diff --git a/lib/model/index.js b/lib/model/index.js
index 7d1c5d8..3a3fcf2 100644
--- a/lib/model/index.js
+++ b/lib/model/index.js
@@ -1,5 +1,9 @@
 var Model = {};
 
 Model.Wallet = require('./wallet');
+Model.Copayer = require('./copayer');
+Model.TxProposal = require('./txproposal');
+Model.Address = require('./address');
+Model.Notification = require('./notification');
 
 module.exports = Model;
diff --git a/lib/storage_mongo.js b/lib/storage_mongo.js
index 1e3ec37..cb0e9bd 100644
--- a/lib/storage_mongo.js
+++ b/lib/storage_mongo.js
@@ -1,7 +1,6 @@
 'use strict';
 
 var _ = require('lodash');
-var levelup = require('mongodb');
 var async = require('async');
 var $ = require('preconditions').singleton();
 var log = require('npmlog');
@@ -11,11 +10,7 @@ var util = require('util');
 
 var mongodb = require('mongodb');
 
-var Wallet = require('./model/wallet');
-var Copayer = require('./model/copayer');
-var Address = require('./model/address');
-var TxProposal = require('./model/txproposal');
-var Notification = require('./model/notification');
+var Model = require('./model');
 
 var Storage = function(opts) {
   opts = opts || {};
@@ -34,87 +29,51 @@ var Storage = function(opts) {
   }
 };
 
-var zeroPad = function(x, length) {
-  return _.padLeft(parseInt(x), length, '0');
-};
-
-var walletPrefix = function(id) {
-  return 'w!' + id;
-};
-
-var opKey = function(key) {
-  return key ? '!' + key : '';
-};
-
-var MAX_TS = _.repeat('9', 14);
-
-
-var KEY = {
-  WALLET: function(walletId) {
-    return walletPrefix(walletId) + '!main';
-  },
-  COPAYER: function(id) {
-    return 'copayer!' + id;
-  },
-  TXP: function(walletId, txProposalId) {
-    return walletPrefix(walletId) + '!txp' + opKey(txProposalId);
-  },
-  NOTIFICATION: function(walletId, notificationId) {
-    return walletPrefix(walletId) + '!not' + opKey(notificationId);
-  },
-  PENDING_TXP: function(walletId, txProposalId) {
-    return walletPrefix(walletId) + '!ptxp' + opKey(txProposalId);
-  },
-  ADDRESS: function(walletId, address) {
-    return walletPrefix(walletId) + '!addr' + opKey(address);
-  },
-};
-
 Storage.prototype.fetchWallet = function(id, cb) {
-  this.db.get(KEY.WALLET(id), function(err, data) {
-    if (err) {
-      if (err.notFound) return cb();
-      return cb(err);
-    }
-    return cb(null, Wallet.fromObj(data));
+  this.db.collection('wallets').findOne({
+    id: id
+  }, function(err, result) {
+    if (err) return cb(err);
+    if (!result) return cb();
+    return cb(null, Model.Wallet.fromObj(result));
   });
 };
 
 Storage.prototype.storeWallet = function(wallet, cb) {
-  this.db.put(KEY.WALLET(wallet.id), wallet, cb);
+  this.db.collection('wallets').update({
+    id: wallet.id
+  }, wallet, {
+    w: 1,
+    upsert: true,
+  }, cb);
 };
 
 Storage.prototype.storeWalletAndUpdateCopayersLookup = function(wallet, cb) {
-  var ops = [];
-  ops.push({
-    type: 'put',
-    key: KEY.WALLET(wallet.id),
-    value: wallet
-  });
-  _.each(wallet.copayers, function(copayer) {
-    var value = {
-      walletId: wallet.id,
-      requestPubKey: copayer.requestPubKey,
-    };
-    ops.push({
-      type: 'put',
-      key: KEY.COPAYER(copayer.id),
-      value: value
-    });
-  });
-  this.db.batch(ops, cb);
+  return this.storeWallet(wallet, cb);
 };
 
