diff --git a/src/crypto/cryptoApi.ts b/src/crypto/cryptoApi.ts
index d3a93ff8d..5e3237836 100644
--- a/src/crypto/cryptoApi.ts
+++ b/src/crypto/cryptoApi.ts
@@ -41,6 +41,7 @@ import { BenchmarkResult, CoinWithDenom, PayCoinInfo } from "../walletTypes";
 import * as timer from "../timer";
 
 import { startWorker } from "./startWorker";
+import { throws } from "assert";
 
 /**
  * State of a crypto worker.
@@ -98,6 +99,11 @@ export class CryptoApi {
    */
   private numBusy: number = 0;
 
+  /**
+   * Did we stop accepting new requests?
+   */
+  private stopped: boolean = false;
+
   public enableTracing = false;
 
   /**
@@ -106,6 +112,7 @@ export class CryptoApi {
   terminateWorkers() {
     for (let worker of this.workers) {
       if (worker.w) {
+        this.enableTracing && console.log("terminating worker");
         worker.w.terminate();
         if (worker.terminationTimerHandle) {
           worker.terminationTimerHandle.clear();
@@ -120,10 +127,19 @@ export class CryptoApi {
     }
   }
 
+  stop() {
+    this.terminateWorkers();
+    this.stopped = true;
+  }
+
   /**
    * Start a worker (if not started) and set as busy.
    */
   wake(ws: WorkerState, work: WorkItem): void {
+    if (this.stopped) {
+      this.enableTracing && console.log("not waking, as cryptoApi is stopped");
+      return;
+    }
     if (ws.currentWorkItem !== null) {
       throw Error("assertion failed");
     }
@@ -158,7 +174,7 @@ export class CryptoApi {
         ws.w = null;
       }
     };
-    ws.terminationTimerHandle = timer.after(5 * 1000, destroy);
+    ws.terminationTimerHandle = timer.after(15 * 1000, destroy);
   }
 
   handleWorkerError(ws: WorkerState, e: ErrorEvent) {
@@ -253,6 +269,7 @@ export class CryptoApi {
     priority: number,
     ...args: any[]
   ): Promise<T> {
+    this.enableTracing && console.log("cryptoApi: doRpc called");
     const p: Promise<T> = new Promise<T>((resolve, reject) => {
       const rpcId = this.nextRpcId++;
       const workItem: WorkItem = {
diff --git a/src/crypto/nodeWorker.ts b/src/crypto/nodeWorker.ts
index fa942387a..b5a2e8b44 100644
--- a/src/crypto/nodeWorker.ts
+++ b/src/crypto/nodeWorker.ts
@@ -92,6 +92,7 @@ export class Worker {
    * Forcibly terminate the worker thread.
    */
   terminate () {
+    console.log("terminating node.js worker");
     this.child.kill("SIGINT");
   }
 }
diff --git a/src/headless/taler-wallet-cli.ts b/src/headless/taler-wallet-cli.ts
index c57c3ab00..e2b8b54ac 100644
--- a/src/headless/taler-wallet-cli.ts
+++ b/src/headless/taler-wallet-cli.ts
@@ -9,6 +9,9 @@ import Axios from "axios";
 import URI = require("urijs");
 
 import querystring = require("querystring");
+import { CheckPaymentResponse } from "../talerTypes";
+
+const enableTracing = false;
 
 class ConsoleNotifier implements Notifier {
   notify(): void {
@@ -18,29 +21,29 @@ class ConsoleNotifier implements Notifier {
 
 class ConsoleBadge implements Badge {
   startBusy(): void {
-    console.log("NOTIFICATION: busy");
+    enableTracing && console.log("NOTIFICATION: busy");
   }
   stopBusy(): void {
-    console.log("NOTIFICATION: busy end");
+    enableTracing && console.log("NOTIFICATION: busy end");
   }
   showNotification(): void {
-    console.log("NOTIFICATION: show");
+    enableTracing && console.log("NOTIFICATION: show");
   }
   clearNotification(): void {
-    console.log("NOTIFICATION: cleared");
+    enableTracing && console.log("NOTIFICATION: cleared");
   }
 }
 
 export class NodeHttpLib implements HttpRequestLibrary {
   async get(url: string): Promise<import("../http").HttpResponse> {
-    console.log("making GET request to", url);
+    enableTracing && console.log("making GET request to", url);
     const resp = await Axios({
       method: "get",
       url: url,
       responseType: "json",
     });
-    console.log("got response", resp.data);
-    console.log("resp type", typeof resp.data);
+    enableTracing && console.log("got response", resp.data);
+    enableTracing && console.log("resp type", typeof resp.data);
     return {
       responseJson: resp.data,
       status: resp.status,
@@ -51,15 +54,15 @@ export class NodeHttpLib implements HttpRequestLibrary {
     url: string,
     body: any,
   ): Promise<import("../http").HttpResponse> {
-    console.log("making POST request to", url);
+    enableTracing && console.log("making POST request to", url);
     const resp = await Axios({
       method: "post",
       url: url,
       responseType: "json",
       data: body,
     });
-    console.log("got response", resp.data);
-    console.log("resp type", typeof resp.data);
+    enableTracing && console.log("got response", resp.data);
+    enableTracing && console.log("resp type", typeof resp.data);
     return {
       responseJson: resp.data,
       status: resp.status,
@@ -70,15 +73,15 @@ export class NodeHttpLib implements HttpRequestLibrary {
     url: string,
     form: any,
   ): Promise<import("../http").HttpResponse> {
-    console.log("making POST request to", url);
+    enableTracing && console.log("making POST request to", url);
     const resp = await Axios({
       method: "post",
       url: url,
       data: querystring.stringify(form),
       responseType: "json",
     });
-    console.log("got response", resp.data);
-    console.log("resp type", typeof resp.data);
+    enableTracing && console.log("got response", resp.data);
+    enableTracing && console.log("resp type", typeof resp.data);
     return {
       responseJson: resp.data,
       status: resp.status,
@@ -152,6 +155,66 @@ async function createBankReserve(
   }
 }
 
