockd add graphql --path /graphql --operation hello |
| WebSocket | 4280 | mockd add websocket --path /ws --echo |
| MQTT | 1883 | mockd add mqtt --topic sensors/temp --payload '{"temp":72}' |
| SSE | 4280 | mockd add http --path /events --sse --sse-event 'data: hello' |
| SOAP | 4280 | mockd add soap --path /soap --operation GetWeather --response '<OK/>' |
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
All 7 protocols multiplexed through a single secure connection on port 443. Works behind NAT and firewalls.
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
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.
mockd works fully offline with no account required. For teams that want shared environments:
Coming soon. Join the waitlist.
Full guides, API reference, and config docs at mockd.io.
Contributions welcome! See CONTRIBUTING.md for setup.
Apache License 2.0 — free for commercial use.
Source-derived launch command. Check the maintainer’s required arguments and credentials before running:
docker run -i --rm ghcr.io/getmockd/mockdMerge this template into ~/Library/Application Support/Claude/claude_desktop_config.json. Keep existing servers. Add any arguments, credentials, and permissions required by the maintainer; this template has not been install-tested.
{
"mcpServers": {
"io-mockd-mockd": {
"command": "docker",
"args": [
"run",
"-i",
"--rm",
"ghcr.io/getmockd/mockd"
]
}
}
}Restart Claude Desktop completely for changes to take effect. Confirm the server appears connected in the client’s tool list, then try a read-only example from its documentation.
Claude Desktop setup referenceghcr.io/getmockd/mockddockermockd works with any MCP-compatible client. Copy the config snippet from the Configuration section above and add it to the file shown for your client, then restart the application.
~/Library/Application Support/Claude/claude_desktop_config.jsonRestart Claude Desktop completely for changes to take effect.~/.cursor/mcp.jsonRestart Cursor for changes to take effect..vscode/mcp.jsonReload VS Code window for changes to take effect.~/.codeium/windsurf/mcp_config.jsonRestart Windsurf for changes to take effect..mcp.jsonSave at the project root, then start Claude Code in that project and review the MCP server approval prompt. Keep real credentials out of shared files.