lexe-wrapper 1.1.0

Unofficial, open-source Python wrapper for Lexe Bitcoin Lightning Network wallet integration

Lexe Wrapper

A simple Python package for integrating Bitcoin Lightning Network payments using the Lexe wallet. Install with pip and start building Lightning apps in under 30 seconds.

pip install lexe-wrapper

⚠️ Important: This is an unofficial, open-source wrapper around the Lexe Sidecar SDK. It is not officially associated with or endorsed by Lexe. This project is independently developed to help developers integrate with Lexe's Lightning wallet services.

What This Package Solves

The Lexe Sidecar API is already clean and simple, but there are several setup gotchas that slow down development:

1. Binary Management: Downloading and extracting the correct Lexe sidecar binary
2. Process Management: Starting and stopping the sidecar subprocess
3. Credentials Handling: Properly encoding and validating base64 client credentials
4. Connection Management: Ensuring the sidecar is healthy and ready to accept requests
5. Port Configuration: Managing the correct port (5393) for communication

This package handles all of these automatically, so you can focus on building great Lightning applications.

⚡ Quick Start (30 seconds)

1. Install from PyPI

pip install lexe-wrapper

2. Set Your Lexe Credentials

export LEXE_CLIENT_CREDENTIALS="your_base64_encoded_credentials_here"

Need credentials? Get them from the Lexe mobile app - create a wallet and export client credentials.

3. Start Building Lightning Apps

Copy-Paste Example

from lexe_wrapper import LexeManager
import requests

# Automatic setup and cleanup
with LexeManager() as lexe:
    lexe.start_sidecar()  # Downloads binary, starts process, health checks
    
    # Get node info and balance
    node_response = requests.get("http://localhost:5393/v1/node/node_info")
    node_info = node_response.json()
    print(f"💰 Wallet balance: {node_info['balance']} sats")
    
    # Create a Lightning invoice (uses standard Lexe API at localhost:5393)
    response = requests.post("http://localhost:5393/v1/node/create_invoice", json={
        "amount": "1000", 
        "description": "Test payment",
        "expiration_secs": 3600  # 1 hour expiration
    })
    invoice_data = response.json()
    
    # CRITICAL: Store payment_index for monitoring payment completion
    payment_index = invoice_data['index']  # Save this!
    
    print(f"⚡ Lightning invoice created successfully!")
    print(f"📋 Invoice: {invoice_data.get('invoice', 'Generated')[:50]}...")
    print(f"🔍 Payment index (save this): {payment_index}")
    
    # Sidecar automatically stops when exiting the context

That's it! Lightning payments are now working in your Python app. 🎉

Web App Integration

from lexe_wrapper import LexeManager

# Initialize once when your web app starts
lexe = LexeManager()
lexe.start_for_webapp()  # Robust startup with error handling

# Use throughout your app's lifetime
@app.route('/create-invoice', methods=['POST'])
def create_invoice():
    response = requests.post("http://localhost:5393/v1/node/create_invoice", 
                           json=request.json)
    return response.json()

# Stop when app shuts down
lexe.stop_sidecar()

Manual Management

from lexe_wrapper import LexeManager

lexe = LexeManager()

try:
    lexe.start_sidecar()
    
    if lexe.check_health():
        print("Lexe is ready!")
        
        # Get node info using the wrapper method
        node_info = lexe.get_node_info()
        print(f"Balance: {node_info['balance']} sats")
        
finally:
    lexe.stop_sidecar()

For Coding Agents

When using this package in automated coding environments:

Essential Setup Steps

1. Install package: pip install lexe-wrapper
2. Set credentials: export LEXE_CLIENT_CREDENTIALS="your_credentials"
3. Import and start: Use the context manager pattern for automatic cleanup

