diff --git a/packages/taler-integrationtests/src/harness.ts b/packages/taler-integrationtests/src/harness.ts
index 84b5bc5c4..ecb0758da 100644
--- a/packages/taler-integrationtests/src/harness.ts
+++ b/packages/taler-integrationtests/src/harness.ts
@@ -35,7 +35,7 @@ import {
   AmountJson,
   Amounts,
   Codec,
-  makeCodecForObject,
+  buildCodecForObject,
   codecForString,
   Duration,
   CoreApiResponse,
@@ -627,9 +627,9 @@ export interface WithdrawalOperationInfo {
 }
 
 const codecForWithdrawalOperationInfo = (): Codec<WithdrawalOperationInfo> =>
-  makeCodecForObject<WithdrawalOperationInfo>()
-    .property("withdrawal_id", codecForString)
-    .property("taler_withdraw_uri", codecForString)
+  buildCodecForObject<WithdrawalOperationInfo>()
+    .property("withdrawal_id", codecForString())
+    .property("taler_withdraw_uri", codecForString())
     .build("WithdrawalOperationInfo");
 
 export const defaultCoinConfig = [
diff --git a/packages/taler-integrationtests/src/merchantApiTypes.ts b/packages/taler-integrationtests/src/merchantApiTypes.ts
index 3c0965813..d08c354a1 100644
--- a/packages/taler-integrationtests/src/merchantApiTypes.ts
+++ b/packages/taler-integrationtests/src/merchantApiTypes.ts
@@ -28,19 +28,20 @@ import {
   ContractTerms,
   Duration,
   Codec,
-  makeCodecForObject,
+  buildCodecForObject,
   codecForString,
-  makeCodecOptional,
-  makeCodecForConstString,
+  codecOptional,
+  codecForConstString,
   codecForBoolean,
   codecForNumber,
   codecForContractTerms,
   codecForAny,
-  makeCodecForUnion,
+  buildCodecForUnion,
   AmountString,
   Timestamp,
   CoinPublicKeyString,
 } from "taler-wallet-core";
+import { codecForAmountString } from "taler-wallet-core/lib/util/amounts";
 
 export interface PostOrderRequest {
   // The order must at least contain the minimal
@@ -72,43 +73,43 @@ export interface PostOrderResponse {
 }
 
 export const codecForPostOrderResponse = (): Codec<PostOrderResponse> =>
-  makeCodecForObject<PostOrderResponse>()
-    .property("order_id", codecForString)
-    .property("token", makeCodecOptional(codecForString))
+  buildCodecForObject<PostOrderResponse>()
+    .property("order_id", codecForString())
+    .property("token", codecOptional(codecForString()))
     .build("PostOrderResponse");
 
 export const codecForCheckPaymentPaidResponse = (): Codec<
   CheckPaymentPaidResponse
 > =>
-  makeCodecForObject<CheckPaymentPaidResponse>()
-    .property("order_status", makeCodecForConstString("paid"))
+  buildCodecForObject<CheckPaymentPaidResponse>()
+    .property("order_status", codecForConstString("paid"))
     .property("refunded", codecForBoolean)
     .property("wired", codecForBoolean)
-    .property("deposit_total", codecForString)
-    .property("exchange_ec", codecForNumber)
-    .property("exchange_hc", codecForNumber)
-    .property("refund_amount", codecForString)
+    .property("deposit_total", codecForAmountString())
+    .property("exchange_ec", codecForNumber())
+    .property("exchange_hc", codecForNumber())
+    .property("refund_amount", codecForAmountString())
     .property("contract_terms", codecForContractTerms())
     // FIXME: specify
-    .property("wire_details", codecForAny)
-    .property("wire_reports", codecForAny)
-    .property("refund_details", codecForAny)
+    .property("wire_details", codecForAny())
+    .property("wire_reports", codecForAny())
+    .property("refund_details", codecForAny())
     .build("CheckPaymentPaidResponse");
 
 export const codecForCheckPaymentUnpaidResponse = (): Codec<
   CheckPaymentUnpaidResponse
 > =>
-  makeCodecForObject<CheckPaymentUnpaidResponse>()
-    .property("order_status", makeCodecForConstString("unpaid"))
-    .property("taler_pay_uri", codecForString)
-    .property("order_status_url", codecForString)
-    .property("already_paid_order_id", makeCodecOptional(codecForString))
+  buildCodecForObject<CheckPaymentUnpaidResponse>()
+    .property("order_status", codecForConstString("unpaid"))
+    .property("taler_pay_uri", codecForString())
+    .property("order_status_url", codecForString())
+    .property("already_paid_order_id", codecOptional(codecForString()))
     .build("CheckPaymentPaidResponse");
 
 export const codecForMerchantOrderPrivateStatusResponse = (): Codec<
   MerchantOrderPrivateStatusResponse
 > =>
-  makeCodecForUnion<MerchantOrderPrivateStatusResponse>()
+  buildCodecForUnion<MerchantOrderPrivateStatusResponse>()
     .discriminateOn("order_status")
     .alternative("paid", codecForCheckPaymentPaidResponse())
     .alternative("unpaid", codecForCheckPaymentUnpaidResponse())
diff --git a/packages/taler-wallet-cli/src/index.ts b/packages/taler-wallet-cli/src/index.ts
index 16897b7aa..a32ed2267 100644
--- a/packages/taler-wallet-cli/src/index.ts
+++ b/packages/taler-wallet-cli/src/index.ts
@@ -31,7 +31,7 @@ import {
   TalerUriType,
   decodeCrock,
   addPaytoQueryParams,
-  makeCodecForList,
+  codecForList,
   codecForString,
   printTestVectors,
 } from "taler-wallet-core";
@@ -548,7 +548,7 @@ advancedCli
     });
   });
 
-const coinPubListCodec = makeCodecForList(codecForString);
+const coinPubListCodec = codecForList(codecForString());
 
 advancedCli
   .subcommand("suspendCoins", "suspend-coins", {
diff --git a/packages/taler-wallet-core/src/operations/testing.ts b/packages/taler-wallet-core/src/operations/testing.ts
index 71cee1f3a..3ccfafc93 100644
--- a/packages/taler-wallet-core/src/operations/testing.ts
+++ b/packages/taler-wallet-core/src/operations/testing.ts
@@ -112,7 +112,7 @@ async function createBankWithdrawalUri(
       },
     },
   );
-  const respJson = await readSuccessResponseJsonOrThrow(resp, codecForAny);
+  const respJson = await readSuccessResponseJsonOrThrow(resp, codecForAny());
   return respJson;
 }
 
@@ -135,7 +135,7 @@ async function confirmBankWithdrawalUri(
       },
     },
   );
-  await readSuccessResponseJsonOrThrow(resp, codecForAny);
+  await readSuccessResponseJsonOrThrow(resp, codecForAny());
   return;
 }
 
diff --git a/packages/taler-wallet-core/src/operations/transactions.ts b/packages/taler-wallet-core/src/operations/transactions.ts
index 8de204d49..5521dda90 100644
--- a/packages/taler-wallet-core/src/operations/transactions.ts
+++ b/packages/taler-wallet-core/src/operations/transactions.ts
@@ -37,7 +37,6 @@ import {
   PaymentShortInfo,
 } from "../types/transactions";
 import { getFundingPaytoUris } from "./reserves";
-import { ResultLevel } from "idb-bridge";
 
