diff --git a/packages/ripple-binary-codec/README.md b/packages/ripple-binary-codec/README.md
index 631dc841..e151433b 100644
--- a/packages/ripple-binary-codec/README.md
+++ b/packages/ripple-binary-codec/README.md
@@ -42,6 +42,11 @@ Encode a transaction object into a hex-string.
 '1100612200000000240000000125000000072D0000000055DF530FB14C5304852F20080B0A8EEF3A6BDD044F41F4EBBD68B8B321145FE4FF6240000002540BE4008114D0F5430B66E06498D4CEEC816C7B3337F9982337'
 ```
 
+#### X-Address Compatibility 
+  * ripple-binary-codec handles X-addresses by looking for a few specific files (Account/SourceTag, Destination/DestinationTag).
+  * If other fields (in the future) must to support X-addresses with tags, this library will need to be updated.
+  * When decoding rippled binary, the output will always output classic address + tag, with no X-addresses. X-address support only applies when encoding to binary.
+
 ### encodeForSigning(json: object): string
 
 Encode the transaction object for signing.
diff --git a/packages/ripple-binary-codec/src/types/account-id.ts b/packages/ripple-binary-codec/src/types/account-id.ts
index 609f85e4..7bb351a4 100644
--- a/packages/ripple-binary-codec/src/types/account-id.ts
+++ b/packages/ripple-binary-codec/src/types/account-id.ts
@@ -1,6 +1,8 @@
 import { decodeAccountID, encodeAccountID } from "ripple-address-codec";
 import { Hash160 } from "./hash-160";
 
+const HEX_REGEX = /^[A-F0-9]{40}$/;
+
 /**
  * Class defining how to encode and decode an AccountID
  */
@@ -27,9 +29,9 @@ class AccountID extends Hash160 {
         return new AccountID();
       }
 
-      return /^r/.test(value)
-        ? this.fromBase58(value)
-        : new AccountID(Buffer.from(value, "hex"));
+      return HEX_REGEX.test(value)
+        ? new AccountID(Buffer.from(value, "hex"))
+        : this.fromBase58(value);
     }
 
     throw new Error("Cannot construct AccountID from value given");
diff --git a/packages/ripple-binary-codec/src/types/st-object.ts b/packages/ripple-binary-codec/src/types/st-object.ts
index 578c0efa..791346fd 100644
--- a/packages/ripple-binary-codec/src/types/st-object.ts
+++ b/packages/ripple-binary-codec/src/types/st-object.ts
@@ -1,11 +1,53 @@
 import { Field, FieldInstance } from "../enums";
 import { SerializedType, JsonObject } from "./serialized-type";
+import {
+  xAddressToClassicAddress,
+  isValidXAddress,
+} from "ripple-address-codec";
 import { BinaryParser } from "../serdes/binary-parser";
 import { BinarySerializer, BytesList } from "../serdes/binary-serializer";
 
-const OBJECT_END_MARKER = Buffer.from([0xe1]);
-const OBJECT_END_MARKER_NAME = "ObjectEndMarker";
-const OBJECT_FIELD_TYPE_NAME = "STObject";
+const OBJECT_END_MARKER_BYTE = Buffer.from([0xe1]);
+const OBJECT_END_MARKER = "ObjectEndMarker";
+const ST_OBJECT = "STObject";
+const DESTINATION = "Destination";
+const ACCOUNT = "Account";
+const SOURCE_TAG = "SourceTag";
+const DEST_TAG = "DestinationTag";
+
+/**
+ * Break down an X-Address into an account and a tag
+ *
+ * @param field Name of field
