diff --git a/bin/bcoin-cli b/bin/bcoin-cli
index 013b686e..3415a9da 100755
--- a/bin/bcoin-cli
+++ b/bin/bcoin-cli
@@ -1,5 +1,7 @@
 #!/usr/bin/env node
 
+'use strict';
+
 var argv = parseArg(process.argv);
 
 var bcoin = require('../').set(argv.network);
diff --git a/bin/node b/bin/node
index 02bbc47f..204e4302 100755
--- a/bin/node
+++ b/bin/node
@@ -1,5 +1,7 @@
 #!/usr/bin/env node
 
+'use strict';
+
 var bcoin = require('../').set({ debug: true, debugFile: true });
 var utils = bcoin.utils;
 var assert = utils.assert;
diff --git a/bin/spvnode b/bin/spvnode
index c3a2fcd9..b5f29ccc 100755
--- a/bin/spvnode
+++ b/bin/spvnode
@@ -1,5 +1,7 @@
 #!/usr/bin/env node
 
+'use strict';
+
 var bcoin = require('../').set({ debug: true, debugFile: true });
 var utils = bcoin.utils;
 var assert = utils.assert;
diff --git a/browser/index.html b/browser/index.html
index 627928e6..89fa039f 100644
--- a/browser/index.html
+++ b/browser/index.html
@@ -93,6 +93,8 @@ more bitcoin magic).</small>
 <div id="floating" class="floating"></div>
 <script>
 ;(function() {
+  'use strict';
+
   var utils = bcoin.utils;
   var body = document.getElementsByTagName('body')[0];
   var log = document.getElementById('log');
diff --git a/browser/proxysocket.js b/browser/proxysocket.js
index 32f14e64..63fb47fa 100644
--- a/browser/proxysocket.js
+++ b/browser/proxysocket.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var bcoin = require('../lib/bcoin/env');
 var utils = require('../lib/bcoin/utils');
 var BufferWriter = require('../lib/bcoin/writer');
diff --git a/browser/server.js b/browser/server.js
index e110eb72..dff19ea3 100644
--- a/browser/server.js
+++ b/browser/server.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var HTTPBase = require('../lib/bcoin/http/base');
 var fs = require('fs');
 
diff --git a/browser/wsproxy.js b/browser/wsproxy.js
index 4ebb8d04..b112c6e0 100644
--- a/browser/wsproxy.js
+++ b/browser/wsproxy.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var http = require('http');
 var net = require('net');
 var IOServer = require('socket.io');
diff --git a/lib/bcoin.js b/lib/bcoin.js
index 8c1efb0f..801c4680 100644
--- a/lib/bcoin.js
+++ b/lib/bcoin.js
@@ -8,6 +8,8 @@
  * https://github.com/indutny/bcoin
  */
 
+'use strict';
+
 var env = require('./bcoin/env');
 var utils = require('./bcoin/utils');
 var global = utils.global;
diff --git a/lib/bcoin/abstractblock.js b/lib/bcoin/abstractblock.js
index 4a217274..11ee092d 100644
--- a/lib/bcoin/abstractblock.js
+++ b/lib/bcoin/abstractblock.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var constants = bcoin.protocol.constants;
 var utils = bcoin.utils;
diff --git a/lib/bcoin/address.js b/lib/bcoin/address.js
index 5381279b..43bbefff 100644
--- a/lib/bcoin/address.js
+++ b/lib/bcoin/address.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var networks = bcoin.protocol.network;
 var utils = require('./utils');
diff --git a/lib/bcoin/aes.js b/lib/bcoin/aes.js
index 392b1b6c..0b46286b 100644
--- a/lib/bcoin/aes.js
+++ b/lib/bcoin/aes.js
@@ -10,6 +10,8 @@
 