 /**
  * Create an event ID from the type and the primary key for the event.
diff --git a/packages/taler-wallet-core/src/types/ReserveStatus.ts b/packages/taler-wallet-core/src/types/ReserveStatus.ts
index 18601b9a7..8a6092a7f 100644
--- a/packages/taler-wallet-core/src/types/ReserveStatus.ts
+++ b/packages/taler-wallet-core/src/types/ReserveStatus.ts
@@ -23,8 +23,8 @@
  */
 import {
   codecForString,
-  makeCodecForObject,
-  makeCodecForList,
+  buildCodecForObject,
+  codecForList,
   Codec,
 } from "../util/codec";
 import { AmountString } from "./talerTypes";
@@ -51,7 +51,7 @@ export interface ReserveStatus {
 }
 
 export const codecForReserveStatus = (): Codec<ReserveStatus> =>
-  makeCodecForObject<ReserveStatus>()
-    .property("balance", codecForString)
-    .property("history", makeCodecForList(codecForReserveTransaction()))
+  buildCodecForObject<ReserveStatus>()
+    .property("balance", codecForString())
+    .property("history", codecForList(codecForReserveTransaction()))
     .build("ReserveStatus");
diff --git a/packages/taler-wallet-core/src/types/ReserveTransaction.ts b/packages/taler-wallet-core/src/types/ReserveTransaction.ts
index bdd9b0f93..0d946518f 100644
--- a/packages/taler-wallet-core/src/types/ReserveTransaction.ts
+++ b/packages/taler-wallet-core/src/types/ReserveTransaction.ts
@@ -23,9 +23,9 @@
  */
 import {
   codecForString,
-  makeCodecForObject,
-  makeCodecForConstString,
-  makeCodecForUnion,
+  buildCodecForObject,
+  codecForConstString,
+  buildCodecForUnion,
   Codec,
 } from "../util/codec";
 import {
@@ -182,54 +182,54 @@ export type ReserveTransaction =
 export const codecForReserveWithdrawTransaction = (): Codec<
   ReserveWithdrawTransaction
 > =>
-  makeCodecForObject<ReserveWithdrawTransaction>()
-    .property("amount", codecForString)
-    .property("h_coin_envelope", codecForString)
-    .property("h_denom_pub", codecForString)
-    .property("reserve_sig", codecForString)
-    .property("type", makeCodecForConstString(ReserveTransactionType.Withdraw))
-    .property("withdraw_fee", codecForString)
+  buildCodecForObject<ReserveWithdrawTransaction>()
+    .property("amount", codecForString())
+    .property("h_coin_envelope", codecForString())
+    .property("h_denom_pub", codecForString())
+    .property("reserve_sig", codecForString())
+    .property("type", codecForConstString(ReserveTransactionType.Withdraw))
+    .property("withdraw_fee", codecForString())
     .build("ReserveWithdrawTransaction");
 
 export const codecForReserveCreditTransaction = (): Codec<
   ReserveCreditTransaction
 > =>
-  makeCodecForObject<ReserveCreditTransaction>()
-    .property("amount", codecForString)
-    .property("sender_account_url", codecForString)
+  buildCodecForObject<ReserveCreditTransaction>()
+    .property("amount", codecForString())
+    .property("sender_account_url", codecForString())
     .property("timestamp", codecForTimestamp)
-    .property("wire_reference", codecForString)
-    .property("type", makeCodecForConstString(ReserveTransactionType.Credit))
+    .property("wire_reference", codecForString())
+    .property("type", codecForConstString(ReserveTransactionType.Credit))
     .build("ReserveCreditTransaction");
 
 export const codecForReserveClosingTransaction = (): Codec<
   ReserveClosingTransaction
 > =>
-  makeCodecForObject<ReserveClosingTransaction>()
-    .property("amount", codecForString)
-    .property("closing_fee", codecForString)
-    .property("exchange_pub", codecForString)
-    .property("exchange_sig", codecForString)
-    .property("h_wire", codecForString)
+  buildCodecForObject<ReserveClosingTransaction>()
+    .property("amount", codecForString())
+    .property("closing_fee", codecForString())
+    .property("exchange_pub", codecForString())
+    .property("exchange_sig", codecForString())
+    .property("h_wire", codecForString())
     .property("timestamp", codecForTimestamp)
-    .property("type", makeCodecForConstString(ReserveTransactionType.Closing))
-    .property("wtid", codecForString)
+    .property("type", codecForConstString(ReserveTransactionType.Closing))
+    .property("wtid", codecForString())
     .build("ReserveClosingTransaction");
 
 export const codecForReserveRecoupTransaction = (): Codec<
   ReserveRecoupTransaction
 > =>
-  makeCodecForObject<ReserveRecoupTransaction>()
-    .property("amount", codecForString)
-    .property("coin_pub", codecForString)
-    .property("exchange_pub", codecForString)
-    .property("exchange_sig", codecForString)
+  buildCodecForObject<ReserveRecoupTransaction>()
+    .property("amount", codecForString())
+    .property("coin_pub", codecForString())
+    .property("exchange_pub", codecForString())
+    .property("exchange_sig", codecForString())
     .property("timestamp", codecForTimestamp)
-    .property("type", makeCodecForConstString(ReserveTransactionType.Recoup))
+    .property("type", codecForConstString(ReserveTransactionType.Recoup))
     .build("ReserveRecoupTransaction");
 
 export const codecForReserveTransaction = (): Codec<ReserveTransaction> =>
-  makeCodecForUnion<ReserveTransaction>()
+  buildCodecForUnion<ReserveTransaction>()
     .discriminateOn("type")
     .alternative(
       ReserveTransactionType.Withdraw,
diff --git a/packages/taler-wallet-core/src/types/talerTypes.ts b/packages/taler-wallet-core/src/types/talerTypes.ts
index acebbda95..bb0118a78 100644
--- a/packages/taler-wallet-core/src/types/talerTypes.ts
+++ b/packages/taler-wallet-core/src/types/talerTypes.ts
@@ -28,18 +28,18 @@
  */
 
 import {
-  makeCodecForObject,
+  buildCodecForObject,
   codecForString,
-  makeCodecForList,
-  makeCodecOptional,
+  codecForList,
+  codecOptional,
   codecForAny,
   codecForNumber,
   codecForBoolean,
-  makeCodecForMap,
+  codecForMap,
   Codec,
-  makeCodecForConstNumber,
-  makeCodecForUnion,
-  makeCodecForConstString,
+  codecForConstNumber,
+  buildCodecForUnion,
+  codecForConstString,
 } from "../util/codec";
 import {
   Timestamp,
@@ -48,6 +48,7 @@ import {
   codecForDuration,
 } from "../util/time";
 import { ExchangeListItem } from "./walletTypes";
+import { codecForAmountString } from "../util/amounts";
 
 /**
  * Denomination as found in the /keys response from the exchange.
@@ -951,7 +952,7 @@ export interface BankWithdrawalOperationPostResponse {
 export const codecForBankWithdrawalOperationPostResponse = (): Codec<
   BankWithdrawalOperationPostResponse
 > =>
-  makeCodecForObject<BankWithdrawalOperationPostResponse>()
+  buildCodecForObject<BankWithdrawalOperationPostResponse>()
     .property("transfer_done", codecForBoolean)
     .build("BankWithdrawalOperationPostResponse");
 
