diff --git a/packages/taler-wallet-core/src/db.ts b/packages/taler-wallet-core/src/db.ts
index ac3c79e20..ecc5509dc 100644
--- a/packages/taler-wallet-core/src/db.ts
+++ b/packages/taler-wallet-core/src/db.ts
@@ -39,11 +39,11 @@ export function openTalerDatabase(
     if (oldVersion === 0) {
       for (const n in Stores) {
         if ((Stores as any)[n] instanceof Store) {
-          const si: Store<any> = (Stores as any)[n];
+          const si: Store<string, any> = (Stores as any)[n];
           const s = db.createObjectStore(si.name, si.storeParams);
           for (const indexName in si as any) {
             if ((si as any)[indexName] instanceof Index) {
-              const ii: Index<any, any> = (si as any)[indexName];
+              const ii: Index<string, string, any, any> = (si as any)[indexName];
               s.createIndex(ii.indexName, ii.keyPath, ii.options);
             }
           }
@@ -57,7 +57,7 @@ export function openTalerDatabase(
     logger.info(`upgrading database from ${oldVersion} to ${newVersion}`);
     for (const n in Stores) {
       if ((Stores as any)[n] instanceof Store) {
-        const si: Store<any> = (Stores as any)[n];
+        const si: Store<string, any> = (Stores as any)[n];
         let s: IDBObjectStore;
         if ((si.storeParams?.versionAdded ?? 1) > oldVersion) {
           s = db.createObjectStore(si.name, si.storeParams);
@@ -66,7 +66,7 @@ export function openTalerDatabase(
         }
         for (const indexName in si as any) {
           if ((si as any)[indexName] instanceof Index) {
-            const ii: Index<any, any> = (si as any)[indexName];
+            const ii: Index<string, string, any, any> = (si as any)[indexName];
             if ((ii.options?.versionAdded ?? 0) > oldVersion) {
               s.createIndex(ii.indexName, ii.keyPath, ii.options);
             }
diff --git a/packages/taler-wallet-core/src/operations/balance.ts b/packages/taler-wallet-core/src/operations/balance.ts
index 91c5e639e..b82e4c9d1 100644
--- a/packages/taler-wallet-core/src/operations/balance.ts
+++ b/packages/taler-wallet-core/src/operations/balance.ts
@@ -38,7 +38,13 @@ interface WalletBalance {
  */
 export async function getBalancesInsideTransaction(
   ws: InternalWalletState,
-  tx: TransactionHandle,
+  tx: TransactionHandle<
+    | typeof Stores.reserves
+    | typeof Stores.coins
+    | typeof Stores.reserves
+    | typeof Stores.refreshGroups
+    | typeof Stores.withdrawalGroups
+  >,
 ): Promise<BalancesResponse> {
   const balanceStore: Record<string, WalletBalance> = {};
 
diff --git a/packages/taler-wallet-core/src/operations/pending.ts b/packages/taler-wallet-core/src/operations/pending.ts
index 4f6477d50..a42d89c9a 100644
--- a/packages/taler-wallet-core/src/operations/pending.ts
+++ b/packages/taler-wallet-core/src/operations/pending.ts
@@ -37,7 +37,7 @@ import {
   getDurationRemaining,
   durationMin,
 } from "../util/time";
-import { TransactionHandle } from "../util/query";
+import { Store, TransactionHandle } from "../util/query";
 import { InternalWalletState } from "./state";
 import { getBalancesInsideTransaction } from "./balance";
 
@@ -52,7 +52,7 @@ function updateRetryDelay(
 }
 
 async function gatherExchangePending(
-  tx: TransactionHandle,
+  tx: TransactionHandle<typeof Stores.exchanges>,
   now: Timestamp,
   resp: PendingOperationsResponse,
   onlyDue = false,
@@ -171,7 +171,7 @@ async function gatherExchangePending(
 }
 
 async function gatherReservePending(
-  tx: TransactionHandle,
+  tx: TransactionHandle<typeof Stores.reserves>,
   now: Timestamp,
   resp: PendingOperationsResponse,
   onlyDue = false,
@@ -226,7 +226,7 @@ async function gatherReservePending(
 }
 
 async function gatherRefreshPending(
-  tx: TransactionHandle,
+  tx: TransactionHandle<typeof Stores.refreshGroups>,
   now: Timestamp,
   resp: PendingOperationsResponse,
   onlyDue = false,
@@ -255,7 +255,7 @@ async function gatherRefreshPending(
 }
 