 /* jshint latedef: false */
 
+'use strict';
+
 var assert = require('assert');
 var U32Array = typeof Uint32Array === 'function' ? Uint32Array : Array;
 var AES = exports;
diff --git a/lib/bcoin/block.js b/lib/bcoin/block.js
index 7b5552cc..5ee84f28 100644
--- a/lib/bcoin/block.js
+++ b/lib/bcoin/block.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = require('./utils');
 var assert = utils.assert;
diff --git a/lib/bcoin/bloom.js b/lib/bcoin/bloom.js
index fea8a1cc..529064a4 100644
--- a/lib/bcoin/bloom.js
+++ b/lib/bcoin/bloom.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var constants = require('./protocol/constants');
 
 /*
diff --git a/lib/bcoin/bst.js b/lib/bcoin/bst.js
index 1bca1d07..87bdc478 100644
--- a/lib/bcoin/bst.js
+++ b/lib/bcoin/bst.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var utils = require('./utils');
 var assert = utils.assert;
 var DUMMY = new Buffer([0]);
diff --git a/lib/bcoin/chachapoly.js b/lib/bcoin/chachapoly.js
index 9642ba38..c652b9b1 100644
--- a/lib/bcoin/chachapoly.js
+++ b/lib/bcoin/chachapoly.js
@@ -4,6 +4,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var assert = require('assert');
 
 /**
diff --git a/lib/bcoin/chain.js b/lib/bcoin/chain.js
index 4c0de3ef..e9bc8de2 100644
--- a/lib/bcoin/chain.js
+++ b/lib/bcoin/chain.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var EventEmitter = require('events').EventEmitter;
 var constants = bcoin.protocol.constants;
diff --git a/lib/bcoin/chaindb.js b/lib/bcoin/chaindb.js
index 074f8e89..d25e377e 100644
--- a/lib/bcoin/chaindb.js
+++ b/lib/bcoin/chaindb.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var EventEmitter = require('events').EventEmitter;
 var constants = bcoin.protocol.constants;
diff --git a/lib/bcoin/chainentry.js b/lib/bcoin/chainentry.js
index 4c71035a..e94ebc7e 100644
--- a/lib/bcoin/chainentry.js
+++ b/lib/bcoin/chainentry.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var bn = require('bn.js');
 var constants = bcoin.protocol.constants;
diff --git a/lib/bcoin/coin.js b/lib/bcoin/coin.js
index ffd5e412..8c146d6f 100644
--- a/lib/bcoin/coin.js
+++ b/lib/bcoin/coin.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = require('./utils');
 var assert = utils.assert;
diff --git a/lib/bcoin/coins.js b/lib/bcoin/coins.js
index 22ca4789..501996b1 100644
--- a/lib/bcoin/coins.js
+++ b/lib/bcoin/coins.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = bcoin.utils;
 var assert = utils.assert;
diff --git a/lib/bcoin/coinview.js b/lib/bcoin/coinview.js
index 13ed1133..6f9d85d6 100644
--- a/lib/bcoin/coinview.js
+++ b/lib/bcoin/coinview.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = bcoin.utils;
 var assert = utils.assert;
diff --git a/lib/bcoin/ec.js b/lib/bcoin/ec.js
index 9fbe7d90..7fa8c20d 100644
--- a/lib/bcoin/ec.js
+++ b/lib/bcoin/ec.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var elliptic = require('elliptic');
 var bn = require('bn.js');
 var utils = require('./utils');
diff --git a/lib/bcoin/env.js b/lib/bcoin/env.js
index d127ce90..21274203 100644
--- a/lib/bcoin/env.js
+++ b/lib/bcoin/env.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var utils = require('./utils');
 var global = utils.global;
 var fs;
diff --git a/lib/bcoin/errors.js b/lib/bcoin/errors.js
index 7b0c2f44..a48d8912 100644
--- a/lib/bcoin/errors.js
+++ b/lib/bcoin/errors.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = bcoin.utils;
 var constants = bcoin.protocol.constants;
diff --git a/lib/bcoin/fees.js b/lib/bcoin/fees.js
index 61465978..1f5f3781 100644
--- a/lib/bcoin/fees.js
+++ b/lib/bcoin/fees.js
@@ -6,6 +6,8 @@
  * https://github.com/bitcoin/bitcoin/blob/master/src/policy/fees.cpp
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var constants = bcoin.protocol.constants;
 var global = bcoin.utils.global;
diff --git a/lib/bcoin/fullnode.js b/lib/bcoin/fullnode.js
index b63b7044..3b686159 100644
--- a/lib/bcoin/fullnode.js
+++ b/lib/bcoin/fullnode.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = require('./utils');
 var assert = utils.assert;
diff --git a/lib/bcoin/hd.js b/lib/bcoin/hd.js
index 7e16bb1b..0659963e 100644
--- a/lib/bcoin/hd.js
+++ b/lib/bcoin/hd.js
@@ -76,6 +76,8 @@
  * SOFTWARE.
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var bn = require('bn.js');
 var utils = require('./utils');
diff --git a/lib/bcoin/headers.js b/lib/bcoin/headers.js
index ee79adc0..ff05fbf4 100644
--- a/lib/bcoin/headers.js
+++ b/lib/bcoin/headers.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = require('./utils');
 