+class MerchantBackendConnection {
+  constructor(
+    public merchantBaseUrl: string,
+    public merchantInstance: string,
+    public apiKey: string,
+  ) {}
+
+  async createOrder(
+    amount: string,
+    summary: string,
+    fulfillmentUrl: string,
+  ): Promise<{ orderId: string }> {
+    const reqUrl = new URI("order").absoluteTo(this.merchantBaseUrl).href();
+    const orderReq = {
+      order: {
+        amount,
+        summary,
+        fulfillment_url: fulfillmentUrl,
+        instance: this.merchantInstance,
+      },
+    };
+    const resp = await Axios({
+      method: "post",
+      url: reqUrl,
+      data: orderReq,
+      responseType: "json",
+      headers: {
+        Authorization: `ApiKey ${this.apiKey}`,
+      },
+    });
+    if (resp.status != 200) {
+      throw Error("failed to create bank reserve");
+    }
+    const orderId = resp.data.order_id;
+    if (!orderId) {
+      throw Error("no order id in response");
+    }
+    return { orderId };
+  }
+
+  async checkPayment(orderId: string): Promise<CheckPaymentResponse> {
+    const reqUrl = new URI("check-payment")
+      .absoluteTo(this.merchantBaseUrl)
+      .href();
+    const resp = await Axios({
+      method: "get",
+      url: reqUrl,
+      params: { order_id: orderId, instance: this.merchantInstance },
+      responseType: "json",
+      headers: {
+        Authorization: `ApiKey ${this.apiKey}`,
+      },
+    });
+    if (resp.status != 200) {
+      throw Error("failed to check payment");
+    }
+    return CheckPaymentResponse.checked(resp.data);
+  }
+}
+
 async function main() {
   const myNotifier = new ConsoleNotifier();
 
@@ -216,15 +279,54 @@ async function main() {
 
   await myWallet.confirmReserve({ reservePub: reserveResponse.reservePub });
 
-  //await myWallet.waitForReserveDrained(reserveResponse.reservePub);
+  await myWallet.processReserve(reserveResponse.reservePub);
 
-  //myWallet.clearNotification();
+  console.log("process reserve returned");
 
-  //myWallet.stop();
+  const balance = await myWallet.getBalances();
 
-  const dbContents = await exportDb(myDb);
+  console.log(JSON.stringify(balance, null, 2));
 
-  console.log("db:", JSON.stringify(dbContents, null, 2));
+  const myMerchant = new MerchantBackendConnection(
+    "https://backend.test.taler.net/",
+    "default",
+    "sandbox",
+  );
+
+  const orderResp = await myMerchant.createOrder(
+    "TESTKUDOS:5",
+    "hello world",
+    "https://example.com/",
+  );
+
+  console.log("created order with orderId", orderResp.orderId);
+
+  const paymentStatus = await myMerchant.checkPayment(orderResp.orderId);
+
+  console.log("payment status", paymentStatus);
+
+  const contractUrl = paymentStatus.contract_url;
+  if (!contractUrl) {
+    throw Error("no contract URL in payment response");
+  }
+
+  const proposalId = await myWallet.downloadProposal(contractUrl);
+
+  console.log("proposal id", proposalId);
+
+  const checkPayResult = await myWallet.checkPay(proposalId);
+
+  console.log("check pay result", checkPayResult);
+
+  const confirmPayResult = await myWallet.confirmPay(proposalId, undefined);
+
+  console.log("confirmPayResult", confirmPayResult);
+
+  const paymentStatus2 = await myMerchant.checkPayment(orderResp.orderId);
+
+  console.log("payment status after wallet payment:", paymentStatus2);
+
+  myWallet.stop();
 }
 
 main().catch(err => {
diff --git a/src/logging.ts b/src/logging.ts
index ca073c10c..4e7b60b93 100644
--- a/src/logging.ts
+++ b/src/logging.ts
@@ -21,8 +21,8 @@
 import {
   QueryRoot,
   Store,
-  openPromise,
 } from "./query";
+import { openPromise } from "./promiseUtils";
 
 /**
  * Supported log levels.
diff --git a/src/promiseUtils.ts b/src/promiseUtils.ts
new file mode 100644
index 000000000..eb649471b
--- /dev/null
+++ b/src/promiseUtils.ts
@@ -0,0 +1,39 @@
+/*
+ This file is part of GNU Taler
+ (C) 2019 GNUnet e.V.
+
+ TALER is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+ export interface OpenedPromise<T> {
+  promise: Promise<T>;
+  resolve: (val: T) => void;
+  reject: (err: any) => void;
+ }
+
+/**
+ * Get an unresolved promise together with its extracted resolve / reject
+ * function.
+ */
+export function openPromise<T>(): OpenedPromise<T> {
+  let resolve: ((x?: any) => void) | null = null;
+  let reject: ((reason?: any) => void) | null = null;
+  const promise = new Promise<T>((res, rej) => {
+    resolve = res;
+    reject = rej;
+  });
+  if (!(resolve && reject)) {
+    // Never happens, unless JS implementation is broken
+    throw Error();
+  }
+  return { resolve, reject, promise };
+}
\ No newline at end of file
diff --git a/src/query.ts b/src/query.ts
index 5feb29a55..7308d9ede 100644
--- a/src/query.ts
+++ b/src/query.ts
@@ -14,13 +14,13 @@
  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
  */
 
-
 /**
  * Database query abstractions.
  * @module Query
  * @author Florian Dold
  */
 
+ import { openPromise } from "./promiseUtils";
 
 /**
  * Result of an inner join.
@@ -38,18 +38,17 @@ export interface JoinLeftResult<L, R> {
   right?: R;
 }
 
-
 /**
  * Definition of an object store.
  */
 export class Store<T> {
-  constructor(public name: string,
-              public storeParams?: IDBObjectStoreParameters,
-              public validator?: (v: T) => T) {
-  }
+  constructor(
+    public name: string,
+    public storeParams?: IDBObjectStoreParameters,
+    public validator?: (v: T) => T,
+  ) {}
 }
 
-
 /**
  * Options for an index.
  */
@@ -63,7 +62,6 @@ export interface IndexOptions {
   multiEntry?: boolean;
 }
 
-
 /**
  * Definition of an index.
  */
@@ -78,7 +76,12 @@ export class Index<S extends IDBValidKey, T> {
    */
   options: IndexOptions;
 
-  constructor(s: Store<T>, public indexName: string, public keyPath: string | string[], options?: IndexOptions) {
+  constructor(
+    s: Store<T>,
+    public indexName: string,
+    public keyPath: string | string[],
+    options?: IndexOptions,
+  ) {
     const defaultOptions = {
       multiEntry: false,
     };
@@ -91,7 +94,7 @@ export class Index<S extends IDBValidKey, T> {
    * because otherwise the compiler complains.  In iterIndex the
    * key type is pretty useful.
    */
-  protected _dummyKey: S|undefined;
+  protected _dummyKey: S | undefined;
 }
 
