Webhook and messaging glossary
Short, practical definitions of the terms you run into when building webhooks and event-driven systems. Each entry explains what the term means and when it matters, with links to longer guides where one exists. For a structured walkthrough of how these pieces fit together, start with Webhooks University.
Webhook fundamentals
- What is a webhook?
- What is a webhook endpoint?
- What is a webhook URL?
- What is a webhook payload?
- Fat vs. thin webhook payloads
- What is a webhook provider?
- What is a webhook consumer?
- What is a webhook retry?
- webhook-timeout
- Webhook Rate Limit
- What is webhook fan-out?
- Callback URL
- Event Types
Security and verification
- What is webhook security?
- Webhook Authentication
- What is a webhook signature?
- What is a webhook secret?
- What is secret rotation?
- What is a replay attack?
- What is timestamp tolerance?
- What is an IP allowlist?
- HMAC (Hash-based Message Authentication Code)
- SSRF (Server Side Request Forgery)
Delivery semantics
- What is at-least-once delivery?
- What is exactly-once delivery?
- What is idempotency?
- What is webhook deduplication?
Webhook infrastructure
Queues and message brokers
- Message Broker
- Event Broker
- Distributed Message Broker
- Distributed Message Queue
- Background Queue
- Priority Queue
- Quorum Queue
- Dead Letter Queue
- SQS Visibility Timeout
- Exponential backoff