Example Implementation

from lexe_wrapper import LexeManager
import requests

def setup_lexe_integration():
    """Initialize Lexe for your application"""
    lexe = LexeManager()
    lexe.start_sidecar()  # Downloads binary, starts process, waits for health
    return "http://localhost:5393"  # Ready to use Lexe API

def create_lightning_invoice(amount_sats, description):
    """Create a Lightning invoice using Lexe API"""
    response = requests.post("http://localhost:5393/v1/node/create_invoice", json={
        "amount": str(amount_sats),
        "description": description
    })
    return response.json()

# The package handles all the complexity - just use the API directly!

Key Benefits for Automation

• Standard pip installation - pip install lexe-wrapper (published on PyPI)
• Clean imports - from lexe_wrapper import LexeManager
• Zero configuration files needed - everything is handled programmatically
• Automatic binary management - downloads and extracts the right version
• Built-in health checks - ensures the connection is ready before returning
• Error handling - clear error messages when credentials are invalid or missing
• Process lifecycle management - clean startup and shutdown

Advanced Usage

For Development from Source

If you want to contribute or modify the package:

git clone https://github.com/lexe-app/lexe-wrapper.git
cd lexe-wrapper
pip install -e .

⚡ Payment Monitoring (Critical Information)

Based on real developer feedback, here are the essential patterns for monitoring Lightning payments:

🚨 Critical Fixes (Must Read!)

1. Payment Status Value

# ❌ WRONG - Documentation was incorrect
if payment['status'] == 'settled':

# ✅ CORRECT - API returns 'completed'
if payment['status'] == 'completed':

2. Store Payment Index

# When creating invoice, MUST store the 'index' field!
response = requests.post("http://localhost:5393/v1/node/create_invoice", json={...})
invoice_data = response.json()

# CRITICAL: Store this for payment monitoring
payment_index = invoice_data['index']  # Required for status checking
payment_hash = invoice_data['payment_hash']  # Also recommended

3. Correct API Endpoint

# Correct endpoint for payment status
endpoint = f"http://localhost:5393/v1/node/payment?index={payment_index}"
response = requests.get(endpoint)

Complete Working Example

from lexe_wrapper import LexeManager
import requests
import time

def complete_payment_flow():
    with LexeManager() as lexe:
        lexe.start_sidecar()
        
        # 1. Create invoice and store essential fields
        invoice_response = requests.post("http://localhost:5393/v1/node/create_invoice", json={
            "amount": "1000",
            "description": "Premium subscription",
            "expiration_secs": 3600
        })
        
        invoice_data = invoice_response.json()
        
        # CRITICAL: Store these fields in your database
        payment_record = {
            'invoice': invoice_data['invoice'],           # BOLT11 for user
            'payment_hash': invoice_data['payment_hash'], # Unique ID
            'payment_index': invoice_data['index'],       # REQUIRED for monitoring
            'amount': 1000,
            'status': 'pending'
        }
        
        # 2. Show invoice to user
        print(f"Pay this: {payment_record['invoice']}")
        
        # 3. Monitor payment completion
        payment_index = payment_record['payment_index']
        
        while True:
            # Check payment status using correct endpoint
            response = requests.get(f"http://localhost:5393/v1/node/payment?index={payment_index}")
            
            if response.status_code == 200:
                payment_data = response.json()
                payment = payment_data['payment']
                
                # CORRECT: Check for 'completed' status
                if payment['status'] == 'completed':
                    print(f"🎉 Payment received! Amount: {payment['amount']} sats")
                    # Update your database: status = 'completed'
                    break
                elif payment['status'] == 'pending':
                    print("⏳ Still waiting...")
                    time.sleep(3)  # Check every 3 seconds
                else:
                    print(f"❌ Payment failed: {payment['status']}")
                    break
            else:
                print("Error checking payment status")
                break

Web App Integration (Flask)

@app.route('/create-invoice', methods=['POST'])
def create_invoice():
    response = requests.post("http://localhost:5393/v1/node/create_invoice", json=request.json)
    invoice_data = response.json()
    
