How to Build a Reliable Webhook Processor

Aleksandr Kubarskii · Inquir Compute | CTO · · 4 min read
How to Build a Reliable Webhook Processor

A webhook processor looks simple at first. A service sends an HTTP request. Your endpoint receives it. You run some code.

In production, webhooks are more complicated.

Providers retry failed events. Requests can arrive more than once. Events can arrive out of order. Some providers require fast responses. Some require signature verification. Your own processing can fail halfway through.

A reliable webhook processor is not just an endpoint. It is a small event-handling system.

The basic webhook flow

A typical webhook flow looks like this:

provider → webhook endpoint → verify → store event → process → update system

For example, Stripe may send a payment event, GitHub may send a repository event, Slack may send a command, or a CRM may send a contact update.

The endpoint is only the entry point. The real work is everything after the request arrives.

Pattern 1: verify the request

Most important providers support request signing. You should verify the signature before trusting the payload.

Verification usually protects against:

  • fake events;
  • modified payloads;
  • accidental public endpoint abuse;
  • incorrect provider configuration.

A webhook endpoint should reject invalid signatures before doing any work.

Pattern 2: return quickly

Many webhook providers expect a fast response. If your handler performs slow work before returning, you increase the chance of timeout and duplicate retries.

A safer pattern is:

receive webhook
→ verify signature
→ store event or enqueue job
→ return 200 quickly
→ process asynchronously

This keeps the provider happy and gives your system time to do real work.

Pattern 3: make processing idempotent

Webhook providers may send the same event more than once. Your processor must handle duplicates safely.

For example, a payment event should not create two invoices just because the webhook was retried.

The usual approach is to store a provider event ID:

event_id: evt_123
processed: true
processed_at: 2026-04-24T10:00:00Z

Before processing an event, check whether it was already handled. If yes, return success without repeating side effects.

Pattern 4: separate acknowledgement from work

Do not treat the provider response as proof that your business process finished.

Returning 200 OK usually means:

we received the event

It should not necessarily mean:

we completed all downstream processing

That downstream processing may include database writes, API calls, emails, file generation, AI summarization, or notifications. Those should often run in a background job.

Pattern 5: log by event ID

Webhook debugging is difficult without event-level logs.

You should be able to search by:

  • provider;
  • event type;
  • event ID;
  • status;
  • processing duration;
  • error code;
  • retry count.

When a customer says “I paid but nothing happened”, you need to find the exact payment event and see what your system did with it.

Pattern 6: handle event order carefully

Some providers do not guarantee perfect ordering. Even when they do, network and retry behavior can make order tricky.

For example:

customer.updated
subscription.created
invoice.paid

Your system should not assume every related record already exists. It should handle missing records gracefully, fetch current state if needed, and make updates idempotent.

Pattern 7: design for retries

There are two kinds of retries:

  1. provider retries when your endpoint fails;
  2. internal retries when your processing fails.

These should be handled separately.

A webhook endpoint can return 200 after storing the event, even if internal processing later fails. Then your internal job system can retry processing without asking the provider to resend the event.

Provider-specific examples

Stripe

A Stripe webhook processor should verify the raw body signature, store event.id, avoid duplicate processing, and return quickly. Fulfillment can continue asynchronously.

GitHub

A GitHub webhook handler should verify the signature, branch by event type, and avoid doing heavy CI or indexing work inside the request.

Slack

Slack commands often require a fast response. Slow AI processing should move to a background job, with the final result sent later.

Where Inquir Compute fits

Inquir Compute can host webhook processors as API routes and move slow work into background jobs or pipelines.

A webhook architecture can look like this:

/webhooks/stripe
→ verify event
→ store event ID
→ start background job
→ return 200

job: fulfill-order
→ update database
→ call external APIs
→ send notification
→ log result

This avoids holding the provider request open while still keeping the work observable.

When a simple webhook endpoint is enough

A simple endpoint may be enough if:

  • the action is fast;
  • duplicate events are harmless;
  • the provider is low-risk;
  • the webhook is internal;
  • failures do not affect users.

But for payments, account changes, provisioning, notifications, or automation, reliability matters.

Webhook processor checklist

Before shipping a webhook endpoint, check:

  • Is the request verified?
  • Is there an idempotency key?
  • Does the handler return quickly?
  • Are events logged by provider event ID?
  • Can processing be retried safely?
  • Are failures visible?
  • Are secrets stored safely?
  • Is slow work moved to a job?

Conclusion

Reliable webhook processing is about controlling uncertainty.

Events may arrive twice. External APIs may fail. Providers may retry. Users may expect results immediately. Your system needs to acknowledge quickly, process safely, and keep enough context to debug failures.

A webhook endpoint is easy. A reliable webhook processor is architecture.