diff --git a/.gitignore b/.gitignore
index 1db612194..6f947faca 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,4 +9,6 @@ contracts/flattened
 .vscode
 
 yarn.lock
-package-lock.json
\ No newline at end of file
+package-lock.json
+
+.old
\ No newline at end of file
diff --git a/contracts/UsingWitnet.sol b/contracts/UsingWitnet.sol
index ec43c349b..99fb8c8d4 100644
--- a/contracts/UsingWitnet.sol
+++ b/contracts/UsingWitnet.sol
@@ -3,9 +3,8 @@
 pragma solidity >=0.6.0 <0.7.0;
 
 import "./Request.sol";
-import "./Witnet.sol";
 import "./WitnetRequestBoardProxy.sol";
-
+import "./libs/Witnet.sol";
 
 /**
  * @title The UsingWitnet contract
diff --git a/contracts/WitnetRequestBoardProxy.sol b/contracts/WitnetRequestBoardProxy.sol
index 4665ddf11..c10820e33 100644
--- a/contracts/WitnetRequestBoardProxy.sol
+++ b/contracts/WitnetRequestBoardProxy.sol
@@ -29,19 +29,23 @@ contract WitnetRequestBoardProxy {
   // Array with the controllers that have been used in the Proxy
   ControllerInfo[] internal controllers;
 
+
+  /// =======================================================================
+  /// --- Modifiers ---------------------------------------------------------
+
   modifier notIdentical(address _newAddress) {
     require(_newAddress != address(currentWitnetRequestBoard), "The provided Witnet Requests Board instance address is already in use");
     _;
   }
 
- /**
-  * @notice Include an address to specify the Witnet Request Board.
-  * @param _witnetRequestBoardAddress WitnetRequestBoard address.
-  */
-  constructor(address _witnetRequestBoardAddress) public {
+
+  /// =======================================================================
+  /// --- Constructor -------------------------------------------------------
+
+  /// @notice Constructor: initialize controllers list
+    constructor() public {
     // Initialize the first epoch pointing to the first controller
-    controllers.push(ControllerInfo({controllerAddress: _witnetRequestBoardAddress, lastId: 0}));
-    currentWitnetRequestBoard = WitnetRequestBoardInterface(_witnetRequestBoardAddress);
+    controllers.push(ControllerInfo({controllerAddress: address(0), lastId: 0}));
   }
 
   /// @dev Posts a data request into the WRB in expectation that it will be relayed and resolved in Witnet with a total reward that equals to msg.value.
@@ -106,11 +110,17 @@ contract WitnetRequestBoardProxy {
 
