diff --git a/src/Ada.ts b/src/Ada.ts
index 1c5f2454..aae568a4 100644
--- a/src/Ada.ts
+++ b/src/Ada.ts
@@ -180,6 +180,9 @@ export class Ada {
     ]
     this.transport.decorateAppAPIMethods(this, methods, scrambleKey)
     this._send = async (params: SendParams): Promise<Buffer> => {
+      if (params.data.length > 255) {
+        throw new Error('APDU too large, likely a bug')
+      }
       let response = await wrapConvertDeviceStatusError(this.transport.send)(
         CLA,
         params.ins,
diff --git a/src/types/internal.ts b/src/types/internal.ts
index aa381c2f..ba9a6c50 100644
--- a/src/types/internal.ts
+++ b/src/types/internal.ts
@@ -69,8 +69,8 @@ export const SCRIPT_DATA_HASH_LENGTH = 32
 export const DATUM_HASH_LENGTH = 32
 export const ANCHOR_HASH_LENGTH = 32
 
-export const MAX_URL_LENGTH = 64
-export const MAX_DNS_NAME_LENGTH = 64
+export const MAX_URL_LENGTH = 128
+export const MAX_DNS_NAME_LENGTH = 128
 
 export type ParsedInput = {
   txHashHex: FixLenHexString<typeof TX_HASH_LENGTH>
diff --git a/test/integration/__fixtures__/signTx.ts b/test/integration/__fixtures__/signTx.ts
index fce704de..1167d9fa 100644
--- a/test/integration/__fixtures__/signTx.ts
+++ b/test/integration/__fixtures__/signTx.ts
@@ -931,7 +931,7 @@ export const testsConwayWithCertificates: SignTxTestCase[] = [
               keyPath: str_to_path("1852'/1815'/0'/4/0"),
             },
             anchor: {
-              url: 'www.vacuumlabs.com',
+              url: 'x'.repeat(128), // max url length in anchor
               hashHex:
                 '1afd028b504c3668102b129b37a86c09a2872f76741dc7a68e2149c8deadbeef',
             },
@@ -951,20 +951,20 @@ export const testsConwayWithCertificates: SignTxTestCase[] = [
     signingMode: TransactionSigningMode.ORDINARY_TRANSACTION,
     additionalWitnessPaths: [],
     txBody:
-      'a500818258203b40265111d8bb3c3c608d95b3a0bf83461ace32d79336579a1939b3aad1c0b700018182582b82d818582183581c9e1c71de652ec8b85fec296f0685ca3988781c94a2e1a5d89d92f45fa0001a0d0c25611a002dd2e802182a030a0482830f8200581ccf737588be6e9edeb737eb2e6d06e5cbd292bd8ee32e410c0bba1ba682727777772e76616375756d6c6162732e636f6d58201afd028b504c3668102b129b37a86c09a2872f76741dc7a68e2149c8deadbeef830f8200581ccf737588be6e9edeb737eb2e6d06e5cbd292bd8ee32e410c0bba1ba6f6',
+      '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',
     expectedResult: {
       txHashHex:
-        '1817433dfe1082c43c67375977e08b6cf7654161b9f8227bdae79f962cd5d391',
+        '5b6d2cc6f1401d783dd5012200337aa2df4407e28267c4ea7d39914adacde25d',
       witnesses: [
         {
           path: str_to_path("1852'/1815'/0'/0/0"),
           witnessSignatureHex:
-            '84ee1d069b3b851330a2c1bd4c2423500551400c53182a36792f1559148409bdda2ccaf0bdfc9a7885042092b9e316b12d21e3912cc47579f190df8a80b28c04',
+            '82f826cea558d08e833e3657f6afaba0175813a7de5bda7c0e075f4b08a2833a6e61f7a2587d9b88e919b4b4aa465cc689a6a611c8cf96fe1249f47ffd22ba05',
         },
         {
           path: str_to_path("1852'/1815'/0'/4/0"),
           witnessSignatureHex:
-            '6d2a387455c55590c3ea9f5432dbb55ecdded67db163d53ba5ac3ad4ad30a4a715990866440ba164ba790bf24c86192d4d68c86382a299cd5de56f8293fe540a',
+            '6eff66993a624cb218bf84dbdd3481212b4586bf1d8ef0a9c6e5bf32c977afbb1e09a1c0f3810f6828b17f9d4f3acee7d59af098e98d46d9a95d5d60fd9a8f07',
         },
       ],
       auxiliaryDataSupplement: null,
diff --git a/test/integration/__fixtures__/signTxPoolRegistrationRejects.ts b/test/integration/__fixtures__/signTxPoolRegistrationRejects.ts
index b152ae89..188ef726 100644
--- a/test/integration/__fixtures__/signTxPoolRegistrationRejects.ts
+++ b/test/integration/__fixtures__/signTxPoolRegistrationRejects.ts
@@ -180,7 +180,7 @@ export const invalidPoolMetadataTestCases: TestCaseRejectShelley[] = [
             ...defaultPoolRegistration,
             metadata: {
               metadataUrl:
-                'https://www.vacuumlabs.com/aaaaaaaaaaaaaaaaaaaaaaaasampleUrl.json',
+                'a'.repeat(129),
               metadataHashHex:
                 'cdb714fd722c24aeb10c93dbb0ff03bd4783441cd5ba2a8b6f373390520535bb',
             },