diff --git a/lib/bcoin/http/base.js b/lib/bcoin/http/base.js
index 53d015a0..d173b029 100644
--- a/lib/bcoin/http/base.js
+++ b/lib/bcoin/http/base.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var EventEmitter = require('events').EventEmitter;
 var utils = require('../utils');
 
diff --git a/lib/bcoin/http/client.js b/lib/bcoin/http/client.js
index 8194bb54..34798201 100644
--- a/lib/bcoin/http/client.js
+++ b/lib/bcoin/http/client.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('../env');
 var EventEmitter = require('events').EventEmitter;
 var utils = require('../utils');
diff --git a/lib/bcoin/http/index.js b/lib/bcoin/http/index.js
index 543405bd..40f26678 100644
--- a/lib/bcoin/http/index.js
+++ b/lib/bcoin/http/index.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var utils = require('../utils');
 
 exports.request = require('./request');
diff --git a/lib/bcoin/http/request.js b/lib/bcoin/http/request.js
index d0a223b9..08a5f4be 100644
--- a/lib/bcoin/http/request.js
+++ b/lib/bcoin/http/request.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 /* jshint -W069 */
 
 /**
diff --git a/lib/bcoin/http/server.js b/lib/bcoin/http/server.js
index f27f32cb..dc7013e7 100644
--- a/lib/bcoin/http/server.js
+++ b/lib/bcoin/http/server.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('../env');
 var EventEmitter = require('events').EventEmitter;
 var constants = bcoin.protocol.constants;
diff --git a/lib/bcoin/http/wallet.js b/lib/bcoin/http/wallet.js
index 121dc5e5..f5f7f020 100644
--- a/lib/bcoin/http/wallet.js
+++ b/lib/bcoin/http/wallet.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('../env');
 var EventEmitter = require('events').EventEmitter;
 
diff --git a/lib/bcoin/input.js b/lib/bcoin/input.js
index fafa8b99..b87fe0bb 100644
--- a/lib/bcoin/input.js
+++ b/lib/bcoin/input.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = require('./utils');
 var assert = utils.assert;
diff --git a/lib/bcoin/ip.js b/lib/bcoin/ip.js
index a2db451b..1b9639a0 100644
--- a/lib/bcoin/ip.js
+++ b/lib/bcoin/ip.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var IP = require('../../vendor/ip');
 var assert = require('assert');
 