    # CRITICAL: Store payment_index for monitoring
    # Save to your database: invoice_data['index']
    
    return {'invoice': invoice_data['invoice'], 'payment_index': invoice_data['index']}

@app.route('/check-payment/<payment_index>')
def check_payment_status(payment_index):
    try:
        response = requests.get(f'http://localhost:5393/v1/node/payment?index={payment_index}')
        
        if response.status_code == 200:
            payment = response.json()['payment']
            
            # CRITICAL: Check for 'completed' not 'settled'
            return {
                'paid': payment['status'] == 'completed',
                'status': payment['status'],
                'amount': payment['amount']
            }
        else:
            return {'error': 'Payment not found'}, 404
            
    except Exception as e:
        return {'error': str(e)}, 500

Database Schema Recommendations

-- Store these fields when creating invoices
CREATE TABLE lightning_payments (
    id SERIAL PRIMARY KEY,
    invoice TEXT NOT NULL,           -- BOLT11 string
    payment_hash TEXT NOT NULL,      -- Unique payment identifier  
    payment_index TEXT NOT NULL,     -- REQUIRED for status checking
    amount_sats INTEGER NOT NULL,
    description TEXT,
    status VARCHAR(20) DEFAULT 'pending',  -- pending, completed, failed
    created_at TIMESTAMP DEFAULT NOW(),
    finalized_at TIMESTAMP,
    
    UNIQUE(payment_index)
);

📁 See examples/correct_payment_flow.py for complete, tested examples.

API Reference

LexeManager Class

Constructor

from lexe_wrapper import LexeManager

LexeManager(client_credentials=None, port=5393)

• client_credentials: Base64 encoded credentials (uses LEXE_CLIENT_CREDENTIALS env var if None)
• port: Port for sidecar to listen on (default: 5393)

Methods

start_sidecar(wait_for_health=True, health_timeout=30)

• Downloads binary if needed, starts process, optionally waits for health check
• Returns: bool - True if started successfully

start_for_webapp(health_timeout=30)

• Web app specific startup with robust error handling
• Returns: bool - True if started successfully
• Raises: RuntimeError if startup fails

stop_sidecar()

• Gracefully stops the sidecar process
• Returns: bool - True if stopped successfully

check_health()

• Checks if sidecar is responding to health checks
• Returns: bool - True if healthy

ensure_running()

• Ensures sidecar is running and healthy (great for health check endpoints)
• Returns: bool - True if running and healthy

restart_if_needed()

• Restarts sidecar if not running or unhealthy
• Returns: bool - True if now running and healthy

get_node_info()

• Gets node information from Lexe API
• Returns: dict - Node information including balance, channels, etc.

is_running()

• Checks if the sidecar process is currently running
• Returns: bool - True if running

CLI Reference

The package includes a command-line interface for testing and development:

# Using the installed package
python -m lexe_wrapper <command> [options]

# Or directly (if you cloned the repo)
python cli.py <command> [options]

Commands:
  start       Start the sidecar
  stop        Stop the sidecar  
  status      Show sidecar status
  health      Check sidecar health
  node-info   Get node information
  download    Download sidecar binary only

Options:
  --credentials TEXT    Override credentials from env var
  --port INTEGER       Port for sidecar (default: 5393)
  --timeout INTEGER    Health check timeout (default: 30)
  --no-wait           Don't wait for health check when starting
  --verbose           Enable verbose logging

Web App Integration (Long-Lived Connections)

The wrapper is specifically designed to support long-lived connections for web applications. Here's how to integrate it:

Flask Example

from flask import Flask, jsonify, request
from lexe_manager import LexeManager
import requests
import atexit

app = Flask(__name__)

