diff --git a/lib/bcoin/keyring.js b/lib/bcoin/keyring.js
index 7f450ea8..a2a88e0b 100644
--- a/lib/bcoin/keyring.js
+++ b/lib/bcoin/keyring.js
@@ -14,8 +14,6 @@ var assert = utils.assert;
  * @exports KeyRing
  * @constructor
  * @param {Object} options
- * @param {String?} options.label
- * @param {Boolean?} options.derived
  * @param {HDPrivateKey|HDPublicKey} options.key
  * @param {String?} options.path
  * @param {Boolean?} options.change
@@ -40,10 +38,9 @@ function KeyRing(options) {
     options = {};
 
   this.options = options;
-  this.label = options.label || '';
-  this.derived = !!options.derived;
   this.addressMap = null;
 
+  this.network = bcoin.network.get(options.network);
   this.key = options.key;
   this.path = options.path;
   this.change = !!options.change;
@@ -63,7 +60,7 @@ function KeyRing(options) {
   if (this.m < 1 || this.m > this.n)
     throw new Error('m ranges between 1 and n');
 
-  this.addKey(this.getPublicKey());
+  this.addKey(this.key);
 
   if (options.keys) {
     for (i = 0; i < options.keys.length; i++)
@@ -129,7 +126,13 @@ KeyRing.prototype.removeKey = function removeKey(key) {
  */
 
 KeyRing.prototype.getPublicKey = function getPublicKey(enc) {
-  return this.key.getPublicKey(enc);
+  if (enc === 'base58')
+    return utils.toBase58(this.key);
+
+  if (enc === 'hex')
+    return this.key.toString('hex');
+
+  return this.key;
 };
 
 /**
@@ -455,6 +458,7 @@ KeyRing.prototype.scriptInputs = function scriptInputs(tx, index) {
  * Build input scripts and sign inputs for a transaction. Only attempts
  * to build/sign inputs that are redeemable by this address.
  * @param {MTX} tx
+ * @param {HDPrivateKey|KeyPair|Buffer} key - Private key.
  * @param {Number?} index - Index of input. If not present,
  * it will attempt to build and sign all redeemable inputs.
  * @param {SighashType?} type
@@ -539,6 +543,54 @@ KeyRing.prototype.__defineGetter__('address', function() {
   return this.getAddress();
 });
 
