Outgoing Webhooks

Manual Retry & Synthetic Event Dispatcher

Trigger immediate synthetic webhook events on demand to test receiver handlers, or replay previously failed dispatches using the redelivery endpoint without modifying underlying database records.

Interactive Retry & Synthetic Dispatcher

Select a simulation scenario below to dispatch an ad-hoc event or replay a delivery log:

Dispatch Synthetic Event

Dispatches an on-demand test webhook to any target URL to verify receiver processing.

POST

response.json

{

// Click "Send" above to execute this request against the live server.

}

Receiver Idempotency Architecture

Because network retries and manual replays can cause duplicate deliveries ("at-least-once delivery"), webhook receivers must record the X-Playground-Delivery header before processing mutations:

// Redis Idempotency Pattern for Webhook Consumers (Node.js/Express)

import Redis from 'ioredis';

const redis = new Redis(process.env.REDIS_URL);

app.post('/api/webhooks', async (req, res) => {

const deliveryId = req.headers['x-playground-delivery'];

if (!deliveryId) {

return res.status(400).json({ error: 'Missing X-Playground-Delivery header' });

}

// 1. Atomic lock with 24-hour expiration (SETNX)

const lockKey = webhook:processed:${deliveryId};

const isNew = await redis.set(lockKey, '1', 'EX', 86400, 'NX');

if (!isNew) {

console.warn(Duplicate webhook delivery detected [${deliveryId}]. Skipping reprocessing.);

// Return 200 OK immediately so dispatcher does not retry

return res.status(200).json({ status: 'already_processed', deliveryId });

}

try {

// 2. Process domain business logic safely

await handleEvent(req.body.event, req.body.data);

return res.status(200).json({ status: 'success', deliveryId });

} catch (err) {

// Release key on fatal failure to allow legitimate manual retry

await redis.del(lockKey);

return res.status(500).json({ error: 'Processing failure' });

}

});

Retry Strategies & Failure Recovery

Comparison of standard delivery recovery patterns in event-driven systems:

Pattern	Trigger Mechanism	Payload Guarantee	Best Use Case
Automated Exponential Backoff	Non-2xx response or network timeout (retried at 5s, 30s, 5m, 1h).	Same payload, new timestamp	Transient network blips, cold starts, and rolling server deployments.
Dead-Letter Queue (DLQ)	Exhaustion of maximum automated retries (e.g. after 5 failures).	Archived immutable payload	Long-term outage isolation and manual engineering triage.
Manual Redelivery API	Explicit POST to `/deliveries/:id/redeliver`.	Exact replay with original event	Debugging receiver bugfixes, local tunnel testing, and idempotency tests.

PreviousDelivery Logs

NextNetwork Latency Delay

Manual Retry & Synthetic Event Dispatcher

Interactive Retry & Synthetic Dispatcher

Dispatch Synthetic Event

Re-deliver Delivery Record

Replay via /retry Alias

Dispatch Synthetic Event

Receiver Idempotency Architecture

Retry Strategies & Failure Recovery

Manual Retry & Synthetic Event Dispatcher

Interactive Retry & Synthetic Dispatcher

Dispatch Synthetic Event

Re-deliver Delivery Record

Replay via /retry Alias

Dispatch Synthetic Event

Receiver Idempotency Architecture

Retry Strategies & Failure Recovery