Documentation
Python
Flask

Use mekong-flask to run your Flask development server and expose it publicly — perfect for testing webhooks, sharing work-in-progress, and mobile device testing.

Quick Start

pip install mekong-tunnel flask
# Same as: flask run
mekong-flask

Or with an explicit app module:

mekong-flask --app myapp:app

A public URL like https://swift-river-b3c4d5e6.mekongtunnel.dev is printed immediately.

Open in Browser

mekong-flask --domain          # Opens tunnel URL in browser
mekong-flask --local           # Opens http://localhost:5000 in browser

Custom Port

mekong-flask --port 5001 --app myapp:app

Full Example

# app.py
from flask import Flask, jsonify, request
 
app = Flask(__name__)
 
@app.route("/")
def index():
    return jsonify({"message": "Hello from Flask via MekongTunnel!"})
 
@app.route("/webhook", methods=["POST"])
def webhook():
    data = request.json
    print("Received:", data)
    return jsonify({"status": "received"})
FLASK_APP=app.py mekong-flask --debug --domain

Passing Flask Arguments

mekong-flask wraps flask run, so all flask CLI arguments are supported:

mekong-flask \
  --app app:create_app \
  --debug \
  --port 5000 \
  --host 0.0.0.0 \
  --reload

With Flask Application Factory

# myapp/__init__.py
from flask import Flask
 
def create_app():
    app = Flask(__name__)
    # ... register blueprints, etc.
    return app
mekong-flask --app myapp:create_app --debug --domain

Flask Blueprints + Webhooks

from flask import Blueprint, request, abort
import hmac, hashlib, os
 
webhooks = Blueprint("webhooks", __name__, url_prefix="/webhooks")
 
@webhooks.route("/stripe", methods=["POST"])
def stripe_webhook():
    payload = request.data
    sig = request.headers.get("Stripe-Signature")
    # Verify with stripe.Webhook.construct_event(...)
    return "", 200
mekong-flask --app myapp:create_app --debug --domain
# → Paste https://your-tunnel.mekongtunnel.dev/webhooks/stripe to Stripe dashboard

Programmatic API

from mekong_tunnel import start_tunnel
from myapp import create_app
 
tunnel = start_tunnel(port=5000)
print("Share this URL:", tunnel.url)
 
app = create_app()
app.run(port=5000, debug=True)

Flask + CORS

If your frontend uses the tunnel URL as an API origin:

pip install flask-cors
from flask_cors import CORS
 
app = Flask(__name__)
CORS(app)  # Allow all origins, or specify: CORS(app, origins=["https://*.mekongtunnel.dev"])

Environment Variables

MEKONG_TOKEN=your_token FLASK_APP=app.py mekong-flask --debug

Or in .flaskenv:

FLASK_APP=app.py
FLASK_DEBUG=1
MEKONG_TOKEN=your_token

Notes

  • Flask's built-in reloader works normally with the tunnel
  • The debugger PIN is shown in the terminal as usual
  • For production, use mekong-gunicorn instead of mekong-flask (Flask's dev server is not production-safe)
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