+ * @param xAddress X-Address corresponding to the field
+ */
+function handleXAddress(field: string, xAddress: string): JsonObject {
+  const decoded = xAddressToClassicAddress(xAddress);
+
+  let tagName;
+  if (field === DESTINATION) tagName = DEST_TAG;
+  else if (field === ACCOUNT) tagName = SOURCE_TAG;
+  else if (decoded.tag !== false)
+    throw new Error(`${field} cannot have an associated tag`);
+
+  return decoded.tag !== false
+    ? { [field]: decoded.classicAddress, [tagName]: decoded.tag }
+    : { [field]: decoded.classicAddress };
+}
+
+/**
+ * Validate that two objects don't both have the same tag fields
+ *
+ * @param obj1 First object to check for tags
+ * @param obj2 Second object to check for tags
+ * @throws When both objects have SourceTag or DestinationTag
+ */
+function checkForDuplicateTags(obj1: JsonObject, obj2: JsonObject): void {
+  if (!(obj1[SOURCE_TAG] === undefined || obj2[SOURCE_TAG] === undefined))
+    throw new Error("Cannot have Account X-Address and SourceTag");
+  if (!(obj1[DEST_TAG] === undefined || obj2[DEST_TAG] === undefined))
+    throw new Error("Cannot have Destination X-Address and DestinationTag");
+}
 
 /**
  * Class for Serializing/Deserializing objects
@@ -23,15 +65,15 @@ class STObject extends SerializedType {
 
     while (!parser.end()) {
       const field = parser.readField();
-      if (field.name === OBJECT_END_MARKER_NAME) {
+      if (field.name === OBJECT_END_MARKER) {
         break;
       }
 
       const associatedValue = parser.readFieldValue(field);
 
       bytes.writeFieldAndValue(field, associatedValue);
-      if (field.type.name === OBJECT_FIELD_TYPE_NAME) {
-        bytes.put(OBJECT_END_MARKER);
+      if (field.type.name === ST_OBJECT) {
+        bytes.put(OBJECT_END_MARKER_BYTE);
       }
     }
 
@@ -56,7 +98,16 @@ class STObject extends SerializedType {
     const list: BytesList = new BytesList();
     const bytes: BinarySerializer = new BinarySerializer(list);
 
-    let sorted = Object.keys(value)
+    const xAddressDecoded = Object.entries(value).reduce((acc, [key, val]) => {
+      let handled: JsonObject | undefined = undefined;
+      if (isValidXAddress(val)) {
+        handled = handleXAddress(key, val);
+        checkForDuplicateTags(handled, value as JsonObject);
+      }
+      return Object.assign(acc, handled ?? { [key]: val });
+    }, {});
+
+    let sorted = Object.keys(xAddressDecoded)
       .map((f: string): FieldInstance => Field[f] as FieldInstance)
       .filter((f: FieldInstance): boolean => f !== undefined && f.isSerialized)
       .sort((a, b) => {
@@ -68,11 +119,13 @@ class STObject extends SerializedType {
     }
 
     sorted.forEach((field) => {
-      const associatedValue = field.associatedType.from(value[field.name]);
+      const associatedValue = field.associatedType.from(
+        xAddressDecoded[field.name]
+      );
 
       bytes.writeFieldAndValue(field, associatedValue);
-      if (field.type.name === OBJECT_FIELD_TYPE_NAME) {
-        bytes.put(OBJECT_END_MARKER);