 Storage.prototype.fetchCopayerLookup = function(copayerId, cb) {
-  this.db.get(KEY.COPAYER(copayerId), function(err, data) {
-    if (err) {
-      if (err.notFound) return cb();
-      return cb(err);
-    }
-    return cb(null, data);
+  this.db.collection('wallets').findOne({
+    'copayers.id': copayerId
+  }, {
+    fields: {
+      id: 1,
+      copayers: 1,
+    },
+  }, function(err, result) {
+    if (err) return cb(err);
+    if (!result) return cb();
+    var copayer = _.find(result.copayers, {
+      id: copayerId
+    });
+    return cb(null, {
+      walletId: result.id,
+      requestPubKey: copayer.requestPubKey,
+    });
   });
 };
 
+// TODO: should be done client-side
 Storage.prototype._completeTxData = function(walletId, txs, cb) {
   var txList = [].concat(txs);
   this.fetchWallet(walletId, function(err, wallet) {
@@ -131,12 +90,14 @@ Storage.prototype._completeTxData = function(walletId, txs, cb) {
 
 Storage.prototype.fetchTx = function(walletId, txProposalId, cb) {
   var self = this;
-  this.db.get(KEY.TXP(walletId, txProposalId), function(err, data) {
-    if (err) {
-      if (err.notFound) return cb();
-      return cb(err);
-    }
-    return self._completeTxData(walletId, TxProposal.fromObj(data), cb);
+
+  this.db.collection('txs').findOne({
+    id: txProposalId,
+    walletId: walletId
+  }, function(err, result) {
+    if (err) return cb(err);
+    if (!result) return cb();
+    return self._completeTxData(walletId, Model.TxProposal.fromObj(result), cb);
   });
 };
 
@@ -144,22 +105,19 @@ Storage.prototype.fetchTx = function(walletId, txProposalId, cb) {
 Storage.prototype.fetchPendingTxs = function(walletId, cb) {
   var self = this;
 
-  var txs = [];
-  var key = KEY.PENDING_TXP(walletId);
-  this.db.createReadStream({
-    gte: key,
-    lt: key + '~'
-  })
-    .on('data', function(data) {
-      txs.push(TxProposal.fromObj(data.value));
-    })
-    .on('error', function(err) {
-      if (err.notFound) return cb();
-      return cb(err);
-    })
-    .on('end', function() {
-      return self._completeTxData(walletId, txs, cb);
+  this.db.collection('txs').find({
+    walletId: walletId,
+    isPending: true
+  }).sort({
+    createdOn: 1
+  }).toArray(function(err, result) {
+    if (err) return cb(err);
+    if (!result) return cb();
+    var txs = _.map(result, function(tx) {
+      return Model.TxProposal.fromObj(tx);
     });
+    return self._completeTxData(walletId, txs, cb);
+  });
 };
 
 /**
@@ -173,31 +131,30 @@ Storage.prototype.fetchPendingTxs = function(walletId, cb) {
 Storage.prototype.fetchTxs = function(walletId, opts, cb) {
   var self = this;
 
-  var txs = [];
   opts = opts || {};
-  opts.limit = _.isNumber(opts.limit) ? parseInt(opts.limit) : -1;
-  opts.minTs = _.isNumber(opts.minTs) ? zeroPad(opts.minTs, 11) : 0;
-  opts.maxTs = _.isNumber(opts.maxTs) ? zeroPad(opts.maxTs, 11) : MAX_TS;
 
-  var key = KEY.TXP(walletId, opts.minTs);
-  var endkey = KEY.TXP(walletId, opts.maxTs);
+  var tsFilter = {};
+  if (_.isNumber(opts.minTs)) tsFilter.$gte = opts.minTs;
+  if (_.isNumber(opts.maxTs)) tsFilter.$lte = opts.maxTs;
 