@@ -962,292 +963,292 @@ export type EddsaPublicKeyString = string;
 export type CoinPublicKeyString = string;
 
 export const codecForDenomination = (): Codec<Denomination> =>
-  makeCodecForObject<Denomination>()
-    .property("value", codecForString)
-    .property("denom_pub", codecForString)
-    .property("fee_withdraw", codecForString)
-    .property("fee_deposit", codecForString)
-    .property("fee_refresh", codecForString)
-    .property("fee_refund", codecForString)
+  buildCodecForObject<Denomination>()
+    .property("value", codecForString())
+    .property("denom_pub", codecForString())
+    .property("fee_withdraw", codecForString())
+    .property("fee_deposit", codecForString())
+    .property("fee_refresh", codecForString())
+    .property("fee_refund", codecForString())
     .property("stamp_start", codecForTimestamp)
     .property("stamp_expire_withdraw", codecForTimestamp)
     .property("stamp_expire_legal", codecForTimestamp)
     .property("stamp_expire_deposit", codecForTimestamp)
-    .property("master_sig", codecForString)
+    .property("master_sig", codecForString())
     .build("Denomination");
 
 export const codecForAuditorDenomSig = (): Codec<AuditorDenomSig> =>
-  makeCodecForObject<AuditorDenomSig>()
-    .property("denom_pub_h", codecForString)
-    .property("auditor_sig", codecForString)
+  buildCodecForObject<AuditorDenomSig>()
+    .property("denom_pub_h", codecForString())
+    .property("auditor_sig", codecForString())
     .build("AuditorDenomSig");
 
 export const codecForAuditor = (): Codec<Auditor> =>
-  makeCodecForObject<Auditor>()
-    .property("auditor_pub", codecForString)
-    .property("auditor_url", codecForString)
-    .property("denomination_keys", makeCodecForList(codecForAuditorDenomSig()))
+  buildCodecForObject<Auditor>()
+    .property("auditor_pub", codecForString())
+    .property("auditor_url", codecForString())
+    .property("denomination_keys", codecForList(codecForAuditorDenomSig()))
     .build("Auditor");
 
 export const codecForExchangeHandle = (): Codec<ExchangeHandle> =>
-  makeCodecForObject<ExchangeHandle>()
-    .property("master_pub", codecForString)
-    .property("url", codecForString)
+  buildCodecForObject<ExchangeHandle>()
+    .property("master_pub", codecForString())
+    .property("url", codecForString())
     .build("ExchangeHandle");
 
 export const codecForAuditorHandle = (): Codec<AuditorHandle> =>
-  makeCodecForObject<AuditorHandle>()
-    .property("name", codecForString)
-    .property("master_pub", codecForString)
-    .property("url", codecForString)
+  buildCodecForObject<AuditorHandle>()
+    .property("name", codecForString())
+    .property("master_pub", codecForString())
+    .property("url", codecForString())
     .build("AuditorHandle");
 
 export const codecForMerchantInfo = (): Codec<MerchantInfo> =>
-  makeCodecForObject<MerchantInfo>()
-    .property("name", codecForString)
-    .property("address", makeCodecOptional(codecForString))
-    .property("jurisdiction", makeCodecOptional(codecForString))
+  buildCodecForObject<MerchantInfo>()
+    .property("name", codecForString())
+    .property("address", codecOptional(codecForString()))
+    .property("jurisdiction", codecOptional(codecForString()))
     .build("MerchantInfo");
 
 export const codecForTax = (): Codec<Tax> =>
-  makeCodecForObject<Tax>()
-    .property("name", codecForString)
-    .property("tax", codecForString)
+  buildCodecForObject<Tax>()
+    .property("name", codecForString())
+    .property("tax", codecForString())
     .build("Tax");
 
 export const codecForI18n = (): Codec<{ [lang_tag: string]: string }> =>
-  makeCodecForMap(codecForString);
+  codecForMap(codecForString());
 
 export const codecForProduct = (): Codec<Product> =>
-  makeCodecForObject<Product>()
-    .property("product_id", makeCodecOptional(codecForString))
-    .property("description", codecForString)
-    .property("description_i18n", makeCodecOptional(codecForI18n()))
-    .property("quantity", makeCodecOptional(codecForNumber))
-    .property("unit", makeCodecOptional(codecForString))
-    .property("price", makeCodecOptional(codecForString))
-    .property("delivery_date", makeCodecOptional(codecForTimestamp))
-    .property("delivery_location", makeCodecOptional(codecForString))
+  buildCodecForObject<Product>()
+    .property("product_id", codecOptional(codecForString()))
+    .property("description", codecForString())
+    .property("description_i18n", codecOptional(codecForI18n()))
+    .property("quantity", codecOptional(codecForNumber()))
+    .property("unit", codecOptional(codecForString()))
+    .property("price", codecOptional(codecForString()))
+    .property("delivery_date", codecOptional(codecForTimestamp))
+    .property("delivery_location", codecOptional(codecForString()))
     .build("Tax");
 
 export const codecForContractTerms = (): Codec<ContractTerms> =>
-  makeCodecForObject<ContractTerms>()
-    .property("order_id", codecForString)
-    .property("fulfillment_url", codecForString)
-    .property("merchant_base_url", codecForString)
-    .property("h_wire", codecForString)
-    .property("auto_refund", makeCodecOptional(codecForDuration))
-    .property("wire_method", codecForString)
-    .property("summary", codecForString)
-    .property("summary_i18n", makeCodecOptional(codecForI18n()))
-    .property("nonce", codecForString)
-    .property("amount", codecForString)
-    .property("auditors", makeCodecForList(codecForAuditorHandle()))
+  buildCodecForObject<ContractTerms>()
+    .property("order_id", codecForString())
+    .property("fulfillment_url", codecForString())
+    .property("merchant_base_url", codecForString())
+    .property("h_wire", codecForString())
+    .property("auto_refund", codecOptional(codecForDuration))
+    .property("wire_method", codecForString())
+    .property("summary", codecForString())
+    .property("summary_i18n", codecOptional(codecForI18n()))
+    .property("nonce", codecForString())
+    .property("amount", codecForString())
+    .property("auditors", codecForList(codecForAuditorHandle()))
     .property("pay_deadline", codecForTimestamp)
     .property("refund_deadline", codecForTimestamp)
     .property("wire_transfer_deadline", codecForTimestamp)
     .property("timestamp", codecForTimestamp)
-    .property("locations", codecForAny)
-    .property("max_fee", codecForString)
-    .property("max_wire_fee", makeCodecOptional(codecForString))
+    .property("locations", codecForAny())
+    .property("max_fee", codecForString())
+    .property("max_wire_fee", codecOptional(codecForString()))
     .property("merchant", codecForMerchantInfo())
-    .property("merchant_pub", codecForString)
-    .property("exchanges", makeCodecForList(codecForExchangeHandle()))
+    .property("merchant_pub", codecForString())
+    .property("exchanges", codecForList(codecForExchangeHandle()))
     .property(
       "products",
-      makeCodecOptional(makeCodecForList(codecForProduct())),
+      codecOptional(codecForList(codecForProduct())),
     )
-    .property("extra", codecForAny)
+    .property("extra", codecForAny())
     .build("ContractTerms");
 