 /**
@@ -104,21 +107,29 @@ export interface QueryStream<T> {
    * The left side of the join is extracted via a function from the stream's
    * result, the right side of the join is the key of the index.
    */
-  indexJoin<S, I extends IDBValidKey>(index: Index<I, S>, keyFn: (obj: T) => I): QueryStream<JoinResult<T, S>>;
+  indexJoin<S, I extends IDBValidKey>(
+    index: Index<I, S>,
+    keyFn: (obj: T) => I,
+  ): QueryStream<JoinResult<T, S>>;
   /**
    * Join the current query with values from an index, and keep values in the
    * current stream that don't have a match.  The left side of the join is
    * extracted via a function from the stream's result, the right side of the
    * join is the key of the index.
    */
-  indexJoinLeft<S, I extends IDBValidKey>(index: Index<I, S>,
-                                          keyFn: (obj: T) => I): QueryStream<JoinLeftResult<T, S>>;
+  indexJoinLeft<S, I extends IDBValidKey>(
+    index: Index<I, S>,
+    keyFn: (obj: T) => I,
+  ): QueryStream<JoinLeftResult<T, S>>;
   /**
    * Join the current query with values from another object store.
    * The left side of the join is extracted via a function over the current query,
    * the right side of the join is the key of the object store.
    */
-  keyJoin<S, I extends IDBValidKey>(store: Store<S>, keyFn: (obj: T) => I): QueryStream<JoinResult<T, S>>;
+  keyJoin<S, I extends IDBValidKey>(
+    store: Store<S>,
+    keyFn: (obj: T) => I,
+  ): QueryStream<JoinResult<T, S>>;
 
   /**
    * Only keep elements in the result stream for which the predicate returns
@@ -166,7 +177,6 @@ export interface QueryStream<T> {
   run(): Promise<void>;
 }
 
-
 /**
  * Query result that consists of at most one value.
  */
@@ -184,20 +194,25 @@ export interface QueryValue<T> {
    * branch).  This is necessary since IndexedDB does not allow long-lived
    * transactions.
    */
-  cond<R>(f: (x: T) => boolean, onTrue: (r: QueryRoot) => R, onFalse: (r: QueryRoot) => R): Promise<void>;
+  cond<R>(
+    f: (x: T) => boolean,
+    onTrue: (r: QueryRoot) => R,
+    onFalse: (r: QueryRoot) => R,
+  ): Promise<void>;
 }
 
-
 abstract class BaseQueryValue<T> implements QueryValue<T> {
-
-  constructor(public root: QueryRoot) {
-  }
+  constructor(public root: QueryRoot) {}
 
   map<S>(f: (x: T) => S): QueryValue<S> {
     return new MapQueryValue<T, S>(this, f);
   }
 
-  cond<R>(f: (x: T) => boolean, onTrue: (r: QueryRoot) => R, onFalse: (r: QueryRoot) => R): Promise<void> {
+  cond<R>(
+    f: (x: T) => boolean,
+    onTrue: (r: QueryRoot) => R,
+    onFalse: (r: QueryRoot) => R,
+  ): Promise<void> {
     return new Promise<void>((resolve, reject) => {
       this.subscribeOne((v, tx) => {
         if (f(v)) {
@@ -228,7 +243,7 @@ class FirstQueryValue<T> extends BaseQueryValue<T> {
         return;
       }
       if (isDone) {
-          f(undefined, tx);
+        f(undefined, tx);
       } else {
         f(value, tx);
       }
@@ -247,37 +262,16 @@ class MapQueryValue<T, S> extends BaseQueryValue<S> {
   }
 }
 
-
 /**
  * Exception that should be thrown by client code to abort a transaction.
  */
 export const AbortTransaction = Symbol("abort_transaction");
 
-/**
- * Get an unresolved promise together with its extracted resolve / reject
- * function.
- */
-export function openPromise<T>(): any {
-  let resolve: ((x?: any) => void) | null = null;
-  let reject: ((reason?: any) => void) | null = null;
-  const promise = new Promise<T>((res, rej) => {
-    resolve = res;
-    reject = rej;
-  });
-  if (!(resolve && reject)) {
-    // Never happens, unless JS implementation is broken
-    throw Error();
-  }
-  return {resolve, reject, promise};
-}
-
-
 abstract class QueryStreamBase<T> implements QueryStream<T> {
-  abstract subscribe(f: (isDone: boolean,
-                         value: any,
-                         tx: IDBTransaction) => void): void;
-  constructor(public root: QueryRoot) {
-  }
+  abstract subscribe(
+    f: (isDone: boolean, value: any, tx: IDBTransaction) => void,
+  ): void;
+  constructor(public root: QueryRoot) {}
 
   first(): QueryValue<T> {
     return new FirstQueryValue(this);
@@ -291,20 +285,36 @@ abstract class QueryStreamBase<T> implements QueryStream<T> {
     return new QueryStreamMap(this, f);
   }
 
-  indexJoin<S, I extends IDBValidKey>(index: Index<I, S>,
-                                      keyFn: (obj: T) => I): QueryStream<JoinResult<T, S>> {
+  indexJoin<S, I extends IDBValidKey>(
+    index: Index<I, S>,
+    keyFn: (obj: T) => I,
+  ): QueryStream<JoinResult<T, S>> {
     this.root.addStoreAccess(index.storeName, false);
-    return new QueryStreamIndexJoin<T, S>(this, index.storeName, index.indexName, keyFn);
+    return new QueryStreamIndexJoin<T, S>(
+      this,
+      index.storeName,
+      index.indexName,
+      keyFn,
+    );
   }
 
-  indexJoinLeft<S, I extends IDBValidKey>(index: Index<I, S>,
-                                          keyFn: (obj: T) => I): QueryStream<JoinLeftResult<T, S>> {
+  indexJoinLeft<S, I extends IDBValidKey>(
+    index: Index<I, S>,
+    keyFn: (obj: T) => I,
+  ): QueryStream<JoinLeftResult<T, S>> {
     this.root.addStoreAccess(index.storeName, false);
-    return new QueryStreamIndexJoinLeft<T, S>(this, index.storeName, index.indexName, keyFn);
+    return new QueryStreamIndexJoinLeft<T, S>(
+      this,
+      index.storeName,
+      index.indexName,
+      keyFn,
+    );
   }
 