-  this.db.createReadStream({
-    gt: key,
-    lt: endkey + '~',
-    reverse: true,
-    limit: opts.limit,
-  })
-    .on('data', function(data) {
-      txs.push(TxProposal.fromObj(data.value));
-    })
-    .on('error', function(err) {
-      if (err.notFound) return cb();
-      return cb(err);
-    })
-    .on('end', function() {
-      return self._completeTxData(walletId, txs, cb);
+  var filter = {
+    walletId: walletId
+  };
+  if (!_.isEmpty(tsFilter)) filter.createdOn = tsFilter;
+
+  var mods = {};
+  if (_.isNumber(opts.limit)) mods.limit = opts.limit;
+
+  this.db.collection('txs').find(filter, mods).sort({
+    createdOn: 1
+  }).toArray(function(err, result) {
+    if (err) return cb(err);
+    if (!result) return cb();
+    var txs = _.map(result, function(tx) {
+      return Model.TxProposal.fromObj(tx);
     });
+    return self._completeTxData(walletId, txs, cb);
+  });
 };
 
 
@@ -210,181 +167,133 @@ Storage.prototype.fetchTxs = function(walletId, opts, cb) {
  * @param opts.limit
  */
 Storage.prototype.fetchNotifications = function(walletId, opts, cb) {
-  var txs = [];
+  var self = this;
+
   opts = opts || {};
-  opts.limit = _.isNumber(opts.limit) ? parseInt(opts.limit) : -1;
-  opts.minTs = _.isNumber(opts.minTs) ? zeroPad(opts.minTs, 11) : 0;
-  opts.maxTs = _.isNumber(opts.maxTs) ? zeroPad(opts.maxTs, 11) : MAX_TS;
 
-  var key = KEY.NOTIFICATION(walletId, opts.minTs);
-  var endkey = KEY.NOTIFICATION(walletId, opts.maxTs);
+  var tsFilter = {};
+  if (_.isNumber(opts.minTs)) tsFilter.$gte = opts.minTs;
+  if (_.isNumber(opts.maxTs)) tsFilter.$lte = opts.maxTs;
 
-  this.db.createReadStream({
-    gt: key,
-    lt: endkey + '~',
-    reverse: opts.reverse,
-    limit: opts.limit,
-  })
-    .on('data', function(data) {
-      txs.push(Notification.fromObj(data.value));
-    })
-    .on('error', function(err) {
-      if (err.notFound) return cb();
-      return cb(err);
-    })
-    .on('end', function() {
-      return cb(null, txs);
+  var filter = {
+    walletId: walletId
+  };
+  if (!_.isEmpty(tsFilter)) filter.createdOn = tsFilter;
+
+  var mods = {};
+  if (_.isNumber(opts.limit)) mods.limit = opts.limit;
+
+  this.db.collection('notifications').find(filter, mods).sort({
+    createdOn: 1
+  }).toArray(function(err, result) {
+    if (err) return cb(err);
+    if (!result) return cb();
+    var notifications = _.map(result, function(notification) {
+      return Model.Notification.fromObj(notification);
     });
+    return cb(null, notifications);
+  });
 };
 
 
+// TODO: remove walletId from signature
 Storage.prototype.storeNotification = function(walletId, notification, cb) {
-  this.db.put(KEY.NOTIFICATION(walletId, notification.id), notification, cb);
+  this.db.collection('notifications').insert(notification, {
+    w: 1
+  }, cb);
 };
 
-
-// TODO should we store only txp.id on keys for indexing
-// or the whole txp? For now, the entire record makes sense
-// (faster + easier to access)
+// TODO: remove walletId from signature
 Storage.prototype.storeTx = function(walletId, txp, cb) {
-  var ops = [{
-    type: 'put',
-    key: KEY.TXP(walletId, txp.id),
-    value: txp,
-  }];
-
-  if (txp.isPending()) {
-    ops.push({
-      type: 'put',
-      key: KEY.PENDING_TXP(walletId, txp.id),
-      value: txp,
-    });
-  } else {
-    ops.push({
-      type: 'del',
-      key: KEY.PENDING_TXP(walletId, txp.id),
-    });
-  }
-  this.db.batch(ops, cb);
+  txp.isPending = txp.isPending(); // Persist attribute to use when querying
+  this.db.collection('txs').update({
+    id: txp.id,
+    walletId: walletId
+  }, txp, {
+    w: 1,
+    upsert: true,
+  }, cb);
 };
 
