Webhook Delivery Cost Calculator

How webhook costs actually work

The raw event count you see in your dashboard is not your billable message count. Most services count at the delivery attempt level — which means fan-out and retries compound your volume:

Fan-out: 1 event → N endpoints = N delivery attempts. 1M events to 50 endpoints = 50M attempts billed.
Retries: a 3% failure rate with 3 retries adds ~9% more attempts on top.
Storage/log retention: some services charge separately to retain event payloads beyond 7 days.

The calculator above accounts for retries. Fan-out is not applied by default (it would make most managed services look expensive for single-endpoint use cases) — if you fan-out to many customers, multiply your event count by average endpoints-per-event before entering it.

Svix — best developer experience, mid-range cost

Svix is the most popular managed webhook service. It handles fan-out natively, provides customer-facing dashboards your users can log into to inspect and replay deliveries, and has SDKs for every major language. Pricing starts on a flat monthly plan with a per-message overage above the included quota (~$0.99–$1.25/1k messages depending on tier).

Best for: SaaS products where your customers need to manage their own webhook subscriptions. The white-label portal is the differentiator.

Hookdeck — event gateway with observability

Hookdeck bills by connections (source → destination pairs) per day and by events ingested. It's more of an event gateway than a pure webhook service — it also handles inbound event ingestion, throttling, and filtering. Price scales with active connections; quiet endpoints don't cost much.

Best for: teams that need to transform, filter or route events between services, or who need inbound webhook handling (catching events from Stripe, Shopify etc.) alongside outbound delivery.

DIY with SQS + Lambda — cheapest infra, most work

SQS charges $0.40/1M messages. Lambda at 128MB + 200ms/invocation is roughly $0.20–0.40/1M. Total: ~$0.80–$1.00 per 1M deliveries in raw AWS compute. But you build: retry scheduling, fan-out logic, dead-letter handling, payload storage, delivery logs, per-endpoint circuit breakers, and the UI for debugging. At 5M events/month that's realistic $200–500 AWS bill plus 10–20h/month of maintenance. The crossover point where DIY saves money vs a managed service is typically around 5–10M events/month.

Frequently asked questions

Is it cheaper to build webhooks yourself or use a service?

At low volume (under ~500k events/month) managed services like Svix or Hookdeck are usually cheaper than DIY when you factor in developer time. At high volume (millions of events/month) a self-hosted Convoy or SQS+Lambda stack often wins on raw compute cost — but you own the ops burden: retries, fan-out, dashboards, failure queues. This calculator shows the infrastructure cost only; add engineering time separately.

What does a webhook service actually cost at scale?

Svix charges $0.99–$1.25 per 1,000 messages beyond their base plan; Hookdeck charges per connection-day and event. At 5 million events/month through 50 endpoints, managed services typically cost $500–$2,000/month. A DIY SQS+Lambda stack at the same volume runs $100–$400 in AWS compute but requires engineering to maintain retries, fan-out, dashboards and dead-letter handling.

What is fan-out in webhooks?

Fan-out means one event triggers delivery to multiple endpoints. If you have 50 customers each subscribed to 'payment.created', one event creates 50 delivery attempts. Services like Svix handle fan-out natively; DIY stacks need to implement it explicitly. Fan-out multiplies your monthly message count — make sure to account for it in cost estimates.

Webhook delivery cost calculator