diff --git a/lib/models/paynym/paynym_claim.dart b/lib/models/paynym/paynym_claim.dart
index 0f1e66373a..36afef7bd1 100644
--- a/lib/models/paynym/paynym_claim.dart
+++ b/lib/models/paynym/paynym_claim.dart
@@ -15,7 +15,7 @@ class PaynymClaim {
   PaynymClaim(this.claimed, this.token);
 
   PaynymClaim.fromMap(Map<String, dynamic> map)
-      : claimed = map["claimed"] as String,
+      : claimed = map["claimed"].toString(),
         token = map["token"] as String;
 
   Map<String, dynamic> toMap() => {
diff --git a/lib/pages/paynym/paynym_claim_view.dart b/lib/pages/paynym/paynym_claim_view.dart
index 8d61e139c5..4eb3c9b936 100644
--- a/lib/pages/paynym/paynym_claim_view.dart
+++ b/lib/pages/paynym/paynym_claim_view.dart
@@ -240,12 +240,24 @@ class _PaynymClaimViewState extends ConsumerState<PaynymClaimView> {
                   final token =
                       await ref.read(paynymAPIProvider).token(pCode.toString());
 
+                  debugPrint("token result: $token");
+
                   if (shouldCancel) return;
 
+                  if (token.value == null) {
+                    debugPrint("token fetch failed: ${token.message}");
+                    if (mounted) {
+                      Navigator.of(context, rootNavigator: isDesktop).pop();
+                    }
+                    return;
+                  }
+
                   // sign token with notification private key
                   final signature =
                       await wallet.signStringWithNotificationKey(token.value!);
 
+                  debugPrint("signature: $signature");
+
                   if (shouldCancel) return;
 
                   // claim paynym account
@@ -253,9 +265,13 @@ class _PaynymClaimViewState extends ConsumerState<PaynymClaimView> {
                       .read(paynymAPIProvider)
                       .claim(token.value!, signature);
 
+                  debugPrint("claim result: $claim");
+
                   if (shouldCancel) return;
 
-                  if (claim.value?.claimed == pCode.toString()) {
+                  if (claim.value != null &&
+                      (claim.value!.claimed == pCode.toString() ||
+                          claim.value!.claimed == "true")) {
                     final account =
                         await ref.read(paynymAPIProvider).nym(pCode.toString());
                     // if (!account.value!.segwit) {
@@ -286,6 +302,13 @@ class _PaynymClaimViewState extends ConsumerState<PaynymClaimView> {
                       );
                     }
                   } else if (mounted && !shouldCancel) {
+                    debugPrint(
+                      "claim failed or mismatch: "
+                      "claimed=${claim.value?.claimed}, "
+                      "expected=${pCode.toString()}, "
+                      "statusCode=${claim.statusCode}, "
+                      "message=${claim.message}",
+                    );
                     Navigator.of(context, rootNavigator: isDesktop).pop();
                   }
                 },
diff --git a/lib/utilities/paynym_is_api.dart b/lib/utilities/paynym_is_api.dart
index 9285fef7f6..5230f1734e 100644
--- a/lib/utilities/paynym_is_api.dart
+++ b/lib/utilities/paynym_is_api.dart
@@ -65,10 +65,16 @@ class PaynymIsApi {
     // debugPrint("Paynym response code: ${response.code}");
     // debugPrint("Paynym response body: ${response.body}");
 
-    return Tuple2(
-      jsonDecode(response.body) as Map<String, dynamic>,
-      response.code,
-    );
+    Map<String, dynamic> parsedBody;
+    try {
+      final bodyStr = response.body.trim();
+      parsedBody = bodyStr.isEmpty
+          ? {}
+          : jsonDecode(bodyStr) as Map<String, dynamic>;
+    } catch (_) {
+      parsedBody = {};
+    }
+    return Tuple2(parsedBody, response.code);
   }
 
