Hosting, CDN & Edge

The territory

28 core terms mapped for this field, ranked by how often builders reach for them. Each one is a future entry. Want to bust one? One entry, one file, one pull request.

• CDN (content delivery network)global cache network serving files from nearby locations"make images load fast worldwide" · "copies of my site everywhere"
• Edge functioncode that runs in a datacenter near the user"run my code close to people" · "serverless but nearer"
• Cache invalidation / purgeforcibly clearing stale cached copies after a change"site still shows the old version" · "how do I force a refresh"
• Origin serverthe true source the CDN pulls content from"the real server behind the cache" · "where files actually live"
• Cache hit / cache misswhether edge cache serves a request or forwards it to origin"did it come from the cache" · "why is it still hitting my server"
• Cache-Control / cache TTLheader and lifetime telling caches how long to keep content"how long before it refreshes" · "expiry setting"
• DNS records (A, AAAA, CNAME)mappings that point a domain at a server"connect my domain to the host" · "point the name somewhere"
• DNS propagationdelay before DNS changes become visible across recursive resolvers"why isn't my domain working yet" · "waiting for DNS to update"
• TLS certificate / TLS terminationthe padlock, and where encryption is decrypted"make it https" · "SSL certificate setup" · "HTTPS termination"
• Cold startdelay when a serverless function boots after idling"first visit is always slow" · "spins up before responding"
• Serverless computing / functions as a service (FaaS)run code without managing servers, billed per invocation"no server to babysit" · "just upload the function"
• Reverse proxyserver in front that routes and caches requests to backends"thing that sits in front" · "traffic director"
• Region / multi-regionwhich geography your compute and data live in"servers in Europe too" · "closer to my users"
• Stale-while-revalidateserve old copy instantly while fetching a fresh one"instant but updates behind the scenes"
• Cache keythe exact identity a cached response is stored under"why are two pages sharing one cached copy" · "what makes a cache entry unique"
• Edge middlewaretiny code intercepting requests before they hit a route"redirect or rewrite before the page loads"
• Rewrite vs redirectserve other content silently vs send browser elsewhere"keep the URL but show something else"
• Edge runtime vs Node.js runtimelimited fast V8 sandbox vs full server runtime"this npm package won't run on the edge" · "which runtime do I pick"
• Container image / containerpackaged app plus environment, and the running copy of it"ship the whole environment" · "Docker thing"
• PaaS vs IaaSmanaged platform versus raw infrastructure you run yourself"managed hosting or my own server" · "how much infra do I have to manage"
• Object storage / storage bucketflat file store for assets, addressed by key"somewhere to dump images and videos" · "S3-style storage"
• Egress feescharges for data leaving the provider's network"why is my bandwidth bill huge"
• Load balancerspreads incoming traffic across multiple servers"share the traffic out"
• Autoscalingcapacity grows and shrinks with demand automatically"handles a traffic spike by itself"
• Immutable asset / content hashingfilenames change on change, so caching is forever"cache my JS and CSS forever" · "hashed filenames"
• Brotli / gzip compressionshrinking text responses in transit"turn on compression" · "make my responses smaller"
• Image CDN / on-the-fly transformsresize, crop, reformat images at request time"auto-resize images per device"
• Bandwidth throttlingcapping data throughput per client or connection"cap how much data one client pulls" · "slow down heavy downloads"

Deeper in the field

• Vary header cache splits by device, language, or encoding
• Surrogate key / cache tag label letting you purge groups of pages at once
• Cache warming preloads content to avoid initial cache misses
• Edge cache hit ratio share of requests served without touching origin
• Origin shield extra cache layer protecting the origin from stampedes
• Cache stampede / thundering herd many misses hit origin at once when cache expires
• Anycast routing / point of presence (PoP) one IP routed to the nearest edge location
• HTTP/3 / QUIC newer transport with faster connection setup
• DNS TTL how long resolvers cache a DNS answer before refreshing
• Nameserver (NS record) delegates a domain's DNS authority to another provider
• Wildcard domain / subdomain routing one deploy serving many customer subdomains
• Health check probe deciding whether an origin should receive traffic
• Failover routes traffic to a healthy backup when the primary fails
• Request timeout / execution limit maximum time a request or function may run
• Vertical vs horizontal scaling bigger machine vs more machines
• Compute instance / virtual machine persistent virtual server the builder provisions and manages
• Bare-metal server / virtual private server (VPS) rented physical machine versus a virtualized slice of one
• Ephemeral filesystem local files may vanish when an instance restarts or moves
• Persistent volume durable disk attached to a hosted instance or container
• Edge KV / distributed key-value store small globally replicated data readable at the edge