diff --git a/lib/bcoin/keypair.js b/lib/bcoin/keypair.js
index a537c13e..d4b94098 100644
--- a/lib/bcoin/keypair.js
+++ b/lib/bcoin/keypair.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = require('./utils');
 var assert = utils.assert;
diff --git a/lib/bcoin/keyring.js b/lib/bcoin/keyring.js
index f91b0c5c..47409117 100644
--- a/lib/bcoin/keyring.js
+++ b/lib/bcoin/keyring.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = bcoin.utils;
 var assert = utils.assert;
diff --git a/lib/bcoin/ldb.js b/lib/bcoin/ldb.js
index c7518c6a..007a4d88 100644
--- a/lib/bcoin/ldb.js
+++ b/lib/bcoin/ldb.js
@@ -7,6 +7,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var LowlevelUp = require('./lowlevelup');
 var utils = bcoin.utils;
diff --git a/lib/bcoin/locker.js b/lib/bcoin/locker.js
index ce36e2fd..7ef0cead 100644
--- a/lib/bcoin/locker.js
+++ b/lib/bcoin/locker.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var EventEmitter = require('events').EventEmitter;
 var utils = require('./utils');
 var assert = utils.assert;
diff --git a/lib/bcoin/lowlevelup.js b/lib/bcoin/lowlevelup.js
index e62a4d48..a1536a93 100644
--- a/lib/bcoin/lowlevelup.js
+++ b/lib/bcoin/lowlevelup.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var utils = require('./utils');
 var assert = utils.assert;
 var EventEmitter = require('events').EventEmitter;
diff --git a/lib/bcoin/lru.js b/lib/bcoin/lru.js
index b8ed47ae..8c73fc6c 100644
--- a/lib/bcoin/lru.js
+++ b/lib/bcoin/lru.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var utils = require('./utils');
 var assert = utils.assert;
 
diff --git a/lib/bcoin/memblock.js b/lib/bcoin/memblock.js
index 13dcf2b8..7e3911d1 100644
--- a/lib/bcoin/memblock.js
+++ b/lib/bcoin/memblock.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = require('./utils');
 
diff --git a/lib/bcoin/mempool.js b/lib/bcoin/mempool.js
index 893c9875..b0379766 100644
--- a/lib/bcoin/mempool.js
+++ b/lib/bcoin/mempool.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 /*
  * Database Layout:
  *  (inherits all from txdb)
diff --git a/lib/bcoin/merkleblock.js b/lib/bcoin/merkleblock.js
index 8295ceb1..f26e8914 100644
--- a/lib/bcoin/merkleblock.js
+++ b/lib/bcoin/merkleblock.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = require('./utils');
 var assert = utils.assert;
diff --git a/lib/bcoin/miner.js b/lib/bcoin/miner.js
index 853f5000..bd1c7b27 100644
--- a/lib/bcoin/miner.js
+++ b/lib/bcoin/miner.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = require('./utils');
 var assert = utils.assert;
diff --git a/lib/bcoin/mtx.js b/lib/bcoin/mtx.js
index 94cb0795..8e75c3fa 100644
--- a/lib/bcoin/mtx.js
+++ b/lib/bcoin/mtx.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = require('./utils');
 var assert = utils.assert;
diff --git a/lib/bcoin/network.js b/lib/bcoin/network.js
index d60ea64d..c276236d 100644
--- a/lib/bcoin/network.js
+++ b/lib/bcoin/network.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var utils = require('./utils');
 var assert = utils.assert;
 var constants = require('./protocol/constants');
diff --git a/lib/bcoin/node.js b/lib/bcoin/node.js
index 7a5c6937..98fce7b1 100644
--- a/lib/bcoin/node.js
+++ b/lib/bcoin/node.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var EventEmitter = require('events').EventEmitter;
 var utils = require('./utils');
diff --git a/lib/bcoin/output.js b/lib/bcoin/output.js
index 4ff7047d..ec316acc 100644
--- a/lib/bcoin/output.js
+++ b/lib/bcoin/output.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = require('./utils');
 var constants = bcoin.protocol.constants;
diff --git a/lib/bcoin/peer.js b/lib/bcoin/peer.js
index 91841f47..ad54b2d1 100644
--- a/lib/bcoin/peer.js
+++ b/lib/bcoin/peer.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var EventEmitter = require('events').EventEmitter;
 var utils = require('./utils');
diff --git a/lib/bcoin/pool.js b/lib/bcoin/pool.js
index cff0d4a9..7a80a79d 100644
--- a/lib/bcoin/pool.js
+++ b/lib/bcoin/pool.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var EventEmitter = require('events').EventEmitter;
 var utils = require('./utils');
diff --git a/lib/bcoin/profiler.js b/lib/bcoin/profiler.js
index 4d433477..d1e2d470 100644
--- a/lib/bcoin/profiler.js
+++ b/lib/bcoin/profiler.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 /**
  * @exports profiler
  */
diff --git a/lib/bcoin/protocol/constants.js b/lib/bcoin/protocol/constants.js
index dcecb689..e6170dd2 100644
--- a/lib/bcoin/protocol/constants.js
+++ b/lib/bcoin/protocol/constants.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 /**
  * @module constants
  */
diff --git a/lib/bcoin/protocol/framer.js b/lib/bcoin/protocol/framer.js
index 52f7f8bf..354cd200 100644
--- a/lib/bcoin/protocol/framer.js
+++ b/lib/bcoin/protocol/framer.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('../env');
 var constants = require('./constants');
 var utils = require('../utils');
diff --git a/lib/bcoin/protocol/index.js b/lib/bcoin/protocol/index.js
index 485fa442..2ed8f258 100644
--- a/lib/bcoin/protocol/index.js
+++ b/lib/bcoin/protocol/index.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 exports.constants = require('./constants');
 exports.network = require('./network');
 exports.framer = require('./framer');
diff --git a/lib/bcoin/protocol/network.js b/lib/bcoin/protocol/network.js
index 20edb876..dbf16556 100644
--- a/lib/bcoin/protocol/network.js
+++ b/lib/bcoin/protocol/network.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bn = require('bn.js');
 var utils = require('../utils');
 
