Definition
A webhook is a mechanism whereby one system automatically sends an HTTP request (typically POST) to a pre-registered endpoint at another service - immediately when a specific event occurs. Unlike polling, where the client periodically asks 'is there anything new?', the webhook source proactively pushes data: 'something just happened, here is the data.' This provides real-time updates without unnecessary network load or delay. Webhooks are used for event-drivenArchitecture principle where system components communicate via events rather than direct calls - increases loose coupling and scalability. integration between systems - for example: a KISCustomer Information System - the core system at power suppliers and grid companies for customer management and billing. receives a webhook call from SAMTYGDTvimenning platform for Elhub integration - handles all message types and processes to Elhub. when a supplier switchProcess where an electricity customer changes their power supplier - handled through standardised messages via Elhub. has been confirmed by ElhubNational hub for metering data and market processes in the Norwegian electricity market., or an MDMMeter Data Management - system for collection, storage, quality assurance and distribution of metering data from the electricity grid. system is notified instantly when new metering dataData from electricity meters - the foundation for billing, balance settlement and market processes in the power market. becomes available. Webhook receivers must implement validationThe first step in VEE - automated checks of metering data against technical and logical limits to detect obviously erroneous values. (signature, token) to ensure that incoming calls genuinely originate from the expected source, rather than from a malicious third party. For systems with reliability requirements, webhooks should be combined with retry logicPattern for handling temporary failures in distributed systems - automatic retry with exponential backoff. and acknowledgement mechanisms.