+      if (field.type.name === ST_OBJECT) {
+        bytes.put(OBJECT_END_MARKER_BYTE);
       }
     });
 
@@ -90,7 +143,7 @@ class STObject extends SerializedType {
 
     while (!objectParser.end()) {
       const field = objectParser.readField();
-      if (field.name === OBJECT_END_MARKER_NAME) {
+      if (field.name === OBJECT_END_MARKER) {
         break;
       }
       accumulator[field.name] = objectParser.readFieldValue(field).toJSON();
diff --git a/packages/ripple-binary-codec/test/fixtures/x-codec-fixtures.json b/packages/ripple-binary-codec/test/fixtures/x-codec-fixtures.json
new file mode 100644
index 00000000..7012e4b5
--- /dev/null
+++ b/packages/ripple-binary-codec/test/fixtures/x-codec-fixtures.json
@@ -0,0 +1,188 @@
+{
+  "transactions": [{
+    "rjson": {
+      "Account": "r3kmLJN5D28dHuH8vZNUZpMC43pEHpaocV",
+      "Destination": "rLQBHVhFnaC5gLEkgr6HgBJJ3bgeZHg9cj",
+      "TransactionType": "Payment",
+      "TxnSignature": "3045022022EB32AECEF7C644C891C19F87966DF9C62B1F34BABA6BE774325E4BB8E2DD62022100A51437898C28C2B297112DF8131F2BB39EA5FE613487DDD611525F1796264639",
+      "SigningPubKey": "034AADB09CFF4A4804073701EC53C3510CDC95917C2BB0150FB742D0C66E6CEE9E",
+      "Amount": "10000000000",
+      "DestinationTag": 1010,
+      "SourceTag": 84854,
+      "Fee": "10",
+      "Flags": 0,
+      "Sequence": 62
+    },
+    "xjson": {
+      "Account": "X7tFPvjMH7nDxP8nTGkeeggcUpCZj8UbyT2QoiRHGDfjqrB",
+      "Destination": "XVYmGpJqHS95ir411XvanwY1xt5Z2314WsamHPVgUNABUGV",
+      "TransactionType": "Payment",
+      "TxnSignature": "3045022022EB32AECEF7C644C891C19F87966DF9C62B1F34BABA6BE774325E4BB8E2DD62022100A51437898C28C2B297112DF8131F2BB39EA5FE613487DDD611525F1796264639",
+      "SigningPubKey": "034AADB09CFF4A4804073701EC53C3510CDC95917C2BB0150FB742D0C66E6CEE9E",
+      "Amount": "10000000000",
+      "Fee": "10",
+      "Flags": 0,
+      "Sequence": 62
+    }
+  }, 
+  {
+    "rjson": {
+      "Account": "r4DymtkgUAh2wqRxVfdd3Xtswzim6eC6c5",
+      "Amount": "199000000",
+      "Destination": "rsekGH9p9neiPxym2TMJhqaCzHFuokenTU",
+      "DestinationTag": 3663729509,
+      "Fee": "6335",
+      "Flags": 2147483648,
+      "LastLedgerSequence": 57313352,
+      "Sequence": 105791,
+      "SigningPubKey": "02053A627976CE1157461336AC65290EC1571CAAD1B327339980F7BF65EF776F83",
+      "TransactionType": "Payment",
+      "TxnSignature": "30440220086D3330CD6CE01D891A26BA0355D8D5A5D28A5C9A1D0C5E06E321C81A02318A0220027C3F6606E41FEA35103EDE5224CC489B6514ACFE27543185B0419DD02E301C"
+    },
+    "xjson": {
+      "Account": "r4DymtkgUAh2wqRxVfdd3Xtswzim6eC6c5",
+      "Amount": "199000000",
+      "Destination": "X7cBoj6a5xSEfPCr6AStN9YPhbMAA2yaN2XYWwRJKAKb3y5",
+      "Fee": "6335",
+      "Flags": 2147483648,
+      "LastLedgerSequence": 57313352,
+      "Sequence": 105791,
+      "SigningPubKey": "02053A627976CE1157461336AC65290EC1571CAAD1B327339980F7BF65EF776F83",
+      "TransactionType": "Payment",
