Glossary
The language of
wallet passes.
Every term you meet when evaluating, building or running a wallet pass program, defined in plain language.
Pass formats & distribution
Add to walletThe moment a pass is offered to a phone, typically a button or link that delivers a PKPass on iPhone or a save link on Android.ArtworkThe full-bleed image behind an Apple Wallet poster pass, filling the pass with fields laid over it.Featured actionsUp to two tappable tiles on the face of an Apple Wallet pass, introduced in iOS 27, deep-linking into rewards, benefits or membership details.Hero imageThe wide banner image on a Google Wallet pass, set on the class or the object and shown across the card.LocalizationShipping a single wallet pass with labels, values and images in several languages, so the wallet shows each member the pass in the language their phone is set to.Manifest and signatureThe two files in every PKPass that prove it is genuine; manifest.json lists a hash of every other file and signature is a detached signature over the manifest, made with the pass type ID certificate.Pass bundleA set of related passes a wallet stacks together as one entry, so several tickets or offers occupy a single place in the member's wallet.Pass fieldsThe labeled slots on a wallet pass, header, primary, secondary, auxiliary and back, that hold a pass's text, with the layout fixed by the pass style and the values updated by the issuer.Pass imagesThe named image slots in a wallet pass, icon, logo, strip, thumbnail, background and footer on Apple Wallet, logo and hero on Google Wallet, each with a fixed place and size.Pass sharingWhether a wallet pass can be sent from one person's wallet to another; a per-pass setting an issuer decides based on whether the pass is personal or transferable.PKPassThe signed file format for Apple Wallet passes, a zip bundle containing the pass definition, images and a cryptographic signature.Poster layoutApple Wallet's full-bleed pass design, introduced for event tickets in iOS 18 and extended to other pass styles in iOS 27, with artwork filling the pass.Save linkA signed URL that adds a pass to Google Wallet with one tap, the Android counterpart to downloading a PKPass file.Semantic tagsMachine-readable metadata in an Apple Wallet pass that tells the system what the pass means, powering Siri suggestions, relevance and richer pass experiences.Strip imageThe wide banner image across the top of an Apple Wallet store card, coupon or event ticket, sitting behind the primary fields.Wallet passA digital card stored in a phone's wallet app, such as Apple Wallet or Google Wallet, that can display live information and be scanned or tapped at a point of sale.
Certificates & identifiers
Authentication tokenThe per-pass secret baked into an Apple Wallet pass that a device presents when talking to the pass web service; without it a pass cannot update.Class IDThe identifier of a Google Wallet class, the shared template every pass object in a program is built on.Class review statusThe state of a Google Wallet pass class in Google's review, draft, under review, approved or rejected; a class is submitted for review when it is ready to issue real passes.Device registrationThe link an iPhone creates between an added pass and the issuer's web service, which is what makes push updates to the pass possible.Issuer IDThe Google Wallet account identifier that owns a program's pass classes and objects, Google's counterpart to Apple's pass type identifier.Pass objectOne member's pass in Google Wallet, an API record holding their identifier, balance and state, built on a shared class.Pass Type ID certificateThe certificate Apple issues for one pass type identifier, obtained by uploading a certificate signing request in the developer portal; its private key signs every pass of that type.Pass type identifierThe reverse-domain identifier registered in an Apple Developer account that ties every Apple Wallet pass to its issuer and signing certificate.Pass web serviceThe HTTPS service named in an Apple Wallet pass that devices call to register, check for changes and fetch a fresh copy; the channel every live update travels through.pass.jsonThe JSON file inside a PKPass bundle that defines a pass's type, fields, colors, barcodes and behavior.PKCSA password-protected file bundling a certificate and its private key, the format signing certificates and NFC keys usually travel in.Serial numberThe unique identifier of one individual pass within a pass type, the half of the address that names a specific member's pass.Service account (Google Wallet)The Google Cloud identity, with its own private key, that a platform uses to call the Google Wallet API and to sign save links; it must be granted access to the issuer account whose passes it manages.Team IDThe ten-character identifier Apple assigns to a developer account, declared in every Apple Wallet pass and required to match the signing certificate.VAS ProviderA company approved by Apple to issue NFC-enabled wallet passes and to bring merchants through Apple's VAS entitlement process.WWDR certificateApple's intermediate certificate that vouches for pass signing certificates; every valid .pkpass signature chains through it.X.509 (DER encoding)The standard format for digital certificates; DER is its raw binary encoding, PEM the same bytes wrapped in base64 text.