 export const codecForMerchantRefundPermission = (): Codec<
   MerchantAbortPayRefundDetails
 > =>
-  makeCodecForObject<MerchantAbortPayRefundDetails>()
-    .property("refund_amount", codecForString)
-    .property("refund_fee", codecForString)
-    .property("coin_pub", codecForString)
-    .property("rtransaction_id", codecForNumber)
-    .property("exchange_http_status", codecForNumber)
-    .property("exchange_code", makeCodecOptional(codecForNumber))
-    .property("exchange_reply", makeCodecOptional(codecForAny))
-    .property("exchange_sig", makeCodecOptional(codecForString))
-    .property("exchange_pub", makeCodecOptional(codecForString))
+  buildCodecForObject<MerchantAbortPayRefundDetails>()
+    .property("refund_amount", codecForAmountString())
+    .property("refund_fee", codecForAmountString())
+    .property("coin_pub", codecForString())
+    .property("rtransaction_id", codecForNumber())
+    .property("exchange_http_status", codecForNumber())
+    .property("exchange_code", codecOptional(codecForNumber()))
+    .property("exchange_reply", codecOptional(codecForAny()))
+    .property("exchange_sig", codecOptional(codecForString()))
+    .property("exchange_pub", codecOptional(codecForString()))
     .build("MerchantRefundPermission");
 
 export const codecForMerchantRefundResponse = (): Codec<
   MerchantRefundResponse
 > =>
-  makeCodecForObject<MerchantRefundResponse>()
-    .property("merchant_pub", codecForString)
-    .property("h_contract_terms", codecForString)
-    .property("refunds", makeCodecForList(codecForMerchantRefundPermission()))
+  buildCodecForObject<MerchantRefundResponse>()
+    .property("merchant_pub", codecForString())
+    .property("h_contract_terms", codecForString())
+    .property("refunds", codecForList(codecForMerchantRefundPermission()))
     .build("MerchantRefundResponse");
 
 export const codecForReserveSigSingleton = (): Codec<ReserveSigSingleton> =>
-  makeCodecForObject<ReserveSigSingleton>()
-    .property("reserve_sig", codecForString)
+  buildCodecForObject<ReserveSigSingleton>()
+    .property("reserve_sig", codecForString())
     .build("ReserveSigSingleton");
 
 export const codecForTipResponse = (): Codec<TipResponse> =>
-  makeCodecForObject<TipResponse>()
-    .property("reserve_pub", codecForString)
-    .property("reserve_sigs", makeCodecForList(codecForReserveSigSingleton()))
+  buildCodecForObject<TipResponse>()
+    .property("reserve_pub", codecForString())
+    .property("reserve_sigs", codecForList(codecForReserveSigSingleton()))
     .build("TipResponse");
 
 export const codecForRecoup = (): Codec<Recoup> =>
-  makeCodecForObject<Recoup>()
-    .property("h_denom_pub", codecForString)
+  buildCodecForObject<Recoup>()
+    .property("h_denom_pub", codecForString())
     .build("Recoup");
 
 export const codecForExchangeSigningKey = (): Codec<ExchangeSignKeyJson> =>
-  makeCodecForObject<ExchangeSignKeyJson>()
-    .property("key", codecForString)
-    .property("master_sig", codecForString)
+  buildCodecForObject<ExchangeSignKeyJson>()
+    .property("key", codecForString())
+    .property("master_sig", codecForString())
     .property("stamp_end", codecForTimestamp)
     .property("stamp_start", codecForTimestamp)
     .property("stamp_expire", codecForTimestamp)
     .build("ExchangeSignKeyJson");
 
 export const codecForExchangeKeysJson = (): Codec<ExchangeKeysJson> =>
-  makeCodecForObject<ExchangeKeysJson>()
-    .property("denoms", makeCodecForList(codecForDenomination()))
-    .property("master_public_key", codecForString)
-    .property("auditors", makeCodecForList(codecForAuditor()))
+  buildCodecForObject<ExchangeKeysJson>()
+    .property("denoms", codecForList(codecForDenomination()))
+    .property("master_public_key", codecForString())
+    .property("auditors", codecForList(codecForAuditor()))
     .property("list_issue_date", codecForTimestamp)
-    .property("recoup", makeCodecOptional(makeCodecForList(codecForRecoup())))
-    .property("signkeys", makeCodecForList(codecForExchangeSigningKey()))
-    .property("version", codecForString)
+    .property("recoup", codecOptional(codecForList(codecForRecoup())))
+    .property("signkeys", codecForList(codecForExchangeSigningKey()))
+    .property("version", codecForString())
     .build("KeysJson");
 
 export const codecForWireFeesJson = (): Codec<WireFeesJson> =>
-  makeCodecForObject<WireFeesJson>()
-    .property("wire_fee", codecForString)
-    .property("closing_fee", codecForString)
-    .property("sig", codecForString)
+  buildCodecForObject<WireFeesJson>()
+    .property("wire_fee", codecForString())
+    .property("closing_fee", codecForString())
+    .property("sig", codecForString())
     .property("start_date", codecForTimestamp)
     .property("end_date", codecForTimestamp)
     .build("WireFeesJson");
 
 export const codecForAccountInfo = (): Codec<AccountInfo> =>
-  makeCodecForObject<AccountInfo>()
-    .property("payto_uri", codecForString)
-    .property("master_sig", codecForString)
+  buildCodecForObject<AccountInfo>()
+    .property("payto_uri", codecForString())
+    .property("master_sig", codecForString())
     .build("AccountInfo");
 
 export const codecForExchangeWireJson = (): Codec<ExchangeWireJson> =>
-  makeCodecForObject<ExchangeWireJson>()
-    .property("accounts", makeCodecForList(codecForAccountInfo()))
-    .property("fees", makeCodecForMap(makeCodecForList(codecForWireFeesJson())))
+  buildCodecForObject<ExchangeWireJson>()
+    .property("accounts", codecForList(codecForAccountInfo()))
+    .property("fees", codecForMap(codecForList(codecForWireFeesJson())))
     .build("ExchangeWireJson");
 
 export const codecForProposal = (): Codec<Proposal> =>
-  makeCodecForObject<Proposal>()
-    .property("contract_terms", codecForAny)
-    .property("sig", codecForString)
+  buildCodecForObject<Proposal>()
+    .property("contract_terms", codecForAny())
+    .property("sig", codecForString())
     .build("Proposal");
 
 export const codecForCheckPaymentResponse = (): Codec<CheckPaymentResponse> =>
-  makeCodecForObject<CheckPaymentResponse>()
-    .property("order_status", codecForString)
-    .property("refunded", makeCodecOptional(codecForBoolean))
-    .property("refunded_amount", makeCodecOptional(codecForString))
-    .property("contract_terms", makeCodecOptional(codecForAny))
-    .property("taler_pay_uri", makeCodecOptional(codecForString))
-    .property("contract_url", makeCodecOptional(codecForString))
+  buildCodecForObject<CheckPaymentResponse>()
+    .property("order_status", codecForString())
+    .property("refunded", codecOptional(codecForBoolean))
+    .property("refunded_amount", codecOptional(codecForString()))
+    .property("contract_terms", codecOptional(codecForAny()))
+    .property("taler_pay_uri", codecOptional(codecForString()))
+    .property("contract_url", codecOptional(codecForString()))
     .build("CheckPaymentResponse");
 
 export const codecForWithdrawOperationStatusResponse = (): Codec<
   WithdrawOperationStatusResponse
 > =>
-  makeCodecForObject<WithdrawOperationStatusResponse>()
+  buildCodecForObject<WithdrawOperationStatusResponse>()
     .property("selection_done", codecForBoolean)
     .property("transfer_done", codecForBoolean)
-    .property("amount", codecForString)
-    .property("sender_wire", makeCodecOptional(codecForString))
-    .property("suggested_exchange", makeCodecOptional(codecForString))
-    .property("confirm_transfer_url", makeCodecOptional(codecForString))
-    .property("wire_types", makeCodecForList(codecForString))
+    .property("amount", codecForString())
+    .property("sender_wire", codecOptional(codecForString()))
+    .property("suggested_exchange", codecOptional(codecForString()))
+    .property("confirm_transfer_url", codecOptional(codecForString()))
+    .property("wire_types", codecForList(codecForString()))
     .build("WithdrawOperationStatusResponse");
 