+      "TxnSignature": "30440220086D3330CD6CE01D891A26BA0355D8D5A5D28A5C9A1D0C5E06E321C81A02318A0220027C3F6606E41FEA35103EDE5224CC489B6514ACFE27543185B0419DD02E301C"
+    }
+  },
+  {
+    "rjson": {
+      "Account": "rDsbeomae4FXwgQTJp9Rs64Qg9vDiTCdBv",
+      "Amount": "105302107",
+      "Destination": "r33hypJXDs47LVpmvta7hMW9pR8DYeBtkW",
+      "DestinationTag": 1658156118,
+      "Fee": "60000",
+      "Flags": 2147483648,
+      "LastLedgerSequence": 57313566,
+      "Sequence": 1113196,
+      "SigningPubKey": "03D847C2DBED3ABF0453F71DCD7641989136277218DF516AD49519C9693F32727E",
+      "TransactionType": "Payment",
+      "TxnSignature": "3045022100FCA10FBAC65EA60C115A970CD52E6A526B1F9DDB6C4F843DA3DE7A97DFF9492D022037824D0FC6F663FB08BE0F2812CBADE1F61836528D44945FC37F10CC03215111"
+    },
+    "xjson": {
+      "Account": "rDsbeomae4FXwgQTJp9Rs64Qg9vDiTCdBv",
+      "Amount": "105302107",
+      "Destination": "X7ikFY5asEwp6ikt2AJdTfBLALEs5JN35kkeqKVeT1GdvY1",
+      "Fee": "60000",
+      "Flags": 2147483648,
+      "LastLedgerSequence": 57313566,
+      "Sequence": 1113196,
+      "SigningPubKey": "03D847C2DBED3ABF0453F71DCD7641989136277218DF516AD49519C9693F32727E",
+      "TransactionType": "Payment",
+      "TxnSignature": "3045022100FCA10FBAC65EA60C115A970CD52E6A526B1F9DDB6C4F843DA3DE7A97DFF9492D022037824D0FC6F663FB08BE0F2812CBADE1F61836528D44945FC37F10CC03215111"
+    }
+  }, 
+  {
+    "rjson": {
+      "Account": "rDsbeomae4FXwgQTJp9Rs64Qg9vDiTCdBv",
+      "Amount": "3899911571",
+      "Destination": "rU2mEJSLqBRkYLVTv55rFTgQajkLTnT6mA",
+      "DestinationTag": 255406,
+      "Fee": "60000",
+      "Flags": 2147483648,
+      "LastLedgerSequence": 57313566,
+      "Sequence": 1113197,
+      "SigningPubKey": "03D847C2DBED3ABF0453F71DCD7641989136277218DF516AD49519C9693F32727E",
+      "TransactionType": "Payment",
+      "TxnSignature": "3044022077642D94BB3C49BF3CB4C804255EC830D2C6009EA4995E38A84602D579B8AAD702206FAD977C49980226E8B495BF03C8D9767380F1546BBF5A4FD47D604C0D2CCF9B"
+    },
+    "xjson": {
+      "Account": "rDsbeomae4FXwgQTJp9Rs64Qg9vDiTCdBv",
+      "Amount": "3899911571",
+      "Destination": "XVfH8gwNWVbB5Kft16jmTNgGTqgw1dzA8ZTBkNjSLw6JdXS",
+      "Fee": "60000",
+      "Flags": 2147483648,
+      "LastLedgerSequence": 57313566,
+      "Sequence": 1113197,
+      "SigningPubKey": "03D847C2DBED3ABF0453F71DCD7641989136277218DF516AD49519C9693F32727E",
+      "TransactionType": "Payment",
+      "TxnSignature": "3044022077642D94BB3C49BF3CB4C804255EC830D2C6009EA4995E38A84602D579B8AAD702206FAD977C49980226E8B495BF03C8D9767380F1546BBF5A4FD47D604C0D2CCF9B"
+    }
+  },
+  {
+    "rjson": {
+      "Account": "r4eEbLKZGbVSBHnSUBZW8i5XaMjGLdqT4a",
+      "Amount": "820370849",
+      "Destination": "rDhmyBh4JwDAtXyRZDarNgg52UcLLRoGje",
+      "DestinationTag": 2017780486,
+      "Fee": "6000",
+      "Flags": 2147483648,
+      "LastLedgerSequence": 57315579,
+      "Sequence": 234254,
+      "SigningPubKey": "038CF47114672A12B269AEE015BF7A8438609B994B0640E4B28B2F56E93D948B15",
+      "TransactionType": "Payment",