# Global Lexe manager instance
lexe_manager = None

def init_lexe():
    """Initialize Lexe sidecar when app starts"""
    global lexe_manager
    lexe_manager = LexeManager()
    
    try:
        # Use the web app specific startup method
        lexe_manager.start_for_webapp(health_timeout=30)
        print("✅ Lexe sidecar started successfully")
        return True
    except RuntimeError as e:
        print(f"❌ Failed to start Lexe: {e}")
        return False

def cleanup_lexe():
    """Clean shutdown when app stops"""
    global lexe_manager
    if lexe_manager:
        lexe_manager.stop_sidecar()
        print("🛑 Lexe sidecar stopped")

# Initialize Lexe when app starts
with app.app_context():
    if not init_lexe():
        exit(1)

# Register cleanup function
atexit.register(cleanup_lexe)

@app.route('/health')
def health_check():
    """App health check - includes Lexe status"""
    if lexe_manager and lexe_manager.ensure_running():
        return jsonify({"status": "healthy", "lexe": "connected"})
    else:
        return jsonify({"status": "degraded", "lexe": "disconnected"}), 503

@app.route('/node-info')
def node_info():
    """Get Lexe node information"""
    try:
        # Use direct API call (the whole point of this wrapper!)
        response = requests.get("http://localhost:5393/v1/node/node_info", timeout=10)
        response.raise_for_status()
        return jsonify(response.json())
    except Exception as e:
        return jsonify({"error": str(e)}), 500

@app.route('/create-invoice', methods=['POST'])
def create_invoice():
    """Create a Lightning invoice"""
    try:
        amount = request.json.get('amount', '1000')
        description = request.json.get('description', 'Payment')
        
        # Direct Lexe API usage
        response = requests.post("http://localhost:5393/v1/node/create_invoice", 
                               json={
                                   "amount": str(amount),
                                   "description": description
                               }, timeout=15)
        response.raise_for_status()
        return jsonify(response.json())
    except Exception as e:
        return jsonify({"error": str(e)}), 500

@app.route('/restart-lexe', methods=['POST'])
def restart_lexe():
    """Restart Lexe if having issues"""
    if lexe_manager and lexe_manager.restart_if_needed():
        return jsonify({"status": "restarted"})
    else:
        return jsonify({"error": "restart failed"}), 500

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5000)

FastAPI Example

from fastapi import FastAPI, HTTPException
from contextlib import asynccontextmanager
from lexe_manager import LexeManager
import requests

# Global Lexe manager
lexe_manager = None

@asynccontextmanager
async def lifespan(app: FastAPI):
    # Startup
    global lexe_manager
    lexe_manager = LexeManager()
    
    try:
        lexe_manager.start_for_webapp()
        print("✅ Lexe sidecar started")
        yield
    except RuntimeError as e:
        print(f"❌ Lexe startup failed: {e}")
        raise
    finally:
        # Shutdown
        if lexe_manager:
            lexe_manager.stop_sidecar()
            print("🛑 Lexe sidecar stopped")

app = FastAPI(lifespan=lifespan)

@app.get("/health")
def health_check():
    if lexe_manager and lexe_manager.ensure_running():
        return {"status": "healthy", "lexe": "connected"}
    raise HTTPException(503, "Lexe not available")

@app.post("/invoices")
def create_invoice(amount: int, description: str = "Payment"):
    try:
        response = requests.post("http://localhost:5393/v1/node/create_invoice",
                               json={"amount": str(amount), "description": description})
        response.raise_for_status()
        return response.json()
    except Exception as e:
        raise HTTPException(500, str(e))

Web App Best Practices

1. Startup Pattern: Use start_for_webapp() during app initialization
2. Health Monitoring: Use ensure_running() in your health check endpoints
3. Recovery: Use restart_if_needed() for automatic recovery
4. Shutdown: Ensure stop_sidecar() is called when your app shuts down
5. Direct API Usage: Once started, use standard HTTP requests to localhost:5393

Process Management for Production

import signal
import sys
from lexe_manager import LexeManager

# Global manager for signal handlers
lexe_manager = None

def signal_handler(signum, frame):
    """Handle shutdown signals gracefully"""
    global lexe_manager
    print("🔄 Received shutdown signal, stopping Lexe...")
    if lexe_manager:
        lexe_manager.stop_sidecar()
    sys.exit(0)

