diff --git a/lib/bcoin/coin.js b/lib/bcoin/coin.js
index df439fac..51439cfe 100644
--- a/lib/bcoin/coin.js
+++ b/lib/bcoin/coin.js
@@ -30,18 +30,22 @@ function Coin(tx, index) {
     return tx;
 
   if (tx instanceof bcoin.tx) {
-    this.hash = tx.hash('hex');
-    this.index = index;
+    this.version = tx.version;
+    this.height = tx.height;
     this.value = tx.outputs[index].value;
     this.script = tx.outputs[index].script;
-    this.height = tx.height;
+    this.hash = tx.hash('hex');
+    this.index = index;
+    this.spent = false;
   } else {
     options = tx;
-    this.hash = options.hash;
-    this.index = options.index;
+    this.version = options.version;
+    this.height = options.height;
     this.value = options.value;
     this.script = options.script;
-    this.height = options.height;
+    this.hash = options.hash;
+    this.index = options.index;
+    this.spent = options.spent;
   }
 
   if (utils.isBuffer(this.hash))
@@ -49,13 +53,15 @@ function Coin(tx, index) {
 
   this.rhash = utils.revHex(this.hash);
 
-  assert(typeof this.hash === 'string');
-  assert(utils.isFinite(this.index));
+  // Object.freeze(this);
+
+  assert(typeof this.version === 'number');
+  assert(utils.isFinite(this.height));
   assert(this.value instanceof bn);
   assert(Array.isArray(this.script));
-  assert(utils.isFinite(this.height));
-
-  // Object.freeze(this);
+  assert(typeof this.hash === 'string');
+  assert(utils.isFinite(this.index));
+  assert(typeof this.spent === 'boolean');
 }
 
 inherits(Coin, bcoin.output);
@@ -107,42 +113,54 @@ Coin.prototype.__defineGetter__('age', function() {
 
 Coin.prototype.toJSON = function toJSON() {
   return {
-    hash: this.hash,
-    index: this.index,
+    version: this.version,
+    height: this.height,
     value: utils.btc(this.value),
     script: utils.toHex(bcoin.script.encode(this.script)),
-    height: this.height,
+    hash: this.hash,
+    index: this.index,
+    spent: this.spent,
     address: this.getAddress()
   };
 };
 
 Coin.fromJSON = function fromJSON(json) {
   return new Coin({
-    hash: json.hash,
-    index: json.index,
+    version: json.version,
+    height: json.height,
     value: utils.satoshi(json.value),
     script: bcoin.script.decode(utils.toArray(json.script, 'hex')),
-    height: json.height,
+    hash: json.hash,
+    index: json.index,
+    spent: json.spent,
     address: json.address
   });
 };
 
-// Not totally necessary, but this is 3 times
-// faster than JSON serialization if high performance
-// is a goal.
-Coin.prototype.toRaw = function toRaw(enc) {
+// This is basically BIP64 with some
+// extra fields tacked on the end.
+Coin.prototype.toRaw = function toRaw(enc, strict) {
   var script = bcoin.script.encode(this.script);
+  var intSize = utils.sizeIntv(script.length);
   var height = this.height;
-  var data = new Buffer(48 + script.length);
+  var data = new Buffer(16 + intSize + script.length + (!strict ? 37 : 0));
+  var off = 0;
 
   if (height === -1)
-    height = 0xffffffff;
+    height = 0x7fffffff;
 
-  utils.copy(utils.toArray(this.hash, 'hex'), data, 0);
-  utils.writeU32(data, this.index, 32);
-  utils.writeU32(data, height, 36);
-  utils.write64(data, this.value, 40);
-  utils.copy(script, data, 48);
+  off += utils.writeU32(data, this.version, off);
+  off += utils.writeU32(data, height, off);
+  off += utils.write64(data, this.value, off);
+  assert(this.value.byteLength() <= 8);
+  off += utils.writeIntv(data, script.length, off);
+  off += utils.copy(script, data, off);
+
+  if (!strict) {
+    off += utils.copy(utils.toArray(this.hash, 'hex'), data, off);
+    off += utils.writeU32(data, this.index, off);
+    off += utils.writeU8(data, this.spent ? 1 : 0, off);
+  }
 
   if (enc === 'hex')
     data = utils.toHex(data);
@@ -150,23 +168,60 @@ Coin.prototype.toRaw = function toRaw(enc) {
   return data;
 };
 
-Coin.fromRaw = function fromRaw(data, enc) {
-  var height;
+Coin.fromRaw = function fromRaw(data, enc, strict) {
+  var off = 0;
+  var version, height, value, script, hash, index, spent, scriptLen;
 
   if (enc === 'hex')
     data = utils.toArray(data, 'hex');
 
-  height = utils.readU32(data, 36);
+  if (data.length < 17 + (!strict ? 37 : 0))
+    throw new Error('Invalid utxo size');
 
-  if (height === 0xffffffff)
+  version = utils.readU32(data, off);
+  off += 4;
+
+  height = utils.readU32(data, off);
+  if (height === 0x7fffffff)
     height = -1;
+  off += 4;
+
+  value = utils.read64(data, off);
+  off += 8;
+
+  scriptLen = utils.readIntv(data, off);
+  off = scriptLen.off;
+  scriptLen = scriptLen.r;
+
+  if (off + scriptLen > data.length - (!strict ? 37 : 0))
+    throw new Error('Invalid utxo script length');
+
+  script = bcoin.script.decode(utils.toArray(data.slice(off, off + scriptLen)));
+  off += scriptLen;
+
+  if (!strict) {
+    hash = utils.toHex(data.slice(off, off + 32));
+    off += 32;
+
+    index = utils.readU32(data, off);
+    off += 4;
+
+    spent = utils.readU8(data, off) === 1;
+    off += 1;
+  } else {
+    hash = constants.zeroHash.slice();
+    index = 0xffffffff;
+    spent = false;
+  }
 
   return new Coin({
-    hash: utils.toHex(data.slice(0, 32)),
-    index: utils.readU32(data, 32),
+    version: version,
     height: height,
-    value: utils.read64(data, 40),
-    script: bcoin.script.decode(utils.toArray(data.slice(48)))
+    value: value,
+    script: script,
+    hash: hash,
+    index: index,
+    spent: spent
   });
 };
 
diff --git a/lib/bcoin/utils.js b/lib/bcoin/utils.js
index 18646121..96eaf68b 100644
--- a/lib/bcoin/utils.js
+++ b/lib/bcoin/utils.js
@@ -1314,3 +1314,22 @@ utils.writeIntv = function writeIntv(dst, num, off) {
   utils.writeU64(dst, num, off + 1);
   return 9;
 };
+
+utils.sizeIntv = function sizeIntv(num) {
+  if (num instanceof bn) {
+    if (num.cmpn(0xffffffff) > 0)
+      return 9;
+    num = num.toNumber();
+  }
+
+  if (num < 0xfd)
+    return 1;
+
+  if (num <= 0xffff)
+    return 3;
+
+  if (num <= 0xffffffff)
+    return 5;
+
+  return 9;
+};