-  keyJoin<S, I extends IDBValidKey>(store: Store<S>,
-                                    keyFn: (obj: T) => I): QueryStream<JoinResult<T, S>> {
+  keyJoin<S, I extends IDBValidKey>(
+    store: Store<S>,
+    keyFn: (obj: T) => I,
+  ): QueryStream<JoinResult<T, S>> {
     this.root.addStoreAccess(store.name, false);
     return new QueryStreamKeyJoin<T, S>(this, store.name, keyFn);
   }
@@ -314,7 +324,7 @@ abstract class QueryStreamBase<T> implements QueryStream<T> {
   }
 
   toArray(): Promise<T[]> {
-    const {resolve, promise} = openPromise();
+    const { resolve, promise } = openPromise<T[]>();
     const values: T[] = [];
 
     this.subscribe((isDone, value) => {
@@ -326,12 +336,12 @@ abstract class QueryStreamBase<T> implements QueryStream<T> {
     });
 
     return Promise.resolve()
-                  .then(() => this.root.finish())
-                  .then(() => promise);
+      .then(() => this.root.finish())
+      .then(() => promise);
   }
 
   fold<A>(f: (x: T, acc: A) => A, init: A): Promise<A> {
-    const {resolve, promise} = openPromise();
+    const { resolve, promise } = openPromise<A>();
     let acc = init;
 
     this.subscribe((isDone, value) => {
@@ -343,12 +353,12 @@ abstract class QueryStreamBase<T> implements QueryStream<T> {
     });
 
     return Promise.resolve()
-                  .then(() => this.root.finish())
-                  .then(() => promise);
+      .then(() => this.root.finish())
+      .then(() => promise);
   }
 
   forEach(f: (x: T) => void): Promise<void> {
-    const {resolve, promise} = openPromise();
+    const { resolve, promise } = openPromise<void>();
 
     this.subscribe((isDone, value) => {
       if (isDone) {
@@ -359,12 +369,12 @@ abstract class QueryStreamBase<T> implements QueryStream<T> {
     });
 
     return Promise.resolve()
-                  .then(() => this.root.finish())
-                  .then(() => promise);
+      .then(() => this.root.finish())
+      .then(() => promise);
   }
 
   run(): Promise<void> {
-    const {resolve, promise} = openPromise();
+    const { resolve, promise } = openPromise<void>();
 
     this.subscribe((isDone, value) => {
       if (isDone) {
@@ -374,8 +384,8 @@ abstract class QueryStreamBase<T> implements QueryStream<T> {
     });
 
     return Promise.resolve()
-                  .then(() => this.root.finish())
-                  .then(() => promise);
+      .then(() => this.root.finish())
+      .then(() => promise);
   }
 }
 
@@ -401,7 +411,6 @@ class QueryStreamFilter<T> extends QueryStreamBase<T> {
   }
 }
 
-
 class QueryStreamFlatMap<T, S> extends QueryStreamBase<S> {
   constructor(public s: QueryStreamBase<T>, public flatMapFn: (v: T) => S[]) {
     super(s.root);
@@ -421,7 +430,6 @@ class QueryStreamFlatMap<T, S> extends QueryStreamBase<S> {
   }
 }
 
-
 class QueryStreamMap<S, T> extends QueryStreamBase<T> {
   constructor(public s: QueryStreamBase<S>, public mapFn: (v: S) => T) {
     super(s.root);
@@ -439,10 +447,13 @@ class QueryStreamMap<S, T> extends QueryStreamBase<T> {
   }
 }
 
-
 class QueryStreamIndexJoin<T, S> extends QueryStreamBase<JoinResult<T, S>> {
-  constructor(public s: QueryStreamBase<T>, public storeName: string, public indexName: string,
-              public key: any) {
+  constructor(
+    public s: QueryStreamBase<T>,
+    public storeName: string,
+    public indexName: string,
+    public key: any,
+  ) {
     super(s.root);
   }
 
@@ -457,7 +468,7 @@ class QueryStreamIndexJoin<T, S> extends QueryStreamBase<JoinResult<T, S>> {
       req.onsuccess = () => {
         const cursor = req.result;
         if (cursor) {
-          f(false, {left: value, right: cursor.value}, tx);
+          f(false, { left: value, right: cursor.value }, tx);
           cursor.continue();
         }
       };
@@ -465,10 +476,15 @@ class QueryStreamIndexJoin<T, S> extends QueryStreamBase<JoinResult<T, S>> {
   }
 }
 
-
-class QueryStreamIndexJoinLeft<T, S> extends QueryStreamBase<JoinLeftResult<T, S>> {
-  constructor(public s: QueryStreamBase<T>, public storeName: string, public indexName: string,
-              public key: any) {
+class QueryStreamIndexJoinLeft<T, S> extends QueryStreamBase<
+  JoinLeftResult<T, S>
+> {
+  constructor(
+    public s: QueryStreamBase<T>,
+    public storeName: string,
+    public indexName: string,
+    public key: any,
+  ) {
     super(s.root);
   }
 
@@ -485,11 +501,11 @@ class QueryStreamIndexJoinLeft<T, S> extends QueryStreamBase<JoinLeftResult<T, S
         const cursor = req.result;
         if (cursor) {
           gotMatch = true;
-          f(false, {left: value, right: cursor.value}, tx);
+          f(false, { left: value, right: cursor.value }, tx);
           cursor.continue();
         } else {
           if (!gotMatch) {
-            f(false, {left: value}, tx);
+            f(false, { left: value }, tx);
           }
         }
       };
@@ -497,10 +513,12 @@ class QueryStreamIndexJoinLeft<T, S> extends QueryStreamBase<JoinLeftResult<T, S
   }
 }
 
-
 class QueryStreamKeyJoin<T, S> extends QueryStreamBase<JoinResult<T, S>> {
-  constructor(public s: QueryStreamBase<T>, public storeName: string,
-              public key: any) {
+  constructor(
+    public s: QueryStreamBase<T>,
+    public storeName: string,
+    public key: any,
+  ) {
     super(s.root);
   }
 
@@ -515,7 +533,7 @@ class QueryStreamKeyJoin<T, S> extends QueryStreamBase<JoinResult<T, S>> {
       req.onsuccess = () => {
         const cursor = req.result;
         if (cursor) {
-          f(false, {left: value, right: cursor.value}, tx);
+          f(false, { left: value, right: cursor.value }, tx);
           cursor.continue();
         } else {
           f(true, undefined, tx);
@@ -525,7 +543,6 @@ class QueryStreamKeyJoin<T, S> extends QueryStreamBase<JoinResult<T, S>> {
   }
 }
 
