iot-core (parlel)

A zero-dependency, in-process fake of AWS IoT Core. Covers the control-plane Thing registry and the device-shadow REST surface.

Field	Value
Service	`iot-core`
Port	`4743`
Protocol	REST / JSON
Health	`GET /_parlel/health`
Reset	`POST /_parlel/reset`

Default connection

AWS_ENDPOINT_URL=http://127.0.0.1:4743
AWS_REGION=us-east-1
AWS_ACCESS_KEY_ID=parlel
AWS_SECRET_ACCESS_KEY=parlel

Supported operations

Operation	HTTP
CreateThing	`POST /things/{name}`
ListThings	`GET /things`
DescribeThing	`GET /things/{name}`
UpdateThing	`PATCH /things/{name}`
DeleteThing	`DELETE /things/{name}`
GetThingShadow	`GET /things/{name}/shadow[?name={shadowName}]`
UpdateThingShadow	`POST /things/{name}/shadow[?name={shadowName}]`
DeleteThingShadow	`DELETE /things/{name}/shadow[?name={shadowName}]`

Shadows track desired/reported state and compute the delta (keys whose desired value differs from reported). Each update bumps the shadow version. Named shadows are supported via the name query parameter; the default shadow is $default.

MQTT over WebSocket

MQTT (incl. MQTT-over-WebSocket on wss://<endpoint>/mqtt) is not implemented in this fake. Only the HTTPS control plane and the shadow REST surface are emulated. For pub/sub message flows, point your code at the parlel rabbitmq or sns/sqs fakes instead.

SDK example

import { IoTClient, CreateThingCommand } from "@aws-sdk/client-iot";

const iot = new IoTClient({
  endpoint: "http://127.0.0.1:4743",
  region: "us-east-1",
  credentials: { accessKeyId: "parlel", secretAccessKey: "parlel" },
});

await iot.send(new CreateThingCommand({
  thingName: "sensor-1",
  attributePayload: { attributes: { room: "kitchen" } },
}));

For shadows, use the IoT Data Plane client (@aws-sdk/client-iot-data-plane) pointed at the same endpoint.

Access via MCP / preview URL

Under the parlel pool, reach this service through the MCP gateway and the pool's preview URL.

Surface coverage

This emulator faithfully replicates the API surface most application code and agents exercise. Anything below the supported lines is either an intentional design choice for a fast, zero-cost local emulator (✓ By design) or a candidate for a future release (⟳ Roadmap) — never a silent inaccuracy.

Legend: ✅ fully supported · ◐ accepted (stored, not strictly enforced) · ✓ by design · ⟳ on the roadmap.

Area	Limitation
MQTT	No MQTT broker / WebSocket transport.
Certificates / policies	Not implemented.
Thing types / groups	`thingTypeName` is stored but not validated.
Rules engine	Not implemented.
Jobs / fleet provisioning	Not implemented.

Configuration — `test.env`

Copy these into your test.env (used by the bridge sidecar flow). Tokens are Parlel's seeded test credentials — any non-empty value is accepted by the emulator, so you rarely need to change them. Swap in real credentials only when pointing at the live service in prod.env.

AWS_ACCESS_KEY_ID=parlel
AWS_SECRET_ACCESS_KEY=parlel
AWS_REGION=us-east-1
AWS_ENDPOINT_URL=http://parlel-bridge:4743