diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..9d67558
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/manuals/
diff --git a/README.md b/README.md
index 3cabd35..de238b0 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,17 @@
 # slmm
-Dashboard for talking to RION SLM
+Standalone NL43 addon module (keep separate from the SFM/terra-view codebase).
+
+Run the addon API:
+```bash
+pip install -r requirements.txt
+uvicorn app.main:app --reload --port 8100
+```
+
+Endpoints:
+- `GET /health`
+- `GET /api/nl43/{unit_id}/config`
+- `PUT /api/nl43/{unit_id}/config`
+- `GET /api/nl43/{unit_id}/status`
+- `POST /api/nl43/{unit_id}/status`
+
+Use `app/services.py` to wire in the TCP connector and call `persist_snapshot` with parsed DOD/DRD data.
diff --git a/app/__init__.py b/app/__init__.py
new file mode 100644
index 0000000..147ff99
--- /dev/null
+++ b/app/__init__.py
@@ -0,0 +1 @@
+# SLMM addon package for NL43 integration.
diff --git a/app/database.py b/app/database.py
new file mode 100644
index 0000000..91c5630
--- /dev/null
+++ b/app/database.py
@@ -0,0 +1,27 @@
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+import os
+
+# Ensure data directory exists for the SLMM addon
+os.makedirs("data", exist_ok=True)
+
+SQLALCHEMY_DATABASE_URL = "sqlite:///./data/slmm.db"
+
+engine = create_engine(SQLALCHEMY_DATABASE_URL, connect_args={"check_same_thread": False})
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+Base = declarative_base()
+
+
+def get_db():
+    """Dependency for database sessions."""
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+
+
+def get_db_session():
+    """Get a database session directly (not as a dependency)."""
+    return SessionLocal()
diff --git a/app/main.py b/app/main.py
new file mode 100644
index 0000000..8e0c92e
--- /dev/null
+++ b/app/main.py
@@ -0,0 +1,36 @@
+import os
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from app.database import Base, engine
+from app import routers
+
+# Ensure database tables exist for the addon
+Base.metadata.create_all(bind=engine)
+
+app = FastAPI(
+    title="SLMM NL43 Addon",
+    description="Standalone module for NL43 configuration and status APIs",
+    version="0.1.0",
+)
+
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+app.include_router(routers.router)
+
+
+@app.get("/health")
+def health():
+    return {"status": "ok"}
+
+
+if __name__ == "__main__":
+    import uvicorn
+
+    uvicorn.run("app.main:app", host="0.0.0.0", port=int(os.getenv("PORT", "8100")), reload=True)
diff --git a/app/models.py b/app/models.py
new file mode 100644
index 0000000..5c9d52d
--- /dev/null
+++ b/app/models.py
@@ -0,0 +1,39 @@
+from sqlalchemy import Column, String, DateTime, Boolean, Integer, Text
+from datetime import datetime
+from app.database import Base
+
+
+class NL43Config(Base):
+    """
+    NL43 connection/config metadata for the standalone SLMM addon.
+    """
+
+    __tablename__ = "nl43_config"
+
+    unit_id = Column(String, primary_key=True, index=True)
+    tcp_port = Column(Integer, default=80)  # NL43 TCP control port (via RX55)
+    tcp_enabled = Column(Boolean, default=True)
+    ftp_enabled = Column(Boolean, default=False)
+    web_enabled = Column(Boolean, default=False)
+
+
+class NL43Status(Base):
+    """
+    Latest NL43 status snapshot for quick dashboard/API access.
+    """
+
+    __tablename__ = "nl43_status"
+
+    unit_id = Column(String, primary_key=True, index=True)
+    last_seen = Column(DateTime, default=datetime.utcnow)
+    measurement_state = Column(String, default="unknown")  # Measure/Stop
+    lp = Column(String, nullable=True)
+    leq = Column(String, nullable=True)
+    lmax = Column(String, nullable=True)
+    lmin = Column(String, nullable=True)
+    lpeak = Column(String, nullable=True)
+    battery_level = Column(String, nullable=True)
+    power_source = Column(String, nullable=True)
+    sd_remaining_mb = Column(String, nullable=True)
+    sd_free_ratio = Column(String, nullable=True)
+    raw_payload = Column(Text, nullable=True)
diff --git a/app/routers.py b/app/routers.py
new file mode 100644
index 0000000..612920a
--- /dev/null
+++ b/app/routers.py
@@ -0,0 +1,124 @@
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy.orm import Session
+from datetime import datetime
+from pydantic import BaseModel
+
+from app.database import get_db
+from app.models import NL43Config, NL43Status
+
+router = APIRouter(prefix="/api/nl43", tags=["nl43"])
+
+
+class ConfigPayload(BaseModel):
+    tcp_port: int | None = None
+    tcp_enabled: bool | None = None
+    ftp_enabled: bool | None = None
+    web_enabled: bool | None = None
+
+
+@router.get("/{unit_id}/config")
+def get_config(unit_id: str, db: Session = Depends(get_db)):
+    cfg = db.query(NL43Config).filter_by(unit_id=unit_id).first()
+    if not cfg:
+        raise HTTPException(status_code=404, detail="NL43 config not found")
+    return {
+        "unit_id": unit_id,
+        "tcp_port": cfg.tcp_port,
+        "tcp_enabled": cfg.tcp_enabled,
+        "ftp_enabled": cfg.ftp_enabled,
+        "web_enabled": cfg.web_enabled,