 Storage.prototype.removeTx = function(walletId, txProposalId, cb) {
-  var ops = [{
-    type: 'del',
-    key: KEY.TXP(walletId, txProposalId),
+  this.db.collection('txs').findAndRemove({
+    id: txProposalId,
+    walletId: walletId
   }, {
-    type: 'del',
-    key: KEY.PENDING_TXP(walletId, txProposalId),
-  }];
-
-  this.db.batch(ops, cb);
-};
-
-Storage.prototype._delByKey = function(key, cb) {
-  var self = this;
-  var keys = [];
-  this.db.createKeyStream({
-    gte: key,
-    lt: key + '~',
-  })
-    .on('data', function(key) {
-      keys.push(key);
-    })
-    .on('error', function(err) {
-      if (err.notFound) return cb();
-      return cb(err);
-    })
-    .on('end', function(err) {
-      self.db.batch(_.map(keys, function(k) {
-        return {
-          key: k,
-          type: 'del'
-        };
-      }), function(err) {
-        return cb(err);
-      });
-    });
-};
-
-Storage.prototype._removeCopayers = function(walletId, cb) {
-  var self = this;
-
-  this.fetchWallet(walletId, function(err, w) {
-    if (err || !w) return cb(err);
-
-    self.db.batch(_.map(w.copayers, function(c) {
-      return {
-        type: 'del',
-        key: KEY.COPAYER(c.id),
-      };
-    }), cb);
-  });
+    w: 1
+  }, cb);
 };
 
 Storage.prototype.removeWallet = function(walletId, cb) {
   var self = this;
 
-  async.series([
+  async.parallel([
 
     function(next) {
-      // This should be the first step. Will check the wallet exists
-      self._removeCopayers(walletId, next);
+      this.db.collections('wallets').findAndRemove({
+        id: walletId
+      }, next);
     },
     function(next) {
-      self._delByKey(walletPrefix(walletId), cb);
+      this.db.collections('addresses').findAndRemove({
+        walletId: walletId
+      }, next);
+    },
+    function(next) {
+      this.db.collections('txs').findAndRemove({
+        walletId: walletId
+      }, next);
+    },
+    function(next) {
+      this.db.collections('notifications').findAndRemove({
+        walletId: walletId
+      }, next);
     },
   ], cb);
 };
 
 
 Storage.prototype.fetchAddresses = function(walletId, cb) {
-  var addresses = [];
-  var key = KEY.ADDRESS(walletId);
-  this.db.createReadStream({
-    gte: key,
-    lt: key + '~'
-  })
-    .on('data', function(data) {
-      addresses.push(Address.fromObj(data.value));
-    })
-    .on('error', function(err) {
-      if (err.notFound) return cb();
-      return cb(err);
-    })
-    .on('end', function() {
-      return cb(null, addresses);
+  var self = this;
+
+  this.db.collection('addresses').find({
+    walletId: walletId,
+  }).sort({
+    createdOn: 1
+  }).toArray(function(err, result) {
+    if (err) return cb(err);
+    if (!result) return cb();
+    var addresses = _.map(result, function(address) {
+      return Model.Address.fromObj(address);
     });
+    return cb(null, addresses);
+  });
 };
 
 Storage.prototype.storeAddressAndWallet = function(wallet, addresses, cb) {
-  var ops = _.map([].concat(addresses), function(address) {
-    return {
-      type: 'put',
-      key: KEY.ADDRESS(wallet.id, address.address),
-      value: address,
-    };
+  var self = this;
+  this.db.collection('addresses').insert([].concat(addresses), {
+    w: 1
+  }, function(err) {
+    if (err) return cb(err);
+    self.storeWallet(wallet, cb);
   });
-  ops.unshift({
-    type: 'put',
-    key: KEY.WALLET(wallet.id),
-    value: wallet,
-  });
-
-  this.db.batch(ops, cb);
 };
 
