diff --git a/packages/components-shared/src/components/Authenticate.svelte b/packages/components-shared/src/components/Authenticate.svelte
index 61e7150be..b24573299 100644
--- a/packages/components-shared/src/components/Authenticate.svelte
+++ b/packages/components-shared/src/components/Authenticate.svelte
@@ -2,7 +2,15 @@
 	import { onMount, type Snippet } from 'svelte';
 
 	import { requestAuthenticate, requestReplay } from 'rgs-requests';
-	import { stateUrlDerived, stateBet, stateConfig, stateModal, stateUi } from 'state-shared';
+	import {
+		stateUrlDerived,
+		stateBet,
+		stateConfig,
+		stateMeta,
+		stateModal,
+		stateUi,
+		reconcileBetModeMeta,
+	} from 'state-shared';
 	import { API_AMOUNT_MULTIPLIER, MOST_USED_BET_INDEXES } from 'constants-shared/bet';
 
 	type Props = { children: Snippet };
@@ -66,6 +74,15 @@
 				stateConfig.betMenuOptions = stateConfig.betAmountOptions.filter((_, index) =>
 					MOST_USED_BET_INDEXES.includes(index),
 				);
+
+				// Example of authenticateData.config.gameModes
+				// [
+				// 	{ "mode": "base", "costMultiplier": 1, "maxBet": 2000000000 },
+				// 	{ "mode": "bonus", "costMultiplier": 200, "maxBet": 2000000000 }
+				// ]
+				if (authenticateData.config?.gameModes?.length) {
+					stateMeta.betModeMeta = reconcileBetModeMeta(authenticateData.config.gameModes);
+				}
 			}
 
 			// round
diff --git a/packages/state-shared/src/stateMeta.svelte.ts b/packages/state-shared/src/stateMeta.svelte.ts
index de5d69c80..950754e62 100644
--- a/packages/state-shared/src/stateMeta.svelte.ts
+++ b/packages/state-shared/src/stateMeta.svelte.ts
@@ -59,3 +59,35 @@ export const stateMeta = $state({
 export const stateMetaDerived = {
 	betModeMetaList: () => Object.values(stateMeta.betModeMeta),
 };
+
+/**
+ * Reconcile `betModeMeta` against the bet modes the RGS reports at authentication.
+ *
+ * `betModeMeta` defaults to a placeholder table that does not describe any
+ * particular game. Modes it lists that the RGS does not know are rejected with
+ * ERR_VAL "invalid amount" when played, and a costMultiplier that disagrees with
+ * the published math is wrong in the UI before it is ever sent.
+ *
+ * Server-reported modes win on identity and cost; presentation a game has already
+ * set (assets, copy, type) is kept for the modes that survive.
+ */
+export const reconcileBetModeMeta = (
+	gameModes: { mode: string; costMultiplier: number }[],
+): BetModeMeta => {
+	const reconciled: BetModeMeta = {};
+
+	gameModes.forEach(({ mode, costMultiplier }) => {
+		const key = mode.toUpperCase();
+		const existing = stateMeta.betModeMeta[key] ?? stateMeta.betModeMeta[mode.toLowerCase()];
+
+		reconciled[key] = {
+			...(existing ?? DEFAULT_BET_MODE_META.BASE),
+			mode: key,
+			costMultiplier,
+			// only infer when the game has not described this mode itself
+			type: existing?.type ?? (costMultiplier === 1 ? 'default' : 'buy'),
+		} as BetModeData;
+	});
+
+	return reconciled;
+};