   // ### `/api/v1/create`
diff --git a/lib/wallets/wallet/wallet_mixin_interfaces/paynym_interface.dart b/lib/wallets/wallet/wallet_mixin_interfaces/paynym_interface.dart
index 0d993036d3..bb6958418d 100644
--- a/lib/wallets/wallet/wallet_mixin_interfaces/paynym_interface.dart
+++ b/lib/wallets/wallet/wallet_mixin_interfaces/paynym_interface.dart
@@ -342,10 +342,26 @@ mixin PaynymInterface<T extends PaynymCurrencyInterface>
   }
 
   Future<String> signStringWithNotificationKey(String data) async {
-    final bytes = await signWithNotificationKey(
-      Uint8List.fromList(utf8.encode(data)),
+    final myPrivateKeyNode = await deriveNotificationBip32Node();
+    final key = coinlib.ECPrivateKey(myPrivateKeyNode.privateKey!);
+
+    // Clean prefix: strip leading length byte if present (coinlib recalculates)
+    final prefixBytes =
+        cryptoCurrency.networkParams.messagePrefix.toUint8ListFromUtf8;
+    final ignoreFirstByte =
+        prefixBytes.first == prefixBytes.length - 1;
+    final prefix = (ignoreFirstByte
+            ? prefixBytes.sublist(1)
+            : prefixBytes)
+        .toUtf8String;
+
+    final signed = coinlib.MessageSignature.sign(
+      key: key,
+      message: data,
+      prefix: prefix,
     );
-    return Format.uint8listToString(bytes);
+
+    return base64Encode(signed.signature.compact);
   }
 