-
 class IterQueryStream<T> extends QueryStreamBase<T> {
   private storeName: string;
   private options: any;
@@ -538,11 +555,10 @@ class IterQueryStream<T> extends QueryStreamBase<T> {
     this.subscribers = [];
 
     const doIt = (tx: IDBTransaction) => {
-      const {indexName = void 0, only = void 0} = this.options;
+      const { indexName = void 0, only = void 0 } = this.options;
       let s: any;
       if (indexName !== void 0) {
-        s = tx.objectStore(this.storeName)
-              .index(this.options.indexName);
+        s = tx.objectStore(this.storeName).index(this.options.indexName);
       } else {
         s = tx.objectStore(this.storeName);
       }
@@ -574,12 +590,11 @@ class IterQueryStream<T> extends QueryStreamBase<T> {
   }
 }
 
-
 /**
  * Root wrapper around an IndexedDB for queries with a fluent interface.
  */
 export class QueryRoot {
-  private work: Array<((t: IDBTransaction) => void)> = [];
+  private work: Array<(t: IDBTransaction) => void> = [];
   private stores: Set<string> = new Set();
   private kickoffPromise: Promise<void>;
 
@@ -595,13 +610,12 @@ export class QueryRoot {
 
   private keys: { [keyName: string]: IDBValidKey } = {};
 
-  constructor(public db: IDBDatabase) {
-  }
+  constructor(public db: IDBDatabase) {}
 
   /**
    * Get a named key that was created during the query.
    */
-  key(keyName: string): IDBValidKey|undefined {
+  key(keyName: string): IDBValidKey | undefined {
     return this.keys[keyName];
   }
 
@@ -626,7 +640,7 @@ export class QueryRoot {
    */
   count<T>(store: Store<T>): Promise<number> {
     this.checkFinished();
-    const {resolve, promise} = openPromise();
+    const { resolve, promise } = openPromise<number>();
 
     const doCount = (tx: IDBTransaction) => {
       const s = tx.objectStore(store.name);
@@ -638,15 +652,17 @@ export class QueryRoot {
 
     this.addWork(doCount, store.name, false);
     return Promise.resolve()
-                  .then(() => this.finish())
-                  .then(() => promise);
-
+      .then(() => this.finish())
+      .then(() => promise);
   }
 
   /**
    * Delete all objects in a store that match a predicate.
    */
-  deleteIf<T>(store: Store<T>, predicate: (x: T, n: number) => boolean): QueryRoot {
+  deleteIf<T>(
+    store: Store<T>,
+    predicate: (x: T, n: number) => boolean,
+  ): QueryRoot {
     this.checkFinished();
     const doDeleteIf = (tx: IDBTransaction) => {
       const s = tx.objectStore(store.name);
@@ -666,8 +682,10 @@ export class QueryRoot {
     return this;
   }
 
-  iterIndex<S extends IDBValidKey, T>(index: Index<S, T>,
-                                      only?: S): QueryStream<T> {
+  iterIndex<S extends IDBValidKey, T>(
+    index: Index<S, T>,
+    only?: S,
+  ): QueryStream<T> {
     this.checkFinished();
     this.stores.add(index.storeName);
     this.scheduleFinish();
@@ -688,7 +706,7 @@ export class QueryRoot {
       const req = tx.objectStore(store.name).put(val);
       if (keyName) {
         req.onsuccess = () => {
-            this.keys[keyName] = req.result;
+          this.keys[keyName] = req.result;
         };
       }
     };
@@ -702,7 +720,7 @@ export class QueryRoot {
    */
   putOrGetExisting<T>(store: Store<T>, val: T, key: IDBValidKey): Promise<T> {
     this.checkFinished();
-    const {resolve, promise} = openPromise();
+    const { resolve, promise } = openPromise<T>();
     const doPutOrGet = (tx: IDBTransaction) => {
       const objstore = tx.objectStore(store.name);
       const req = objstore.get(key);
@@ -722,10 +740,9 @@ export class QueryRoot {
     return promise;
   }
 
-
   putWithResult<T>(store: Store<T>, val: T): Promise<IDBValidKey> {
     this.checkFinished();
-    const {resolve, promise} = openPromise();
+    const { resolve, promise } = openPromise<IDBValidKey>();
     const doPutWithResult = (tx: IDBTransaction) => {
       const req = tx.objectStore(store.name).put(val);
       req.onsuccess = () => {
@@ -735,18 +752,17 @@ export class QueryRoot {
     };
     this.addWork(doPutWithResult, store.name, true);
     return Promise.resolve()
-                  .then(() => this.finish())
-                  .then(() => promise);
+      .then(() => this.finish())
+      .then(() => promise);
   }
 
-
   /**
    * Update objects inside a transaction.
    *
    * If the mutation function throws AbortTransaction, the whole transaction will be aborted.
    * If the mutation function returns undefined or null, no modification will be made.
    */
-  mutate<T>(store: Store<T>, key: any, f: (v: T) => T|undefined): QueryRoot {
+  mutate<T>(store: Store<T>, key: any, f: (v: T) => T | undefined): QueryRoot {
     this.checkFinished();
     const doPut = (tx: IDBTransaction) => {
       const req = tx.objectStore(store.name).openCursor(IDBKeyRange.only(key));
@@ -754,7 +770,7 @@ export class QueryRoot {
         const cursor = req.result;
         if (cursor) {
           const value = cursor.value;
-          let modifiedValue: T|undefined;
+          let modifiedValue: T | undefined;
           try {
             modifiedValue = f(value);
           } catch (e) {
@@ -776,7 +792,6 @@ export class QueryRoot {
     return this;
   }
 
-
   /**
    * Add all object from an iterable to the given object store.
    */
@@ -810,13 +825,13 @@ export class QueryRoot {
   /**
    * Get one object from a store by its key.
    */
-  get<T>(store: Store<T>, key: any): Promise<T|undefined> {
+  get<T>(store: Store<T>, key: any): Promise<T | undefined> {
     this.checkFinished();
     if (key === void 0) {
       throw Error("key must not be undefined");
     }
 
-    const {resolve, promise} = openPromise();
+    const { resolve, promise } = openPromise<T | undefined>();
 
     const doGet = (tx: IDBTransaction) => {
       const req = tx.objectStore(store.name).get(key);
@@ -827,8 +842,8 @@ export class QueryRoot {
 
     this.addWork(doGet, store.name, false);
     return Promise.resolve()
-                  .then(() => this.finish())
-                  .then(() => promise);
+      .then(() => this.finish())
+      .then(() => promise);
   }
 
   /**
@@ -839,7 +854,7 @@ export class QueryRoot {
   getMany<T>(store: Store<T>, keys: any[]): Promise<T[]> {
     this.checkFinished();
 