 Storage.prototype._dump = function(cb, fn) {
   fn = fn || console.log;
 
-  this.db.readStream()
-    .on('data', function(data) {
-      fn(util.inspect(data, {
-        depth: 10
-      }));
-    })
-    .on('end', function() {
-      if (cb) return cb();
-    });
+  var self = this;
+  this.db.collections(function(err, collections) {
+    if (err) return cb(err);
+    async.eachSeries(collections, function(col, next) {
+      fn('--------' + col);
+      col.find().toArray(function(err, item) {
+        fn(item);
+        next(err);
+      });
+    }, cb);
+  });
 };
 
 module.exports = Storage;
diff --git a/package.json b/package.json
index d670edf..66b52f3 100644
--- a/package.json
+++ b/package.json
@@ -52,7 +52,8 @@
     "memdown": "^1.0.0",
     "mocha": "^1.18.2",
     "sinon": "^1.10.3",
-    "supertest": "*"
+    "supertest": "*",
+    "tingodb": "^0.3.4"
   },
   "scripts": {
     "start": "node bws.js",
@@ -60,14 +61,11 @@
     "test": "./node_modules/.bin/mocha",
     "coveralls": "./node_modules/.bin/istanbul cover ./node_modules/mocha/bin/_mocha --report lcovonly -- -R spec && cat ./coverage/lcov.info | ./node_modules/coveralls/bin/coveralls.js && rm -rf ./coverage"
   },
-  "contributors": [
-    {
-      "name": "Ivan Socolsky",
-      "email": "ivan@bitpay.com"
-    },
-    {
-      "name": "Matias Alejo Garcia",
-      "email": "ematiu@gmail.com"
-    }
-  ]
+  "contributors": [{
+    "name": "Ivan Socolsky",
+    "email": "ivan@bitpay.com"
+  }, {
+    "name": "Matias Alejo Garcia",
+    "email": "ematiu@gmail.com"
+  }]
 }
diff --git a/test/storage.js b/test/storage.js
index 0378d61..143259d 100644
--- a/test/storage.js
+++ b/test/storage.js
@@ -1,24 +1,62 @@
 'use strict';
 
 var _ = require('lodash');
+var async = require('async');
 var chai = require('chai');
 var sinon = require('sinon');
 var should = chai.should();
 var levelup = require('levelup');
 var memdown = require('memdown');
-var Storage = require('../lib/storage');
+var mongodb = require('mongodb');
 
+
+var StorageLevelDb = require('../lib/storage');
+var StorageMongoDb = require('../lib/storage_mongo');
 var Model = require('../lib/model');
 