   Future<TxData> preparePaymentCodeSend({
diff --git a/scripts/linux/build_secp256k1.sh b/scripts/linux/build_secp256k1.sh
index e139cc9377..b6037a3060 100755
--- a/scripts/linux/build_secp256k1.sh
+++ b/scripts/linux/build_secp256k1.sh
@@ -6,8 +6,9 @@ fi
 cd secp256k1
 git checkout 68b55209f1ba3e6c0417789598f5f75649e9c14c
 git reset --hard
+rm -rf build
 mkdir -p build && cd build
-cmake ..
+cmake .. -DSECP256K1_ENABLE_MODULE_RECOVERY=ON
 cmake --build .
 mkdir -p ../../../../../build
 cp lib/libsecp256k1.so.2.*.* "../../../../../build/libsecp256k1.so"
diff --git a/scripts/windows/build_secp256k1.bat b/scripts/windows/build_secp256k1.bat
index bae7c97888..b619e6e78e 100644
--- a/scripts/windows/build_secp256k1.bat
+++ b/scripts/windows/build_secp256k1.bat
@@ -4,7 +4,8 @@ git clone https://github.com/bitcoin-core/secp256k1
 cd secp256k1
 git checkout 68b55209f1ba3e6c0417789598f5f75649e9c14c
 git reset --hard
-cmake -G "Visual Studio 17 2022" -A x64 -S . -B build
+if exist "build" rmdir /s /q "build"
+cmake -G "Visual Studio 17 2022" -A x64 -S . -B build -DSECP256K1_ENABLE_MODULE_RECOVERY=ON
 cd build
 cmake --build .
 if not exist "..\..\..\..\..\build\" mkdir "..\..\..\..\..\build\"
diff --git a/scripts/windows/build_secp256k1_wsl.sh b/scripts/windows/build_secp256k1_wsl.sh
index a39cd3bee3..cedb2bc2c1 100644
--- a/scripts/windows/build_secp256k1_wsl.sh
+++ b/scripts/windows/build_secp256k1_wsl.sh
@@ -6,8 +6,9 @@ fi
 cd secp256k1
 git checkout 68b55209f1ba3e6c0417789598f5f75649e9c14c
 git reset --hard
+rm -rf build
 mkdir -p build && cd build
-cmake .. -DCMAKE_TOOLCHAIN_FILE=../cmake/x86_64-w64-mingw32.toolchain.cmake
+cmake .. -DCMAKE_TOOLCHAIN_FILE=../cmake/x86_64-w64-mingw32.toolchain.cmake -DSECP256K1_ENABLE_MODULE_RECOVERY=ON
 cmake --build .
 mkdir -p ../../../../../build
 cp bin/libsecp256k1-2.dll "../../../../../build/secp256k1.dll"
diff --git a/test/services/paynym/paynym_is_api_test.dart b/test/services/paynym/paynym_is_api_test.dart
new file mode 100644
index 0000000000..fa2e651a2e
--- /dev/null
+++ b/test/services/paynym/paynym_is_api_test.dart
@@ -0,0 +1,245 @@
+import 'dart:convert';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/annotations.dart';
+import 'package:mockito/mockito.dart';
+import 'package:stackwallet/networking/http.dart';
+import 'package:stackwallet/utilities/paynym_is_api.dart';
+
+import 'paynym_is_api_test.mocks.dart';
+
+@GenerateMocks([HTTP])
+void main() {
+  late PaynymIsApi api;
+  late MockHTTP client;
+
+  setUp(() {
+    client = MockHTTP();
+    api = PaynymIsApi();
+    api.client = client;
+  });
+
+  void stubPost(
+    String endpoint,
+    String responseBody,
+    int statusCode, {
+    Map<String, String>? extraHeaders,
+  }) {
+    when(
+      client.post(
+        url: Uri.parse('https://paynym.rs/api/v1$endpoint'),
+        headers: anyNamed('headers'),
+        proxyInfo: anyNamed('proxyInfo'),
+        body: anyNamed('body'),
+        encoding: anyNamed('encoding'),
+      ),
+    ).thenAnswer((_) async => Response(utf8.encode(responseBody), statusCode));
+  }
+
+  group('create', () {
+    test('400 with empty body returns typed error', () async {
+      stubPost('/create', '', 400);
+      final r = await api.create('PM8Ttest');
+      expect(r.statusCode, 400);
+      expect(r.message, 'Bad request');
+      expect(r.value, isNull);
+    });
+
+    test('201 with valid JSON returns CreatedPaynym', () async {
+      stubPost(
+        '/create',
+        '{"claimed":false,"nymID":"abc","nymName":"foo","segwit":true,"token":"tok"}',
+        201,
+      );
+      final r = await api.create('PM8Ttest');
+      expect(r.statusCode, 201);
+      expect(r.message, 'PayNym created successfully');
+      expect(r.value, isNotNull);
+      expect(r.value!.nymId, 'abc');
+    });
+
+    test('200 returns existing PayNym', () async {
+      stubPost(
+        '/create',
+        '{"claimed":true,"nymID":"abc","nymName":"foo","segwit":true,"token":"tok"}',
+        200,
+      );
+      final r = await api.create('PM8Ttest');
+      expect(r.statusCode, 200);
+      expect(r.message, 'PayNym already exists');
+      expect(r.value, isNotNull);
+    });
+  });
+
+  group('token', () {
+    test('404 with empty body returns typed error', () async {
+      stubPost('/token', '', 404);
+      final r = await api.token('PM8Ttest');
+      expect(r.statusCode, 404);
+      expect(r.message, 'Payment code was not found');