-    const { resolve, promise } = openPromise();
+    const { resolve, promise } = openPromise<T[]>();
     const results: T[] = [];
 
     const doGetMany = (tx: IDBTransaction) => {
@@ -859,26 +874,29 @@ export class QueryRoot {
 
     this.addWork(doGetMany, store.name, false);
     return Promise.resolve()
-                  .then(() => this.finish())
-                  .then(() => promise);
+      .then(() => this.finish())
+      .then(() => promise);
   }
 
   /**
    * Get one object from a store by its key.
    */
-  getIndexed<I extends IDBValidKey, T>(index: Index<I, T>,
-                                       key: I): Promise<T|undefined> {
+  getIndexed<I extends IDBValidKey, T>(
+    index: Index<I, T>,
+    key: I,
+  ): Promise<T | undefined> {
     this.checkFinished();
     if (key === void 0) {
       throw Error("key must not be undefined");
     }
 
-    const {resolve, promise} = openPromise<void>();
+    const { resolve, promise } = openPromise<T | undefined>();
 
     const doGetIndexed = (tx: IDBTransaction) => {
-      const req = tx.objectStore(index.storeName)
-                    .index(index.indexName)
-                    .get(key);
+      const req = tx
+        .objectStore(index.storeName)
+        .index(index.indexName)
+        .get(key);
       req.onsuccess = () => {
         resolve(req.result);
       };
@@ -886,8 +904,8 @@ export class QueryRoot {
 
     this.addWork(doGetIndexed, index.storeName, false);
     return Promise.resolve()
-                  .then(() => this.finish())
-                  .then(() => promise);
+      .then(() => this.finish())
+      .then(() => promise);
   }
 
   private scheduleFinish() {
@@ -917,10 +935,12 @@ export class QueryRoot {
         resolve();
       };
       tx.onabort = () => {
-        console.warn(`aborted ${mode} transaction on stores [${[... this.stores]}]`);
+        console.warn(
+          `aborted ${mode} transaction on stores [${[...this.stores]}]`,
+        );
         reject(Error("transaction aborted"));
       };
-      tx.onerror = (e) => {
+      tx.onerror = e => {
         console.warn(`error in transaction`, (e.target as any).error);
       };
       for (const w of this.work) {
@@ -946,9 +966,11 @@ export class QueryRoot {
   /**
    * Low-level function to add a task to the internal work queue.
    */
-  addWork(workFn: (t: IDBTransaction) => void,
-          storeName?: string,
-          isWrite?: boolean) {
+  addWork(
+    workFn: (t: IDBTransaction) => void,
+    storeName?: string,
+    isWrite?: boolean,
+  ) {
     this.work.push(workFn);
     if (storeName) {
       this.addStoreAccess(storeName, isWrite);
diff --git a/src/talerTypes.ts b/src/talerTypes.ts
index e8bb2e510..9176daf77 100644
--- a/src/talerTypes.ts
+++ b/src/talerTypes.ts
@@ -905,3 +905,30 @@ export class Proposal {
    */
   static checked: (obj: any) => Proposal;
 }
+
+/**
+ * Response from the internal merchant API.
+ */
+@Checkable.Class({extra: true})
+export class CheckPaymentResponse {
+  @Checkable.Boolean()
+  paid: boolean;
+
+  @Checkable.Optional(Checkable.Boolean())
+  refunded: boolean | undefined;
+
+  @Checkable.Optional(Checkable.String())
+  refunded_amount: string | undefined;
+
+  @Checkable.Optional(Checkable.Value(() => ContractTerms))
+  contract_terms: ContractTerms | undefined;
+
+  @Checkable.Optional(Checkable.String())
+  contract_url: string | undefined;
+
+  /**
+   * Verify that a value matches the schema of this class and convert it into a
+   * member.
+   */
+  static checked: (obj: any) => CheckPaymentResponse;
+}
\ No newline at end of file
diff --git a/src/wallet.ts b/src/wallet.ts
index 4fc108a11..6d4eeb26c 100644
--- a/src/wallet.ts
+++ b/src/wallet.ts
@@ -105,6 +105,7 @@ import {
   WalletBalance,
   WalletBalanceEntry,
 } from "./walletTypes";
+import { openPromise } from "./promiseUtils";
 
 interface SpeculativePayData {
   payCoinInfo: PayCoinInfo;
@@ -327,6 +328,7 @@ export class Wallet {
    * IndexedDB database used by the wallet.
    */
   db: IDBDatabase;
+  private enableTracing = false;
   private http: HttpRequestLibrary;
   private badge: Badge;
   private notifier: Notifier;
@@ -337,6 +339,12 @@ export class Wallet {
   private speculativePayData: SpeculativePayData | undefined;
   private cachedNextUrl: { [fulfillmentUrl: string]: NextUrlResult } = {};
   private activeTipOperations: { [s: string]: Promise<TipRecord> } = {};
+  private activeProcessReserveOperations: {
+    [reservePub: string]: Promise<void>;
+  } = {};
+  private activeProcessPreCoinOperations: {
+    [preCoinPub: string]: Promise<void>;
+  } = {};
 
   /**
    * Set of identifiers for running operations.
@@ -426,14 +434,14 @@ export class Wallet {
       .iter(Stores.reserves)
       .forEach(reserve => {
         console.log("resuming reserve", reserve.reserve_pub);
-        this.processReserve(reserve);
+        this.processReserve(reserve.reserve_pub);
       });
 
     this.q()
       .iter(Stores.precoins)
       .forEach(preCoin => {
         console.log("resuming precoin");
-        this.processPreCoin(preCoin);
+        this.processPreCoin(preCoin.coinPub);
       });
 
     this.q()
@@ -1073,151 +1081,184 @@ export class Wallet {
    * First fetch information requred to withdraw from the reserve,
    * then deplete the reserve, withdrawing coins until it is empty.
    */
-  private async processReserve(
-    reserveRecord: ReserveRecord,
-    retryDelayMs: number = 250,
-  ): Promise<void> {
-    const opId = "reserve-" + reserveRecord.reserve_pub;
+  async processReserve(reservePub: string): Promise<void> {
+    const activeOperation = this.activeProcessReserveOperations[reservePub];
+
+    if (activeOperation) {
+      return activeOperation;
+    }
+
+    const opId = "reserve-" + reservePub;
     this.startOperation(opId);
 
