diff --git a/apps/web/src/BoothScreen.tsx b/apps/web/src/BoothScreen.tsx
index 60c1630..d81c8af 100644
--- a/apps/web/src/BoothScreen.tsx
+++ b/apps/web/src/BoothScreen.tsx
@@ -112,6 +112,9 @@ function eventBadges(p: LedgerEvent["payload"]): string[] {
   if (p.permitRefused) keys.push("booth.badgeSubRefused");
   if (p.ticketPrinted === false) keys.push("booth.badgeNoTicket");
   if (p.subscriptionSale) keys.push("booth.badgeSubSale");
+  // Subscriber entered/exited outside their plan's allowed window → owes a deferred
+  // transient charge, collected (gated) at exit. Flag it so the operator KNOWS now.
+  if (typeof p.windowOwedMinor === "number" && p.windowOwedMinor > 0) keys.push("booth.badgeWindowCharge");
   if (p.source === "manual" && !p.subscriptionSale) keys.push("booth.badgeManualOpen");
   return keys;
 }
diff --git a/apps/web/src/lib/i18n/en.ts b/apps/web/src/lib/i18n/en.ts
index 74e8590..488a08c 100644
--- a/apps/web/src/lib/i18n/en.ts
+++ b/apps/web/src/lib/i18n/en.ts
@@ -157,6 +157,7 @@ export const en: Catalog = {
     badgeManualOpen: "manual open",
     badgeSubRefused: "subscription refused",
     badgeSubSale: "subscription sale",
+    badgeWindowCharge: "out-of-window — owes fee",
     badgeNoTicket: "ticket not printed",
     feedSourceBooth: "booth",
     feedSourceReader: "reader",
diff --git a/apps/web/src/lib/i18n/sq.ts b/apps/web/src/lib/i18n/sq.ts
index 31f30e3..2e90d6a 100644
--- a/apps/web/src/lib/i18n/sq.ts
+++ b/apps/web/src/lib/i18n/sq.ts
@@ -161,6 +161,7 @@ export const sq = {
     badgeManualOpen: "hapje manuale",
     badgeSubRefused: "abonimi u refuzua",
     badgeSubSale: "shitje abonimi",
+    badgeWindowCharge: "jashtë orarit — detyrim",
     badgeNoTicket: "bileta nuk u printua",
     feedSourceBooth: "kabinë",
     feedSourceReader: "lexues",
diff --git a/packages/shared/src/index.ts b/packages/shared/src/index.ts
index 8e122e8..84529da 100644
--- a/packages/shared/src/index.ts
+++ b/packages/shared/src/index.ts
@@ -287,6 +287,15 @@ export interface LedgerPayload {
   /** cash_in / cash_out voucher: a human-facing voucher number printed on the slip
    *  (Mandat Nr.). Sequential per type; signed for reproducibility. */
   readonly voucherNo?: string;
+  /** subscription tariff-bridge: an early-entry / late-exit transient charge OWED for
+   *  parking outside the plan's allowed window, stamped on the vehicle_entry and collected
+   *  (gated) at exit. The priced gap + tariff version travel alongside for reproducibility.
+   *  See wiki/entities/subscription.md ("tariff bridge"). */
+  readonly windowOwedMinor?: number;
+  readonly windowCurrency?: string;
+  readonly windowTariffVersionId?: string;
+  readonly windowGapStart?: string;
+  readonly windowGapEnd?: string;
   /** Free-form for forward-compat without a schema change. */
   readonly [k: string]: unknown;
 }