   /// @notice Upgrades the Witnet Requests Board if the current one is upgradeable.
   /// @param _newAddress address of the new block relay to upgrade.
-  function upgradeWitnetRequestBoard(address _newAddress) external notIdentical(_newAddress) {
-    // Require the WRB is upgradable
-    require(currentWitnetRequestBoard.isUpgradable(msg.sender), "The upgrade has been rejected by the current implementation");
+  function upgradeWitnetRequestBoard(address _newAddress) public notIdentical(_newAddress) {
+    // Require current WRB to be upgradable:
+    require(
+        address(currentWitnetRequestBoard) == address(0) 
+          || currentWitnetRequestBoard.isUpgradable(msg.sender)
+        , "The upgrade has been rejected by the current implementation"
+      );
+
     // Map the currentLastId to the corresponding witnetRequestBoardAddress and add it to controllers
     controllers.push(ControllerInfo({controllerAddress: _newAddress, lastId: currentLastId}));
+
     // Upgrade the WRB
     currentWitnetRequestBoard = WitnetRequestBoardInterface(_newAddress);
   }
diff --git a/contracts/BufferLib.sol b/contracts/libs/BufferLib.sol
similarity index 100%
rename from contracts/BufferLib.sol
rename to contracts/libs/BufferLib.sol
diff --git a/contracts/CBOR.sol b/contracts/libs/CBOR.sol
similarity index 100%
rename from contracts/CBOR.sol
rename to contracts/libs/CBOR.sol
diff --git a/contracts/Witnet.sol b/contracts/libs/Witnet.sol
similarity index 100%
rename from contracts/Witnet.sol
rename to contracts/libs/Witnet.sol
diff --git a/contracts/Migrations.sol b/contracts/utils/Migrations.sol
similarity index 100%
rename from contracts/Migrations.sol
rename to contracts/utils/Migrations.sol
diff --git a/contracts/utils/SingletonFactory.sol b/contracts/utils/SingletonFactory.sol
new file mode 100644
index 000000000..58ca8daaf
--- /dev/null
+++ b/contracts/utils/SingletonFactory.sol
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: CC0-1.0
+
+pragma solidity ^0.6.2;
+
+
+/**
+ * @title Based on Singleton Factory (EIP-2470), authored by Guilherme Schmidt (Status Research & Development GmbH)
+ * @notice Exposes CREATE2 (EIP-1014) to deploy bytecode on deterministic addresses based on initialization code and salt.
+ * @dev Exposes also helper method to pre-determine contract address gieve
+ * @author Ricardo Guilherme Schmidt (Status Research & Development GmbH)
+ */
+contract SingletonFactory {
+    /**
+     * @notice Deploys `_initCode` using `_salt` for defining the deterministic address.
+     * @param _initCode Initialization code.
+     * @param _salt Arbitrary value to modify resulting address.
+     * @return createdContract Created contract address.
+     */
+    function deploy(bytes memory _initCode, bytes32 _salt)
+        public
+        returns (address payable createdContract)
+    {
+        assembly {
+            createdContract := create2(0, add(_initCode, 0x20), mload(_initCode), _salt)
+        }
+    }
+
+    /**
+     * @notice Deploys a deterministic address based on `_initCode` and `_salt`.
+      using `_salt` for defining the deterministic address.
+     * @param _initCode Initialization code.
+     * @param _initCall Calldata to be made to created contract.
+     * @param _salt Arbitrary value to modify resulting address.
+     * @return createdContract Created contract address.
+     */
+    function deployAndInit(bytes memory _initCode, bytes memory _initCall, bytes32 _salt)
+        public
+        returns (address payable createdContract)
+    {
+        assembly {
+            createdContract := create2(0, add(_initCode, 0x20), mload(_initCode), _salt)
+        }
+        if (_initCall.length > 0) {
+            // solhint-disable-next-line avoid-low-level-calls
+            (bool success, bytes memory reason) = createdContract.call(_initCall);
+            require(success, string(reason));
+        }
+    }
+
+
+    /**
+     * @notice Determine singleton contract address that might be created from this factory, given its `_initCode` and a `_salt`.
+     * @param _initCode Initialization code.
+     * @param _salt Arbitrary value to modify resulting address.
+     * @return expectedAddr Expected contract address.
+     */
+     function determineAddr(bytes memory _initCode, bytes32 _salt)
+        public
+        view
+        returns (address)
+    {
+        return address(
+            uint160(uint(keccak256(
+                abi.encodePacked(
+                    bytes1(0xff),
+                    address(this),
+                    _salt,
+                    keccak256(_initCode)
+                )
+            )))
+        );
+    }
+}
diff --git a/migrations/01_initial.js b/migrations/01_initial.js
new file mode 100644
index 000000000..4cf572299
--- /dev/null
+++ b/migrations/01_initial.js
@@ -0,0 +1,44 @@
+const fs = require("fs")
+const Migrations = artifacts.require("Migrations")
+
+module.exports = async function (deployer, network) {
+  if (!fs.existsSync("./migrations/addresses.json")) {
+    await fs.open("./migrations/addresses.json", "w", function (err, file) {
+      if (err) throw new Error("Fatal: cannot create ./migrations/addreses.json")
+      console.log("> Created ./migrations/addresses.json file.")