diff --git a/lib/bcoin/protocol/parser.js b/lib/bcoin/protocol/parser.js
index cb58db0e..304d9570 100644
--- a/lib/bcoin/protocol/parser.js
+++ b/lib/bcoin/protocol/parser.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('../env');
 var bn = require('bn.js');
 var EventEmitter = require('events').EventEmitter;
diff --git a/lib/bcoin/reader.js b/lib/bcoin/reader.js
index e6ac2832..fadd07cc 100644
--- a/lib/bcoin/reader.js
+++ b/lib/bcoin/reader.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var utils = require('./utils');
 var assert = utils.assert;
 
diff --git a/lib/bcoin/script.js b/lib/bcoin/script.js
index a915edec..06e8858b 100644
--- a/lib/bcoin/script.js
+++ b/lib/bcoin/script.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var bn = require('bn.js');
 var constants = bcoin.protocol.constants;
diff --git a/lib/bcoin/scrypt-async.js b/lib/bcoin/scrypt-async.js
index 97e32a9c..7ab38242 100644
--- a/lib/bcoin/scrypt-async.js
+++ b/lib/bcoin/scrypt-async.js
@@ -31,6 +31,8 @@
  * SUCH DAMAGE.
  */
 
+'use strict';
+
 var crypto = require('crypto');
 var utils = require('./utils');
 
diff --git a/lib/bcoin/scrypt.js b/lib/bcoin/scrypt.js
index 355f7b29..b6e40871 100644
--- a/lib/bcoin/scrypt.js
+++ b/lib/bcoin/scrypt.js
@@ -31,6 +31,8 @@
  * SUCH DAMAGE.
  */
 
+'use strict';
+
 var utils = require('./utils');
 
 /**
diff --git a/lib/bcoin/siphash.js b/lib/bcoin/siphash.js
index 8943f9ee..807e6ced 100644
--- a/lib/bcoin/siphash.js
+++ b/lib/bcoin/siphash.js
@@ -7,6 +7,8 @@
  * https://github.com/bitcoin/bitcoin/blob/master/src/hash.cpp
  */
 
