diff --git a/browser/index.js b/browser/index.js
index 21e964d7..66863e58 100644
--- a/browser/index.js
+++ b/browser/index.js
@@ -222,6 +222,10 @@ function formatWallet(wallet) {
   });
 }
 
+bcoin.set({
+  useWorkers: true
+});
+
 node = new bcoin.fullnode({
   hash: true,
   query: true,
diff --git a/lib/bcoin.js b/lib/bcoin.js
index d64184c7..ad0bfbeb 100644
--- a/lib/bcoin.js
+++ b/lib/bcoin.js
@@ -23,12 +23,13 @@ var util = require('./utils/util');
 var global = util.global;
 
 /*
- * Expose bcoin globally in the
- * browser. Necessary for workers.
+ * Expose bcoin globally in the browser.
  */
 
-if (util.isBrowser)
+if (typeof window !== 'undefined'
+    || typeof self !== 'undefined') {
   global.bcoin = env;
+}
 
 /*
  * Expose
diff --git a/lib/node/config.js b/lib/node/config.js
index 796f050e..fdc01caf 100644
--- a/lib/node/config.js
+++ b/lib/node/config.js
@@ -711,9 +711,13 @@ Config.prototype.parseArg = function parseArg(argv) {
   if (!argv || typeof argv !== 'object')
     argv = process.argv;
 
+  assert(Array.isArray(argv));
+
   for (i = 2; i < argv.length; i++) {
     arg = argv[i];
 
+    assert(typeof arg === 'string');
+
     if (arg.indexOf('--') === 0) {
       // e.g. --opt
       arg = arg.split('=');
@@ -794,6 +798,8 @@ Config.prototype.parseEnv = function parseEnv(env) {
   if (!env || typeof env !== 'object')
     env = process.env;
 
+  assert(env && typeof env === 'object');
+
   keys = Object.keys(env);
 
   for (i = 0; i < keys.length; i++) {
@@ -802,6 +808,8 @@ Config.prototype.parseEnv = function parseEnv(env) {
     if (key.indexOf(prefix) !== 0)
       continue;
 
+    assert(typeof env[key] === 'string');
+
     value = env[key].trim();
 
     key = key.substring(prefix.length);
@@ -829,10 +837,13 @@ Config.prototype.parseEnv = function parseEnv(env) {
 
 Config.prototype.parseQuery = function parseQuery(query) {
   if (typeof query !== 'string') {
-    if (!util.isBrowser || !global.location)
+    if (!global.location)
       return {};
 
-    query = global.location.search || '';
+    query = global.location.search;
+
+    if (typeof query !== 'string')
+      return {};
   }
 
   return this.parseForm(query, this.query);
@@ -846,10 +857,13 @@ Config.prototype.parseQuery = function parseQuery(query) {
 
 Config.prototype.parseHash = function parseHash(hash) {
   if (typeof hash !== 'string') {
-    if (!util.isBrowser || !global.location)
+    if (!global.location)
       return {};
 
-    hash = global.location.hash || '';
+    hash = global.location.hash;
+
+    if (typeof hash !== 'string')
+      return {};
   }
 
   return this.parseForm(hash, this.hash);
diff --git a/lib/node/logger.js b/lib/node/logger.js
index 7a011aa7..ffc89659 100644
--- a/lib/node/logger.js
+++ b/lib/node/logger.js
@@ -550,7 +550,7 @@ Logger.prototype.writeConsole = function writeConsole(level, module, args) {
   if (!this.console)
     return;
 
-  if (util.isBrowser) {
+  if (!process.stdout) {
     msg += '[' + name + '] ';
 
     if (module)
@@ -639,7 +639,7 @@ Logger.prototype.logError = function logError(level, module, err) {
   if (this.closed)
     return;
 
-  if (util.isBrowser && this.console) {
+  if (fs.unsupported && this.console) {
     if (level <= Logger.levels.WARNING)
       console.error(err);
   }
diff --git a/lib/utils/encoding.js b/lib/utils/encoding.js
index f0d6c64c..4eef2162 100644
--- a/lib/utils/encoding.js
+++ b/lib/utils/encoding.js
@@ -14,20 +14,6 @@
 var BN = require('bn.js');
 var encoding = exports;
 
-/**
- * UINT32_MAX
- * @const {BN}
- */
-
-encoding.U32_MAX = new BN(0xffffffff);
-
-/**
- * UINT64_MAX
- * @const {BN}
- */
-
-encoding.U64_MAX = new BN('ffffffffffffffff', 'hex');
-
 /**
  * Max safe integer (53 bits).
  * @const {Number}
@@ -36,15 +22,6 @@ encoding.U64_MAX = new BN('ffffffffffffffff', 'hex');
 
 encoding.MAX_SAFE_INTEGER = 0x1fffffffffffff;
 
