diff --git a/docs/URI.md b/docs/URI.md
new file mode 100644
index 0000000..17578eb
--- /dev/null
+++ b/docs/URI.md
@@ -0,0 +1,44 @@
+# URI
+
+Represents a bitcoin payment uri. Bitcoin URI strings became the most popular
+way to share payment request, sometimes as a bitcoin link and others using a QR code.
+
+URI Examples:
+```
+bitcoin:12A1MyfXbW6RhdRAZEqofac5jCQQjwEPBu
+bitcoin:12A1MyfXbW6RhdRAZEqofac5jCQQjwEPBu?amount=1.2
+bitcoin:12A1MyfXbW6RhdRAZEqofac5jCQQjwEPBu?amount=1.2&message=Payment&label=Satoshi&extra=other-param
+```
+
+The main use that we expect you'll have for the `URI` class in bitcore is
+validating and parsing bitcoin URIs. A `URI` instance exposes the address as a
+bitcore `Address` object and the amount in Satoshis, if present.
+
+The code for validating uris looks like this:
+```javascript
+var uriString = 'bitcoin:12A1MyfXbW6RhdRAZEqofac5jCQQjwEPBu?amount=1.2';
+var valid = URI.isValid(uriString);
+var uri = new URI(uriString);
+console.log(uri.address.network, uri.amount); // 'livenet', 120000000
+```
+
+All standard parameters can be found as members of the `URI` instance. However
+a bitcoin uri may contain other non-standard parameters, all those can be found
+under the `extra` namespace.
+
+See [the official BIP21 spec](https://github.com/bitcoin/bips/blob/master/bip-0021.mediawiki)
+for more information.
+
+Other usecase important usecase for the `URI` class is creating a bitcoin URI for
+sharing a payment request. That can be acomplished by using an Object to create
+an instance of URI.
+
+The code for creating an URI from an Object looks like this:
+```javascript
+var uriString = new URI({
+  address: '12A1MyfXbW6RhdRAZEqofac5jCQQjwEPBu',
+  amount : 10000, // in satoshis
+  message: 'My payment request'
+});
+var uriString = uri.toString();
+```
diff --git a/lib/address.js b/lib/address.js
index 957f53c..fe3d6ec 100644
--- a/lib/address.js
+++ b/lib/address.js
@@ -329,7 +329,7 @@ Address.getValidationError = function(data, network, type) {
  * @param {String} data - The encoded data
  * @param {String} network - The network: 'mainnet' or 'testnet'
  * @param {String} type - The type of address: 'script' or 'pubkey'
- * @returns {null|Error} The corresponding error message
+ * @returns {boolean} The corresponding error message
  */
 Address.isValid = function(data, network, type) {
   return !Address.getValidationError(data, network, type);
diff --git a/lib/uri.js b/lib/uri.js
index c8bc3eb..668aa2c 100644
--- a/lib/uri.js
+++ b/lib/uri.js
@@ -1,34 +1,79 @@
 'use strict';
 
 var _ = require('lodash');
-
 var URL = require('url');
+
 var Address = require('./address');
 
-var URI = function(arg, knownArgs) {
+/**
+ *
+ * Bitcore URI
+ *
+ * Instantiate an URI from a bitcoin URI String or an Object. An URI instance
+ * can be created with a bitcoin uri string or an object. All instances of
+ * URI are valid, the static method isValid allows checking before instanciation.
+ *
+ * All standard parameters can be found as members of the class, the address
+ * is represented using an {Address} instance and the amount is represented in
+ * satoshis. Any other non-standard parameters can be found under the extra member.
+ *
+ * @example
+ *
+ * var uri = new URI('bitcoin:12A1MyfXbW6RhdRAZEqofac5jCQQjwEPBu?amount=1.2');
+ * console.log(uri.address, uri.amount);
+ *
+ * @param {string|Object} data - A bitcoin URI string or an Object
+ * @param {Array.<string>} [knownParams] - Required non-standard params
+ * @throws {TypeError} Invalid bitcoin address
+ * @throws {TypeError} Invalid amount
+ * @throws {Error} Unknown required argument
+ * @returns {URI} A new valid and frozen instance of URI
+ */
+var URI = function(data, knownParams) {
   this.extras = {};
-  this.knownArgs = knownArgs || [];
+  this.knownParams = knownParams || [];
   this.address = this.network = this.amount = this.message = null;
 
