# Glossary Plain definitions for the terms that come up when you ship deep links, attribute installs, and read link analytics. Each entry stands on its own and points at the page that goes deeper. ## deep link A deep link is a URL that opens a specific screen inside a mobile app instead of a web page. On iOS and Android the same HTTPS address can open the app when it is installed and verified, and load the web page in a browser when it is not. See: [Deep linking](https://warplink.app/docs/concepts/deep-linking) ## Universal Link A Universal Link is Apple's verified deep link. iOS checks the apple-app-site-association file on the link domain against the app's Associated Domains entitlement, then hands a matching URL to the installed app rather than Safari. iOS fetches that file at install and on app update, so edits do not reach devices immediately. See: [Universal Links not opening](https://warplink.app/blog/universal-links-not-opening) ## Android App Link An Android App Link is a verified HTTPS deep link. Android fetches assetlinks.json from the link domain and compares its SHA-256 certificate fingerprints with the installed app's signature. A verified host opens the app directly. An unverified host falls back to the browser or to a chooser dialog. See: [Android App Links autoVerify failed](https://warplink.app/blog/android-app-links-autoverify-failed) ## custom URL scheme A custom URL scheme is an app-private address such as myapp://product/42. It is not verified against any domain and nothing on the web answers it, so a device without the app gets an error or silence. Useful as a fallback inside embedded browsers, never as the address you publish. See: [Deep links in in-app browsers](https://warplink.app/blog/deep-linking-in-app-browsers) ## apple-app-site-association (AASA) The apple-app-site-association file is the JSON document iOS reads to decide which app may open a domain's links. It is served at /.well-known/apple-app-site-association over HTTPS, with a 200 status, an application/json content type, and no redirects. Each appIDs entry is the Team ID joined to the bundle identifier. See: [The AASA debug checklist](https://warplink.app/blog/apple-app-site-association-not-working) ## assetlinks.json assetlinks.json is the Digital Asset Links file Android reads to verify App Links. It lives at /.well-known/assetlinks.json and holds a JSON array of statements, each naming a package and the SHA-256 fingerprints of the certificates that sign it. With Play App Signing, list the app signing key, not the upload key. See: [The assetlinks.json verification checklist](https://warplink.app/blog/android-app-links-autoverify-failed) ## associated domains Associated Domains is the iOS capability that lists the hosts an app may claim, written as applinks:example.com in the entitlement. The bare host is required, with no scheme, path, or port, and it does not cover subdomains. The provisioning profile that signs the build must carry the capability too. See: [Universal Links not opening](https://warplink.app/blog/universal-links-not-opening) ## intent filter and autoVerify An intent filter declares the URLs an Android activity can handle. Adding android:autoVerify="true" to a filter that uses the https scheme, the VIEW action, and the BROWSABLE and DEFAULT categories asks the system to verify the host against assetlinks.json. Without it, Android never verifies and shows the browser or a chooser instead. See: [Android App Links autoVerify failed](https://warplink.app/blog/android-app-links-autoverify-failed) ## deferred deep link A deferred deep link preserves a link's destination through an app install. The tap is recorded before the visitor reaches the store, and on first launch the app asks the server which recent click it belongs to. The original destination and its parameters come back, so a new user lands on the shared content. See: [Deferred deep links](https://warplink.app/docs/concepts/deferred-deep-links) ## install attribution Install attribution connects a new app install back to the click that produced it, and to the link, campaign, or share behind that click. Mobile makes the join hard because the store sits between the tap and the launch, so the connection is rebuilt from whatever signals survived the install. See: [Install attribution](https://warplink.app/docs/concepts/attribution) ## Play Install Referrer The Play Install Referrer is a string the Google Play Store carries through an install and hands to the app afterwards. The app reads it on first launch through the Play Install Referrer library, which gives an exact, deterministic attribution match. It is attached only when the visitor is sent to a play.google.com address. See: [Deferred deep linking on Android](https://warplink.app/blog/deferred-deep-linking-android) ## IDFV The IDFV, or Identifier for Vendor, is an iOS identifier shared by every app from the same vendor on one device. It cannot follow a user into another company's apps, it is readable without a permission prompt, and it is exempt from App Tracking Transparency. WarpLink uses it only to recognize an install that asks again. See: [Deferred deep linking on iOS](https://warplink.app/blog/deferred-deep-linking-ios) ## probabilistic matching Probabilistic matching is the fallback when no deterministic signal exists. The server hashes the request IP, language, and time zone when sent, and finds a recent click with the same hash. Each tap can be matched only within the app's match window, and pending entries expire automatically. A matched install keeps that hash for your plan's data retention period. See: [Deferred deep links](https://warplink.app/docs/concepts/deferred-deep-links) ## deterministic and probabilistic matching A deterministic match reads an exact identifier, so it is certain: the install referrer carried through the Play Store on Android, and a referral invitation token on iOS. A vendor identifier only recognizes a device already on record. A probabilistic match compares coarse signals and returns a scored match. See also probabilistic matching. See: [Install attribution](https://warplink.app/docs/concepts/attribution) ## match confidence Match confidence is the score WarpLink returns with an attributed install, from 0.0 to 1.0. A deterministic match is always 1.0. A probabilistic match starts from the age of the click