[{"data":1,"prerenderedAt":216},["ShallowReactive",2],{"content-query-VjMJOaVIeE":3,"reference-index-/glossary":72},{"_path":4,"_dir":5,"_draft":6,"_partial":6,"_locale":5,"title":7,"description":8,"layout":9,"cta":10,"related":18,"body":31,"_type":65,"_id":66,"_source":67,"_file":68,"_stem":69,"_extension":70,"sitemap":71},"/glossary","",false,"Webhook glossary: key terms in plain English","Plain-English definitions of webhook terms: webhook endpoint, callback URL, payload, signature, secret, retries, idempotency, fan-out, dead-letter queue and tunnels.","reference",{"eyebrow":11,"title":12,"text":13,"to":14,"label":15,"secondaryTo":16,"secondaryLabel":17},"Webhook Relay","Webhook forwarding with retries, logs and localhost delivery","Receive webhooks on a permanent public URL, then filter, transform, retry and deliver them to any destination, including localhost and private networks.","/webhook-gateway/","See webhook forwarding","/webhook-bin/","Try the free Webhook Bin",[19,22,25,28],{"title":20,"to":21},"What is a webhook?","/blog/what-is-webhook/",{"title":23,"to":24},"HTTP errors explained","/http-errors/",{"title":26,"to":27},"Localhost ports","/localhost/",{"title":29,"to":30},"Webhook best practices","/blog/webhook-best-practices/",{"type":32,"children":33,"toc":62},"root",[34,58],{"type":35,"tag":36,"props":37,"children":38},"element","p",{},[39,42,48,50,56],{"type":40,"value":41},"text","Webhooks have their own vocabulary: endpoints, payloads, signatures, retries, idempotency keys. Each entry gives a short definition and an example. New to the topic? Start with ",{"type":35,"tag":43,"props":44,"children":45},"a",{"href":21},[46],{"type":40,"value":47},"what is a webhook",{"type":40,"value":49},", then the ",{"type":35,"tag":43,"props":51,"children":53},{"href":52},"/glossary/webhook-endpoint/",[54],{"type":40,"value":55},"webhook endpoint",{"type":40,"value":57}," entry.",{"type":35,"tag":59,"props":60,"children":61},"reference-index",{"section":4},[],{"title":5,"searchDepth":63,"depth":63,"links":64},3,[],"markdown","content:glossary:index.md","content","glossary/index.md","glossary/index","md",{"loc":4},[73,81,88,95,102,110,117,125,132,139,146,153,160,167,174,181,188,195,202,209],{"_path":74,"title":75,"description":76,"crumb":77,"summary":78,"group":79,"order":80},"/glossary/at-least-once-delivery","What is at-least-once delivery? Webhook delivery guarantees","At-least-once delivery guarantees a message is delivered one or more times, never zero, so duplicates are possible. How it compares to at-most-once and exactly-once, and why webhooks use it.","At-least-once delivery","Every message arrives, possibly more than once.","Delivery and reliability",23,{"_path":82,"title":83,"description":84,"crumb":85,"summary":86,"group":87,"order":63},"/glossary/callback-url","What is a callback URL? Callback URL vs webhook URL","A callback URL is an address you give a service so it can call you back later. How callback URLs work in OAuth, payments and async APIs, and how they differ from webhook URLs.","Callback URL","An address a service calls you back on: OAuth redirects, async jobs, webhooks.","Basics",{"_path":89,"title":90,"description":91,"crumb":92,"summary":93,"group":79,"order":94},"/glossary/dead-letter-queue","What is a dead-letter queue (DLQ)? Definition and examples","A dead-letter queue (DLQ) holds messages that couldn't be processed or delivered after all retries, so they aren't lost. How DLQs work in SQS and for webhooks, and how to handle them.","Dead-letter queue","Where messages go after they run out of retries, so they aren't lost.",24,{"_path":96,"title":97,"description":98,"crumb":99,"summary":100,"group":79,"order":101},"/glossary/exponential-backoff","What is exponential backoff? Formula, jitter and examples","Exponential backoff is a retry strategy that doubles the wait after each failed attempt, usually with random jitter and a cap. The formula, code examples and how webhooks use it.","Exponential backoff","Retry with growing waits, usually doubling, plus jitter and a cap.",21,{"_path":103,"title":104,"description":105,"crumb":106,"summary":107,"group":108,"order":109},"/glossary/hmac","What is HMAC? Hash-based message authentication explained","HMAC (hash-based message authentication code) combines a secret key and a hash function to prove a message is authentic and unmodified. How it works, code examples and why webhooks use it.","HMAC","A keyed hash that proves a message is authentic and unmodified.","Security",12,{"_path":111,"title":112,"description":113,"crumb":114,"summary":115,"group":79,"order":116},"/glossary/idempotency","What is idempotency? Idempotent webhooks and APIs","Idempotency means doing an operation twice has the same effect as doing it once. Why webhook handlers must be idempotent, idempotency keys, and code for deduplicating events.","Idempotency","Doing it twice has the same effect as doing it once.",22,{"_path":118,"title":119,"description":120,"crumb":121,"summary":122,"group":123,"order":124},"/glossary/reverse-proxy","What is a reverse proxy? Definition and nginx example","A reverse proxy is a server that sits in front of your app, receives client requests and forwards them to it. How it works, an nginx config, and the 502 and 504 errors it causes.","Reverse proxy","A server in front of your app that receives requests and passes them on.","Infrastructure",33,{"_path":126,"title":127,"description":128,"crumb":129,"summary":130,"group":108,"order":131},"/glossary/standard-webhooks","What