 async function gatherWithdrawalPending(
-  tx: TransactionHandle,
+  tx: TransactionHandle<typeof Stores.withdrawalGroups>,
   now: Timestamp,
   resp: PendingOperationsResponse,
   onlyDue = false,
@@ -295,7 +295,7 @@ async function gatherWithdrawalPending(
 }
 
 async function gatherProposalPending(
-  tx: TransactionHandle,
+  tx: TransactionHandle<typeof Stores.proposals>,
   now: Timestamp,
   resp: PendingOperationsResponse,
   onlyDue = false,
@@ -346,7 +346,7 @@ async function gatherProposalPending(
 }
 
 async function gatherTipPending(
-  tx: TransactionHandle,
+  tx: TransactionHandle<typeof Stores.tips>,
   now: Timestamp,
   resp: PendingOperationsResponse,
   onlyDue = false,
@@ -376,7 +376,7 @@ async function gatherTipPending(
 }
 
 async function gatherPurchasePending(
-  tx: TransactionHandle,
+  tx: TransactionHandle<typeof Stores.purchases>,
   now: Timestamp,
   resp: PendingOperationsResponse,
   onlyDue = false,
@@ -419,7 +419,7 @@ async function gatherPurchasePending(
 }
 
 async function gatherRecoupPending(
-  tx: TransactionHandle,
+  tx: TransactionHandle<typeof Stores.recoupGroups>,
   now: Timestamp,
   resp: PendingOperationsResponse,
   onlyDue = false,
diff --git a/packages/taler-wallet-core/src/operations/recoup.ts b/packages/taler-wallet-core/src/operations/recoup.ts
index 634869ece..585c91a09 100644
--- a/packages/taler-wallet-core/src/operations/recoup.ts
+++ b/packages/taler-wallet-core/src/operations/recoup.ts
@@ -46,7 +46,7 @@ import {
 import { Amounts } from "../util/amounts";
 import { createRefreshGroup, processRefreshGroup } from "./refresh";
 import { RefreshReason, TalerErrorDetails } from "../types/walletTypes";
-import { TransactionHandle } from "../util/query";
+import { Store, StoreParams, TransactionHandle } from "../util/query";
 import { encodeCrock, getRandomBytes } from "../crypto/talerCrypto";
 import { getTimestampNow } from "../util/time";
 import { guardOperationException } from "./errors";
@@ -82,7 +82,7 @@ async function incrementRecoupRetry(
 
 async function putGroupAsFinished(
   ws: InternalWalletState,
-  tx: TransactionHandle,
+  tx: TransactionHandle<typeof Stores.recoupGroups>,
   recoupGroup: RecoupGroupRecord,
   coinIdx: number,
 ): Promise<void> {
@@ -366,7 +366,7 @@ async function processRecoupGroupImpl(
 
 export async function createRecoupGroup(
   ws: InternalWalletState,
-  tx: TransactionHandle,
+  tx: TransactionHandle<typeof Stores.recoupGroups | typeof Stores.coins>,
   coinPubs: string[],
 ): Promise<string> {
   const recoupGroupId = encodeCrock(getRandomBytes(32));
diff --git a/packages/taler-wallet-core/src/operations/refresh.ts b/packages/taler-wallet-core/src/operations/refresh.ts
index c92ce9209..21c884d48 100644
--- a/packages/taler-wallet-core/src/operations/refresh.ts
+++ b/packages/taler-wallet-core/src/operations/refresh.ts
@@ -52,9 +52,7 @@ import {
   durationMax,
   durationMul,
 } from "../util/time";
-import {
-  readSuccessResponseJsonOrThrow,
-} from "../util/http";
+import { readSuccessResponseJsonOrThrow } from "../util/http";
 import {
   codecForExchangeMeltResponse,
   codecForExchangeRevealResponse,
@@ -567,7 +565,11 @@ async function processRefreshSession(
  */
 export async function createRefreshGroup(
   ws: InternalWalletState,
-  tx: TransactionHandle,
+  tx: TransactionHandle<
+    | typeof Stores.denominations
+    | typeof Stores.coins
+    | typeof Stores.refreshGroups
+  >,
   oldCoinPubs: CoinPublicKey[],
   reason: RefreshReason,
 ): Promise<RefreshGroupId> {
diff --git a/packages/taler-wallet-core/src/operations/refund.ts b/packages/taler-wallet-core/src/operations/refund.ts
index 49d03ea15..e0d060376 100644
--- a/packages/taler-wallet-core/src/operations/refund.ts
+++ b/packages/taler-wallet-core/src/operations/refund.ts
@@ -103,7 +103,7 @@ function getRefundKey(d: MerchantCoinRefundStatus): string {
 }
 