+/**
+ * Convert an KeyRing to a more json-friendly object.
+ * @param {String?} passphrase - KeyRing passphrase
+ * @returns {Object}
+ */
+
+KeyRing.prototype.toJSON = function toJSON() {
+  return {
+    v: 1,
+    name: 'address',
+    address: this.getAddress(),
+    network: this.network.type,
+    change: this.change,
+    index: this.index,
+    path: this.path,
+    key: utils.toBase58(this.key),
+    type: this.type,
+    witness: this.witness,
+    keys: this.keys.map(utils.toBase58),
+    m: this.m,
+    n: this.n
+  };
+};
+
+/**
+ * Instantiate an KeyRing from a jsonified transaction object.
+ * @param {Object} json - The jsonified transaction object.
+ * @param {String?} passphrase - KeyRing passphrase
+ * @returns {KeyRing}
+ */
+
+KeyRing.fromJSON = function fromJSON(json) {
+  assert.equal(json.v, 1);
+  assert.equal(json.name, 'address');
+  return new KeyRing({
+    nework: json.network,
+    change: json.change,
+    index: json.index,
+    path: json.path,
+    key: utils.fromBase58(json.key),
+    type: json.type,
+    witness: json.witness,
+    keys: json.keys.map(utils.fromBase58),
+    m: json.m,
+    n: json.n
+  });
+};
+
 /*
  * Expose
  */
diff --git a/lib/bcoin/mtx.js b/lib/bcoin/mtx.js
index 6fb036d2..b8edf49c 100644
--- a/lib/bcoin/mtx.js
+++ b/lib/bcoin/mtx.js
@@ -353,8 +353,9 @@ MTX.prototype.createSignature = function createSignature(index, prev, key, type,
 /**
  * Sign an input.
  * @param {Number} index - Index of input being signed.
- * @param {Address} addr - Address used to sign. The address
+ * @param {KeyRing} addr - Address used to sign. The address
  * must be able to redeem the coin.
+ * @param {HDPrivateKey|KeyPair|Buffer} key - Private key.
  * @param {SighashType} type
  * @returns {Boolean} Whether the input was able to be signed.
  * @throws on unavailable coins.
@@ -623,8 +624,9 @@ MTX.prototype.isSigned = function isSigned() {
 /**
  * Built input scripts (or witnesses) and sign the inputs.
  * @param {Number} index - Index of input being signed.
- * @param {Address} addr - Address used to sign. The address
+ * @param {KeyRing} addr - Address used to sign. The address
  * must be able to redeem the coin.
+ * @param {HDPrivateKey|KeyPair|Buffer} key - Private key.
  * @param {SighashType} type
  * @returns {Boolean} Whether the input was able to be signed.
  * @throws on unavailable coins.
@@ -656,7 +658,7 @@ MTX.prototype.sign = function sign(index, addr, key, type) {
  * tx.addOutput({ address: ..., value: new bn(100000) });
  * tx.addOutput({ address: ..., value: utils.satoshi('0.1') });
  * tx.addOutput(receivingWallet, utils.satoshi('0.1'));
- * @param {Wallet|Address|Object} obj - Wallet, Address,
+ * @param {Wallet|KeyRing|Object} obj - Wallet, Address,
  * or options (see {@link Script.createOutputScript} for options).
  * @param {Amount?} value - Only needs to be present for non-options.
  */
diff --git a/lib/bcoin/wallet.js b/lib/bcoin/wallet.js
index 73edeb69..7733e560 100644
--- a/lib/bcoin/wallet.js
+++ b/lib/bcoin/wallet.js
@@ -83,6 +83,7 @@ function Wallet(options) {
   this.copayBIP45 = options.copayBIP45 || false;
   this.lookahead = options.lookahead != null ? options.lookahead : 5;
   this.cosignerIndex = -1;
+  this.initialized = false;
 
   this.type = options.type || 'pubkeyhash';
   this.derivation = options.derivation || 'bip44';
@@ -154,8 +155,9 @@ Wallet.prototype._init = function _init() {
   var self = this;
   var i;
 
-  assert(!this._initialized);
-  this._initialized = true;
+  assert(!this.initialized);
+
+  this.initialized = true;
 
   if (Object.keys(this.addressMap).length === 0) {
     for (i = 0; i < this.receiveDepth - 1; i++)
@@ -178,15 +180,32 @@ Wallet.prototype._init = function _init() {
   assert(!this.receiveAddress.change);
   assert(this.changeAddress.change);
 
-  if (!this.provider)
-    return;
-
-  this.provider.setID(this.id);
-
   this.on('error', function(err) {
     bcoin.debug('Wallet Error: %s', err.message);
   });
 
+  this.setProvider(this.provider, function(err) {
+    if (err)
+      return self.emit('error', err);
+
+    self.loaded = true;
+    self.emit('open');
+  });
+};
+
+Wallet.prototype.setProvider = function setProvider(provider, callback) {
+  var self = this;
+
+  if (!provider)
+    return callback();
+
+  if (this.provider !== provider)
+    this.provider.destroy();
+
+  this.provider = provider;
+
+  this.provider.setID(this.id);
+
   this.provider.on('error', function(err) {
     self.emit('error', err);
   });
@@ -212,13 +231,7 @@ Wallet.prototype._init = function _init() {
     self.emit('unconfirmed', tx);
   });
 
-  this.provider.open(function(err) {
-    if (err)
-      return self.emit('error', err);
-
-    self.loaded = true;
-    self.emit('open');
-  });
+  this.provider.open(callback);
 };
 
 /**
@@ -392,9 +405,6 @@ Wallet.prototype.getID = function getID() {
   var publicKey = this.accountKey.publicKey;
   var p;
 
-  if (this.options.id)
-    return this.options.id;
-
   p = new BufferWriter();
   p.writeU8(0x03);
   p.writeU8(0xbe);
@@ -484,9 +494,9 @@ Wallet.prototype.deriveChange = function deriveChange(index) {
  */
 