+    // This opened promise gets resolved only once the
+    // reserve withdraw operation succeeds, even after retries.
+    const op = openPromise<void>();
+
+    const processReserveInternal = async (retryDelayMs: number = 250) => {
+      try {
+        const reserve = await this.updateReserve(reservePub);
+        await this.depleteReserve(reserve);
+        op.resolve();
+      } catch (e) {
+        // random, exponential backoff truncated at 3 minutes
+        const nextDelay = Math.min(
+          2 * retryDelayMs + retryDelayMs * Math.random(),
+          3000 * 60,
+        );
+        console.warn(
+          `Failed to deplete reserve, trying again in ${retryDelayMs} ms`,
+        );
+        this.timerGroup.after(retryDelayMs, () =>
+          processReserveInternal(nextDelay),
+        );
+      }
+    };
+
     try {
-      const reserve = await this.updateReserve(reserveRecord.reserve_pub);
-      await this.depleteReserve(reserve);
-    } catch (e) {
-      // random, exponential backoff truncated at 3 minutes
-      const nextDelay = Math.min(
-        2 * retryDelayMs + retryDelayMs * Math.random(),
-        3000 * 60,
-      );
-      console.warn(
-        `Failed to deplete reserve, trying again in ${retryDelayMs} ms`,
-      );
-      this.timerGroup.after(retryDelayMs, () =>
-        this.processReserve(reserveRecord, nextDelay),
-      );
+      processReserveInternal();
+      this.activeProcessReserveOperations[reservePub] = op.promise;
+      await op.promise;
     } finally {
       this.stopOperation(opId);
+      delete this.activeProcessReserveOperations[reservePub];
     }
   }
 
   /**
    * Given a planchet, withdraw a coin from the exchange.
    */
-  private async processPreCoin(
-    preCoin: PreCoinRecord,
-    retryDelayMs = 200,
-  ): Promise<void> {
-    // Throttle concurrent executions of this function, so we don't withdraw too many coins at once.
-    if (
-      this.processPreCoinConcurrent >= 4 ||
-      this.processPreCoinThrottle[preCoin.exchangeBaseUrl]
-    ) {
-      console.log("delaying processPreCoin");
-      this.timerGroup.after(retryDelayMs, () =>
-        this.processPreCoin(preCoin, Math.min(retryDelayMs * 2, 5 * 60 * 1000)),
-      );
-      return;
+  private async processPreCoin(preCoinPub: string): Promise<void> {
+    const activeOperation = this.activeProcessPreCoinOperations[preCoinPub];
+    if (activeOperation) {
+      return activeOperation;
     }
-    console.log("executing processPreCoin", preCoin);
-    this.processPreCoinConcurrent++;
-    try {
-      const exchange = await this.q().get(
-        Stores.exchanges,
-        preCoin.exchangeBaseUrl,
-      );
-      if (!exchange) {
-        console.error("db inconsistent: exchange for precoin not found");
+
+    const op = openPromise<void>();
+
+    const processPreCoinInternal = async (retryDelayMs: number = 200) => {
+      const preCoin = await this.q().get(Stores.precoins, preCoinPub);
+      if (!preCoin) {
+        console.log("processPreCoin: preCoinPub not found");
         return;
       }
-      const denom = await this.q().get(Stores.denominations, [
-        preCoin.exchangeBaseUrl,
-        preCoin.denomPub,
-      ]);
-      if (!denom) {
-        console.error("db inconsistent: denom for precoin not found");
-        return;
+      // Throttle concurrent executions of this function,
+      // so we don't withdraw too many coins at once.
+      if (
+        this.processPreCoinConcurrent >= 4 ||
+        this.processPreCoinThrottle[preCoin.exchangeBaseUrl]
+      ) {
+        this.enableTracing && console.log("delaying processPreCoin");
+        this.timerGroup.after(retryDelayMs, () =>
+          processPreCoinInternal(Math.min(retryDelayMs * 2, 5 * 60 * 1000)),
+        );
+        return op.promise;
       }
 
-      const coin = await this.withdrawExecute(preCoin);
-      console.log("processPreCoin: got coin", coin);
+      //console.log("executing processPreCoin", preCoin);
+      this.processPreCoinConcurrent++;
 
-      const mutateReserve = (r: ReserveRecord) => {
-        console.log(
-          `before committing coin: current ${amountToPretty(
-            r.current_amount!,
-          )}, precoin: ${amountToPretty(r.precoin_amount)})}`,
+      try {
+        const exchange = await this.q().get(
+          Stores.exchanges,
+          preCoin.exchangeBaseUrl,
         );
-
-        const x = Amounts.sub(
-          r.precoin_amount,
-          preCoin.coinValue,
-          denom.feeWithdraw,
-        );
-        if (x.saturated) {
-          console.error("database inconsistent");
-          throw AbortTransaction;
+        if (!exchange) {
+          console.error("db inconsistent: exchange for precoin not found");
+          return;
+        }
+        const denom = await this.q().get(Stores.denominations, [
+          preCoin.exchangeBaseUrl,
+          preCoin.denomPub,
+        ]);
+        if (!denom) {
+          console.error("db inconsistent: denom for precoin not found");
+          return;
         }
-        r.precoin_amount = x.amount;
-        return r;
-      };
 
-      await this.q()
-        .mutate(Stores.reserves, preCoin.reservePub, mutateReserve)
-        .delete(Stores.precoins, coin.coinPub)
-        .add(Stores.coins, coin)
-        .finish();
+        const coin = await this.withdrawExecute(preCoin);
 
-      if (coin.status === CoinStatus.TainedByTip) {
-        const tip = await this.q().getIndexed(
-          Stores.tips.coinPubIndex,
-          coin.coinPub,
-        );
-        if (!tip) {
-          throw Error(
-            `inconsistent DB: tip for coin pub ${coin.coinPub} not found.`,
+        const mutateReserve = (r: ReserveRecord) => {
+          const x = Amounts.sub(
+            r.precoin_amount,
+            preCoin.coinValue,
+            denom.feeWithdraw,
           );
-        }
+          if (x.saturated) {
+            console.error("database inconsistent");
+            throw AbortTransaction;
+          }
+          r.precoin_amount = x.amount;
+          return r;
+        };
 
