VERSION 1.0.0

API & Operations

NexGen GSM is a private cellular edge gateway. Every data or control API requires a secure session or scoped bearer key; only dependency health is public.

Architecture

PL2303 serial → serialized AT engine → SIM900 driver
              → GSM service → SQLite/WAL → REST + SSE → Web UI

The daemon dynamically verifies ATI before accepting a serial candidate. Optional firmware commands may return unsupported without failing initialization. USB voice audio is not available.

Authentication

Create a minimal key under Settings. Send it as Authorization: Bearer $NEXGEN_GSM_API_KEY. Keys are shown once and stored as keyed hashes.

Send an SMS

curl -X POST https://gsm.nexgenhome.in/api/v1/messages \
  -H "Authorization: Bearer $NEXGEN_GSM_API_KEY" \
  -H "Idempotency-Key: server-temp-001" \
  -H "Content-Type: application/json" \
  -d '{"to":"+91xxxxxxxxxx","message":"Server temperature warning","source":"nexgenhome"}'

A request is accepted only when the modem is registered. The quota increments only after a positive +CMGS. Retries must reuse the same idempotency key.

Automation alerts

POST /api/v1/alerts resolves configured:owner-style aliases, applies cooldown and state deduplication, then performs separate controlled sends.

C# / Python / JavaScript

// C# HttpClient
using var req = new HttpRequestMessage(HttpMethod.Post, baseUrl + "/api/v1/alerts");
req.Headers.Authorization = new("Bearer", apiKey);
req.Headers.Add("Idempotency-Key", "office-temp-critical-20260907");
req.Content = JsonContent.Create(new { severity="critical", title="Server Temperature",
  message="Office server exhaust reached 45°C", recipients=new[]{"configured:owner"},
  source="nexgenhome", dedupe_key="office-server-temp-critical" });
var response = await client.SendAsync(req);
response.EnsureSuccessStatusCode();

# Python
httpx.post(base + "/api/v1/alerts", headers={"Authorization": "Bearer " + key,
 "Idempotency-Key": "alarm-001"}, json=payload, timeout=30).raise_for_status()

// JavaScript
await fetch(base + "/api/v1/alerts", {method:"POST", headers:{
  Authorization:"Bearer " + key, "Idempotency-Key":"alarm-001",
  "Content-Type":"application/json"}, body:JSON.stringify(payload)});

Hardware & operations

The stable link is /dev/nexgen-gsm, created from the verified PL2303 attributes. The service starts without hardware and reconnects with bounded exponential backoff. See the repository documentation for udev, backup/restore, upgrades, troubleshooting, AT reference, SSE, webhooks, and Home Assistant examples.

Interactive OpenAPI reference ↗ · OpenAPI JSON ↗