+    })
+  }
+
+  // Prepare "addresses.json" structure if necessary:
+  let addresses = await fs.readFileSync("./migrations/addresses.json")
+  if (addresses.length === 0) addresses = "{}"
+  addresses = JSON.parse(addresses)
+
+  let changes = false
+  if (!("networks" in addresses)) {
+    addresses.networks = {}
+    changes = true
+  }
+  if (!(network in addresses.networks)) {
+    addresses.networks[network] = {}
+    changes = true
+  }
+  if (!("singletons" in addresses)) {
+    addresses.singletons = {}
+    changes = true
+  }
+  if (!("libraries" in addresses.singletons)) {
+    addresses.singletons.libraries = {}
+    changes = true
+  }
+  if (!("contracts" in addresses.singletons)) {
+    addresses.singletons.contracts = {}
+    changes = true
+  }
+  if (changes) {
+    await fs.writeFileSync("./migrations/addresses.json", JSON.stringify(addresses, null, 2))
+  }
+
+  // Deploy "Migrations" contract:
+  await deployer.deploy(Migrations)
+}
diff --git a/migrations/02_singleton_libs.js b/migrations/02_singleton_libs.js
new file mode 100644
index 000000000..c46554b33
--- /dev/null
+++ b/migrations/02_singleton_libs.js
@@ -0,0 +1,115 @@
+const ethUtils = require("ethereumjs-util")
+const fs = require("fs")
+const utils = require("../utils")
+
+const SingletonFactory = artifacts.require("SingletonFactory")
+
+module.exports = async function (deployer, network, accounts) {
+  const addresses = require("./addresses.json")
+  const singletons = require("./singletons.json")
+
+  const from = singletons.from || deployer.networks[network].from || accounts[0]
+
+  // Generate SingletonFactory deployment transaction:
+  const res = utils.generateDeployTx(
+    SingletonFactory.toJSON(),
+    singletons.sender.r,
+    singletons.sender.s,
+    singletons.sender.gasprice,
+    singletons.sender.gas
+  )
+
+  const deployedCode = await web3.eth.getCode(res.contractAddr)
+
+  if (deployedCode.length <= 3) {
+    // Deploy SingletonFactory instance, if not yet deployed on this `network`:
+    utils.traceHeader("Inception of 'SingletonFactory':")
+
+    const balance = await web3.eth.getBalance(from)
+    const estimatedGas = res.gasLimit
+    const value = estimatedGas * res.gasPrice
+    let makerBalance = await web3.eth.getBalance(res.sender)
+
+    if (makerBalance < value) {
+      // transfer ETH funds to sender address, if currently not enough:
+      await web3.eth.sendTransaction({
+        from: from,
+        to: res.sender,
+        value: value - makerBalance,
+      })
+      makerBalance = await web3.eth.getBalance(res.sender)
+    }
+
+    const tx = await web3.eth.sendSignedTransaction(res.rawTx)
+    utils.traceTx(tx, web3.utils.fromWei((balance - await web3.eth.getBalance(from)).toString()))
+  } else {
+    utils.traceHeader("Singleton factory: 'SingletonFactory")
+  }
+
+  // Set SingletonFactory address on current network:
+  SingletonFactory.address = res.contractAddr
+  const factory = await SingletonFactory.deployed()
+
+  // Trace factory relevant data:
+  console.log("  ", "> sender's balance:\t",
+    `${web3.utils.fromWei((await web3.eth.getBalance(res.sender)).toString(), "ether")} ETH`
+  )
+  console.log("  ", "> factory codehash:\t", web3.utils.soliditySha3(await web3.eth.getCode(res.contractAddr)))
+  console.log("  ", "> factory sender:\t", res.sender)
+  console.log("  ", "> factory address:\t", factory.address)
+  console.log("  ", "> factory nonce:\t", await web3.eth.getTransactionCount(factory.address))
+  console.log("")
+
+  // Process all singleton libraries referred in config file:
+  for (const lib in singletons.libs) {
+    const artifact = artifacts.require(lib)
+    const salt = singletons.libs[lib].salt
+      ? "0x" + ethUtils.setLengthLeft(ethUtils.toBuffer(singletons.libs[lib].salt), 32).toString("hex")
+      : "0x0"
+
+    let bytecode = artifact.toJSON().bytecode
+    if (singletons.libs[lib].links) {
+      singletons.libs[lib].links.forEach(
+        // Join dependent library address(es) into the library bytecode to be deployed:
+        // Please note: dependent libraries should have been previously deployed,
+        //   so order in which libraries are declared in the config file actually matters.
+        sublib => {
+          const sublibArtifact = artifacts.require(sublib)
+          const sublibAddr = sublibArtifact.address.slice(2).toLowerCase()
+          const sublibMark = `__${sublibArtifact.contractName}${"_".repeat(38 - sublibArtifact.contractName.length)}`
+          bytecode = bytecode.split(sublibMark).join(sublibAddr)
+        }
+      )
+    }
+    artifact.bytecode = bytecode
+
+    const libAddr = await factory.determineAddr.call(bytecode, salt)
+
+    if ((await web3.eth.getCode(libAddr)).length <= 3) {
+      // Deploy library instance, if not yet deployed on this `network`:
+      utils.traceHeader(`Singleton inception of library '${lib}':`)
+
+      const balance = await web3.eth.getBalance(from)
+      const gas = singletons.libs[lib].gas || 10 ** 6
+      const tx = await factory.deploy(bytecode, salt, { from: from, gas: gas })
+      utils.traceTx(tx.receipt, web3.utils.fromWei((balance - await web3.eth.getBalance(from)).toString()))
+    } else {