 async function applySuccessfulRefund(
-  tx: TransactionHandle,
+  tx: TransactionHandle<typeof Stores.coins | typeof Stores.denominations>,
   p: PurchaseRecord,
   refreshCoinsMap: Record<string, { coinPub: string }>,
   r: MerchantCoinRefundSuccessStatus,
@@ -162,7 +162,7 @@ async function applySuccessfulRefund(
 }
 
 async function storePendingRefund(
-  tx: TransactionHandle,
+  tx: TransactionHandle<typeof Stores.denominations | typeof Stores.coins>,
   p: PurchaseRecord,
   r: MerchantCoinRefundFailureStatus,
 ): Promise<void> {
@@ -212,7 +212,7 @@ async function storePendingRefund(
 }
 
 async function storeFailedRefund(
-  tx: TransactionHandle,
+  tx: TransactionHandle<typeof Stores.coins | typeof Stores.denominations>,
   p: PurchaseRecord,
   refreshCoinsMap: Record<string, { coinPub: string }>,
   r: MerchantCoinRefundFailureStatus,
diff --git a/packages/taler-wallet-core/src/operations/reserves.ts b/packages/taler-wallet-core/src/operations/reserves.ts
index b20570e09..a2a1b3018 100644
--- a/packages/taler-wallet-core/src/operations/reserves.ts
+++ b/packages/taler-wallet-core/src/operations/reserves.ts
@@ -81,7 +81,11 @@ import {
 } from "../util/http";
 import { codecForAny } from "../util/codec";
 import { URL } from "../util/url";
-import { initRetryInfo, getRetryDuration, updateRetryInfoTimeout } from "../util/retries";
+import {
+  initRetryInfo,
+  getRetryDuration,
+  updateRetryInfoTimeout,
+} from "../util/retries";
 
 const logger = new Logger("reserves.ts");
 
@@ -523,7 +527,8 @@ async function updateReserve(
   if (result.isError) {
     if (
       resp.status === 404 &&
-      result.talerErrorResponse.code === TalerErrorCode.EXCHANGE_RESERVES_GET_STATUS_UNKNOWN
+      result.talerErrorResponse.code ===
+        TalerErrorCode.EXCHANGE_RESERVES_GET_STATUS_UNKNOWN
     ) {
       ws.notify({
         type: NotificationType.ReserveNotYetFound,
@@ -863,7 +868,7 @@ export async function createTalerWithdrawReserve(
  * Get payto URIs needed to fund a reserve.
  */
 export async function getFundingPaytoUris(
-  tx: TransactionHandle,
+  tx: TransactionHandle<typeof Stores.reserves | typeof Stores.exchanges>,
   reservePub: string,
 ): Promise<string[]> {
   const r = await tx.get(Stores.reserves, reservePub);
diff --git a/packages/taler-wallet-core/src/util/query.ts b/packages/taler-wallet-core/src/util/query.ts
index fa0d8beb7..08572fbd2 100644
--- a/packages/taler-wallet-core/src/util/query.ts
+++ b/packages/taler-wallet-core/src/util/query.ts
@@ -270,13 +270,21 @@ class ResultStream<T> {
   }
 }
 
-type StrKey<T> = string & keyof T;
-
 type StoreName<S> = S extends Store<infer N, any> ? N : never;
 type StoreContent<S> = S extends Store<any, infer R> ? R : never;
 type IndexRecord<Ind> = Ind extends Index<any, any, any, infer R> ? R : never;
 
