Polaris HTTP API Reference
NORTHSTAR SHOW SYSTEMS
Polaris HTTP API Reference
Frozen interface contract for all Polaris field nodes
v1.0 — May 2026
Polaris HTTP API Reference
Every Polaris field node (A, V, G, X variants) runs an HTTP server on port 80. All responses are JSON with Access-Control-Allow-Origin: *. This document defines every endpoint, its parameters, and its response shape.
Network context
Polaris nodes connect to the TrueNorth Wi-Fi network (SSID: TRUENORTH, subnet 10.0.0.0/24). Nodes receive DHCP addresses starting at 10.0.0.10. The Helm server at 10.0.0.1 is the only client that issues requests to Polaris nodes under normal operation.
Endpoints
GET /trigger?ch=N
Fires a single channel on the node. The ch parameter must be a valid channel number configured on this node.
| Parameter | Type | Description |
|---|---|---|
| ch | Integer or "all" | Channel number (1-based) or the literal string "all" to fire every channel |
Success response (200): {"ok":true,"ch":N}Error response (400):Returned when ch is missing, non-numeric, or references a channel that does not exist on this node.
GET /trigger?ch=all
Fires every configured channel on the node simultaneously. Response: {"ok":true,"ch":"all"}
GET /status
Returns the node’s current operational status. HelmOS polls this endpoint every 5 seconds for liveness monitoring.
| Field | Type | Description |
|---|---|---|
| online | Boolean | Always true when the node responds |
| node | String | Node name as configured in nodes.json |
| ip | String | Node’s current IP address on TrueNorth |
| rssi | Integer | Wi-Fi signal strength in dBm (typical range: -30 to -90) |
| uptime | Integer | Seconds since last boot |
Example response: {"online":true,"node":"Lobby-Audio-1","ip":"10.0.0.12","rssi":-54,"uptime":3621}GET /info
Returns full identity and per-channel configuration detail for the node. Used by Compose (the show designer) during node discovery and by HelmOS at startup for validation.
Client behavior (HelmOS side)
HelmOS enforces the following when making requests to Polaris nodes:
- Request timeout:2 seconds
- Retry policy:One retry on transient errors (timeout, ECONNRESET, ECONNREFUSED) with a 200 ms backoff delay
- Concurrency cap:2 simultaneous requests per IP address. Additional requests queue until a slot opens.
A failed request (after retry) does not abort a running sequence. The error is logged and the sequence continues with subsequent steps.
CORS
All Polaris endpoints return Access-Control-Allow-Origin: *. This allows direct browser-based tools (such as Compose) to communicate with nodes for discovery and testing.
Versioning
This API has no version prefix. The contract is frozen — changes require coordination across NorthLink firmware, HelmOS, and Compose.