+      utils.traceHeader(`Singleton library: '${lib}'`)
+    }
+
+    artifact.address = libAddr
+
+    const libCodehash = web3.utils.soliditySha3(await web3.eth.getCode(artifact.address))
+    if (!libCodehash) {
+      throw new Error(`Fatal: unable to deploy library '${lib}' as singleton. Try providing more gas.`)
+    }
+
+    console.log("  ", "> library codehash:\t", libCodehash)
+    console.log("  ", "> library address:\t", artifact.address)
+    console.log()
+
+    addresses.singletons.libraries[lib] = libAddr
+  }
+
+  fs.writeFileSync("./migrations/addresses.json", JSON.stringify(addresses, null, 2))
+}
diff --git a/migrations/03_new_wrb.js b/migrations/03_new_wrb.js
new file mode 100644
index 000000000..7a22d054f
--- /dev/null
+++ b/migrations/03_new_wrb.js
@@ -0,0 +1,17 @@
+const fs = require("fs")
+const WitnetRequestBoard = artifacts.require("WitnetRequestBoard")
+
+module.exports = async function (deployer, network, accounts) {
+  network = network.split("-")[0]
+
+  const addresses = require("./addresses.json")
+  if (network in addresses.networks && addresses.networks[network].WitnetRequestBoard) {
+    WitnetRequestBoard.address = addresses.networks[network].WitnetRequestBoard
+  } else {
+    console.log(`> Deploying new instance of 'WitnetRequestBoard' into '${network}' network...`)
+    await deployer.deploy(WitnetRequestBoard, [accounts[0]], { from: accounts[0] })
+    addresses.networks[network].WitnetRequestBoard = WitnetRequestBoard.address
+  }
+
+  fs.writeFileSync("./migrations/addresses.json", JSON.stringify(addresses, null, 2))
+}
diff --git a/migrations/04_singleton_proxy.js b/migrations/04_singleton_proxy.js
new file mode 100644
index 000000000..09069bc21
--- /dev/null
+++ b/migrations/04_singleton_proxy.js
@@ -0,0 +1,75 @@
+const ethUtils = require("ethereumjs-util")
+const fs = require("fs")
+const utils = require("../utils")
+
+const SingletonFactory = artifacts.require("SingletonFactory")
+const WitnetRequestBoard = artifacts.require("WitnetRequestBoard")
+
+module.exports = async function (deployer, network, accounts) {
+  const addresses = require("./addresses.json")
+
+  const factory = await SingletonFactory.deployed()
+  const wrb = await WitnetRequestBoard.deployed()
+
+  const singletons = require("./singletons.json")
+  const artifact = artifacts.require("WitnetRequestBoardProxy")
+  const contract = artifact.contractName
+
+  if (singletons.contracts[contract]) {
+    const from = singletons.from || deployer.networks[network].from || accounts[0]
+
+    const salt = singletons.contracts[contract].salt
+      ? "0x" + ethUtils.setLengthLeft(ethUtils.toBuffer(singletons.contracts[contract].salt), 32).toString("hex")
+      : "0x0"
+
+    let bytecode = artifact.toJSON().bytecode
+    if (singletons.contracts[contract].links) {
+      singletons.contracts[contract].links.forEach(
+        // Join every dependent library address into the contract bytecode to be deployed:
+        lib => {
+          const libArtifact = artifacts.require(lib)
+          const libAddr = libArtifact.address.slice(2).toLowerCase()
+          const libMark = `__${libArtifact.contractName}${"_".repeat(38 - libArtifact.contractName.length)}`
+          bytecode = bytecode.split(libMark).join(libAddr)
+        }
+      )
+    }
+    artifact.bytecode = bytecode
+
+    const contractAddr = await factory.determineAddr.call(bytecode, salt)
+
+    if ((await web3.eth.getCode(contractAddr)).length <= 3) {
+      // Deploy contract instance, if not yet deployed on this `network`:
+      utils.traceHeader(`Singleton inception of contract '${contract}':`)
+
+      const balance = await web3.eth.getBalance(from)
+      const gas = singletons.contracts[contract].gas || 10 ** 6
+
+      // Compose initialization call: 'upgradeWitnetRequestBoard(wrb.address)'
+      const initCall = "0x47b1e79b000000000000000000000000" + wrb.address.slice(2)
+
+      const tx = await factory.deployAndInit(bytecode, initCall, salt, { from, gas })
+      utils.traceEvents(tx.logs)
+      utils.traceTx(tx.receipt, web3.utils.fromWei((balance - await web3.eth.getBalance(from)).toString()))
+    } else {
+      utils.traceHeader(`Singleton contract: '${contract}'`)
+    }
+
+    artifact.address = contractAddr
+    const contractCodehash = web3.utils.soliditySha3(await web3.eth.getCode(artifact.address))
+    if (!contractCodehash) {
+      throw new Error(`Fatal: unable to deploy contract '${contract}' as singleton. Try providing more gas.`)
+    }
+
+    console.log("  ", "> contract codehash:  ", web3.utils.soliditySha3(await web3.eth.getCode(artifact.address)))
+    console.log("  ", "> contract address:   ", artifact.address)
+    console.log("  ", "> current WRB address:", await (await artifact.deployed()).currentWitnetRequestBoard())
+    if (singletons.contracts[contract].links && singletons.contracts[contract].links.length > 0) {
+      console.log("  ", "> linked libraries:\t", JSON.stringify(singletons.contracts[contract].links))
+    }
+    addresses.singletons.contracts[contract] = contractAddr
+  }
+
+  console.log()
+  fs.writeFileSync("./migrations/addresses.json", JSON.stringify(addresses, null, 2))
+}
diff --git a/migrations/1_initial_migration.js b/migrations/1_initial_migration.js