+      "TxnSignature": "3044022015004653B1CBDD5CCA1F7B38555F1B37FE3F811E9D5070281CCC6C8A93460D870220679E9899184901EA69750C8A9325768490B1B9C1A733842446727653FF3D1DC0"
+    },
+    "xjson": {
+      "Account": "r4eEbLKZGbVSBHnSUBZW8i5XaMjGLdqT4a",
+      "Amount": "820370849",
+      "Destination": "XV31huWNJQXsAJFwgE6rnC8uf8jRx4H4waq4MyGUxz5CXzS",
+      "Fee": "6000",
+      "Flags": 2147483648,
+      "LastLedgerSequence": 57315579,
+      "Sequence": 234254,
+      "SigningPubKey": "038CF47114672A12B269AEE015BF7A8438609B994B0640E4B28B2F56E93D948B15",
+      "TransactionType": "Payment",
+      "TxnSignature": "3044022015004653B1CBDD5CCA1F7B38555F1B37FE3F811E9D5070281CCC6C8A93460D870220679E9899184901EA69750C8A9325768490B1B9C1A733842446727653FF3D1DC0"
+    }
+  },
+  {
+    "rjson": {
+      "Account": "rsGeDwS4rpocUumu9smpXomzaaeG4Qyifz",
+      "Amount": "1500000000",
+      "Destination": "rDxfhNRgCDNDckm45zT5ayhKDC4Ljm7UoP",
+      "DestinationTag": 1000635172,
+      "Fee": "5000",
+      "Flags": 2147483648,
+      "Sequence": 55741075,
+      "SigningPubKey": "02ECB814477DF9D8351918878E235EE6AF147A2A5C20F1E71F291F0F3303357C36",
+      "SourceTag": 1000635172,
+      "TransactionType": "Payment",
+      "TxnSignature": "304402202A90972E21823214733082E1977F9EA2D6B5101902F108E7BDD7D128CEEA7AF3022008852C8DAD746A7F18E66A47414FABF551493674783E8EA7409C501D3F05F99A"
+    },
+    "xjson": {
+      "Account": "rsGeDwS4rpocUumu9smpXomzaaeG4Qyifz",
+      "Amount": "1500000000",
+      "Destination": "XVBkK1yLutMqFGwTm6hykn7YXGDUrjsZSkpzMgRveZrMbHs",
+      "Fee": "5000",
+      "Flags": 2147483648,
+      "Sequence": 55741075,
+      "SigningPubKey": "02ECB814477DF9D8351918878E235EE6AF147A2A5C20F1E71F291F0F3303357C36",
+      "SourceTag": 1000635172,
+      "TransactionType": "Payment",
+      "TxnSignature": "304402202A90972E21823214733082E1977F9EA2D6B5101902F108E7BDD7D128CEEA7AF3022008852C8DAD746A7F18E66A47414FABF551493674783E8EA7409C501D3F05F99A"
+    }
+  },
+  {
+    "rjson": {
+      "Account": "rHWcuuZoFvDS6gNbmHSdpb7u1hZzxvCoMt",
+      "Amount": "48918500000",
+      "Destination": "rEb8TK3gBgk5auZkwc6sHnwrGVJH8DuaLh",
+      "DestinationTag": 105959914,
+      "Fee": "10",
+      "Flags": 2147483648,
+      "Sequence": 32641,
+      "SigningPubKey": "02E98DA545CCCC5D14C82594EE9E6CCFCF5171108E2410B3E784183E1068D33429",
+      "TransactionType": "Payment",
+      "TxnSignature": "304502210091DCA7AF189CD9DC93BDE24DEAE87381FBF16789C43113EE312241D648982B2402201C6055FEFFF1F119640AAC0B32C4F37375B0A96033E0527A21C1366920D6A524"
+    },
+    "xjson": {
+      "Account": "rHWcuuZoFvDS6gNbmHSdpb7u1hZzxvCoMt",
+      "Amount": "48918500000",
+      "Destination": "XVH3aqvbYGhRhrD1FYSzGooNuxdzbG3VR2fuM47oqbXxQr7",
+      "Fee": "10",
+      "Flags": 2147483648,
+      "Sequence": 32641,
+      "SigningPubKey": "02E98DA545CCCC5D14C82594EE9E6CCFCF5171108E2410B3E784183E1068D33429",
+      "TransactionType": "Payment",
+      "TxnSignature": "304502210091DCA7AF189CD9DC93BDE24DEAE87381FBF16789C43113EE312241D648982B2402201C6055FEFFF1F119640AAC0B32C4F37375B0A96033E0527A21C1366920D6A524"