 Wallet.prototype.deriveAddress = function deriveAddress(change, index) {
-  var path, data, key, options, address;
+  var i, path, data, key, options, address;
 
-  assert(this._initialized);
+  assert(this.initialized);
 
   if (typeof change === 'string')
     path = change;
@@ -517,7 +527,7 @@ Wallet.prototype.deriveAddress = function deriveAddress(change, index) {
 
   options = {
     network: this.network,
-    key: key,
+    key: key.publicKey,
     change: data.change,
     index: data.index,
     path: data.path,
@@ -525,15 +535,15 @@ Wallet.prototype.deriveAddress = function deriveAddress(change, index) {
     witness: this.witness,
     m: this.m,
     n: this.n,
-    keys: [],
-    derived: true
+    keys: []
   };
 
-  this.keys.forEach(function(key, cosignerIndex) {
-    var path = this.createPath(cosignerIndex, data.change, data.index);
+  for (i = 0; i < this.keys.length; i++) {
+    key = this.keys[i];
+    path = this.createPath(i, data.change, data.index);
     key = key.derive(path);
     options.keys.push(key.publicKey);
-  }, this);
+  }
 
   address = new bcoin.keyring(options);
 
@@ -724,7 +734,7 @@ Wallet.prototype.fill = function fill(tx, options, callback) {
   if (!options)
     options = {};
 
-  assert(this._initialized);
+  assert(this.initialized);
 
   this.getCoins(function(err, coins) {
     if (err)
@@ -858,6 +868,9 @@ Wallet.prototype.createTX = function createTX(options, outputs, callback) {
     if (!tx.checkInputs(height))
       return callback(new Error('CheckInputs failed.'));
 
+    if (!self.scriptInputs(tx))
+      return callback(new Error('scriptInputs failed.'));
+
     return callback(null, tx);
   });
 };
@@ -1095,7 +1108,7 @@ Wallet.prototype._scan = function _scan(getByAddress, callback) {
   var depth = { changeDepth: 0, receiveDepth: 0 };
   var all = [];
 
-  assert(this._initialized);
+  assert(this.initialized);
 
   (function chainCheck(change) {
     var addressIndex = 0;
@@ -1501,13 +1514,13 @@ Wallet.prototype.inspect = function inspect() {
     network: this.network.type,
     m: this.m,
     n: this.n,
-    keyAddress: this._initialized
+    keyAddress: this.initialized
       ? this.keyAddress
       : null,
-    scriptAddress: this._initialized
+    scriptAddress: this.initialized
       ? this.scriptAddress
       : null,
-    programAddress: this._initialized
+    programAddress: this.initialized
       ? this.programAddress
       : null,
     witness: this.witness,
@@ -1653,7 +1666,6 @@ MasterKey.fromJSON = function fromJSON(json) {
   });
 };
 
-
 /*
  * Expose
  */
diff --git a/lib/bcoin/walletdb.js b/lib/bcoin/walletdb.js
index 5db57a32..f895c53c 100644
--- a/lib/bcoin/walletdb.js
+++ b/lib/bcoin/walletdb.js
@@ -40,6 +40,7 @@ function WalletDB(options) {
 
   EventEmitter.call(this);
 
+  this.providers = [];
   this.options = options;
   this.loaded = false;
   this.network = bcoin.network.get(options.network);
@@ -136,14 +137,14 @@ WalletDB.prototype._init = function _init() {
   this.tx.on('tx', function(tx, map) {
     self.emit('tx', tx, map);
     map.all.forEach(function(id) {
-      self.emit(id + ' tx', tx);
+      self.fire(id, 'tx', tx);
     });
   });
 
   this.tx.on('confirmed', function(tx, map) {
     self.emit('confirmed', tx, map);
     map.all.forEach(function(id) {
-      self.emit(id + ' confirmed', tx);
+      self.fire(id, 'confirmed', tx);
     });
     utils.forEachSerial(map.output, function(id, next) {
       self.syncOutputDepth(id, tx, next);
@@ -156,7 +157,7 @@ WalletDB.prototype._init = function _init() {
   this.tx.on('unconfirmed', function(tx, map) {
     self.emit('unconfirmed', tx, map);
     map.all.forEach(function(id) {
-      self.emit(id + ' unconfirmed', tx);
+      self.fire(id, 'unconfirmed', tx);
     });
   });
 