deleted file mode 100644
index 0dd845fe0..000000000
--- a/migrations/1_initial_migration.js
+++ /dev/null
@@ -1,6 +0,0 @@
-const Migrations = artifacts.require("Migrations")
-
-module.exports = function (deployer) {
-  console.log("Migrating your contracts...\n===========================")
-  deployer.deploy(Migrations)
-}
diff --git a/migrations/2_deploy_wrb.js b/migrations/2_deploy_wrb.js
deleted file mode 100644
index 8e6d573e6..000000000
--- a/migrations/2_deploy_wrb.js
+++ /dev/null
@@ -1,16 +0,0 @@
-const WitnetRequestBoardProxy = artifacts.require("WitnetRequestBoardProxy")
-const addresses = require("./addresses.json")
-
-module.exports = function (deployer, network, accounts) {
-  network = network.split("-")[0]
-  console.log(network)
-  if (network in addresses && addresses[network].WitnetRequestBoardProxy) {
-    WitnetRequestBoardProxy.address = addresses[network].WitnetRequestBoardProxy
-  } else {
-    const WitnetRequestBoard = artifacts.require("WitnetRequestBoard")
-    console.log(`> Migrating WitnetRequestBoard and WitnetRequestBoardProxy into ${network} network`)
-    deployer.deploy(WitnetRequestBoard, [accounts[0]]).then(function () {
-      return deployer.deploy(WitnetRequestBoardProxy, WitnetRequestBoard.address)
-    })
-  }
-}
diff --git a/migrations/3_deploy_witnet.js b/migrations/3_deploy_witnet.js
deleted file mode 100644
index 46ac0fd43..000000000
--- a/migrations/3_deploy_witnet.js
+++ /dev/null
@@ -1,10 +0,0 @@
-const CBOR = artifacts.require("CBOR")
-const Witnet = artifacts.require("Witnet")
-
-module.exports = function (deployer, network) {
-  console.log(`> Migrating CBOR and Witnet into ${network} network`)
-  deployer.deploy(CBOR).then(function () {
-    deployer.link(CBOR, Witnet)
-    return deployer.deploy(Witnet)
-  })
-}
diff --git a/migrations/99_upgrade_proxy.js b/migrations/99_upgrade_proxy.js
new file mode 100644
index 000000000..6493791b6
--- /dev/null
+++ b/migrations/99_upgrade_proxy.js
@@ -0,0 +1,16 @@
+const WitnetRequestBoardProxy = artifacts.require("WitnetRequestBoardProxy")
+const WitnetRequestBoard = artifacts.require("WitnetRequestBoard")
+
+module.exports = async function (deployer, network, accounts) {
+  const WRB = await WitnetRequestBoard.deployed()
+  const WRBProxy = await WitnetRequestBoardProxy.deployed()
+
+  const currentWRB = await WRBProxy.currentWitnetRequestBoard.call()
+  if (currentWRB !== WRB.address) {
+    console.log(`> Upgrading 'WitnetRequestBoardProxy' singleton on '${network}' network...\n`)
+    console.log("  ", "WRB owner address:", await WRB.owner.call())
+    console.log("  ", "Old WRB address  :", currentWRB)
+    await WRBProxy.upgradeWitnetRequestBoard(WitnetRequestBoard.address, { from: accounts[0] })
+    console.log("  ", "New WRB address  :", await WRBProxy.currentWitnetRequestBoard.call())
+  }
+}
diff --git a/migrations/addresses.json b/migrations/addresses.json
index 2954f8078..93b9606a4 100644
--- a/migrations/addresses.json
+++ b/migrations/addresses.json
@@ -1,16 +1,13 @@
 {
-  "goerli" : {
-    "CBOR": "0x4ADd24Cb572b8951808f81b8235ac302D9910c63",
-    "Migrations": "0xaC43baB88216527560E0A2AC852Ca32130312370",
-    "Witnet": "0x80Dc9287085ea7C103c3EAe117Ad9A1CcCd02C46",
-    "WitnetRequestBoard": "0x156a1E0703fA7e9765949d40c6349501a1e9FB02",
-    "WitnetRequestBoardProxy": "0xd58615B1e77E6eD3a583CB12A7D0016cad7A8438"
+  "networks": {
   },
-  "rinkeby" : {
-    "CBOR": "0xFBB631ec0F7b423d23c649bd5733bc450Ab5b366",
-    "Migrations": "0xa5EBf3DFa0284402Fb640ff6ffaf5102C3AE6959",
-    "Witnet": "0x47689bc2d27770Ab3a358C1C2C9c998028ea0823",
-    "WitnetRequestBoard": "0x90d08bF4e89C9D1fFb69cb4F783c38F6493ae74a",
-    "WitnetRequestBoardProxy": "0xE1EC13d1521B98ee7b826751048806E85DC1F1bA"
+  "singletons": {
+    "libraries": {
+      "CBOR": "0xd75b64FEb11193F9b77BCC3Ec904c89Bd0b9E421",
+      "Witnet": "0xC72d494a355a58A4FFb31434073118c7CB0651CD"
+    },
+    "contracts": {
+      "WitnetRequestBoardProxy": "0x1F1a458dAF4162CC07BDaC1D25F459feCAab6C20"
+    }
   }
-}
+}
\ No newline at end of file
diff --git a/migrations/singletons.json b/migrations/singletons.json
new file mode 100644
index 000000000..bb208a226
--- /dev/null
+++ b/migrations/singletons.json
@@ -0,0 +1,25 @@
+{
+  "sender": {
+    "r": "0x247000",
+    "s": "0x2470",
+    "gasprice": 1e11,
+    "gas": 400000
+  },
+  "libs": {
+    "CBOR": {
+      "gas": 1700000,
+      "salt": 0
+    },
+    "Witnet": {
+      "gas": 2400000,
+      "salt": 0,
+      "links": ["CBOR"]
+    }
+  },
+  "contracts": {
+    "WitnetRequestBoardProxy": {
+      "gas": 3000000,
+      "salt": 0
+    }
+  }
+}
\ No newline at end of file
diff --git a/package.json b/package.json
index e2219b32b..8316c7aea 100644
--- a/package.json
+++ b/package.json
@@ -32,7 +32,8 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "@openzeppelin/contracts": "3.2.0"
+    "@openzeppelin/contracts": "3.2.0",
+    "ethereumjs-util": "^6.2.1"
   },
   "devDependencies": {
     "@openzeppelin/test-helpers": "0.5.5",
diff --git a/test/TestBuffer.sol b/test/TestBuffer.sol
index 5f38b2633..6e2d327ff 100644
--- a/test/TestBuffer.sol
+++ b/test/TestBuffer.sol
@@ -4,7 +4,7 @@ pragma solidity 0.6.12;
 pragma experimental ABIEncoderV2;
 