 export const codecForTipPickupGetResponse = (): Codec<TipPickupGetResponse> =>
-  makeCodecForObject<TipPickupGetResponse>()
-    .property("extra", codecForAny)
-    .property("amount", codecForString)
-    .property("amount_left", codecForString)
-    .property("exchange_url", codecForString)
+  buildCodecForObject<TipPickupGetResponse>()
+    .property("extra", codecForAny())
+    .property("amount", codecForString())
+    .property("amount_left", codecForString())
+    .property("exchange_url", codecForString())
     .property("stamp_expire", codecForTimestamp)
     .property("stamp_created", codecForTimestamp)
     .build("TipPickupGetResponse");
 
 export const codecForRecoupConfirmation = (): Codec<RecoupConfirmation> =>
-  makeCodecForObject<RecoupConfirmation>()
-    .property("reserve_pub", makeCodecOptional(codecForString))
-    .property("old_coin_pub", makeCodecOptional(codecForString))
+  buildCodecForObject<RecoupConfirmation>()
+    .property("reserve_pub", codecOptional(codecForString()))
+    .property("old_coin_pub", codecOptional(codecForString()))
     .build("RecoupConfirmation");
 
 export const codecForWithdrawResponse = (): Codec<WithdrawResponse> =>
-  makeCodecForObject<WithdrawResponse>()
-    .property("ev_sig", codecForString)
+  buildCodecForObject<WithdrawResponse>()
+    .property("ev_sig", codecForString())
     .build("WithdrawResponse");
 
 export const codecForMerchantPayResponse = (): Codec<MerchantPayResponse> =>
-  makeCodecForObject<MerchantPayResponse>()
-    .property("sig", codecForString)
+  buildCodecForObject<MerchantPayResponse>()
+    .property("sig", codecForString())
     .build("MerchantPayResponse");
 
 export const codecForExchangeMeltResponse = (): Codec<ExchangeMeltResponse> =>
-  makeCodecForObject<ExchangeMeltResponse>()
-    .property("exchange_pub", codecForString)
-    .property("exchange_sig", codecForString)
-    .property("noreveal_index", codecForNumber)
-    .property("refresh_base_url", makeCodecOptional(codecForString))
+  buildCodecForObject<ExchangeMeltResponse>()
+    .property("exchange_pub", codecForString())
+    .property("exchange_sig", codecForString())
+    .property("noreveal_index", codecForNumber())
+    .property("refresh_base_url", codecOptional(codecForString()))
     .build("ExchangeMeltResponse");
 
 export const codecForExchangeRevealItem = (): Codec<ExchangeRevealItem> =>
-  makeCodecForObject<ExchangeRevealItem>()
-    .property("ev_sig", codecForString)
+  buildCodecForObject<ExchangeRevealItem>()
+    .property("ev_sig", codecForString())
     .build("ExchangeRevealItem");
 
 export const codecForExchangeRevealResponse = (): Codec<
   ExchangeRevealResponse
 > =>
-  makeCodecForObject<ExchangeRevealResponse>()
-    .property("ev_sigs", makeCodecForList(codecForExchangeRevealItem()))
+  buildCodecForObject<ExchangeRevealResponse>()
+    .property("ev_sigs", codecForList(codecForExchangeRevealItem()))
     .build("ExchangeRevealResponse");
 
 export const codecForMerchantCoinRefundSuccessStatus = (): Codec<
   MerchantCoinRefundSuccessStatus
 > =>
-  makeCodecForObject<MerchantCoinRefundSuccessStatus>()
-    .property("type", makeCodecForConstString("success"))
-    .property("coin_pub", codecForString)
-    .property("exchange_status", makeCodecForConstNumber(200))
-    .property("exchange_sig", codecForString)
-    .property("rtransaction_id", codecForNumber)
-    .property("refund_amount", codecForString)
-    .property("exchange_pub", codecForString)
+  buildCodecForObject<MerchantCoinRefundSuccessStatus>()
+    .property("type", codecForConstString("success"))
+    .property("coin_pub", codecForString())
+    .property("exchange_status", codecForConstNumber(200))
+    .property("exchange_sig", codecForString())
+    .property("rtransaction_id", codecForNumber())
+    .property("refund_amount", codecForString())
+    .property("exchange_pub", codecForString())
     .property("execution_time", codecForTimestamp)
     .build("MerchantCoinRefundSuccessStatus");
 
 export const codecForMerchantCoinRefundFailureStatus = (): Codec<
   MerchantCoinRefundFailureStatus
 > =>
-  makeCodecForObject<MerchantCoinRefundFailureStatus>()
-    .property("type", makeCodecForConstString("failure"))
-    .property("coin_pub", codecForString)
-    .property("exchange_status", makeCodecForConstNumber(200))
-    .property("rtransaction_id", codecForNumber)
-    .property("refund_amount", codecForString)
-    .property("exchange_code", makeCodecOptional(codecForNumber))
-    .property("exchange_reply", makeCodecOptional(codecForAny))
+  buildCodecForObject<MerchantCoinRefundFailureStatus>()
+    .property("type", codecForConstString("failure"))
+    .property("coin_pub", codecForString())
+    .property("exchange_status", codecForConstNumber(200))
+    .property("rtransaction_id", codecForNumber())
+    .property("refund_amount", codecForString())
+    .property("exchange_code", codecOptional(codecForNumber()))
+    .property("exchange_reply", codecOptional(codecForAny()))
     .property("execution_time", codecForTimestamp)
     .build("MerchantCoinRefundSuccessStatus");
 
 export const codecForMerchantCoinRefundStatus = (): Codec<
   MerchantCoinRefundStatus
 > =>
-  makeCodecForUnion<MerchantCoinRefundStatus>()
+  buildCodecForUnion<MerchantCoinRefundStatus>()
     .discriminateOn("type")
     .alternative("success", codecForMerchantCoinRefundSuccessStatus())
     .alternative("failure", codecForMerchantCoinRefundFailureStatus())
@@ -1256,17 +1257,17 @@ export const codecForMerchantCoinRefundStatus = (): Codec<
 export const codecForMerchantOrderStatusPaid = (): Codec<
   MerchantOrderStatusPaid
 > =>
-  makeCodecForObject<MerchantOrderStatusPaid>()
-    .property("merchant_pub", codecForString)
-    .property("refund_amount", codecForString)
+  buildCodecForObject<MerchantOrderStatusPaid>()
+    .property("merchant_pub", codecForString())
+    .property("refund_amount", codecForString())
     .property("refunded", codecForBoolean)
-    .property("refunds", makeCodecForList(codecForMerchantCoinRefundStatus()))
+    .property("refunds", codecForList(codecForMerchantCoinRefundStatus()))
     .build("MerchantOrderStatusPaid");
 
 export const codecForMerchantOrderStatusUnpaid = (): Codec<
   MerchantOrderStatusUnpaid
 > =>
-  makeCodecForObject<MerchantOrderStatusUnpaid>()
-    .property("taler_pay_uri", codecForString)
-    .property("already_paid_order_id", makeCodecOptional(codecForString))
+  buildCodecForObject<MerchantOrderStatusUnpaid>()
+    .property("taler_pay_uri", codecForString())
+    .property("already_paid_order_id", codecOptional(codecForString()))
     .build("MerchantOrderStatusUnpaid");
diff --git a/packages/taler-wallet-core/src/types/transactions.ts b/packages/taler-wallet-core/src/types/transactions.ts
index 47e3e7d5b..f3192e5a4 100644
--- a/packages/taler-wallet-core/src/types/transactions.ts
+++ b/packages/taler-wallet-core/src/types/transactions.ts
@@ -28,8 +28,8 @@ import { Timestamp } from "../util/time";
 import { AmountString, Product } from "./talerTypes";
 import {
   Codec,
-  makeCodecForObject,
-  makeCodecOptional,
+  buildCodecForObject,
+  codecOptional,
   codecForString,
 } from "../util/codec";
 
