Webhook

The difference from traditional API polling: with an API, System B regularly asks System A "anything new?" — introducing delay and unnecessary load. With a webhook, System A initiates contact the moment something happens. For automation, that means processes start in seconds instead of waiting for the next polling interval.

In AI agent projects, webhooks are the typical starting points: new email, new support ticket, new shop order, completed form — each event immediately triggers the relevant processing workflow.

Professional implementations secure webhooks: signature verification (did the message really come from the genuine sender?), retry logic for outages, and detailed logging. This ensures no event gets lost, even if a system is temporarily unreachable.

Three factors determine real-world reliability. First, duplicate delivery: many systems prefer sending an event twice rather than not at all — the receiving automation must recognise it's the same event, or you'll get duplicate records or duplicate emails. Second, ordering: webhooks don't arrive in guaranteed sequence — processes where order matters (order first, then modification) need proper sequence checking. Third, error handling: what happens when the receiver is unreachable? Good senders retry delivery, good receivers buffer incoming events before processing them.

For operational visibility, a central event log works well: every incoming message timestamped with source and processing status. This lets you answer anytime whether a particular event arrived and was processed — the most common question when something goes missing in a workflow.

The biggest risk in live operation is silent failure: a receiver stops responding, the sending service eventually gives up — and nobody notices that events have stopped arriving for hours. Professional setups monitor actively: a monitoring system checks whether events arrived within an expected timeframe and alerts on silence. Simple indicator: if a shop regularly sends orders daily and nothing has arrived for hours, something's wrong.

Your operational plan also needs a defined process for webhook errors: which events failed to process, why, and how are they recovered? Many sending systems keep failed deliveries for a limited time and allow retry — you need to know this window. Errors shouldn't silently vanish into log files; they should surface in a channel someone reviews daily. A simple dashboard with status indicator per webhook connection handles this reliably.

A webhook receiver is an outward-facing address — anyone who knows it can theoretically send data to it. That's exactly why authenticity checking isn't optional, it's the foundation of any serious implementation. Signature verification is standard: the sending service adds a cryptographic signature to each message, which the receiver verifies before processing. Without this check, an attacker could inject fake events and trigger unauthorised actions. Encryption during transmission is essential too, so content can't be read in transit.

The second critical aspect is data protection, since webhooks often carry personal data — a new order contains name and address, a contact form holds prospect details. Standard principles apply: only transfer data fields necessary for the downstream process, and design the reception and processing path to comply with data protection rules. If data flows through a cloud service as an intermediary, that service must be a contractual data processor, and server location matters.

In practice: treat a webhook receiver address like an access point, not a harmless notification. Keep it non-public, secure it, and log its traffic — so you can always trace which events arrived and whether they were genuine.