+      expect(r.value, isNull);
+    });
+
+    test('400 with empty body returns typed error', () async {
+      stubPost('/token', '', 400);
+      final r = await api.token('PM8Ttest');
+      expect(r.statusCode, 400);
+      expect(r.message, 'Bad request');
+      expect(r.value, isNull);
+    });
+
+    test('200 with valid JSON returns token string', () async {
+      stubPost('/token', '{"token":"testToken123"}', 200);
+      final r = await api.token('PM8Ttest');
+      expect(r.statusCode, 200);
+      expect(r.message, 'Token was successfully updated');
+      expect(r.value, 'testToken123');
+    });
+  });
+
+  group('nym', () {
+    test('404 with empty body returns typed error', () async {
+      stubPost('/nym', '', 404);
+      final r = await api.nym('PM8Ttest');
+      expect(r.statusCode, 404);
+      expect(r.message, 'Nym not found');
+      expect(r.value, isNull);
+    });
+
+    test('400 with empty body returns typed error', () async {
+      stubPost('/nym', '', 400);
+      final r = await api.nym('PM8Ttest');
+      expect(r.statusCode, 400);
+      expect(r.message, 'Bad request');
+      expect(r.value, isNull);
+    });
+
+    test('200 with valid JSON returns PaynymAccount', () async {
+      stubPost(
+        '/nym',
+        jsonEncode({
+          'nymID': 'testId',
+          'nymName': 'testName',
+          'segwit': true,
+          'codes': [
+            {'claimed': true, 'segwit': true, 'code': 'PM8Ttest'},
+          ],
+          'followers': <Map<String, dynamic>>[],
+          'following': <Map<String, dynamic>>[],
+        }),
+        200,
+      );
+      final r = await api.nym('PM8Ttest');
+      expect(r.statusCode, 200);
+      expect(r.message, 'Nym found and returned');
+      expect(r.value, isNotNull);
+      expect(r.value!.nymID, 'testId');
+    });
+  });
+
+  group('claim', () {
+    test('400 with empty body returns typed error', () async {
+      stubPost('/claim', '', 400);
+      final r = await api.claim('tok', 'sig');
+      expect(r.statusCode, 400);
+      expect(r.message, 'Bad request');
+      expect(r.value, isNull);
+    });
+
+    test('200 with valid JSON returns PaynymClaim', () async {
+      stubPost('/claim', '{"claimed":"PM8Ttest","token":"newTok"}', 200);
+      final r = await api.claim('tok', 'sig');
+      expect(r.statusCode, 200);
+      expect(r.message, 'Payment code successfully claimed');
+      expect(r.value, isNotNull);
+      expect(r.value!.claimed, 'PM8Ttest');
+    });
+  });
+
+  group('follow', () {
+    test('404 with empty body returns typed error', () async {
+      stubPost('/follow', '', 404);
+      final r = await api.follow('tok', 'sig', 'target');
+      expect(r.statusCode, 404);
+      expect(r.message, 'Payment code not found');
+      expect(r.value, isNull);
+    });
+
+    test('401 with empty body returns typed error', () async {
+      stubPost('/follow', '', 401);
+      final r = await api.follow('tok', 'sig', 'target');
+      expect(r.statusCode, 401);
+      expect(
+        r.message,
+        'Unauthorized token or signature or Unclaimed payment code',
+      );
+      expect(r.value, isNull);
+    });
+
+    test('400 with empty body returns typed error', () async {
+      stubPost('/follow', '', 400);
+      final r = await api.follow('tok', 'sig', 'target');
+      expect(r.statusCode, 400);
+      expect(r.message, 'Bad request');
+      expect(r.value, isNull);
+    });
+  });
+
+  group('unfollow', () {
+    test('404 with empty body returns typed error', () async {
+      stubPost('/unfollow', '', 404);
+      final r = await api.unfollow('tok', 'sig', 'target');
+      expect(r.statusCode, 404);
+      expect(r.message, 'Payment code not found');
+      expect(r.value, isNull);
+    });
+
+    test('401 with empty body returns typed error', () async {
+      stubPost('/unfollow', '', 401);
+      final r = await api.unfollow('tok', 'sig', 'target');
+      expect(r.statusCode, 401);
+      expect(
+        r.message,
+        'Unauthorized token or signature or Unclaimed payment code',
+      );
+      expect(r.value, isNull);
+    });
+
+    test('400 with empty body returns typed error', () async {
+      stubPost('/unfollow', '', 400);
+      final r = await api.unfollow('tok', 'sig', 'target');
+      expect(r.statusCode, 400);
+      expect(r.message, 'Bad request');
+      expect(r.value, isNull);
+    });
+  });
+
+  group('add', () {