 import "truffle/Assert.sol";
-import "../contracts/BufferLib.sol";
+import "../contracts/libs/BufferLib.sol";
 
 
 contract TestBuffer {
diff --git a/test/TestCBOR.sol b/test/TestCBOR.sol
index 3847ea61b..6a441cb85 100644
--- a/test/TestCBOR.sol
+++ b/test/TestCBOR.sol
@@ -4,7 +4,7 @@ pragma solidity 0.6.12;
 pragma experimental ABIEncoderV2;
 
 import "truffle/Assert.sol";
-import "../contracts/CBOR.sol";
+import "../contracts/libs/CBOR.sol";
 
 
 contract TestCBOR {
diff --git a/test/TestWitnet.sol b/test/TestWitnet.sol
index 5c1088808..de78de7eb 100644
--- a/test/TestWitnet.sol
+++ b/test/TestWitnet.sol
@@ -4,7 +4,7 @@ pragma solidity 0.6.12;
 pragma experimental ABIEncoderV2;
 
 import "truffle/Assert.sol";
-import "../contracts/Witnet.sol";
+import "../contracts/libs/Witnet.sol";
 
 
 contract WitnetTest {
diff --git a/test/helpers/UsingWitnetTestHelper.sol b/test/helpers/UsingWitnetTestHelper.sol
index ef755e9cc..902170d7b 100644
--- a/test/helpers/UsingWitnetTestHelper.sol
+++ b/test/helpers/UsingWitnetTestHelper.sol
@@ -4,7 +4,7 @@ pragma solidity 0.6.12;
 pragma experimental ABIEncoderV2;
 
 import "../../contracts/Request.sol";
-import "../../contracts/Witnet.sol";
+import "../../contracts/libs/Witnet.sol";
 import "../../contracts/UsingWitnet.sol";
 
 
diff --git a/test/helpers/WrbProxyTestHelper.sol b/test/helpers/WrbProxyTestHelper.sol
index 955d59dff..53a23c6ed 100644
--- a/test/helpers/WrbProxyTestHelper.sol
+++ b/test/helpers/WrbProxyTestHelper.sol
@@ -13,7 +13,9 @@ import "../../contracts/WitnetRequestBoardProxy.sol";
  */
 contract WrbProxyTestHelper is WitnetRequestBoardProxy {
 
-  constructor (address _witnetRequestBoardAddress) public WitnetRequestBoardProxy(_witnetRequestBoardAddress) {}
+  constructor (address _witnetRequestBoardAddress) public WitnetRequestBoardProxy(/*_witnetRequestBoardAddress*/) {
+    upgradeWitnetRequestBoard(_witnetRequestBoardAddress);
+  }
 
   function checkLastId(uint256 _id) external view returns(bool) {
     return _id == currentLastId;
diff --git a/test/using_witnet.js b/test/using_witnet.js
index 2d1ae1500..88b2930d2 100644
--- a/test/using_witnet.js
+++ b/test/using_witnet.js
@@ -7,8 +7,9 @@ const Witnet = artifacts.require("Witnet")
 const truffleAssert = require("truffle-assertions")
 