@@ -165,12 +166,12 @@ WalletDB.prototype._init = function _init() {
 
     self.emit('updated', tx, map);
     map.all.forEach(function(id) {
-      self.emit(id + ' updated', tx);
+      self.fire(id, 'updated', tx);
     });
 
     utils.forEachSerial(map.output, function(id, next) {
       if (self.listeners('balance').length === 0
-          && self.listeners(id + ' balance').length === 0) {
+          && !self.hasListener(id, ' balance')) {
         return next();
       }
 
@@ -181,7 +182,7 @@ WalletDB.prototype._init = function _init() {
         balances[id] = balance;
 
         self.emit('balance', balance, id);
-        self.emit(id + ' balance', balance);
+        self.fire(id, 'balance', balance);
 
         next();
       });
@@ -447,28 +448,38 @@ WalletDB.prototype.get = function get(id, callback) {
 
 /**
  * Save a wallet to the database (setup ida and encrypt).
- * @param {WalletID?} id
- * @param {Wallet} options
+ * @param {Wallet} wallet
  * @param {Function} callback
  */
 
 WalletDB.prototype.save = function save(wallet, callback) {
+  var self = this;
+  if (Array.isArray(wallet)) {
+    return utils.forEachSerial(wallet, function(wallet, next) {
+      self.save(wallet, next);
+    }, callback);
+  }
   this.saveJSON(wallet.id, wallet.toJSON(), callback);
 };
 
 /**
  * Remove wallet from the database. Destroy wallet if passed in.
- * @param {WalletID|Wallet} id
+ * @param {WalletID} id
  * @param {Function} callback
  */
 
 WalletDB.prototype.remove = function remove(id, callback) {
+  var self = this;
+  if (Array.isArray(wallet)) {
+    return utils.forEachSerial(id, function(id, next) {
+      self.remove(id, next);
+    }, callback);
+  }
   return this.removeJSON(id, callback);
 };
 
 /**
  * Create a new wallet, save to database, setup provider.
- * @param {WalletID?} id
  * @param {Object} options - See {@link Wallet}.
  * @param {Function} callback - Returns [Error, {@link Wallet}].
  */
@@ -703,38 +714,53 @@ WalletDB.prototype.provider = function provider() {
 };
 
 WalletDB.prototype.register = function register(id, provider) {
-  if (!this.listeners[id])
-    this.listeners[id] = [];
+  if (!this.providers[id])
+    this.providers[id] = [];
 
-  if (this.listeners[id].indexOf(provider) !== -1)
-    this.listeners[id].push(provider);
+  if (this.providers[id].indexOf(provider) === -1)
+    this.providers[id].push(provider);
 };
 
 WalletDB.prototype.unregister = function unregister(id, provider) {
-  var listeners = this.listeners[id];
+  var providers = this.providers[id];
   var i;
 
-  if (!listeners)
+  if (!providers)
     return;
 
-  i = listeners.indexOf(provider);
+  i = providers.indexOf(provider);
   if (i !== -1)
-    listeners.splice(i, 1);
+    providers.splice(i, 1);
 
-  if (listeners.length === 0)
-    delete this.listeners[id];
+  if (providers.length === 0)
+    delete this.providers[id];
 };
 
 WalletDB.prototype.fire = function fire(id) {
   var args = Array.prototype.slice.call(arguments, 1);
-  var listeners = this.listeners[id];
+  var providers = this.providers[id];
   var i;
 
-  if (!listeners)
+  if (!providers)
     return;
 
-  for (i = 0; i < listeners.length; i++)
-    listeners.emit.apply(listener, args);
+  for (i = 0; i < providers.length; i++)
+    providers[i].emit.apply(providers[i], args);
+};
+
+WalletDB.prototype.hasListener = function hasListener(id, event) {
+  var providers = this.providers[id];
+  var i;
+
+  if (!providers)
+    return false;
+
+  for (i = 0; i < providers.length; i++) {
+    if (providers[i].listeners(event).length !== 0)
+      return true;
+  }
+
+  return false;
 };
 
