Webhooks are one of the fastest ways to automate a business process: “When X happens in system A, notify system B.” They’re lightweight, event-driven, and often cheaper than polling APIs. They’re also a common source of mysterious bugs—double charges, missing updates, out-of-order events, and workflows that silently stall.
The good news is that webhook reliability is not magic. Most failures fall into a small set of predictable categories: transient network issues, slow downstream processing, duplicate deliveries, and payload drift. If you design for those from the start, you can keep the integration simple while still making it robust.
This post lays out a set of practical patterns you can apply whether you’re wiring up a SaaS tool to your internal system, connecting services within your product, or building an automation pipeline that feeds a CMS. If you want more posts like this, the archive collects similar evergreen guides.
When webhooks help (and when they hurt)
Webhooks are a great fit when you need near-real-time updates, your source system can push events, and you don’t want to manage polling schedules or API rate limits. They shine for order updates, user lifecycle events, content publishing triggers, and “create a task when…” automations.
They become painful when you implicitly treat them like a guaranteed message bus. Many providers deliver webhooks on a “best effort” basis: they retry for a while, then stop. Some don’t guarantee ordering. Many will deliver duplicates by design. You can still build reliable workflows—you just need to assume the webhook is a notification, not a transaction.
Before you implement, decide what “success” means for the workflow:
- Latency target: seconds, minutes, or “eventually consistent”?
- Completeness: must every event be processed, or just the latest state?
- Side effects: does processing create irreversible actions (emails, charges, access changes)?
- Recovery plan: how will you detect and fix missed events?
The core reliability model: acknowledge, retry, and dedupe
Nearly every dependable webhook receiver implements three behaviors:
- Acknowledge quickly. Respond fast (often within a few seconds) so the sender doesn’t time out and retry.
- Retry safely. If your processing fails, you can reprocess without creating duplicates or inconsistent state.
- Dedupe with idempotency. Treat “same event delivered twice” as normal, not exceptional.
These behaviors work together. Quick acknowledgement reduces duplicate deliveries, but it doesn’t eliminate them. Retries are necessary, but retries without deduplication can double-run side effects. Deduplication without a retry strategy can still drop events if you fail mid-processing.
A useful “event envelope” mental model
Most webhook payloads have (or can be mapped into) a small set of fields. Even if your provider sends a large JSON object, it helps to normalize it internally into a compact envelope you can log, store, and replay.
{
"event_id": "unique-per-delivery-or-per-event",
"event_type": "customer.updated",
"occurred_at": "timestamp",
"source": "system-a",
"payload": { "original": "data" }
}
The exact field names don’t matter. What matters is that you can answer: “What happened, when, from where, and how do I uniquely identify it?”
Designing the receiving endpoint
Your webhook endpoint should be boring and predictable. The more logic you cram into the HTTP request/response window, the more timeouts and retries you’ll trigger. Instead, treat the endpoint as an intake valve.
Receiving endpoint checklist
- Verify authenticity: validate the sender’s signature or shared secret before doing any work.
- Validate shape: ensure required fields exist; reject obviously malformed requests.
- Persist first: write the raw event (or normalized envelope) to durable storage.
- Return success promptly: acknowledge receipt after persistence, not after full processing.
- Separate “accept” from “process”: intake and processing can fail independently.
This approach makes failures easier to handle. If processing breaks later, you still have the original event for replay. If the sender retries, your dedupe layer can recognize the event and no-op. And if you need to audit, the raw payload is available.
Keep your HTTP responses consistent. Many webhook senders treat any non-2xx response as a failure. If you need to reject an event (bad signature, missing fields), do it explicitly and log why. If you’re temporarily unhealthy, return an error so the sender can retry—provided your system can actually recover in time.
A simple processing pipeline that scales with you
Once an event is accepted, you need a processing path that’s reliable but not overbuilt. A common minimal pipeline looks like this:
- Intake: store the event and create a “pending” record.
- Dispatch: enqueue a job keyed by event type (or route to a handler).
- Handle: apply business logic and update your systems.
- Finalize: mark processed, record results, and store any derived identifiers.
You don’t need a complex platform to get these benefits. The key is to create a boundary so that “HTTP request succeeded” doesn’t mean “workflow completed.” That boundary can be as simple as a database table that a worker reads from, or a managed queue that triggers a worker process.
Idempotency: how to not do the same thing twice
Idempotency means you can process an event multiple times and still end up with the same outcome. That sounds abstract, but it becomes concrete when you choose an idempotency key and decide what it guards.