# Register signal handlers for graceful shutdown
signal.signal(signal.SIGINT, signal_handler)   # Ctrl+C
signal.signal(signal.SIGTERM, signal_handler)  # Docker/systemd stop

def main():
    global lexe_manager
    lexe_manager = LexeManager()
    
    # Start for long-lived operation
    lexe_manager.start_for_webapp()
    
    # Your web app code here
    # The sidecar stays running until explicitly stopped

After Starting the Sidecar

Once the wrapper starts the sidecar, you can use the standard Lexe Sidecar API directly:

• Health: GET http://localhost:5393/v1/health
• Node Info: GET http://localhost:5393/v1/node/node_info
• Create Invoice: POST http://localhost:5393/v1/node/create_invoice
• Pay Invoice: POST http://localhost:5393/v1/node/pay_invoice
• Check Payment: GET http://localhost:5393/v1/node/payment?index=<index>

Error Handling

The wrapper provides clear error messages for common issues:

• Missing credentials: Clear message about setting LEXE_CLIENT_CREDENTIALS
• Invalid credentials: Validates base64 format and provides specific error
• Download failures: Network issues when downloading the binary
• Health check failures: When sidecar doesn't respond within timeout
• Process management: Issues starting or stopping the sidecar process

Package Structure

lexe-wrapper/
├── lexe_wrapper/           # Main package
│   ├── __init__.py        # Package exports LexeManager
│   ├── manager.py         # Core LexeManager class
│   └── __main__.py        # CLI entry point
├── examples/              # Usage examples
│   └── simple_usage.py    # Simple integration examples
├── setup.py              # Package installation
├── pyproject.toml        # Modern Python packaging
└── README.md             # This documentation

Requirements

• Python 3.7+
• requests library (automatically installed as dependency)
• x86_64 Linux environment (where Lexe sidecar runs)
• Valid Lexe client credentials

Contributing

Contributions are welcome! This is an open-source project and we encourage community involvement:

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests if applicable
5. Submit a pull request

Code of Conduct: Please be respectful and constructive in all interactions.

License

MIT License - This project is free and open-source software. See the LICENSE file for full details.

Copyright (c) 2025 Mat Balez

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software.

About

This package is designed to eliminate the friction in getting started with Lexe Bitcoin Lightning Network integration. The Lexe Sidecar API itself is excellent - this package just handles the setup complexity so you can focus on building great Lightning applications.

Key Design Principles:

• Standard Python packaging - Install with pip, import normally
• Minimal dependencies - Only requires requests
• Clean API surface - Simple import, clear methods
• Production ready - Proper error handling, logging, and lifecycle management
• Direct API access - No unnecessary abstraction over the Lexe Sidecar API

Open Source & Legal

📝 License: This project is released under the MIT License, making it free to use, modify, and distribute.

⚖️ Disclaimer: This is an unofficial, community-developed wrapper around the Lexe Sidecar SDK. It is not officially associated with, endorsed by, or supported by Lexe. This project was independently created to help Python developers integrate with Lexe's Lightning wallet services more easily.

🔧 Open Source:

• Source Code: Available on GitHub for transparency and community contributions
• Issues & Contributions: Welcome! Please submit bug reports and feature requests
• No Warranty: Provided "as is" - please review the code and test thoroughly before production use

🔗 Official Lexe Resources:

• Official Lexe Website: lexe.app
• Official Lexe Sidecar SDK: github.com/lexe-app/lexe-sidecar-sdk
• Lexe Documentation: Follow official Lexe channels for authoritative information

Author

Created and maintained by Mat Balez

This project was developed to help the Python community easily integrate Bitcoin Lightning Network payments using Lexe's excellent infrastructure, with a focus on eliminating common setup friction points.