+'use strict';
+
 /**
  * Javascript siphash implementation. Used for compact block relay.
  * @param {Buffer} data - Blocks are uint64le's.
diff --git a/lib/bcoin/spvnode.js b/lib/bcoin/spvnode.js
index f1b83bdd..bb543bac 100644
--- a/lib/bcoin/spvnode.js
+++ b/lib/bcoin/spvnode.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = require('./utils');
 var assert = utils.assert;
diff --git a/lib/bcoin/timedata.js b/lib/bcoin/timedata.js
index 577242f6..b3624d7c 100644
--- a/lib/bcoin/timedata.js
+++ b/lib/bcoin/timedata.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = require('./utils');
 
diff --git a/lib/bcoin/tx.js b/lib/bcoin/tx.js
index 9003f59b..11395a97 100644
--- a/lib/bcoin/tx.js
+++ b/lib/bcoin/tx.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var utils = require('./utils');
 var assert = utils.assert;
diff --git a/lib/bcoin/txdb.js b/lib/bcoin/txdb.js
index 5c557168..2301fe63 100644
--- a/lib/bcoin/txdb.js
+++ b/lib/bcoin/txdb.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 /*
  * Database Layout:
  *   t/[hash] -> extended tx
diff --git a/lib/bcoin/uri.js b/lib/bcoin/uri.js
index eac88e5f..17580d98 100644
--- a/lib/bcoin/uri.js
+++ b/lib/bcoin/uri.js
@@ -7,6 +7,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var url = require('url');
 var querystring = require('querystring');
 var utils = require('./utils');
diff --git a/lib/bcoin/utils.js b/lib/bcoin/utils.js
index 32ed2245..701965b2 100644
--- a/lib/bcoin/utils.js
+++ b/lib/bcoin/utils.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 /* global gc */
 
 /**
diff --git a/lib/bcoin/wallet.js b/lib/bcoin/wallet.js
index 5cc6e6d1..06a3de22 100644
--- a/lib/bcoin/wallet.js
+++ b/lib/bcoin/wallet.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var EventEmitter = require('events').EventEmitter;
 var utils = require('./utils');
diff --git a/lib/bcoin/walletdb.js b/lib/bcoin/walletdb.js
index 3d4308a1..9ca3666b 100644
--- a/lib/bcoin/walletdb.js
+++ b/lib/bcoin/walletdb.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 /*
  * Database Layout:
  *  (inherits all from txdb)
diff --git a/lib/bcoin/worker.js b/lib/bcoin/worker.js
index 6b5173aa..8713873a 100644
--- a/lib/bcoin/worker.js
+++ b/lib/bcoin/worker.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 /* jshint worker: true */
 
 var bcoin, env;
diff --git a/lib/bcoin/workers.js b/lib/bcoin/workers.js
index 410007b4..fa170523 100644
--- a/lib/bcoin/workers.js
+++ b/lib/bcoin/workers.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var bcoin = require('./env');
 var EventEmitter = require('events').EventEmitter;
 var bn = require('bn.js');
diff --git a/lib/bcoin/writer.js b/lib/bcoin/writer.js
index dddc8285..16dc46cc 100644
--- a/lib/bcoin/writer.js
+++ b/lib/bcoin/writer.js
@@ -5,6 +5,8 @@
  * https://github.com/bcoin-org/bcoin
  */
 
+'use strict';
+
 var utils = require('./utils');
 var assert = utils.assert;
 
