purchase-flow

Purchase Flow

Implements the full client side purchase sequence: build BillingFlowParams, launch launchBillingFlow(), receive callbacks in PurchasesUpdatedListener, handle every response code, then verify, acknowledge, and grant access.

Phase 0: Intent

Use this skill when you need to:

• Launch a purchase from a "Buy" tap for a one time product or a subscription.
• Wire a PurchasesUpdatedListener and handle every BillingResponseCode.
• Decide where to verify, where to acknowledge, and how to grant entitlements idempotently.
• Support pending transactions (cash at convenience store, carrier billing, slow card auth).
• Bundle multiple items into a single transaction (PBL 7.0+).

Out of scope: connecting BillingClient, querying ProductDetails, subscription upgrades or downgrades, and retry or error taxonomy beyond the launch results listed below.

Phase 1: Discovery

Confirm the preconditions before you build params.

Check	How	Why
BillingClient connected	billingClient.isReady == true	Calls fail without a live connection.
ProductDetails cached	Held from a prior queryProductDetailsAsync	Required input to ProductDetailsParams.
Pending purchases enabled	BillingClient.Builder.enablePendingPurchases(...) was called	Users with delayed payment cannot buy otherwise.
Existing ownership known	Ran queryPurchasesAsync() recently	Prevents ITEM_ALREADY_OWNED surprises.
Offer token resolved (subs only)	Selected from subscriptionOfferDetails	Missing token returns DEVELOPER_ERROR.

Record the product type (INAPP vs SUBS), the selected basePlanId, and the chosen offerToken before moving on.

Phase 2: Plan

Decide the following before you call newBuilder().

Account identifiers

• obfuscatedAccountId: attach a one way hash of your internal user id. Never pass raw email or plain text. Helps Google Play detect fraud across devices.
• obfuscatedProfileId: attach only if your app has multiple profiles under one account (family streaming, kid profiles).