-        if (tip.accepted) {
-          console.log("untainting already accepted tip");
-          // Transactionally set coin to fresh.
-          const mutateCoin = (c: CoinRecord) => {
-            if (c.status === CoinStatus.TainedByTip) {
-              c.status = CoinStatus.Fresh;
-            }
-            return c;
-          };
-          await this.q().mutate(Stores.coins, coin.coinPub, mutateCoin);
-          // Show notifications only for accepted tips
+        await this.q()
+          .mutate(Stores.reserves, preCoin.reservePub, mutateReserve)
+          .delete(Stores.precoins, coin.coinPub)
+          .add(Stores.coins, coin)
+          .finish();
+
+        if (coin.status === CoinStatus.TainedByTip) {
+          const tip = await this.q().getIndexed(
+            Stores.tips.coinPubIndex,
+            coin.coinPub,
+          );
+          if (!tip) {
+            throw Error(
+              `inconsistent DB: tip for coin pub ${coin.coinPub} not found.`,
+            );
+          }
+
+          if (tip.accepted) {
+            console.log("untainting already accepted tip");
+            // Transactionally set coin to fresh.
+            const mutateCoin = (c: CoinRecord) => {
+              if (c.status === CoinStatus.TainedByTip) {
+                c.status = CoinStatus.Fresh;
+              }
+              return c;
+            };
+            await this.q().mutate(Stores.coins, coin.coinPub, mutateCoin);
+            // Show notifications only for accepted tips
+            this.badge.showNotification();
+          }
+        } else {
           this.badge.showNotification();
         }
-      } else {
-        this.badge.showNotification();
+
+        this.notifier.notify();
+        op.resolve();
+      } catch (e) {
+        console.error(
+          "Failed to withdraw coin from precoin, retrying in",
+          retryDelayMs,
+          "ms",
+          e,
+        );
+        // exponential backoff truncated at one minute
+        const nextRetryDelayMs = Math.min(retryDelayMs * 2, 5 * 60 * 1000);
+        this.timerGroup.after(retryDelayMs, () =>
+          processPreCoinInternal(nextRetryDelayMs),
+        );
+
+        const currentThrottle =
+          this.processPreCoinThrottle[preCoin.exchangeBaseUrl] || 0;
+        this.processPreCoinThrottle[preCoin.exchangeBaseUrl] =
+          currentThrottle + 1;
+        this.timerGroup.after(retryDelayMs, () => {
+          this.processPreCoinThrottle[preCoin.exchangeBaseUrl]--;
+        });
+      } finally {
+        this.processPreCoinConcurrent--;
       }
+    };
 
-      this.notifier.notify();
-    } catch (e) {
-      console.error(
-        "Failed to withdraw coin from precoin, retrying in",
-        retryDelayMs,
-        "ms",
-        e,
-      );
-      // exponential backoff truncated at one minute
-      const nextRetryDelayMs = Math.min(retryDelayMs * 2, 5 * 60 * 1000);
-      this.timerGroup.after(retryDelayMs, () =>
-        this.processPreCoin(preCoin, nextRetryDelayMs),
-      );
-
-      const currentThrottle =
-        this.processPreCoinThrottle[preCoin.exchangeBaseUrl] || 0;
-      this.processPreCoinThrottle[preCoin.exchangeBaseUrl] =
-        currentThrottle + 1;
-      this.timerGroup.after(retryDelayMs, () => {
-        this.processPreCoinThrottle[preCoin.exchangeBaseUrl]--;
-      });
+    try {
+      this.activeProcessPreCoinOperations[preCoinPub] = op.promise;
+      await processPreCoinInternal();
+      return op.promise;
     } finally {
-      this.processPreCoinConcurrent--;
+      delete this.activeProcessPreCoinOperations[preCoinPub];
     }
   }
 
@@ -1332,9 +1373,8 @@ export class Wallet {
       .finish();
     this.notifier.notify();
 
-    this.processReserve(reserve);
+    this.processReserve(reserve.reserve_pub);
   }
-  
 
   private async withdrawExecute(pc: PreCoinRecord): Promise<CoinRecord> {
     const wd: any = {};
@@ -1424,20 +1464,22 @@ export class Wallet {
           r.timestamp_depleted = new Date().getTime();
         }
 
-        console.log(
-          `after creating precoin: current ${amountToPretty(
-            r.current_amount,
-          )}, precoin: ${amountToPretty(r.precoin_amount)})}`,
-        );
-
         return r;
       }
 
       const preCoin = await this.cryptoApi.createPreCoin(denom, reserve);
-      await this.q()
-        .put(Stores.precoins, preCoin)
-        .mutate(Stores.reserves, reserve.reserve_pub, mutateReserve);
-      await this.processPreCoin(preCoin);
+      // This will fail and throw an exception if the remaining amount in the
+      // reserve is too low to create a pre-coin.
+      try {
+        await this.q()
+          .put(Stores.precoins, preCoin)
+          .mutate(Stores.reserves, reserve.reserve_pub, mutateReserve)
+          .finish();
+      } catch (e) {
+        console.log("can't create pre-coin:", e.name, e.message);
+        return;
+      }
+      await this.processPreCoin(preCoin.coinPub);
     });
 
     await Promise.all(ps);
@@ -1746,7 +1788,10 @@ export class Wallet {
     return ret;
   }
 
-  async getExchangePaytoUri(exchangeBaseUrl: string, supportedTargetTypes: string[]): Promise<string> {
+  async getExchangePaytoUri(
+    exchangeBaseUrl: string,
+    supportedTargetTypes: string[],
+  ): Promise<string> {
     const wireInfo = await this.getWireInfo(exchangeBaseUrl);
     for (let account of wireInfo.accounts) {
       const paytoUri = new URI(account.url);
@@ -1820,8 +1865,6 @@ export class Wallet {
       throw Error("exchange doesn't offer any denominations");
     }
 
-    console.log("updating exchange with wireMethodDetails", wireMethodDetails);
-
     const r = await this.q().get<ExchangeRecord>(Stores.exchanges, baseUrl);
 
     let exchangeInfo: ExchangeRecord;
@@ -2714,7 +2757,7 @@ export class Wallet {
    */
   stop() {
     this.timerGroup.stopCurrentAndFutureTimers();
-    this.cryptoApi.terminateWorkers();
+    this.cryptoApi.stop();
   }
 
   async getSenderWireInfos(): Promise<SenderWireInfos> {
@@ -3199,7 +3242,7 @@ export class Wallet {
         withdrawSig: response.reserve_sigs[i].reserve_sig,
       };
       await this.q().put(Stores.precoins, preCoin);
-      this.processPreCoin(preCoin);
+      this.processPreCoin(preCoin.coinPub);
     }
 
     tipRecord.pickedUp = true;
diff --git a/tsconfig.json b/tsconfig.json
index 7cbde9642..4a2f09e87 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -48,6 +48,7 @@
     "src/libtoolVersion-test.ts",
     "src/libtoolVersion.ts",
     "src/logging.ts",
+    "src/promiseUtils.ts",
     "src/query.ts",
     "src/talerTypes.ts",
     "src/timer.ts",