 /**
@@ -800,26 +826,7 @@ Provider.prototype.setID = function setID(id) {
   assert(!this.id, 'ID has already been set.');
 
   this.id = id;
-
-  this.db.on(id + ' tx', this._onTX = function(tx) {
-    self.emit('tx', tx);
-  });
-
-  this.db.on(id + ' updated', this._onUpdated = function(tx) {
-    self.emit('updated', tx);
-  });
-
-  this.db.on(id + ' confirmed', this._onConfirmed = function(tx) {
-    self.emit('confirmed', tx);
-  });
-
-  this.db.on(id + ' unconfirmed', this._onUnconfirmed = function(tx) {
-    self.emit('unconfirmed', tx);
-  });
-
-  this.db.on(id + ' balance', this._onBalance = function(balance) {
-    self.emit('balance', balance);
-  });
+  this.db.register(this.id, this);
 };
 
 /**
@@ -832,35 +839,12 @@ Provider.prototype.close =
 Provider.prototype.destroy = function destroy(callback) {
   callback = utils.ensure(callback);
 
-  if (!this.db)
+  if (!this.id)
     return utils.nextTick(callback);
 
-  if (this._onTX) {
-    this.db.removeListener(this.id + ' tx', this._onTX);
-    delete this._onTX;
-  }
-
-  if (this._onUpdated) {
-    this.db.removeListener(this.id + ' updated', this._onUpdated);
-    delete this._onUpdated;
-  }
-
-  if (this._onConfirmed) {
-    this.db.removeListener(this.id + ' confirmed', this._onConfirmed);
-    delete this._onConfirmed;
-  }
-
-  if (this._onUnconfirmed) {
-    this.db.removeListener(this.id + ' unconfirmed', this._onUnconfirmed);
-    delete this._onUnconfirmed;
-  }
-
-  if (this._onBalance) {
-    this.db.removeListener(this.id + ' balance', this._onBalance);
-    delete this._onBalance;
-  }
-
+  this.db.unregister(this.id, this);
   this.db = null;
+  this.id = null;
 
   return utils.nextTick(callback);
 };
@@ -999,11 +983,9 @@ Provider.prototype.save = function save(wallet, callback) {
 };
 
 /**
- * Notify the provider backend that a new address was
- * derived (not technically necessary if you're
- * implementing a provider).
- * @param {Wallet} wallet
- * @param {Address} address
+ * Add a key to the wallet.
+ * @param {HDPublicKey} key
+ * @param {Function} callback
  */
 
 Provider.prototype.addKey = function addKey(key, callback) {
@@ -1011,23 +993,9 @@ Provider.prototype.addKey = function addKey(key, callback) {
 };
 
 /**
- * Notify the provider backend that a new address was
- * derived (not technically necessary if you're
- * implementing a provider).
- * @param {Wallet} wallet
- * @param {Address} address
- */
-
-// Provider.prototype.deriveInputs = function deriveInputs(tx, index, callback) {
-//   return this.db.deriveInputs(this.id, tx, index, callback);
-// };
-
-/**
- * Notify the provider backend that a new address was
- * derived (not technically necessary if you're
- * implementing a provider).
- * @param {Wallet} wallet
- * @param {Address} address
+ * Remove a key from the wallet.
+ * @param {HDPublicKey} key
+ * @param {Function} callback
  */
 
 Provider.prototype.removeKey = function removeKey(key, callback) {
@@ -1035,11 +1003,8 @@ Provider.prototype.removeKey = function removeKey(key, callback) {
 };
 
 /**
- * Notify the provider backend that a new address was
- * derived (not technically necessary if you're
- * implementing a provider).
- * @param {Wallet} wallet
- * @param {Address} address
+ * Create a receiving address.
+ * @param {Function} callback
  */
 
 Provider.prototype.createReceive = function createReceive(callback) {
@@ -1047,11 +1012,8 @@ Provider.prototype.createReceive = function createReceive(callback) {
 };
 
 /**
- * Notify the provider backend that a new address was
- * derived (not technically necessary if you're
- * implementing a provider).
- * @param {Wallet} wallet
- * @param {Address} address
+ * Create a change address.
+ * @param {Function} callback
  */
 
 Provider.prototype.createChange = function createChange(callback) {