- Pick the key: ideally the sender provides a stable
event_id. If not, construct one from stable fields (for example, event type + object ID + a version/timestamp). - Define the scope: is idempotency per event, per object, or per side effect? For emails or invoices, it’s usually per side effect.
- Store outcomes: write a record like “event_id processed” with timestamps and key results (e.g., created record IDs).
A practical pattern is: “Check if event_id is already processed; if yes, return success; if no, process and then record it.” To avoid race conditions, make the “record it” step atomic (for example, by using a unique constraint on event_id and handling conflicts as “already done”).
Ordering vs. latest-state reconciliation
Some systems deliver events out of order. If your handler assumes order (update A then update B), you can end up applying stale data. You have two common options:
- Enforce ordering per entity: process events for the same object sequentially. This is simpler but can reduce throughput.
- Reconcile to latest state: treat events as hints, then fetch current state from the source API before applying changes. This costs an API call but avoids stale writes.
For many business automations, “latest state wins” is safer and easier to reason about than strict ordering.
Observability and backfills: your safety net
Reliability isn’t just how you handle the happy path—it’s how quickly you detect and recover from the unhappy path. Webhooks fail silently when nobody is looking. Add lightweight observability early so issues show up as a backlog, not a surprise.
What to track (minimum viable signals)
- Intake rate: events received per type.
- Processing lag: time from
occurred_at(or receipt) to completion. - Failure rate: handler errors and retry counts.
- Dead-letter count: events that exceeded retry policy and need manual attention.
Just as important: make it easy to answer, “What happened to event X?” Store a correlation ID (often the event ID) in your logs and in your processing records. When support or operations asks for a status, you should be able to search and see the full lifecycle.
Key Takeaways
- Design the webhook endpoint for fast acceptance, not full processing.
- Assume duplicates and retries will happen; make handlers idempotent.
- Persist raw events so you can replay and audit without guesswork.
- Track lag and failures; reliability improves fastest when issues are visible.
- Have a backfill path to reconcile missed events and restore consistency.
Backfills: recovering from missed or buggy processing
No matter how careful you are, you’ll eventually need to backfill: replay a time window, re-run a handler with fixed logic, or reconcile records after an outage. Plan for it upfront by answering two questions:
- Can I reprocess safely? Idempotency records and “upsert” style updates make reprocessing low-risk.
- Can I rebuild from source of truth? If the source system has an API, you can periodically reconcile objects (e.g., nightly) to catch anything that slipped through.
Backfills don’t have to be fancy. Even a simple “replay events between timestamps” tool—run carefully and logged well—can turn scary failures into routine operations.
Security and governance basics
Webhook endpoints are internet-facing by nature. A few defensive steps prevent most abuse and reduce the chance of accidental data exposure:
- Verify signatures: treat unsigned requests as untrusted input.
- Rate limit: protect intake from bursts, accidental loops, or malicious traffic.
- Minimize stored data: keep raw payloads only as long as you need for auditing/replay.
- Access control: restrict who can replay events or view sensitive payloads.
- Schema drift handling: ignore unknown fields, and validate required ones so small provider changes don’t break you.
Governance also includes ownership. Decide who responds when the integration breaks, where errors are tracked, and what “done” means when you ship a new webhook-driven workflow. If you run many automations, documenting them in one place (even a simple internal page) saves time later.
Conclusion
Reliable webhook automation is less about complex infrastructure and more about a few disciplined patterns: accept quickly, persist events, process asynchronously, and make every handler safe to retry. When those basics are in place, your integrations become resilient to network blips, provider retries, and your own future changes.
If you’re building multiple workflows, standardize these patterns once and reuse them everywhere. Consistency is what turns “one-off integrations” into a maintainable system.
FAQ
Do I need a message queue to handle webhooks correctly?
Not always. For low volume, storing events in a database table and processing them with a worker can be enough. A queue becomes useful when you need better throughput, isolation, or retry controls, but the real win comes from separating intake from processing.
What should my webhook endpoint return?
Typically a 2xx response as soon as you’ve verified authenticity and persisted the event. Avoid waiting for downstream work. If the request is invalid (bad signature, missing required fields), return a clear non-2xx and log the reason.
How long should I keep raw webhook payloads?
Long enough to support replay and auditing, but not indefinitely by default. Many teams keep raw events for days or weeks, then retain a smaller processed record (event ID, type, timestamps, outcome) for longer.
How do I prevent duplicate side effects like sending two emails?
Use an idempotency key and store a “side effect already performed” record. Make the send action conditional on that record, and write it atomically so concurrent processing can’t double-send.