mockd

Multi-protocol API mock server with 18 MCP tools — mock HTTP, GraphQL, gRPC, WebSocket, MQTT, SSE, and SOAP APIs with chaos engineering, stateful CRUD, and deterministic seeded responses.

GitHub

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

mockd demo

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}}

More install options

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.

Why mockd?

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

	mockd	WireMock	Mockoon	Prism	MockServer	Beeceptor	json-server
Single binary, no runtime	✅	❌ JVM	❌ Electron	✅	❌ JVM	❌ SaaS	❌ Node
All 9 protocols built-in	✅	🔌 Ext	Partial	HTTP only	HTTP only	Partial	REST 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

Full capability matrix (deployment, protocols, capabilities, imports/exports, pricing)

Deployment

	mockd	WireMock	Mockoon	Prism	MockServer	Beeceptor	json-server
Native single binary	✅ Go	❌	❌	✅	❌	❌	❌
Runtime required	none	JVM	Electron/Node	optional Node	JVM	n/a (SaaS)	Node
Docker image	✅	✅	✅ CLI	✅	✅	⚠️ Enterprise	❌
Managed SaaS offering	roadmap	WireMock Cloud	Mockoon Cloud	Stoplight	❌	✅	❌

Protocol support

	mockd	WireMock OSS	Mockoon	Prism	MockServer	Beeceptor	json-server
REST / HTTP	✅	✅	✅	✅	✅	✅	✅
gRPC	✅	🔌 Ext	❌	❌	❌	✅	❌
GraphQL	✅	🔌 Ext	❌	❌	❌	✅	❌
WebSocket	✅	🔌 Ext (beta)	✅	❌	❌	❌	❌
MQTT	✅	❌	❌	❌	❌	❌	❌
SSE	✅	❌	❌	❌	❌	❌	❌
SOAP (WSDL)	✅	❌	Partial	❌	Partial	✅	❌
mTLS	✅	✅	Partial	❌	✅	✅	❌
OAuth flows	✅	❌	❌	❌	❌	❌	❌

Capabilities

	mockd	WireMock OSS	Mockoon	Prism	MockServer	Beeceptor	json-server
Stateful CRUD	✅	❌	✅	Partial	❌	✅	✅
Multi-step stateful flows	✅	✅ Scenarios	Partial	❌	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

	mockd	WireMock OSS	Mockoon	Prism	MockServer	Beeceptor	json-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

	Requests	Mock rules	Cost
mockd	unlimited	unlimited	free (Apache 2.0)
WireMock OSS	unlimited	unlimited	free (Apache 2.0)
Mockoon desktop / CLI	unlimited	unlimited	free (MIT)
Prism	unlimited	unlimited	free (Apache 2.0)
MockServer	unlimited	unlimited	free (Apache 2.0)
Beeceptor free tier	50 / day / endpoint	3	$10/mo+ for more
json-server	unlimited	unlimited	free (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.

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

Multi-Protocol Mocking — 7 protocols, unified CLI

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/>'`

Import & Export — OpenAPI, Postman, HAR, WireMock, cURL, WSDL

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

Chaos Engineering — latency, errors, circuit breakers

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

Cloud Tunnel — share local mocks instantly

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.

Workspaces — isolated mock environments

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

Proxy Recording — record real traffic, replay as mocks

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

Web Dashboard — manage mocks visually

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 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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