+    test('400 with empty body returns typed error', () async {
+      stubPost('/nym/add', '', 400);
+      final r = await api.add('tok', 'sig', 'nym', 'code');
+      expect(r.statusCode, 400);
+      expect(r.message, 'Bad request');
+      expect(r.value, false);
+    });
+
+    test('401 with empty body returns typed error', () async {
+      stubPost('/nym/add', '', 401);
+      final r = await api.add('tok', 'sig', 'nym', 'code');
+      expect(r.statusCode, 401);
+      expect(
+        r.message,
+        'Unauthorized token or signature or Unclaimed payment code',
+      );
+      expect(r.value, false);
+    });
+
+    test('404 with empty body returns typed error', () async {
+      stubPost('/nym/add', '', 404);
+      final r = await api.add('tok', 'sig', 'nym', 'code');
+      expect(r.statusCode, 404);
+      expect(r.message, 'Nym not found');
+      expect(r.value, false);
+    });
+  });
+}
diff --git a/test/services/paynym/paynym_is_api_test.mocks.dart b/test/services/paynym/paynym_is_api_test.mocks.dart
new file mode 100644
index 0000000000..e3d6837fa8
--- /dev/null
+++ b/test/services/paynym/paynym_is_api_test.mocks.dart
@@ -0,0 +1,99 @@
+// Mocks generated by Mockito 5.4.6 from annotations
+// in stackwallet/test/services/paynym/paynym_is_api_test.dart.
+// Do not manually edit this file.
+
+// ignore_for_file: no_leading_underscores_for_library_prefixes
+import 'dart:async' as _i3;
+import 'dart:convert' as _i5;
+import 'dart:io' as _i4;
+
+import 'package:mockito/mockito.dart' as _i1;
+import 'package:stackwallet/networking/http.dart' as _i2;
+
+// ignore_for_file: type=lint
+// ignore_for_file: avoid_redundant_argument_values
+// ignore_for_file: avoid_setters_without_getters
+// ignore_for_file: comment_references
+// ignore_for_file: deprecated_member_use
+// ignore_for_file: deprecated_member_use_from_same_package
+// ignore_for_file: implementation_imports
+// ignore_for_file: invalid_use_of_visible_for_testing_member
+// ignore_for_file: must_be_immutable
+// ignore_for_file: prefer_const_constructors
+// ignore_for_file: unnecessary_parenthesis
+// ignore_for_file: camel_case_types
+// ignore_for_file: subtype_of_sealed_class
+// ignore_for_file: invalid_use_of_internal_member
+
+class _FakeResponse_0 extends _i1.SmartFake implements _i2.Response {
+  _FakeResponse_0(Object parent, Invocation parentInvocation)
+    : super(parent, parentInvocation);
+}
+
+/// A class which mocks [HTTP].
+///
+/// See the documentation for Mockito's code generation for more information.
+class MockHTTP extends _i1.Mock implements _i2.HTTP {
+  MockHTTP() {
+    _i1.throwOnMissingStub(this);
+  }
+
+  @override
+  _i3.Future<_i2.Response> get({
+    required Uri? url,
+    Map<String, String>? headers,
+    required ({_i4.InternetAddress host, int port})? proxyInfo,
+    Duration? connectionTimeout,
+  }) =>
+      (super.noSuchMethod(
+            Invocation.method(#get, [], {
+              #url: url,
+              #headers: headers,
+              #proxyInfo: proxyInfo,
+              #connectionTimeout: connectionTimeout,
+            }),
+            returnValue: _i3.Future<_i2.Response>.value(
+              _FakeResponse_0(
+                this,
+                Invocation.method(#get, [], {
+                  #url: url,
+                  #headers: headers,
+                  #proxyInfo: proxyInfo,
+                  #connectionTimeout: connectionTimeout,
+                }),
+              ),
+            ),
+          )
+          as _i3.Future<_i2.Response>);
+
+  @override
+  _i3.Future<_i2.Response> post({
+    required Uri? url,
+    Map<String, String>? headers,
+    Object? body,
+    _i5.Encoding? encoding,
+    required ({_i4.InternetAddress host, int port})? proxyInfo,
+  }) =>
+      (super.noSuchMethod(
+            Invocation.method(#post, [], {
+              #url: url,
+              #headers: headers,
+              #body: body,
+              #encoding: encoding,
+              #proxyInfo: proxyInfo,
+            }),
+            returnValue: _i3.Future<_i2.Response>.value(
+              _FakeResponse_0(
+                this,
+                Invocation.method(#post, [], {
+                  #url: url,
+                  #headers: headers,
+                  #body: body,
+                  #encoding: encoding,
+                  #proxyInfo: proxyInfo,
+                }),
+              ),
+            ),
+          )
+          as _i3.Future<_i2.Response>);
+}