 
-describe.only('Storage', function() {
-  var storage;
-  beforeEach(function() {
-    var db = levelup(memdown, {
-      valueEncoding: 'json'
+function initStorageLevelDb(cb) {
+  var db = levelup(memdown, {
+    valueEncoding: 'json'
+  });
+  return cb(null, db);
+};
+
+function initStorageMongoDb(cb) {
+  var url = 'mongodb://localhost:27017/bws';
+  mongodb.MongoClient.connect(url, function(err, db) {
+    should.not.exist(err);
+    db.dropDatabase(function(err) {
+      return cb(null, db);
     });
-    storage = new Storage({
-      db: db
+  });
+};
+
+
+
+var Storage, initDb;
+
+
+var useLevel = false;
+
+if (useLevel) {
+  Storage = StorageLevelDb;
+  initDb = initStorageLevelDb;
+} else {
+  Storage = StorageMongoDb;
+  initDb = initStorageMongoDb;
+}
+
+
+describe('Storage', function() {
+  var storage;
+  beforeEach(function(done) {
+    initDb(function(err, db) {
+      should.not.exist(err);
+      storage = new Storage({
+        db: db
+      });
+      done();
     });
   });
   describe('Store & fetch wallet', function() {
@@ -51,4 +89,124 @@ describe.only('Storage', function() {
       });
     });
   });
+  describe('Copayer lookup', function() {
+    it('should correctly store and fetch copayer lookup', function(done) {
+      var wallet = Model.Wallet.create({
+        id: '123',
+        name: 'my wallet',
+        m: 2,
+        n: 3,
+      });
+      _.each(_.range(3), function(i) {
+        var copayer = Model.Copayer.create({
+          name: 'copayer ' + i,
+          xPubKey: 'xPubKey ' + i,
+          requestPubKey: 'requestPubKey ' + i,
+        });
+        wallet.addCopayer(copayer);
+      });
+
+      should.exist(wallet);
+      storage.storeWalletAndUpdateCopayersLookup(wallet, function(err) {
+        should.not.exist(err);
+        storage.fetchCopayerLookup(wallet.copayers[1].id, function(err, lookup) {
+          should.not.exist(err);
+          should.exist(lookup);
+          lookup.walletId.should.equal('123');
+          lookup.requestPubKey.should.equal('requestPubKey 1');
+          done();
+        })
+      });
+    });
+    it('should not return error if copayer not found', function(done) {
+      storage.fetchCopayerLookup('2', function(err, lookup) {
+        should.not.exist(err);
+        should.not.exist(lookup);
+        done();
+      });
+    });
+  });
+
+  describe('Transaction proposals', function() {
+    var wallet, proposals;
+
+    beforeEach(function(done) {
+      wallet = Model.Wallet.create({
+        id: '123',
+        name: 'my wallet',
+        m: 2,
+        n: 3,
+      });
+      _.each(_.range(3), function(i) {
+        var copayer = Model.Copayer.create({
+          name: 'copayer ' + i,
+          xPubKey: 'xPubKey ' + i,
+          requestPubKey: 'requestPubKey ' + i,
+        });
+        wallet.addCopayer(copayer);
+      });
+      should.exist(wallet);
+      storage.storeWalletAndUpdateCopayersLookup(wallet, function(err) {
+        should.not.exist(err);
+
+        proposals = _.map(_.range(4), function(i) {
+          var tx = Model.TxProposal.create({
+            walletId: '123',
+            creatorId: wallet.copayers[0].id,
+            amount: i + 100,
+          });
+          if (i % 2 == 0) {
+            tx.status = 'rejected';
+            tx.isPending().should.be.false;
+          }
+          return tx;
+        });
+        async.each(proposals, function(tx, next) {
+          storage.storeTx('123', tx, next);
+        }, function(err) {
+          should.not.exist(err);
+          done();
+        });
+      });
+    });
+    it('should fetch tx', function(done) {
+      storage.fetchTx('123', proposals[0].id, function(err, tx) {
+        should.not.exist(err);
+        should.exist(tx);
+        tx.id.should.equal(proposals[0].id);
+        tx.walletId.should.equal(proposals[0].walletId);
+        tx.creatorName.should.equal('copayer 0');
+        done();
+      });
+    });
+    it('should fetch all pending txs', function(done) {
+      storage.fetchPendingTxs('123', function(err, txs) {
+        should.not.exist(err);
+        should.exist(txs);
+        txs.length.should.equal(2);
+        txs = _.sortBy(txs, 'amount');
+        txs[0].amount.should.equal(101);
+        txs[1].amount.should.equal(103);
+        done();
+      });
+    });
+    it('should remove tx', function(done) {
+      storage.removeTx('123', proposals[0].id, function(err) {
+        should.not.exist(err);
+        storage.fetchTx('123', proposals[0].id, function(err, tx) {
+          should.not.exist(err);
+          should.not.exist(tx);
+          storage.fetchTxs('123', {}, function(err, txs) {
+            should.not.exist(err);
+            should.exist(txs);
+            txs.length.should.equal(3);
+            _.any(txs, {
+              id: proposals[0].id
+            }).should.be.false;
+            done();
+          });
+        });
+      });
+    });
+  });
 });