 const sha = require("js-sha256")
+const BN = web3.utils.BN
 
-contract("UsingWitnet", accounts => {
+contract("UsingWitnet", ([owner, requestor]) => {
   describe("UsingWitnet \"happy path\" test case. " +
     "This covers pretty much all the life cycle of a Witnet request.", () => {
     const requestHex = "0x01"
@@ -19,15 +20,17 @@ contract("UsingWitnet", accounts => {
     const reward = web3.utils.toWei("1", "ether")
 
     let witnet, clientContract, wrb, wrbProxy, request, requestId, result
-    let lastAccount0Balance
+    let ownerBalance, requestorBalance
 
     before(async () => {
       witnet = await Witnet.deployed()
-      wrb = await WRB.new([accounts[0]])
-      wrbProxy = await WRBProxy.new(wrb.address)
+      wrb = await WRB.new([owner])
+      wrbProxy = await WRBProxy.new()
+      await wrbProxy.upgradeWitnetRequestBoard(wrb.address)
       await UsingWitnetTestHelper.link(Witnet, witnet.address)
       clientContract = await UsingWitnetTestHelper.new(wrbProxy.address)
-      lastAccount0Balance = await web3.eth.getBalance(accounts[0])
+      ownerBalance = await web3.eth.getBalance(owner)
+      requestorBalance = await web3.eth.getBalance(requestor)
     })
 
     it("should create a Witnet request", async () => {
@@ -45,7 +48,7 @@ contract("UsingWitnet", accounts => {
       requestId = await returnData(clientContract._witnetPostRequest(
         request.address,
         {
-          from: accounts[1],
+          from: requestor,
           value: reward,
         }
       ))
@@ -66,10 +69,10 @@ contract("UsingWitnet", accounts => {
       assert.equal(drReward, reward)
     })
 
-    it("requester balance should decrease", async () => {
-      const afterBalance = await web3.eth.getBalance(accounts[0])
-      assert(afterBalance < lastAccount0Balance)
-      lastAccount0Balance = afterBalance
+    it("requestor balance should decrease after post", async () => {
+      const afterBalance = await web3.eth.getBalance(requestor)
+      assert(new BN(afterBalance).lt(new BN(requestorBalance)))
+      requestorBalance = afterBalance
     })
 
     it("client contract balance should remain stable", async () => {
@@ -84,7 +87,7 @@ contract("UsingWitnet", accounts => {
 
     it("should upgrade the rewards of an existing Witnet request", async () => {
       await returnData(clientContract._witnetUpgradeRequest(requestId, {
-        from: accounts[1],
+        from: requestor,
         value: reward,
       }))
     })
@@ -96,10 +99,10 @@ contract("UsingWitnet", accounts => {
       assert.equal(drReward, reward * 2)
     })
 
-    it("requester balance should decrease after rewards upgrade", async () => {
-      const afterBalance = await web3.eth.getBalance(accounts[1])
-      assert(afterBalance < lastAccount0Balance - reward)
-      lastAccount0Balance = afterBalance
+    it("requestor balance should decrease after rewards upgrade", async () => {
+      const afterBalance = await web3.eth.getBalance(requestor)
+      assert(new BN(afterBalance).lt(new BN(requestorBalance).sub(new BN(reward))))
+      requestorBalance = afterBalance
     })
 
     it("client contract balance should remain stable after rewards upgrade", async () => {
@@ -114,18 +117,24 @@ contract("UsingWitnet", accounts => {
 
     it("should post the result of the request into the WRB", async () => {
       await returnData(wrb.reportResult(requestId, drHash, resultHex, {
-        from: accounts[0],
+        from: owner,
       }))
       const requestInfo = await wrb.requests(requestId)
       assert.equal(requestInfo.result, resultHex)
     })
 
+    it("owner balance should increase after report result", async () => {
+      const afterBalance = await web3.eth.getBalance(owner)
+      assert(new BN(afterBalance).gt(new BN(ownerBalance)))
+      ownerBalance = afterBalance
+    })
+
     it("should check if the request is resolved", async () => {
       assert.equal(await clientContract._witnetCheckRequestResolved(requestId), true)
     })
 
     it("should pull the result from the WRB back into the client contract", async () => {
-      await clientContract._witnetReadResult(requestId, { from: accounts[0] })
+      await clientContract._witnetReadResult(requestId)
       result = await clientContract.result()
       assert.equal(result.success, true)
       assert.equal(result.cborValue.buffer.data, resultHex)
@@ -148,7 +157,7 @@ contract("UsingWitnet", accounts => {
 