diff --git a/scripts/gen.js b/scripts/gen.js
index 0c5be4af..a247fb24 100644
--- a/scripts/gen.js
+++ b/scripts/gen.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var bcoin = require('bcoin');
 var constants = bcoin.protocol.constants;
 var network = bcoin.protocol.network;
diff --git a/test/aes-test.js b/test/aes-test.js
index ca4de665..d05d61cc 100644
--- a/test/aes-test.js
+++ b/test/aes-test.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var bn = require('bn.js');
 var utils = require('../lib/bcoin/utils');
 var assert = require('assert');
diff --git a/test/block-test.js b/test/block-test.js
index c4624df0..c9522a38 100644
--- a/test/block-test.js
+++ b/test/block-test.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var bn = require('bn.js');
 var bcoin = require('../').set('main');
 var utils = bcoin.utils;
diff --git a/test/bloom-test.js b/test/bloom-test.js
index 241a1b0c..efb019c7 100644
--- a/test/bloom-test.js
+++ b/test/bloom-test.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var bcoin = require('../').set('main');
 var utils = bcoin.utils;
 var constants = bcoin.protocol.constants;
diff --git a/test/chachapoly-test.js b/test/chachapoly-test.js
index a3a9f8be..53ff99f8 100644
--- a/test/chachapoly-test.js
+++ b/test/chachapoly-test.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var assert = require('assert');
 var chachapoly = require('../lib/bcoin/chachapoly');
 var ChaCha20 = chachapoly.ChaCha20;
diff --git a/test/chain-test.js b/test/chain-test.js
index e49e6790..cf026c85 100644
--- a/test/chain-test.js
+++ b/test/chain-test.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var bn = require('bn.js');
 var bcoin = require('../').set('regtest');
 var constants = bcoin.protocol.constants;
diff --git a/test/hd-test.js b/test/hd-test.js
index c72a786b..d260cba2 100644
--- a/test/hd-test.js
+++ b/test/hd-test.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var bn = require('bn.js');
 var bcoin = require('../').set('main');
 var utils = bcoin.utils;
diff --git a/test/mempool-test.js b/test/mempool-test.js
index b4fa848f..20d58619 100644
--- a/test/mempool-test.js
+++ b/test/mempool-test.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var bn = require('bn.js');
 var bcoin = require('../').set('main');
 var constants = bcoin.protocol.constants;
diff --git a/test/mnemonic-test.js b/test/mnemonic-test.js
index 03d61247..daedd667 100644
--- a/test/mnemonic-test.js
+++ b/test/mnemonic-test.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var bn = require('bn.js');
 var bcoin = require('../').set('main');
 var utils = bcoin.utils;
diff --git a/test/protocol-test.js b/test/protocol-test.js
index 2566e71d..64d52dde 100644
--- a/test/protocol-test.js
+++ b/test/protocol-test.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var bcoin = require('../').set('main');
 var assert = require('assert');
 var constants = bcoin.protocol.constants;
diff --git a/test/script-test.js b/test/script-test.js
index a42ae73f..ae70fac3 100644
--- a/test/script-test.js
+++ b/test/script-test.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var bcoin = require('../').set('main');
 var assert = require('assert');
 var Script = bcoin.script;
diff --git a/test/scrypt-test.js b/test/scrypt-test.js
index 9d75daa4..69827a4a 100644
--- a/test/scrypt-test.js
+++ b/test/scrypt-test.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var assert = require('assert');
 var scrypt = require('../lib/bcoin/scrypt');
 
diff --git a/test/siphash-test.js b/test/siphash-test.js
index 623792c3..0ea36570 100644
--- a/test/siphash-test.js
+++ b/test/siphash-test.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var assert = require('assert');
 var siphash = require('../lib/bcoin/siphash');
 
diff --git a/test/tx-test.js b/test/tx-test.js
index 566b7559..4039f8ab 100644
--- a/test/tx-test.js
+++ b/test/tx-test.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var bn = require('bn.js');
 var bcoin = require('../').set('main');
 var assert = require('assert');
diff --git a/test/utils-test.js b/test/utils-test.js
index ceab9187..542e4a48 100644
--- a/test/utils-test.js
+++ b/test/utils-test.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var bn = require('bn.js');
 var bcoin = require('../').set('main');
 var assert = require('assert');
diff --git a/test/wallet-test.js b/test/wallet-test.js
index f697afec..09e7b73e 100644
--- a/test/wallet-test.js
+++ b/test/wallet-test.js
@@ -1,3 +1,5 @@
+'use strict';
+
 var bn = require('bn.js');
 var bcoin = require('../').set('main');
 var constants = bcoin.protocol.constants;