+    }
+  }]
+}
\ No newline at end of file
diff --git a/packages/ripple-binary-codec/test/hash.test.js b/packages/ripple-binary-codec/test/hash.test.js
index 41615a05..8d896ca9 100644
--- a/packages/ripple-binary-codec/test/hash.test.js
+++ b/packages/ripple-binary-codec/test/hash.test.js
@@ -16,10 +16,14 @@ describe('Hash160', function () {
     expect(h1.lt(h2)).toBe(true)
     expect(h3.lt(h2)).toBe(true)
   })
+  test('throws when constructed from invalid hash length', () => {
+    expect(() => Hash160.from('10000000000000000000000000000000000000')).toThrow('Invalid Hash length 19')
+    expect(() => Hash160.from('100000000000000000000000000000000000000000')).toThrow('Invalid Hash length 21')
+  })
 })
 
 describe('Hash256', function () {
-  test('has a static width membmer', function () {
+  test('has a static width member', function () {
     expect(Hash256.width).toBe(32)
   })
   test('has a ZERO_256 member', function () {
diff --git a/packages/ripple-binary-codec/test/x-address.test.js b/packages/ripple-binary-codec/test/x-address.test.js
new file mode 100644
index 00000000..2e4c6c7c
--- /dev/null
+++ b/packages/ripple-binary-codec/test/x-address.test.js
@@ -0,0 +1,137 @@
+const { encode, decode } = require("./../dist/index");
+const fixtures = require('./fixtures/x-codec-fixtures.json')
+
+let json_x1 = {
+    OwnerCount: 0,
+    Account: "XVXdn5wEVm5G4UhEHWDPqjvdeH361P7BsapL4m2D2XnPSwT",
+    PreviousTxnLgrSeq: 7,
+    LedgerEntryType: "AccountRoot",
+    PreviousTxnID: "DF530FB14C5304852F20080B0A8EEF3A6BDD044F41F4EBBD68B8B321145FE4FF",
+    Flags: 0,
+    Sequence: 1,
+    Balance: "10000000000"
+  }
+
+let json_r1 = {
+    OwnerCount: 0,
+    Account: 'rLs1MzkFWCxTbuAHgjeTZK4fcCDDnf2KRv',
+    PreviousTxnLgrSeq: 7,
+    LedgerEntryType: 'AccountRoot',
+    PreviousTxnID: 'DF530FB14C5304852F20080B0A8EEF3A6BDD044F41F4EBBD68B8B321145FE4FF',
+    Flags: 0,
+    Sequence: 1,
+    Balance: '10000000000',
+    SourceTag: 12345,
+  }
+
+let json_null_x = {
+    "OwnerCount": 0,
+    "Account": "rLs1MzkFWCxTbuAHgjeTZK4fcCDDnf2KRv",
+    "Destination": "rLs1MzkFWCxTbuAHgjeTZK4fcCDDnf2KRv",
+    "Issuer": "XVXdn5wEVm5G4UhEHWDPqjvdeH361P4GETfNyyXGaoqBj71",
+    "PreviousTxnLgrSeq": 7,
+    "LedgerEntryType": "AccountRoot",
+    "PreviousTxnID": "DF530FB14C5304852F20080B0A8EEF3A6BDD044F41F4EBBD68B8B321145FE4FF",
+    "Flags": 0,
+    "Sequence": 1,
+    "Balance": "10000000000"
+}
+
+let json_invalid_x = {
+    "OwnerCount": 0,
+    "Account": "rLs1MzkFWCxTbuAHgjeTZK4fcCDDnf2KRv",
+    "Destination": "rLs1MzkFWCxTbuAHgjeTZK4fcCDDnf2KRv",
+    "Issuer": "XVXdn5wEVm5g4UhEHWDPqjvdeH361P4GETfNyyXGaoqBj71",
+    "PreviousTxnLgrSeq": 7,
+    "LedgerEntryType": "AccountRoot",
+    "PreviousTxnID": "DF530FB14C5304852F20080B0A8EEF3A6BDD044F41F4EBBD68B8B321145FE4FF",
+    "Flags": 0,
+    "Sequence": 1,
+    "Balance": "10000000000"
+}
+
+let json_null_r = {
+    "OwnerCount": 0,
+    "Account": "rLs1MzkFWCxTbuAHgjeTZK4fcCDDnf2KRv",