-/**
- * Max 52 bit integer (safe for additions).
- * `(MAX_SAFE_INTEGER - 1) / 2`
- * @const {Number}
- * @default
- */
-
-encoding.MAX_SAFE_ADDITION = 0xfffffffffffff;
-
 /**
  * An empty buffer.
  * @const {Buffer}
@@ -536,13 +513,14 @@ encoding.read64BEBN = function read64BEBN(data, off) {
  */
 
 encoding._write64BN = function _write64BN(dst, num, off, be) {
+  var bits = num.bitLength();
   var i;
 
-  if (num.bitLength() <= 53)
+  if (bits <= 53)
     return encoding._write64(dst, num.toNumber(), off, be);
 
-  if (num.bitLength() > 64)
-    num = num.uand(encoding.U64_MAX);
+  if (bits > 64)
+    num = num.maskn(64);
 
   if (num.isNeg())
     num = num.neg().inotn(64).iaddn(1);
diff --git a/lib/utils/util.js b/lib/utils/util.js
index 52029453..e98ff10b 100644
--- a/lib/utils/util.js
+++ b/lib/utils/util.js
@@ -10,7 +10,6 @@
 var assert = require('assert');
 var nodeUtil = require('util');
 var os = require('os');
-var Number, Math, Date;
 
 /**
  * @exports utils/util
@@ -41,23 +40,6 @@ util.global = (function() {
   assert(false, 'No global defined.');
 })();
 
-/*
- * Globals
- */
-
-Number = util.global.Number;
-Math = util.global.Math;
-Date = util.global.Date;
-
-/**
- * Whether we're in a browser or not.
- * @const {Boolean}
- */
-
-util.isBrowser =
-  (typeof process !== 'undefined' && process.browser)
-  || typeof window !== 'undefined';
-
 /**
  * The home directory.
  * @const {String}
@@ -123,7 +105,7 @@ util.isBase58 = function isBase58(obj) {
 util.hrtime = function hrtime(time) {
   var now, ms, sec, elapsed;
 
-  if (util.isBrowser) {
+  if (!process.hrtime) {
     now = util.ms();
     if (time) {
       time = time[0] * 1000 + time[1] / 1e6;
@@ -218,15 +200,6 @@ if (Object.assign)
 
 util.MAX_SAFE_INTEGER = 0x1fffffffffffff;
 
-/**
- * Max 52 bit integer (safe for additions).
- * `(MAX_SAFE_INTEGER - 1) / 2`
- * @const {Number}
- * @default
- */
-
-util.MAX_SAFE_ADDITION = 0xfffffffffffff;
-
 /**
  * Test whether a number is below MAX_SAFE_INTEGER.
  * @param {Number} value
@@ -234,9 +207,7 @@ util.MAX_SAFE_ADDITION = 0xfffffffffffff;
  */
 
 util.isSafeInteger = function isSafeInteger(value) {
-  if (Number.isSafeInteger)
-    return Number.isSafeInteger(value);
-  return Math.abs(value) <= util.MAX_SAFE_INTEGER;
+  return value >= -0x1fffffffffffff && value <= 0x1fffffffffffff;
 };
 
 /**
@@ -269,7 +240,7 @@ util.isInt = function isInt(value) {
  */
 
 util.isInt8 = function isInt8(value) {
-  return util.isInt(value) && Math.abs(value) <= 0x7f;
+  return util.isInt(value) && value >= -0x80 && value <= 0x7f;
 };
 
 /**
@@ -289,7 +260,7 @@ util.isUInt8 = function isUInt8(value) {
  */
 
 util.isInt32 = function isInt32(value) {
-  return util.isInt(value) && Math.abs(value) <= 0x7fffffff;
+  return util.isInt(value) && value >= -0x80000000 && value <= 0x7fffffff;
 };
 
 /**
@@ -409,7 +380,7 @@ util.log = function log() {
   for (i = 0; i < args.length; i++)
     args[i] = arguments[i];
 
-  if (util.isBrowser) {
+  if (!process.stdout) {
     msg = typeof args[0] !== 'object'
       ? util.format(args, false)
       : args[0];
@@ -434,7 +405,7 @@ util.error = function error() {
   for (i = 0; i < args.length; i++)
     args[i] = arguments[i];
 
