What is Webhook?

Webhook Explained

A webhook is an automated notification mechanism—when something happens in one system, it sends an HTTP POST request to a URL you specify with data about the event. Think of it as the opposite of polling: instead of repeatedly asking 'did anything change?', the system tells you when something happens. Webhooks are essential for payment processing (Stripe sends webhook events for successful charges, refunds, and disputes), CI/CD pipelines, and third-party integrations. At M3L Software, webhooks are a core part of every payment integration we build. We implement robust webhook handlers with signature verification, idempotency, retry logic, and comprehensive event logging to ensure no events are missed.

Key Features

Common Use Cases

Code Example

from fastapi import FastAPI, Request, HTTPException
import stripe
import hmac
import hashlib

app = FastAPI()
WEBHOOK_SECRET = "whsec_..."

@app.post("/webhooks/stripe")
async def stripe_webhook(request: Request):
    payload = await request.body()
    sig_header = request.headers.get("stripe-signature")
    
    try:
        event = stripe.Webhook.construct_event(
            payload, sig_header, WEBHOOK_SECRET
        )
    except stripe.error.SignatureVerificationError:
        raise HTTPException(status_code=400, detail="Invalid signature")
    
    if event["type"] == "payment_intent.succeeded":
        payment = event["data"]["object"]
        # Process successful payment
        print(f"Payment received: {payment['amount']}")
    elif event["type"] == "customer.subscription.deleted":
        # Handle subscription cancellation
        pass
    
    return {"status": "received"}

A Stripe webhook handler in FastAPI that verifies the webhook signature for security, then processes different event types (successful payment, subscription cancellation). This pattern ensures your system stays synchronized with Stripe.

Frequently Asked Questions

Related Terms