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Definition
A webhook is an automated HTTP request that one system sends to another in real time when a specific event occurs, allowing systems to react to events without constantly polling for updates.
Simple explanation
Imagine subscribing to text alerts from your bank instead of logging in every hour to check your balance. A webhook works the same way for software: you register a URL with a service, and it 'calls' that URL automatically whenever a relevant event happens.
For example, a payments provider can send a webhook to your server the instant a payment succeeds, so your system updates an order's status immediately rather than checking back periodically.
Why it matters
Webhooks make real-time integrations possible without wasteful, constant checking. They are the quiet plumbing behind countless automations — from payment confirmations to chat notifications to deployment alerts.
For businesses connecting software tools together, understanding webhooks is essential to understanding what 'automatically syncs' actually means under the hood.
How it works
- 1RegisterYou provide a URL on your server where the sending service should deliver events.
- 2Event occursSomething happens in the source system, such as a new order or a form submission.
- 3Payload sentThe source system sends an HTTP request with event details to your registered URL.
- 4ProcessYour server receives the request and takes action, such as updating a database.
Real examples
Products named for illustration only. Inclusion is not an endorsement.
- Stripe payment webhooksNotify your server the moment a charge succeeds or fails.
- GitHub webhooksTrigger CI/CD pipelines when code is pushed to a repository.
- Slack incoming webhooksPost automated messages into a channel from external systems.
- Zapier/Make triggersUse webhooks to kick off no-code automations between apps.
Advantages
- Delivers events in real time instead of on a delay.
- Avoids wasteful repeated polling of an API for changes.
- Simple to implement — just an HTTP endpoint that receives data.
- Widely supported across payment, communication and developer platforms.
Limitations
- Requires a publicly reachable endpoint to receive requests.
- Delivery is not always guaranteed — failed webhooks need retry logic.
- Must be secured, typically with a signature check, to avoid spoofed requests.
- Debugging silent failures can be harder than debugging a direct API call.
Common misunderstandings
- ClaimWebhooks and APIs are competing technologies.RealityWebhooks are typically used alongside APIs — one pushes events out, the other lets you pull data on demand.
- ClaimWebhooks always arrive instantly and exactly once.RealityNetworks can delay or duplicate delivery, so receiving systems should be built to handle retries and duplicates.
Frequently asked questions
How is a webhook different from an API call?
An API call is something you initiate to ask for data; a webhook is sent to you automatically when an event happens.
Do I need a server to use webhooks?
Yes, you need a publicly accessible endpoint capable of receiving HTTP requests.
Are webhooks secure?
They can be, if the sender signs requests and the receiver verifies that signature before trusting the payload.
What happens if my server is down when a webhook is sent?
Most providers retry failed deliveries for a period, but you should not assume every event will always arrive.
Can no-code tools use webhooks?
Yes, platforms like Zapier and Make commonly use webhooks to trigger automations from external events.
The Tool Money Lab perspective
Webhooks are one of the simplest, most reliable integration patterns in software, and their absence in a platform's feature set is often a sign of limited automation capability.
When reviewing automation tools, we check how they handle webhook failures and retries — silent data loss from unhandled webhook errors is a common, avoidable problem.
Conclusion
A webhook lets systems tell each other about events the moment they happen, replacing constant checking with real-time notification.
They are unglamorous but essential infrastructure, quietly connecting the tools that businesses rely on to stay in sync with one another.