-  if (util.isBrowser) {
+  if (!process.stderr) {
     msg = typeof args[0] !== 'object'
       ? util.format(args, false)
       : args[0];
@@ -563,17 +534,6 @@ util.strcmp = function strcmp(a, b) {
   return 0;
 };
 
-/**
- * Buffer comparator (memcmp + length comparison).
- * @param {Buffer} a
- * @param {Buffer} b
- * @returns {Number} -1, 1, or 0.
- */
-
-util.cmp = function cmp(a, b) {
-  return a.compare(b);
-};
-
 /**
  * Convert bytes to mb.
  * @param {Number} size
diff --git a/lib/utils/validator.js b/lib/utils/validator.js
index 2fb1bb34..a5a2922f 100644
--- a/lib/utils/validator.js
+++ b/lib/utils/validator.js
@@ -1,3 +1,9 @@
+/*!
+ * validator.js - validator for bcoin
+ * Copyright (c) 2017, Christopher Jeffrey (MIT License).
+ * https://github.com/bcoin-org/bcoin
+ */
+
 'use strict';
 
 var assert = require('assert');
@@ -246,7 +252,7 @@ Validator.prototype.i32 = function i32(key, fallback) {
   if (value === null)
     return fallback;
 
-  if (value % 1 !== 0 || Math.abs(value) > 0x7fffffff)
+  if (value % 1 !== 0 || value < -0x80000000 || value > 0x7fffffff)
     throw new ValidationError(fmt(key) + ' must be an int32.');
 
   return value;
@@ -357,8 +363,10 @@ Validator.prototype.hash = function hash(key, fallback) {
   if (typeof value !== 'string') {
     if (!Buffer.isBuffer(value))
       throw new ValidationError(fmt(key) + ' must be a hash.');
+
     if (value.length !== 32)
       throw new ValidationError(fmt(key) + ' must be a hash.');
+
     return value.toString('hex');
   }
 
diff --git a/lib/workers/master.js b/lib/workers/master.js
index 3c9e7277..4792ea88 100644
--- a/lib/workers/master.js
+++ b/lib/workers/master.js
@@ -16,6 +16,8 @@ var Parser = require('./parser-client');
 var Framer = require('./framer');
 var packets = require('./packets');
 var global = util.global;
+var HAS_WORKERS = typeof global.postMessage === 'function';
+var HAS_CP = !!(process.stdin && process.stdout && process.stderr);
 var server;
 
 /**
@@ -61,12 +63,14 @@ Master.prototype._init = function _init() {
     self.emit('packet', packet);
   });
 
-  if (util.isBrowser) {
+  if (HAS_WORKERS) {
     // Web workers
     this._initWebWorkers();
-  } else {
+  } else if (HAS_CP) {
     // Child process + pipes
     this._initChildProcess();
+  } else {
+    throw new Error('Workers not available.');
   }
 };
 
@@ -135,7 +139,7 @@ Master.prototype.set = function set(network) {
  */
 
 Master.prototype.write = function write(data) {
-  if (util.isBrowser) {
+  if (HAS_WORKERS) {
     if (global.postMessage.length === 2) {
       data.__proto__ = Uint8Array.prototype;
       global.postMessage({ buf: data }, [data]);
@@ -179,7 +183,7 @@ Master.prototype.sendEvent = function sendEvent() {
  */
 
 Master.prototype.destroy = function destroy() {
-  if (util.isBrowser)
+  if (HAS_WORKERS)
     return global.close();
   return process.exit(0);
 };
@@ -268,7 +272,7 @@ Master.prototype.handlePacket = function handlePacket(packet) {
 
 server = new Master();
 
-if (util.isBrowser)
+if (HAS_WORKERS)
   global.master = server;
 
 module.exports = server;
diff --git a/lib/workers/workerpool.js b/lib/workers/workerpool.js
index 89fafc62..e0ec2915 100644
--- a/lib/workers/workerpool.js
+++ b/lib/workers/workerpool.js
@@ -13,12 +13,14 @@ var os = require('os');
 var cp = require('child_process');
 var util = require('../utils/util');
 var co = require('../utils/co');
-var global = util.global;
 var Network = require('../protocol/network');
 var jobs = require('./jobs');
 var Parser = require('./parser');
 var Framer = require('./framer');
 var packets = require('./packets');
+var global = util.global;
+var HAS_WORKERS = typeof global.Worker === 'function';
+var HAS_CP = typeof cp.spawn === 'function';
 
 /**
  * A worker pool.
@@ -57,12 +59,7 @@ util.inherits(WorkerPool, EventEmitter);
  * @const {Boolean}
  */
 