-  if (typeof(arg) == 'string') {
-    var params = URI.parse(arg);
+  if (typeof(data) == 'string') {
+    var params = URI.parse(data);
     this._fromObject(params);
-  } else if (typeof(arg) == 'object') {
-    this._fromObject(arg);
+  } else if (typeof(data) == 'object') {
+    this._fromObject(data);
   } else {
     throw new TypeError('Unrecognized data format.');
   }
 };
 
-URI.isValid = function(arg, knownArgs) {
+/**
+ *
+ * Check if an bitcoin URI string is valid
+ *
+ * @example
+ *
+ * var valid = URI.isValid('bitcoin:12A1MyfXbW6RhdRAZEqofac5jCQQjwEPBu');
+ * // true
+ *
+ * @param {string|Object} data - A bitcoin URI string or an Object
+ * @param {Array.<string>} [knownParams] - Required non-standard params
+ * @returns {boolean} Result of uri validation
+ */
+URI.isValid = function(arg, knownParams) {
   try {
-    var uri = new URI(arg, knownArgs);
+    var uri = new URI(arg, knownParams);
     return true;
   } catch(err) {
     return false;
   }
 };
 
+/**
+ *
+ * Convert a bitcoin URI string into a simple object.
+ *
+ * @param {string} uri - A bitcoin URI string
+ * @throws {TypeError} Invalid bitcoin URI
+ * @returns {Object} An object with the parsed params
+ */
 URI.parse = function(uri) {
   var info = URL.parse(uri, true);
 
@@ -43,9 +88,17 @@ URI.parse = function(uri) {
   return info.query;
 };
 
-
+/**
+ *
+ * Internal function to load the URI instance with an object.
+ *
+ * @param {Object} amount - Amount BTC string
+ * @throws {TypeError} Invalid bitcoin address
+ * @throws {TypeError} Invalid amount
+ * @throws {Error} Unknown required argument
+ */
 URI.prototype._fromObject = function(obj) {
-  var members = ['address', 'amount', 'message', 'label'];
+  var members = ['address', 'amount', 'message', 'label', 'r'];
 
   if (!Address.isValid(obj.address)) throw new TypeError('Invalid bitcoin address');
 
@@ -57,7 +110,7 @@ URI.prototype._fromObject = function(obj) {
   for (var key in obj) {
     if (key === 'address' || key === 'amount') continue;
 
-    if (/^req-/.exec(key) && this.knownArgs.indexOf(key) === -1) {
+    if (/^req-/.exec(key) && this.knownParams.indexOf(key) === -1) {
       throw Error('Unknown required argument ' + key);
     }
 
@@ -66,13 +119,26 @@ URI.prototype._fromObject = function(obj) {
   }
 };
 
+/**
+ *
+ * Internal function to transform a BTC string amount into satoshis
+ *
+ * @param {String} amount - Amount BTC string
+ * @throws {TypeError} Invalid amount
+ * @returns {Object} Amount represented in satoshis
+ */
 URI.prototype._parseAmount = function(amount) {
   var amount = Number(amount);
   if (isNaN(amount)) throw new TypeError('Invalid amount');
   return amount; // TODO: Convert to Satoshis (yemel)
 };
 
-
+/**
+ *
+ * Will return a the string representation of the URI
+ *
+ * @returns {String} Bitcoin URI string
+ */
 URI.prototype.toString = function() {
   var query = _.clone(this.extras);
   if (this.amount) query.amount = this.amount; // TODO: Convert to BTC (yemel)
@@ -85,6 +151,12 @@ URI.prototype.toString = function() {
   });
 };
 
+/**
+ *
+ * Will return a string formatted for the console
+ *
+ * @returns {String} Bitcoin URI
+ */
 URI.prototype.inspect = function() {
   return '<URI: ' + this.toString()+ '>';
 }