+    }
+
+
+@router.put("/{unit_id}/config")
+def upsert_config(unit_id: str, payload: ConfigPayload, db: Session = Depends(get_db)):
+    cfg = db.query(NL43Config).filter_by(unit_id=unit_id).first()
+    if not cfg:
+        cfg = NL43Config(unit_id=unit_id)
+        db.add(cfg)
+
+    if payload.tcp_port is not None:
+        cfg.tcp_port = payload.tcp_port
+    if payload.tcp_enabled is not None:
+        cfg.tcp_enabled = payload.tcp_enabled
+    if payload.ftp_enabled is not None:
+        cfg.ftp_enabled = payload.ftp_enabled
+    if payload.web_enabled is not None:
+        cfg.web_enabled = payload.web_enabled
+
+    db.commit()
+    db.refresh(cfg)
+    return {
+        "unit_id": unit_id,
+        "tcp_port": cfg.tcp_port,
+        "tcp_enabled": cfg.tcp_enabled,
+        "ftp_enabled": cfg.ftp_enabled,
+        "web_enabled": cfg.web_enabled,
+    }
+
+
+@router.get("/{unit_id}/status")
+def get_status(unit_id: str, db: Session = Depends(get_db)):
+    status = db.query(NL43Status).filter_by(unit_id=unit_id).first()
+    if not status:
+        raise HTTPException(status_code=404, detail="No NL43 status recorded")
+    return {
+        "unit_id": unit_id,
+        "last_seen": status.last_seen.isoformat() if status.last_seen else None,
+        "measurement_state": status.measurement_state,
+        "lp": status.lp,
+        "leq": status.leq,
+        "lmax": status.lmax,
+        "lmin": status.lmin,
+        "lpeak": status.lpeak,
+        "battery_level": status.battery_level,
+        "power_source": status.power_source,
+        "sd_remaining_mb": status.sd_remaining_mb,
+        "sd_free_ratio": status.sd_free_ratio,
+        "raw_payload": status.raw_payload,
+    }
+
+
+class StatusPayload(BaseModel):
+    measurement_state: str | None = None
+    lp: str | None = None
+    leq: str | None = None
+    lmax: str | None = None
+    lmin: str | None = None
+    lpeak: str | None = None
+    battery_level: str | None = None
+    power_source: str | None = None
+    sd_remaining_mb: str | None = None
+    sd_free_ratio: str | None = None
+    raw_payload: str | None = None
+
+
+@router.post("/{unit_id}/status")
+def upsert_status(unit_id: str, payload: StatusPayload, db: Session = Depends(get_db)):
+    status = db.query(NL43Status).filter_by(unit_id=unit_id).first()
+    if not status:
+        status = NL43Status(unit_id=unit_id)
+        db.add(status)
+
+    status.last_seen = datetime.utcnow()
+    for field, value in payload.dict().items():
+        if value is not None:
+            setattr(status, field, value)
+
+    db.commit()
+    db.refresh(status)
+    return {
+        "unit_id": unit_id,
+        "last_seen": status.last_seen.isoformat(),
+        "measurement_state": status.measurement_state,
+        "lp": status.lp,
+        "leq": status.leq,
+        "lmax": status.lmax,
+        "lmin": status.lmin,
+        "lpeak": status.lpeak,
+        "battery_level": status.battery_level,
+        "power_source": status.power_source,
+        "sd_remaining_mb": status.sd_remaining_mb,
+        "sd_free_ratio": status.sd_free_ratio,
+        "raw_payload": status.raw_payload,
+    }
diff --git a/app/services.py b/app/services.py
new file mode 100644
index 0000000..dcb8fa1
--- /dev/null
+++ b/app/services.py
@@ -0,0 +1,55 @@
+"""
+Placeholder for NL43 TCP connector.
+Implement TCP session management, command serialization, and DOD/DRD parsing here,
+then call persist_snapshot to store the latest values.
+"""
+
+from dataclasses import dataclass
+from datetime import datetime
+from typing import Optional
+
+from app.database import get_db_session
+from app.models import NL43Status
+
+
+@dataclass
+class NL43Snapshot:
+    unit_id: str
+    measurement_state: str = "unknown"
+    lp: Optional[str] = None
+    leq: Optional[str] = None
+    lmax: Optional[str] = None
+    lmin: Optional[str] = None
+    lpeak: Optional[str] = None
+    battery_level: Optional[str] = None
+    power_source: Optional[str] = None
+    sd_remaining_mb: Optional[str] = None
+    sd_free_ratio: Optional[str] = None
+    raw_payload: Optional[str] = None
+
+
+def persist_snapshot(s: NL43Snapshot):
+    """Persist the latest snapshot for API/dashboard use."""
+    db = get_db_session()
+    try:
+        row = db.query(NL43Status).filter_by(unit_id=s.unit_id).first()
+        if not row:
+            row = NL43Status(unit_id=s.unit_id)
+            db.add(row)
+
+        row.last_seen = datetime.utcnow()
+        row.measurement_state = s.measurement_state
+        row.lp = s.lp
+        row.leq = s.leq
+        row.lmax = s.lmax
+        row.lmin = s.lmin
+        row.lpeak = s.lpeak
+        row.battery_level = s.battery_level
+        row.power_source = s.power_source
+        row.sd_remaining_mb = s.sd_remaining_mb
+        row.sd_free_ratio = s.sd_free_ratio
+        row.raw_payload = s.raw_payload
+
+        db.commit()
+    finally:
+        db.close()
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..0a4249c
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,4 @@
+fastapi
+uvicorn
+sqlalchemy
+pydantic