+    "Destination": "rLs1MzkFWCxTbuAHgjeTZK4fcCDDnf2KRv",
+    "Issuer": "rLs1MzkFWCxTbuAHgjeTZK4fcCDDnf2KRv",
+    "PreviousTxnLgrSeq": 7,
+    "LedgerEntryType": "AccountRoot",
+    "PreviousTxnID": "DF530FB14C5304852F20080B0A8EEF3A6BDD044F41F4EBBD68B8B321145FE4FF",
+    "Flags": 0,
+    "Sequence": 1,
+    "Balance": "10000000000"
+}
+
+let invalid_json_issuer_tagged = {
+    "OwnerCount": 0,
+    "Account": "rLs1MzkFWCxTbuAHgjeTZK4fcCDDnf2KRv",
+    "Destination": "rLs1MzkFWCxTbuAHgjeTZK4fcCDDnf2KRv",
+    "Issuer": "XVXdn5wEVm5G4UhEHWDPqjvdeH361P7BsapL4m2D2XnPSwT",
+    "PreviousTxnLgrSeq": 7,
+    "LedgerEntryType": "AccountRoot",
+    "PreviousTxnID": "DF530FB14C5304852F20080B0A8EEF3A6BDD044F41F4EBBD68B8B321145FE4FF",
+    "Flags": 0,
+    "Sequence": 1,
+    "Balance": "10000000000"
+}
+
+let invalid_json_x_and_tagged = {
+    OwnerCount: 0,
+    Account: 'XVXdn5wEVm5G4UhEHWDPqjvdeH361P7BsapL4m2D2XnPSwT',
+    PreviousTxnLgrSeq: 7,
+    LedgerEntryType: 'AccountRoot',
+    PreviousTxnID: 'DF530FB14C5304852F20080B0A8EEF3A6BDD044F41F4EBBD68B8B321145FE4FF',
+    Flags: 0,
+    Sequence: 1,
+    Balance: '10000000000',
+    SourceTag: 12345,
+  }
+
+describe("X-Address Account is equivalent to a classic address w/ SourceTag", () => {
+    let encoded_x = encode(json_x1);
+    let encoded_r = encode(json_r1); 
+    test("Can encode with x-Address", () => {
+        expect(encoded_x).toEqual(encoded_r);
+    })
+
+    test("decoded X-address is object w/ source and tag", () => {
+        let decoded_x = decode(encoded_x);
+        expect(decoded_x).toEqual(json_r1);
+    })
+
+    test("Encoding issuer X-Address w/ undefined destination tag", () => {
+        expect(encode(json_null_x)).toEqual(encode(json_null_r));
+    })
+
+    test("Throws when X-Address is invalid", () => {
+        expect(() => encode(json_invalid_x)).toThrow("checksum_invalid");
+    })
+})
+
+describe("Invalid X-Address behavior", () => {
+    test("X-Address with tag throws value for invalid field",() => {
+        expect(() => encode(invalid_json_issuer_tagged)).toThrow(new Error("Issuer cannot have an associated tag"))
+    })
+
+    test("Throws when Account has both X-Addr and Destination Tag", () => {
+        expect(() => encode(invalid_json_x_and_tagged)).toThrow(new Error("Cannot have Account X-Address and SourceTag"));
+    });
+})
+
+describe('ripple-binary-codec x-address test', function () {
+    function makeSuite (name, entries) {
+        describe(name, function () {
+        entries.forEach((t, testN) => {
+            test(`${name}[${testN}] encodes X-address json equivalent to classic address json`,
+            () => {
+                expect(encode(t.rjson)).toEqual(encode(t.xjson))
+            })
+            test(`${name}[${testN}] decodes X-address json equivalent to classic address json`, () => {
+                expect(decode(encode(t.xjson))).toEqual(t.rjson);
+            })
+        })
+        })
+    }
+    makeSuite('transactions', fixtures.transactions)
+})
\ No newline at end of file