and the signals available. Use it to choose where to route the user. See: [Install attribution](https://warplink.app/docs/concepts/attribution) ## referral link A referral link is a WarpLink link marked is_referral that credits an install to the person who shared it. A friend taps it, installs, and signs up. Your app or backend then claims the referral, WarpLink records the credit, and a signed webhook tells your backend to grant the reward. See: [Referrals](https://warplink.app/docs/guides/referrals) ## installer id An installer id is an opaque id from your app, up to 128 characters, that identifies the person who signed up from a referral. Use a dedicated random id such as a UUID, not a primary key, email address, or phone number. The first valid claim for an app and installer id wins, and repeating it is safe. See: [Referrals](https://warplink.app/docs/guides/referrals) ## invitation page The invitation page is the short page an iPhone visitor without your app sees after tapping a referral link, before the App Store. It copies an invitation for the app to read after the install. You set its look and wording for each app in the dashboard, and ordinary links never show it. See: [Referrals](https://warplink.app/docs/guides/referrals) ## exact and estimated match An exact match names the link from evidence that survived the install: an invitation token, the Play Install Referrer, or a link open. It scores 1.0 and sets matchGuaranteed. An estimated match comes from probabilistic matching on coarse signals, returns a confidence score, and reports evidence_class estimated. See: [Install attribution](https://warplink.app/docs/concepts/attribution) ## short link A short link is a compact HTTPS URL that redirects to a longer destination. The short path, called the slug, is either generated or chosen. Because the destination lives on the server, a printed or shared short link can be repointed later, and every request through it can be recorded as a click. See: [Deep linking](https://warplink.app/docs/concepts/deep-linking) ## custom domain A custom domain serves short links on a host you own, such as go.yourapp.com, instead of a shared shortener domain. Setup is a CNAME for routing plus a second CNAME that lets the certificate be issued and renewed. Association files are generated for the host, so the links still open your app. See: [Custom domains](https://warplink.app/docs/concepts/custom-domains) ## WarpLink domain A WarpLink domain is any host the SDKs will resolve a link on: the shared aplnk.to domain plus every custom domain you have verified and declared. It is broader than a custom domain, which means only a domain you own and have configured, and does not include aplnk.to. See: [Custom domains](https://warplink.app/docs/concepts/custom-domains) ## click deduplication Click deduplication decides which repeated clicks count once. A link can be tapped many times by one person, so a raw count overstates reach. The rule on this service treats a click as unique per combination of link, visitor address, and a twenty-four hour window, computed in the database at write time rather than at a cache layer. See: [Install attribution](https://warplink.app/docs/concepts/attribution) ## UTM parameters UTM parameters are query string fields that label the source of a visit: utm_source, utm_medium, utm_campaign, utm_term, and utm_content. They ride on the destination URL, so any analytics that reads the landing page can group traffic by campaign. A link can append them at redirect time instead of each share carrying them. See: [Pass UTM parameters through deep links](https://warplink.app/blog/pass-utm-parameters-through-deep-links) ## social preview (Open Graph) A social preview is the card a chat app or social network renders for a shared URL, built from Open Graph and Twitter Card meta tags. A link service detects the crawler by user agent and returns HTML with those tags, while a real visitor gets the redirect. Images want at least 1200 by 630 pixels. See: [Social previews](https://warplink.app/docs/concepts/social-previews) ## in-app browser An in-app browser is a web view an app embeds so links open inside it rather than in the system browser. Some embeds behave like the real browser and route verified deep links normally. Others intercept navigation, so the operating system never sees a tap and the app is never opened. See: [Deep links in in-app browsers](https://warplink.app/blog/deep-linking-in-app-browsers) ## QR deep link A QR deep link is an HTTPS URL printed as a scannable pattern that routes a scan into an app. Neither the iOS nor the Android camera opens an app on its own: each decodes the URL, shows it, and waits for a tap. That tap is what lets a verified link hand off. See: [QR code deep linking](https://warplink.app/blog/qr-code-deep-linking) ## App Tracking Transparency (ATT) App Tracking Transparency is the iOS framework that requires an app to ask permission before tracking a user across other companies' apps and websites. It gates the advertising identifier, the IDFA. Link-based attribution that uses only the vendor identifier and coarse request signals falls outside it, so no prompt is needed. See: [Install Attribution Without an MMP or Click ID: How It Works for Small Apps](https://warplink.app/blog/install-attribution-without-an-mmp) ## MCP server An MCP server exposes a service to AI clients over the Model Context Protocol. WarpLink runs one at api.warplink.app/mcp, so an assistant can create links, register apps, read click analytics, manage keys and domains, and report usage. It is free on every plan, sharing the REST API limit of 60 requests per minute per credential (API key or OAuth token). See: [AI access](https://warplink.app/docs/ai-access) ## SDK key An SDK key is the credential the mobile SDKs use to call WarpLink, created in the dashboard under Keys. It is pre-scoped to link resolution and install attribution, never expires, and can be tied to one app. It can call only the SDK endpoints. See: [Authentication](https://warplink.app/docs/authentication) ## API key An API key is the credential for backend scripts, CI, and AI agents such as the MCP server, created in the dashboard under Keys as an API key with scopes you choose. It is scoped to the REST API and the MCP server. See: [Authentication](https://warplink.app/docs/authentication)