Identification at the till
Account bindingBinding an NFC pass to the member's own account so it cannot be shared, making the pass a personal credential rather than a transferable card.Apple VASApple's NFC protocol for presenting wallet passes such as loyalty and membership cards to a contactless reader, often in the same tap as payment.Auto-presentmentThe wallet surfacing the right pass on its own when the phone or watch nears a compatible reader, with no searching or unlocking by the member.Aztec codeA compact two-dimensional barcode with a central bullseye finder, common in rail and transit ticketing and supported by both major wallets.Card acquisitionThe payment terminal step that reads what the shopper presents, payment card and wallet pass alike, before any payment is processed.CodabarA legacy numeric linear barcode still used by libraries, blood banks and photo labs, and one of the formats a wallet pass can render.Code 128A dense alphanumeric linear barcode supported by both Apple Wallet and Google Wallet, and the usual choice for member numbers on a pass.Code 39An older alphanumeric linear barcode, self-checking and widely readable, still common in membership cards, libraries and industrial labelling.Collector ID (Google Smart Tap)The numeric identifier Google assigns to a merchant for Smart Tap; readers present it over NFC and a pass class lists it to say which merchants may redeem its passes.Data MatrixA compact two-dimensional matrix barcode used for marking small items and regulated goods, and one of the formats a wallet pass can render.EAN-13The thirteen-digit retail barcode standard used worldwide for product identification, and one of the barcode formats a wallet pass can render.EAN-8The eight-digit short form of the EAN retail barcode, made for small packages, and one of the formats a wallet pass can render.ECP (Enhanced Contactless Polling)Apple's extension to NFC polling, in which a reader announces which service it is asking for so the device can select the matching pass before the tap.EMVCoThe standards body owned by the major card networks that defines the chip, contactless, tokenization and PAR specifications payment terminals are built on.Google Smart TapGoogle's NFC protocol for presenting Google Wallet passes to a contactless reader, the Android counterpart to Apple VAS.Interleaved 2 of 5A dense numeric-only linear barcode, used for cartons and logistics labels, with ITF-14 as its fixed-length retail variant.Merchant ID (Apple VAS)The identifier an Apple VAS reader uses to request a specific program's pass; derived by hashing the pass type identifier, so a reader can be configured for a program without any secret.NFC identificationIdentifying a member by an NFC tap of their wallet pass, on a reader or payment terminal, often in the same tap as payment.One-tap identificationPayment and loyalty identification carried in a single tap, so the member is recognized in the same gesture that pays.PAR (Payment Account Reference)An EMVCo-defined value that identifies one payment account across the physical card, its wallet versions and every token, used to match a payment back to an enrolled member.PDF417A stacked two-dimensional barcode with high data capacity, used for boarding passes, tickets and identity documents, and supported by both major wallets.QR and barcode identificationIdentifying a member by scanning the QR code or barcode on their wallet pass, using the scanners a merchant already owns.QR codeA two-dimensional matrix barcode, readable by scanners and phone cameras alike, and the most widely usable code format on a wallet pass.Smart Tap redemptionThe read of a Google Wallet pass over NFC, in which the phone hands a merchant's reader the pass's Smart Tap redemption value, typically the member identifier, encrypted for that merchant.Two-tap identificationA dedicated tap that reads the wallet pass first, followed by a separate tap to pay, on terminals or readers that handle the two steps apart.UPC-AThe twelve-digit North American retail barcode, a subset of EAN-13, and one of the formats a wallet pass can render.Watch passesWallet passes as they appear on a smartwatch; Apple Watch mirrors the iPhone's passes and taps with Apple VAS, while Google Wallet on Wear OS carries a subset of Android passes.
Lifecycle & messaging
APNs (Apple Push Notification service)Apple's push infrastructure; for wallet passes it carries the silent nudge that tells a device to fetch an updated pass.Associated appThe merchant app a wallet pass can point to, shown as an install or open link on the pass; optional, and absent on programs that run entirely from the pass.AutomationA trigger-based message that fires per member when something happens, such as a pass being installed, a birthday, or a tier change.BeaconA small Bluetooth transmitter whose identifier an Apple Wallet pass can list, so the pass appears on the lock screen when the member is within range of it, indoors where GPS is not enough.CampaignA one-time or scheduled push message sent to a chosen audience of pass holders, appearing on the lock screen through the pass.Change messageThe per-field template in an Apple Wallet pass that turns a value change into a lock screen notification, such as announcing a new points balance.Deep link (universal link)A link that lands somewhere specific rather than on a homepage; a universal link is the verified kind that opens the app when installed and the web when not.Estimated reachThe number of pass holders a campaign or segment will actually hit, shown before sending.Frequency capThe per-contact limit on how often automations may message a member, protecting the lock screen from message pile-ups.Live ActivityAn iOS lock screen surface that shows live-updating status; in Apple Wallet it applies to boarding passes only, not loyalty or membership passes.Lock screen messageA message a wallet pass surfaces on the phone's lock screen, triggered by a pass update, an offer, or relevance such as being near a store.Pass migrationMoving a live pass program from one wallet platform to another so that passes already in members' wallets keep working and updating.Pass relevanceThe locations, times and events defined in a pass that make the wallet surface it on the lock screen at the moment it is useful.PlaceholdersPersonalization variables in a message, written as double-brace tokens, that fill in each member's own values at send time.Push updateThe mechanism that refreshes a pass already in a wallet, so balances, tiers and offers stay current without the member doing anything.SegmentA saved audience of pass holders built from rules over loyalty state, such as points, tier, last visit or wallet type.WebhookAn HTTP request Stell sends to your endpoint the moment something happens to a pass, so your systems learn about it without polling.
Programs & enrollment
App ClipA small, installation-free slice of an iOS app that opens instantly from a QR code, NFC tag or link to handle one task.App Clip CodeApple's circular scannable marker, readable by camera or NFC tap, that launches an App Clip on iPhone.CredentialA pass that proves who someone is or what they are entitled to, usually presented at a reader: a gym check-in, a members-only area, a staff benefit.GDPRThe EU's data protection regulation, which governs how loyalty programs collect member data, the consent captured at enrollment, and members' rights over it.Hosted onboardingA hosted enrollment flow that turns a new prospect into a member, ending with a brand-new pass in their wallet.KYCKnow your customer, the regulated process of verifying who a customer is, and the looser retail idea of actually knowing who is buying from you.Pass holderA contact who currently has a pass installed in a wallet, the reachable population of a wallet pass program.Points balanceThe member's current points, carried as a live field on the pass and updated the moment points are earned or spent.Post-purchase enrollmentConverting a paying non-member into a member in the moments after checkout, at the payment terminal or through the receipt.Stamp cardThe buy-X-get-one punch card as a wallet pass, with stamps that update live at each visit instead of ink on paper.TierA member's level in a loyalty program, bronze, silver, gold, shown on the pass and usable as a trigger and a targeting rule.
Next step
See what this looks like on a pass.
The glossary defines it. The next pages show it on the terminals merchants already run, and the merchants running it.