-WorkerPool.support = true;
-
-if (util.isBrowser) {
-  WorkerPool.support = typeof global.Worker === 'function'
-    || typeof global.postMessage === 'function';
-}
+WorkerPool.support = HAS_WORKERS || HAS_CP;
 
 /**
  * Number of CPUs/cores available.
@@ -104,7 +101,7 @@ WorkerPool.bound = false;
  */
 
 WorkerPool.bindExit = function bindExit() {
-  if (util.isBrowser)
+  if (!HAS_CP)
     return;
 
   if (WorkerPool.bound)
@@ -483,12 +480,14 @@ Worker.prototype._init = function _init() {
     self.emit('packet', packet);
   });
 
-  if (util.isBrowser) {
+  if (HAS_WORKERS) {
     // Web workers
     this._initWebWorkers();
-  } else {
+  } else if (HAS_CP) {
     // Child process + pipes
     this._initChildProcess();
+  } else {
+    throw new Error('Workers not available.');
   }
 
   this._bind();
@@ -651,7 +650,7 @@ Worker.prototype.handlePacket = function handlePacket(packet) {
  */
 
 Worker.prototype.write = function write(data) {
-  if (util.isBrowser) {
+  if (HAS_WORKERS) {
     if (this.child.postMessage.length === 2) {
       data.__proto__ = Uint8Array.prototype;
       this.child.postMessage({ buf: data }, [data]);
@@ -695,7 +694,7 @@ Worker.prototype.sendEvent = function sendEvent() {
  */
 
 Worker.prototype.destroy = function destroy() {
-  if (util.isBrowser) {
+  if (HAS_WORKERS) {
     this.child.terminate();
     this.emit('exit', -1, 'SIGTERM');
     return;
@@ -884,7 +883,6 @@ function getCores() {
  */
 
 exports.pool = new WorkerPool();
-exports.pool.enabled = true;
 
 exports.set = function set(options) {
   this.pool.set({
@@ -895,7 +893,7 @@ exports.set = function set(options) {
 };
 
 exports.set({
-  useWorkers: +process.env.BCOIN_USE_WORKERS !== 0,
+  useWorkers: HAS_CP && +process.env.BCOIN_USE_WORKERS !== 0,
   maxWorkers: +process.env.BCOIN_MAX_WORKERS,
   workerTimeout: +process.env.BCOIN_WORKER_TIMEOUT
 });
diff --git a/test/tx-test.js b/test/tx-test.js
index 099d457b..cc99403a 100644
--- a/test/tx-test.js
+++ b/test/tx-test.js
@@ -29,6 +29,9 @@ var tx4 = parseTX('data/tx4.hex');
 var wtx = parseTX('data/wtx.hex');
 var coolest = parseTX('data/coolest-tx-ever-sent.hex');
 
+var MAX_SAFE_INTEGER = Number.MAX_SAFE_INTEGER;
+var MAX_SAFE_ADDITION = 0xfffffffffffff;
+
 function clearCache(tx, noCache) {
   if (!noCache) {
     assert.equal(tx.hash('hex'), tx.clone().hash('hex'));
@@ -554,7 +557,7 @@ describe('TX', function() {
     var tx = new TX({
       version: 1,
       flag: 1,
-      inputs: [createInput(util.MAX_SAFE_INTEGER, view)],
+      inputs: [createInput(MAX_SAFE_INTEGER, view)],
       outputs: [{
         script: [],
         value: consensus.MAX_MONEY
@@ -573,7 +576,7 @@ describe('TX', function() {
       inputs: [createInput(consensus.MAX_MONEY, view)],
       outputs: [{
         script: [],
-        value: util.MAX_SAFE_INTEGER
+        value: MAX_SAFE_INTEGER
       }],
       locktime: 0
     });
@@ -586,7 +589,7 @@ describe('TX', function() {
     var tx = new TX({
       version: 1,
       flag: 1,
-      inputs: [createInput(util.MAX_SAFE_INTEGER, view)],
+      inputs: [createInput(MAX_SAFE_INTEGER, view)],
       outputs: [{
         script: [],
         value: 0
@@ -597,7 +600,7 @@ describe('TX', function() {
     assert.ok(!tx.checkInputs(view, 0));
   });
 
-  [util.MAX_SAFE_ADDITION, util.MAX_SAFE_INTEGER].forEach(function(MAX) {
+  [MAX_SAFE_ADDITION, MAX_SAFE_INTEGER].forEach(function(MAX) {
     it('should fail on >53 bit values from multiple', function() {
       var view = new CoinView();
       var tx = new TX({