In one sentence
An HTTP message one system sends to another the moment an event happens, so the receiver does not have to keep asking.
A webhook is a message that one application sends to a URL you choose when something happens: a form is submitted, a payment succeeds, a lead is created, a shipment status changes. Instead of your automation checking every few minutes for new records, the source system tells it right away. GitHub's documentation describes webhooks as a way to receive event notifications instead of polling an API.
Why webhooks matter for automation
Speed and cost. A new web lead can get a text reply within seconds because the CRM fires a webhook the moment the lead arrives. Polling would add minutes of delay and use API quota on empty checks.
What a webhook contains
Usually a JSON body describing the event, plus headers that identify the sender. Many providers sign each request with a shared secret so the receiver can confirm it is genuine.
What can go wrong:
Missed events
If your endpoint is down, the sender may retry for a while and then give up. Check each provider's retry policy and add a scheduled catch-up job that compares records.
Duplicates
Retries mean the same event can arrive twice. The receiver should be idempotent, keyed on the event ID, so a repeat does nothing.
Out-of-order delivery
Events can arrive in a different order than they happened. Use timestamps or fetch the latest record before acting.
Spoofing
Anyone who finds the URL can send to it. Verify signatures and reject unsigned requests.
Slow handlers
Many senders expect a quick response. Acknowledge fast and do the work in a queue.
In our builds
every webhook endpoint verifies the sender, records the event ID, queues the work and has a catch-up job, so a missed or repeated event does not lose a lead or send a message twice.
Keep following the system
API Integration
A connection that lets software systems exchange approved data and invoke supported operations.
Idempotency
The property that doing the same operation twice has the same effect as doing it once, so retries do not create duplicates.
Workflow Automation
Connecting business systems so repeatable tasks run according to defined rules and exceptions reach the right person.
Retrieval-Augmented Generation (RAG)
A method where an AI system first looks up relevant documents and then writes its answer using them.
Speed to Lead
The time between a new lead reaching a business and the business's first real response to that lead.