-export class TransactionHandle<StoreTypes extends Store<string, {}>> {
+type InferStore<S> = S extends Store<infer N, infer R> ? Store<N, R> : never;
+type InferIndex<Ind> = Ind extends Index<
+  infer StN,
+  infer IndN,
+  infer KT,
+  infer RT
+>
+  ? Index<StN, IndN, KT, RT>
+  : never;
+
+export class TransactionHandle<StoreTypes extends Store<string, any>> {
   constructor(private tx: IDBTransaction) {}
 
   put<S extends StoreTypes>(
@@ -306,14 +314,9 @@ export class TransactionHandle<StoreTypes extends Store<string, {}>> {
   }
 
   getIndexed<
-    StoreName extends StrKey<StoreTypes>,
-    IndexName extends string,
-    S extends IDBValidKey,
-    T
-  >(
-    index: Index<StoreName, IndexName, S, T>,
-    key: any,
-  ): Promise<T | undefined> {
+    St extends StoreTypes,
+    Ind extends Index<StoreName<St>, string, any, any>
+  >(index: InferIndex<Ind>, key: any): Promise<IndexRecord<Ind> | undefined> {
     const req = this.tx
       .objectStore(index.storeName)
       .index(index.indexName)
@@ -321,39 +324,37 @@ export class TransactionHandle<StoreTypes extends Store<string, {}>> {
     return requestToPromise(req);
   }
 
-  iter<N extends StrKey<StoreTypes>, T extends StoreTypes[N]>(
-    store: Store<N, T>,
+  iter<St extends InferStore<StoreTypes>>(
+    store: St,
     key?: any,
-  ): ResultStream<T> {
+  ): ResultStream<StoreContent<St>> {
     const req = this.tx.objectStore(store.name).openCursor(key);
-    return new ResultStream<T>(req);
+    return new ResultStream<StoreContent<St>>(req);
   }
 
   iterIndexed<
-    StoreName extends StrKey<StoreTypes>,
-    IndexName extends string,
-    S extends IDBValidKey,
-    T
-  >(index: Index<StoreName, IndexName, S, T>, key?: any): ResultStream<T> {
+    St extends InferStore<StoreTypes>,
+    Ind extends InferIndex<Index<StoreName<St>, string, any, any>>
+  >(index: Ind, key?: any): ResultStream<IndexRecord<Ind>> {
     const req = this.tx
       .objectStore(index.storeName)
       .index(index.indexName)
       .openCursor(key);
-    return new ResultStream<T>(req);
+    return new ResultStream<IndexRecord<Ind>>(req);
   }
 
-  delete<N extends StrKey<StoreTypes>, T extends StoreTypes[N]>(
-    store: Store<N, T>,
+  delete<St extends StoreTypes>(
+    store: InferStore<St>,
     key: any,
   ): Promise<void> {
     const req = this.tx.objectStore(store.name).delete(key);
     return requestToPromise(req);
   }
 
-  mutate<N extends StrKey<StoreTypes>, T extends StoreTypes[N]>(
-    store: Store<N, T>,
+  mutate<St extends StoreTypes>(
+    store: InferStore<St>,
     key: any,
-    f: (x: T) => T | undefined,
+    f: (x: StoreContent<St>) => StoreContent<St> | undefined,
   ): Promise<void> {
     const req = this.tx.objectStore(store.name).openCursor(key);
     return applyMutation(req, f);
@@ -583,9 +584,7 @@ export class Database {
   }
 
   async getIndexed<Ind extends Index<string, string, any, any>>(
-    index: Ind extends Index<infer IndN, infer StN, any, infer R>
-      ? Index<IndN, StN, any, R>
-      : never,
+    index: InferIndex<Ind>,
     key: any,
   ): Promise<IndexRecord<Ind> | undefined> {
     const tx = this.db.transaction([index.storeName], "readonly");
@@ -624,16 +623,16 @@ export class Database {
     return new ResultStream<T>(req);
   }
 
-  iterIndex<N extends string, I extends string, S extends IDBValidKey, T>(
-    index: Index<N, I, S, T>,
+  iterIndex<Ind extends Index<string, string, any, any>>(
+    index: InferIndex<Ind>,
     query?: any,
-  ): ResultStream<T> {
+  ): ResultStream<IndexRecord<Ind>> {
     const tx = this.db.transaction([index.storeName], "readonly");
     const req = tx
       .objectStore(index.storeName)
       .index(index.indexName)
       .openCursor(query);
-    return new ResultStream<T>(req);
+    return new ResultStream<IndexRecord<Ind>>(req);
   }
 
   async runWithReadTransaction<T, StoreTypes extends Store<string, any>>(