is Standard Webhooks? Headers, signing and examples","Standard Webhooks is an open spec for sending webhooks consistently: webhook-id, webhook-timestamp and webhook-signature headers, whsec_ secrets and HMAC-SHA256 signing.","Standard Webhooks","An open spec for consistent webhook headers, signing and secrets.",13,{"_path":133,"title":134,"description":135,"crumb":136,"summary":137,"group":123,"order":138},"/glossary/tunnel","What is a tunnel (localhost tunnel)? How it works","A localhost tunnel gives a server on your machine or private network a public URL by relaying traffic over an outbound connection. How tunnels work, when to use one, and common pitfalls.","Tunnel","A public URL for a local server, relayed over an outbound connection.",32,{"_path":140,"title":141,"description":142,"crumb":143,"summary":144,"group":87,"order":145},"/glossary/webhook-endpoint","What is a webhook endpoint?","A webhook endpoint is the URL on your server that receives webhook HTTP requests from another service. How it works, an example handler, and what makes a good one.","Webhook endpoint","The URL on your server that receives webhook requests.",1,{"_path":147,"title":148,"description":149,"crumb":150,"summary":151,"group":79,"order":152},"/glossary/webhook-fan-out","What is webhook fan-out? Send one webhook to many endpoints","Webhook fan-out delivers one incoming webhook to several destinations at once. Why providers that allow one URL need it, how to implement it, and the pitfalls to avoid.","Webhook fan-out","Deliver one webhook to several destinations.",26,{"_path":154,"title":155,"description":156,"crumb":157,"summary":158,"group":123,"order":159},"/glossary/webhook-forwarding","What is webhook forwarding? How to forward webhooks","Webhook forwarding receives webhooks on a public URL and relays them to another destination: localhost, a private server or several endpoints. How it works and how to set it up.","Webhook forwarding","Receive webhooks on a public URL and relay them somewhere else.",30,{"_path":161,"title":162,"description":163,"crumb":164,"summary":165,"group":123,"order":166},"/glossary/webhook-gateway","What is a webhook gateway? Definition and features","A webhook gateway sits between webhook senders and your endpoints: it authenticates, stores, retries, routes and fans out webhooks. What it does, when you need one, and how it differs from an API gateway.","Webhook gateway","A layer that receives, stores, retries and routes webhooks for you.",31,{"_path":168,"title":169,"description":170,"crumb":171,"summary":172,"group":87,"order":173},"/glossary/webhook-listener","What is a webhook listener? Definition and example","A webhook listener is the server or process that waits for incoming webhook requests and handles them. How it works, example listeners in Node.js and Python, and how to run one locally.","Webhook listener","The server or process that waits for and handles incoming webhooks.",5,{"_path":175,"title":176,"description":177,"crumb":178,"summary":179,"group":87,"order":180},"/glossary/webhook-payload","What is a webhook payload? Structure and examples","A webhook payload is the data in the body of a webhook request, usually JSON describing the event. Example payloads, formats, size limits and how to handle them safely.","Webhook payload","The event data in the body of a webhook request.",4,{"_path":182,"title":183,"description":184,"crumb":185,"summary":186,"group":79,"order":187},"/glossary/webhook-replay","What is webhook replay? Redelivery vs replay attacks","Webhook replay means resending a past webhook, either deliberately to recover missed events or maliciously as a replay attack. How each works and how to handle both safely.","Webhook replay","Resending a past webhook: recovery tool or replay attack.",25,{"_path":189,"title":190,"description":191,"crumb":192,"summary":193,"group":79,"order":194},"/glossary/webhook-retries","What are webhook retries? How redelivery works","Webhook retries are repeat delivery attempts a provider makes when your endpoint fails or times out. Which responses trigger retries, typical schedules, and how to handle them safely.","Webhook retries","Repeat delivery attempts after a failed or timed-out webhook.",20,{"_path":196,"title":197,"description":198,"crumb":199,"summary":200,"group":108,"order":201},"/glossary/webhook-secret","What is a webhook secret? Signing secrets explained","A webhook secret is a shared key the provider uses to sign each webhook and you use to verify it. Where to find it, how to store and rotate it, and common mistakes.","Webhook secret","The shared key used to sign and verify webhooks.",11,{"_path":203,"title":204,"description":205,"crumb":206,"summary":207,"group":108,"order":208},"/glossary/webhook-signature","What is a webhook signature? How verification works","A webhook signature is an HMAC of the request body, sent in a header, that proves a webhook came from the provider and wasn't modified. Formats, verification code and common mistakes.","Webhook signature","A header that proves a webhook is genuine and unmodified.",10,{"_path":210,"title":211,"description":212,"crumb":213,"summary":214,"group":87,"order":215},"/glossary/webhook-url","What is a webhook URL? Definition and how to get one","A webhook URL is the public HTTPS address a service sends webhook requests to. What it looks like, the two kinds of webhook URL, and how to get one.","Webhook URL","The public address a provider sends webhook requests to.",2,1793199699780]