@@ -305,7 +305,7 @@ interface TransactionRefresh extends TransactionCommon {
 }
 
 export const codecForTransactionsRequest = (): Codec<TransactionsRequest> =>
-  makeCodecForObject<TransactionsRequest>()
-    .property("currency", makeCodecOptional(codecForString))
-    .property("search", makeCodecOptional(codecForString))
+  buildCodecForObject<TransactionsRequest>()
+    .property("currency", codecOptional(codecForString()))
+    .property("search", codecOptional(codecForString()))
     .build("TransactionsRequest");
diff --git a/packages/taler-wallet-core/src/types/walletTypes.ts b/packages/taler-wallet-core/src/types/walletTypes.ts
index d79ade971..7a648dd56 100644
--- a/packages/taler-wallet-core/src/types/walletTypes.ts
+++ b/packages/taler-wallet-core/src/types/walletTypes.ts
@@ -40,13 +40,13 @@ import {
 } from "./dbTypes";
 import { Timestamp } from "../util/time";
 import {
-  makeCodecForObject,
+  buildCodecForObject,
   codecForString,
-  makeCodecOptional,
+  codecOptional,
   Codec,
-  makeCodecForList,
+  codecForList,
   codecForBoolean,
-  makeCodecForConstString,
+  codecForConstString,
   codecForAny,
 } from "../util/codec";
 import { AmountString, codecForContractTerms } from "./talerTypes";
@@ -174,17 +174,17 @@ export interface BalancesResponse {
 }
 
 export const codecForBalance = (): Codec<Balance> =>
-  makeCodecForObject<Balance>()
-    .property("available", codecForString)
+  buildCodecForObject<Balance>()
+    .property("available", codecForString())
     .property("hasPendingTransactions", codecForBoolean)
-    .property("pendingIncoming", codecForString)
-    .property("pendingOutgoing", codecForString)
+    .property("pendingIncoming", codecForString())
+    .property("pendingOutgoing", codecForString())
     .property("requiresUserInput", codecForBoolean)
     .build("Balance");
 
 export const codecForBalancesResponse = (): Codec<BalancesResponse> =>
-  makeCodecForObject<BalancesResponse>()
-    .property("balances", makeCodecForList(codecForBalance()))
+  buildCodecForObject<BalancesResponse>()
+    .property("balances", codecForList(codecForBalance()))
     .build("BalancesResponse");
 
 /**
@@ -270,12 +270,12 @@ export interface CreateReserveRequest {
 }
 
 export const codecForCreateReserveRequest = (): Codec<CreateReserveRequest> =>
-  makeCodecForObject<CreateReserveRequest>()
+  buildCodecForObject<CreateReserveRequest>()
     .property("amount", codecForAmountJson())
-    .property("exchange", codecForString)
-    .property("exchangePaytoUri", codecForString)
-    .property("senderWire", makeCodecOptional(codecForString))
-    .property("bankWithdrawStatusUrl", makeCodecOptional(codecForString))
+    .property("exchange", codecForString())
+    .property("exchangePaytoUri", codecForString())
+    .property("senderWire", codecOptional(codecForString()))
+    .property("bankWithdrawStatusUrl", codecOptional(codecForString()))
     .build("CreateReserveRequest");
 
 /**
@@ -290,8 +290,8 @@ export interface ConfirmReserveRequest {
 }
 
 export const codecForConfirmReserveRequest = (): Codec<ConfirmReserveRequest> =>
-  makeCodecForObject<ConfirmReserveRequest>()
-    .property("reservePub", codecForString)
+  buildCodecForObject<ConfirmReserveRequest>()
+    .property("reservePub", codecForString())
     .build("ConfirmReserveRequest");
 
 /**
@@ -360,43 +360,43 @@ export const enum PreparePayResultType {
 export const codecForPreparePayResultPaymentPossible = (): Codec<
   PreparePayResultPaymentPossible
 > =>
-  makeCodecForObject<PreparePayResultPaymentPossible>()
+  buildCodecForObject<PreparePayResultPaymentPossible>()
     .property("amountEffective", codecForAmountString())
     .property("amountRaw", codecForAmountString())
-    .property("contractTerms", codecForAny)
-    .property("proposalId", codecForString)
+    .property("contractTerms", codecForAny())
+    .property("proposalId", codecForString())
     .property(
       "status",
-      makeCodecForConstString(PreparePayResultType.PaymentPossible),
+      codecForConstString(PreparePayResultType.PaymentPossible),
     )
     .build("PreparePayResultPaymentPossible");
 
 export const codecForPreparePayResultInsufficientBalance = (): Codec<
   PreparePayResultInsufficientBalance
 > =>
-  makeCodecForObject<PreparePayResultInsufficientBalance>()
+  buildCodecForObject<PreparePayResultInsufficientBalance>()
     .property("amountRaw", codecForAmountString())
-    .property("contractTerms", codecForAny)
-    .property("proposalId", codecForString)
+    .property("contractTerms", codecForAny())
+    .property("proposalId", codecForString())
     .property(
       "status",
-      makeCodecForConstString(PreparePayResultType.InsufficientBalance),
+      codecForConstString(PreparePayResultType.InsufficientBalance),
     )
     .build("PreparePayResultInsufficientBalance");
 
 export const codecForPreparePayResultAlreadyConfirmed = (): Codec<
   PreparePayResultAlreadyConfirmed
 > =>
-  makeCodecForObject<PreparePayResultAlreadyConfirmed>()
+  buildCodecForObject<PreparePayResultAlreadyConfirmed>()
     .property(
       "status",
-      makeCodecForConstString(PreparePayResultType.AlreadyConfirmed),
+      codecForConstString(PreparePayResultType.AlreadyConfirmed),
     )
     .property("amountEffective", codecForAmountString())
     .property("amountRaw", codecForAmountString())
-    .property("nextUrl", codecForString)
+    .property("nextUrl", codecForString())
     .property("paid", codecForBoolean)
-    .property("contractTerms", codecForAny)
+    .property("contractTerms", codecForAny())
     .build("PreparePayResultAlreadyConfirmed");
 
 export type PreparePayResult =
diff --git a/packages/taler-wallet-core/src/util/amounts.ts b/packages/taler-wallet-core/src/util/amounts.ts
index 33faa868e..2a8c47905 100644
--- a/packages/taler-wallet-core/src/util/amounts.ts
+++ b/packages/taler-wallet-core/src/util/amounts.ts
@@ -22,7 +22,7 @@
  * Imports.
  */
 import {
-  makeCodecForObject,
+  buildCodecForObject,
   codecForString,
   codecForNumber,
   Codec,
@@ -68,13 +68,13 @@ export interface AmountJson {
 }
 
 export const codecForAmountJson = (): Codec<AmountJson> =>
-  makeCodecForObject<AmountJson>()
-    .property("currency", codecForString)
-    .property("value", codecForNumber)
-    .property("fraction", codecForNumber)
+  buildCodecForObject<AmountJson>()
+    .property("currency", codecForString())
+    .property("value", codecForNumber())
+    .property("fraction", codecForNumber())
     .build("AmountJson");
 
