Lnd Emulator Utility Work May 2026

The emulator is built to satisfy three primary use cases:

Unlike a real LND node, simple emulators are often stateless. A payment that settles should update the channel balance. If your emulator doesn't track balance, you won't catch "insufficient local balance" errors. Solution: Use a stateful emulator like Polar, which maintains a simulated ledger. lnd emulator utility work

invoices = {} balance_sat = 100_000_000

class InvoiceRequest(BaseModel): value_msat: int memo: str = "" The emulator is built to satisfy three primary use cases:

@app.post("/v1/invoices") def add_invoice(req: InvoiceRequest): payment_hash = hashlib.sha256(f"time.time()".encode()).hexdigest() invoices[payment_hash] = "amount_msat": req.value_msat, "paid": False return "payment_request": f"lnbc_payment_hash[:10]...", "r_hash": payment_hash Unlike a real LND node, simple emulators are often stateless

@app.post("/v1/channels/transactions") def send_payment(payment_request: str): global balance_sat # Fake parse invoice (simplified) if "lnbc_" not in payment_request: raise HTTPException(400, "invalid invoice") amount = 10_000 # sats if balance_sat < amount: raise HTTPException(402, "insufficient balance") balance_sat -= amount return "payment_error": "", "payment_preimage": "fake" * 8

Run with: uvicorn lnd_emulator:app --reload