-export const codecForAmountString = (): Codec<AmountString> => codecForString;
+export const codecForAmountString = (): Codec<AmountString> => codecForString();
 
 /**
  * Result of a possibly overflowing operation.
diff --git a/packages/taler-wallet-core/src/util/codec-test.ts b/packages/taler-wallet-core/src/util/codec-test.ts
index b429c318c..f8f4c797c 100644
--- a/packages/taler-wallet-core/src/util/codec-test.ts
+++ b/packages/taler-wallet-core/src/util/codec-test.ts
@@ -21,10 +21,10 @@
 import test from "ava";
 import {
   Codec,
-  makeCodecForObject,
-  makeCodecForConstString,
+  buildCodecForObject,
+  codecForConstString,
   codecForString,
-  makeCodecForUnion,
+  buildCodecForUnion,
 } from "./codec";
 
 interface MyObj {
@@ -44,8 +44,8 @@ interface AltTwo {
 type MyUnion = AltOne | AltTwo;
 
 test("basic codec", (t) => {
-  const myObjCodec = makeCodecForObject<MyObj>()
-    .property("foo", codecForString)
+  const myObjCodec = buildCodecForObject<MyObj>()
+    .property("foo", codecForString())
     .build("MyObj");
   const res = myObjCodec.decode({ foo: "hello" });
   t.assert(res.foo === "hello");
@@ -56,15 +56,15 @@ test("basic codec", (t) => {
 });
 
 test("union", (t) => {
-  const altOneCodec: Codec<AltOne> = makeCodecForObject<AltOne>()
-    .property("type", makeCodecForConstString("one"))
-    .property("foo", codecForString)
+  const altOneCodec: Codec<AltOne> = buildCodecForObject<AltOne>()
+    .property("type", codecForConstString("one"))
+    .property("foo", codecForString())
     .build("AltOne");
-  const altTwoCodec: Codec<AltTwo> = makeCodecForObject<AltTwo>()
-    .property("type", makeCodecForConstString("two"))
-    .property("bar", codecForString)
+  const altTwoCodec: Codec<AltTwo> = buildCodecForObject<AltTwo>()
+    .property("type", codecForConstString("two"))
+    .property("bar", codecForString())
     .build("AltTwo");
-  const myUnionCodec: Codec<MyUnion> = makeCodecForUnion<MyUnion>()
+  const myUnionCodec: Codec<MyUnion> = buildCodecForUnion<MyUnion>()
     .discriminateOn("type")
     .alternative("one", altOneCodec)
     .alternative("two", altTwoCodec)
diff --git a/packages/taler-wallet-core/src/util/codec.ts b/packages/taler-wallet-core/src/util/codec.ts
index 2ce3c2cba..111abc38c 100644
--- a/packages/taler-wallet-core/src/util/codec.ts
+++ b/packages/taler-wallet-core/src/util/codec.ts
@@ -221,18 +221,18 @@ export class UnionCodecPreBuilder<T> {
 /**
  * Return a builder for a codec that decodes an object with properties.
  */
-export function makeCodecForObject<T>(): ObjectCodecBuilder<T, {}> {
+export function buildCodecForObject<T>(): ObjectCodecBuilder<T, {}> {
   return new ObjectCodecBuilder<T, {}>();
 }
 
-export function makeCodecForUnion<T>(): UnionCodecPreBuilder<T> {
+export function buildCodecForUnion<T>(): UnionCodecPreBuilder<T> {
   return new UnionCodecPreBuilder<T>();
 }
 
 /**
  * Return a codec for a mapping from a string to values described by the inner codec.
  */
-export function makeCodecForMap<T>(
+export function codecForMap<T>(
   innerCodec: Codec<T>,
 ): Codec<{ [x: string]: T }> {
   if (!innerCodec) {
@@ -255,7 +255,7 @@ export function makeCodecForMap<T>(
 /**
  * Return a codec for a list, containing values described by the inner codec.
  */
-export function makeCodecForList<T>(innerCodec: Codec<T>): Codec<T[]> {
+export function codecForList<T>(innerCodec: Codec<T>): Codec<T[]> {
   if (!innerCodec) {
     throw Error("inner codec must be defined");
   }
@@ -276,16 +276,18 @@ export function makeCodecForList<T>(innerCodec: Codec<T>): Codec<T[]> {
 /**
  * Return a codec for a value that must be a number.
  */
-export const codecForNumber: Codec<number> = {
-  decode(x: any, c?: Context): number {
-    if (typeof x === "number") {
-      return x;
-    }
-    throw new DecodingError(
-      `expected number at ${renderContext(c)} but got ${typeof x}`,
-    );
-  },
-};
+export function codecForNumber(): Codec<number> {
+  return {
+    decode(x: any, c?: Context): number {
+      if (typeof x === "number") {
+        return x;
+      }
+      throw new DecodingError(
+        `expected number at ${renderContext(c)} but got ${typeof x}`,
+      );
+    },
+  };
+}
 
 /**
  * Return a codec for a value that must be a number.
@@ -304,30 +306,34 @@ export const codecForBoolean: Codec<boolean> = {
 /**
  * Return a codec for a value that must be a string.
  */
-export const codecForString: Codec<string> = {
-  decode(x: any, c?: Context): string {
-    if (typeof x === "string") {
-      return x;
-    }
-    throw new DecodingError(
-      `expected string at ${renderContext(c)} but got ${typeof x}`,
-    );
-  },
-};
+export function codecForString(): Codec<string> {
+  return {
+    decode(x: any, c?: Context): string {
+      if (typeof x === "string") {
+        return x;
+      }
+      throw new DecodingError(
+        `expected string at ${renderContext(c)} but got ${typeof x}`,
+      );
+    },
+  };
+}
 
 /**
  * Codec that allows any value.
  */
-export const codecForAny: Codec<any> = {
-  decode(x: any, c?: Context): any {
-    return x;
-  },
-};
+export function codecForAny(): Codec<any> {
+  return {
+    decode(x: any, c?: Context): any {
+      return x;
+    },
+  };
+}
 
 /**
  * Return a codec for a value that must be a string.
  */
-export function makeCodecForConstString<V extends string>(s: V): Codec<V> {
+export function codecForConstString<V extends string>(s: V): Codec<V> {
   return {
     decode(x: any, c?: Context): V {
       if (x === s) {
@@ -345,7 +351,7 @@ export function makeCodecForConstString<V extends string>(s: V): Codec<V> {
 /**
  * Return a codec for a boolean true constant.
  */
-export function makeCodecForConstTrue(): Codec<true> {
+export function codecForConstTrue(): Codec<true> {
   return {
     decode(x: any, c?: Context): true {
       if (x === true) {
@@ -361,7 +367,7 @@ export function makeCodecForConstTrue(): Codec<true> {
 /**
  * Return a codec for a boolean true constant.
  */
-export function makeCodecForConstFalse(): Codec<false> {
+export function codecForConstFalse(): Codec<false> {
   return {
     decode(x: any, c?: Context): false {
       if (x === false) {
@@ -377,7 +383,7 @@ export function makeCodecForConstFalse(): Codec<false> {
 /**
  * Return a codec for a value that must be a constant number.
  */
-export function makeCodecForConstNumber<V extends number>(n: V): Codec<V> {
+export function codecForConstNumber<V extends number>(n: V): Codec<V> {
   return {
     decode(x: any, c?: Context): V {
       if (x === n) {
@@ -392,9 +398,7 @@ export function makeCodecForConstNumber<V extends number>(n: V): Codec<V> {
   };
 }
 
-export function makeCodecOptional<V>(
-  innerCodec: Codec<V>,
-): Codec<V | undefined> {
+export function codecOptional<V>(innerCodec: Codec<V>): Codec<V | undefined> {
   return {
     decode(x: any, c?: Context): V | undefined {
       if (x === undefined || x === null) {
diff --git a/packages/taler-wallet-core/src/walletCoreApiHandler.ts b/packages/taler-wallet-core/src/walletCoreApiHandler.ts
index 604439186..5bc9005a8 100644
--- a/packages/taler-wallet-core/src/walletCoreApiHandler.ts
+++ b/packages/taler-wallet-core/src/walletCoreApiHandler.ts
@@ -23,10 +23,10 @@ import {
 import { TalerErrorCode } from "./TalerErrorCode";
 import { codecForTransactionsRequest } from "./types/transactions";
 import {
-  makeCodecForObject,
+  buildCodecForObject,
   codecForString,
   Codec,
-  makeCodecOptional,
+  codecOptional,
 } from "./util/codec";
 import { Amounts } from "./util/amounts";
 import { OperationErrorDetails } from "./types/walletTypes";
@@ -36,8 +36,8 @@ export interface AddExchangeRequest {
 }
 
 export const codecForAddExchangeRequest = (): Codec<AddExchangeRequest> =>
-  makeCodecForObject<AddExchangeRequest>()
-    .property("exchangeBaseUrl", codecForString)
+  buildCodecForObject<AddExchangeRequest>()
+    .property("exchangeBaseUrl", codecForString())
     .build("AddExchangeRequest");
 
 export interface GetExchangeTosRequest {
@@ -45,8 +45,8 @@ export interface GetExchangeTosRequest {
 }
 
 export const codecForGetExchangeTosRequest = (): Codec<GetExchangeTosRequest> =>
-  makeCodecForObject<GetExchangeTosRequest>()
-    .property("exchangeBaseUrl", codecForString)
+  buildCodecForObject<GetExchangeTosRequest>()
+    .property("exchangeBaseUrl", codecForString())
     .build("GetExchangeTosRequest");
 
 export interface AcceptManualWithdrawalRequest {
@@ -57,9 +57,9 @@ export interface AcceptManualWithdrawalRequest {
 export const codecForAcceptManualWithdrawalRequet = (): Codec<
   AcceptManualWithdrawalRequest
 > =>
-  makeCodecForObject<AcceptManualWithdrawalRequest>()
-    .property("exchangeBaseUrl", codecForString)
-    .property("amount", codecForString)
+  buildCodecForObject<AcceptManualWithdrawalRequest>()
+    .property("exchangeBaseUrl", codecForString())
+    .property("amount", codecForString())
     .build("AcceptManualWithdrawalRequest");
 
 export interface GetWithdrawalDetailsForAmountRequest {
@@ -75,17 +75,17 @@ export interface AcceptBankIntegratedWithdrawalRequest {
 export const codecForAcceptBankIntegratedWithdrawalRequest = (): Codec<
   AcceptBankIntegratedWithdrawalRequest
 > =>
-  makeCodecForObject<AcceptBankIntegratedWithdrawalRequest>()
-    .property("exchangeBaseUrl", codecForString)
-    .property("talerWithdrawUri", codecForString)
+  buildCodecForObject<AcceptBankIntegratedWithdrawalRequest>()
+    .property("exchangeBaseUrl", codecForString())
+    .property("talerWithdrawUri", codecForString())
     .build("AcceptBankIntegratedWithdrawalRequest");
 
 export const codecForGetWithdrawalDetailsForAmountRequest = (): Codec<
   GetWithdrawalDetailsForAmountRequest
 > =>
-  makeCodecForObject<GetWithdrawalDetailsForAmountRequest>()
-    .property("exchangeBaseUrl", codecForString)
-    .property("amount", codecForString)
+  buildCodecForObject<GetWithdrawalDetailsForAmountRequest>()
+    .property("exchangeBaseUrl", codecForString())
+    .property("amount", codecForString())
     .build("GetWithdrawalDetailsForAmountRequest");
 
 export interface AcceptExchangeTosRequest {
@@ -94,9 +94,9 @@ export interface AcceptExchangeTosRequest {
 }
 
 export const codecForAcceptExchangeTosRequest = (): Codec<AcceptExchangeTosRequest> =>
-  makeCodecForObject<AcceptExchangeTosRequest>()
-    .property("exchangeBaseUrl", codecForString)
-    .property("etag", codecForString)
+  buildCodecForObject<AcceptExchangeTosRequest>()
+    .property("exchangeBaseUrl", codecForString())
+    .property("etag", codecForString())
     .build("AcceptExchangeTosRequest");
 
 export interface ApplyRefundRequest {
@@ -104,8 +104,8 @@ export interface ApplyRefundRequest {
 }
 
 export const codecForApplyRefundRequest = (): Codec<ApplyRefundRequest> =>
-  makeCodecForObject<ApplyRefundRequest>()
-    .property("talerRefundUri", codecForString)
+  buildCodecForObject<ApplyRefundRequest>()
+    .property("talerRefundUri", codecForString())
     .build("ApplyRefundRequest");
 
 export interface GetWithdrawalDetailsForUriRequest {
@@ -115,8 +115,8 @@ export interface GetWithdrawalDetailsForUriRequest {
 export const codecForGetWithdrawalDetailsForUri = (): Codec<
   GetWithdrawalDetailsForUriRequest
 > =>
-  makeCodecForObject<GetWithdrawalDetailsForUriRequest>()
-    .property("talerWithdrawUri", codecForString)
+  buildCodecForObject<GetWithdrawalDetailsForUriRequest>()
+    .property("talerWithdrawUri", codecForString())
     .build("GetWithdrawalDetailsForUriRequest");
 
 export interface AbortProposalRequest {
@@ -124,8 +124,8 @@ export interface AbortProposalRequest {
 }
 
 export const codecForAbortProposalRequest = (): Codec<AbortProposalRequest> =>
-  makeCodecForObject<AbortProposalRequest>()
-    .property("proposalId", codecForString)
+  buildCodecForObject<AbortProposalRequest>()
+    .property("proposalId", codecForString())
     .build("AbortProposalRequest");
 
 export interface PreparePayRequest {
@@ -133,8 +133,8 @@ export interface PreparePayRequest {
 }
 
 const codecForPreparePayRequest = (): Codec<PreparePayRequest> =>
-  makeCodecForObject<PreparePayRequest>()
-    .property("talerPayUri", codecForString)
+  buildCodecForObject<PreparePayRequest>()
+    .property("talerPayUri", codecForString())
     .build("PreparePay");
 
 export interface ConfirmPayRequest {
@@ -143,9 +143,9 @@ export interface ConfirmPayRequest {
 }
 
 export const codecForConfirmPayRequest = (): Codec<ConfirmPayRequest> =>
-  makeCodecForObject<ConfirmPayRequest>()
-    .property("proposalId", codecForString)
-    .property("sessionId", makeCodecOptional(codecForString))
+  buildCodecForObject<ConfirmPayRequest>()
+    .property("proposalId", codecForString())
+    .property("sessionId", codecOptional(codecForString()))
     .build("ConfirmPay");
 
 /**