     before(async () => {
       witnet = await Witnet.deployed()
-      wrb = await WRB.new([accounts[0]])
+      wrb = await WRB.new([owner])
       await UsingWitnetTestHelper.link(Witnet, witnet.address)
       clientContract = await UsingWitnetTestHelper.new(wrb.address)
     })
@@ -168,7 +177,7 @@ contract("UsingWitnet", accounts => {
       requestId = await returnData(clientContract._witnetPostRequest(
         request.address,
         {
-          from: accounts[1],
+          from: requestor,
           value: reward,
         }
       ))
@@ -181,20 +190,20 @@ contract("UsingWitnet", accounts => {
 
     it("should report the result in the WRB", async () => {
       await returnData(wrb.reportResult(requestId, drHash, resultHex, {
-        from: accounts[0],
+        from: owner,
       }))
       const requestinfo = await wrb.requests(requestId)
       assert.equal(requestinfo.result, resultHex)
     })
 
     it("should pull the result from the WRB back to the client contract", async () => {
-      await clientContract._witnetReadResult(requestId, { from: accounts[1] })
+      await clientContract._witnetReadResult(requestId)
       result = await clientContract.result()
       assert.equal(result.cborValue.buffer.data, resultHex)
     })
 
     it("should detect the result is false", async () => {
-      await clientContract._witnetReadResult(requestId, { from: accounts[1] })
+      await clientContract._witnetReadResult(requestId)
       result = await clientContract.result()
       assert.equal(result.success, false)
     })
@@ -204,7 +213,7 @@ contract("UsingWitnet", accounts => {
       const estimatedReward = await clientContract._witnetEstimateGasCost.call(gasPrice)
       await truffleAssert.passes(
         clientContract._witnetPostRequest(request.address, {
-          from: accounts[1],
+          from: requestor,
           value: estimatedReward,
           gasPrice: gasPrice,
         }),
diff --git a/utils/generateDeployTx.js b/utils/generateDeployTx.js
new file mode 100644
index 000000000..929196fe3
--- /dev/null
+++ b/utils/generateDeployTx.js
@@ -0,0 +1,23 @@
+const EthTx = require("ethereumjs-tx").Transaction
+const ethUtils = require("ethereumjs-util")
+const rawTransaction = require("./rawTransaction")
+
+module.exports = function (json, r, s, gasprice, gaslimit) {
+  const rawTx = rawTransaction(json, r, s, gasprice, gaslimit)
+  const tx = new EthTx(rawTx)
+
+  const res = {
+    bytecode: rawTx.data,
+    contractAddr: ethUtils.toChecksumAddress(
+      "0x" + ethUtils.generateAddress(
+        tx.getSenderAddress(),
+        ethUtils.toBuffer(0)
+      ).toString("hex")
+    ),
+    gasLimit: rawTx.gasLimit.toString(),
+    gasPrice: rawTx.gasPrice.toString(),
+    rawTx: "0x" + tx.serialize().toString("hex"),
+    sender: ethUtils.toChecksumAddress("0x" + tx.getSenderAddress().toString("hex")),
+  }
+  return res
+}
diff --git a/utils/index.js b/utils/index.js
new file mode 100644
index 000000000..8be7b0013
--- /dev/null
+++ b/utils/index.js
@@ -0,0 +1,6 @@
+module.exports = {
+  generateDeployTx: require("./generateDeployTx"),
+  traceEvents: require("./traceEvents.js"),
+  traceHeader: require("./traceHeader.js"),
+  traceTx: require("./traceTx.js"),
+}
diff --git a/utils/rawTransaction.js b/utils/rawTransaction.js
new file mode 100644
index 000000000..35b3acc2e
--- /dev/null
+++ b/utils/rawTransaction.js
@@ -0,0 +1,11 @@
+module.exports = function (json, r, s, gasprice, gaslimit) {
+  return {
+    gasPrice: gasprice,
+    value: 0,
+    data: json.bytecode,
+    gasLimit: gaslimit,
+    v: 27,
+    r: r,
+    s: s,
+  }
+}
diff --git a/utils/shortenAddr.js b/utils/shortenAddr.js
new file mode 100644
index 000000000..622a674b0
--- /dev/null
+++ b/utils/shortenAddr.js
@@ -0,0 +1,3 @@
+module.exports = function (addr) {
+  return addr.substring(0, 6) + ".." + addr.slice(-4)
+}
diff --git a/utils/traceEvents.js b/utils/traceEvents.js
new file mode 100644
index 000000000..4e4748263
--- /dev/null
+++ b/utils/traceEvents.js
@@ -0,0 +1,22 @@
+const shortenAddr = require("./shortenAddr")
+
+module.exports = async function (logs, web3) {
+  for (let i = 0; i < logs.length; i++) {
+    const event = logs[i].event
+    const args = logs[i].args
+    let params = ""
+
+    switch (event) {
+      case "PostedRequest":
+      case "PostedResult":
+        params = `from: ${shortenAddr(args[0])}, id: ${args[1].toString(16)}`
+        break
+
+      default:
+        continue
+    }
+    let tabs = "\t"
+    if (event.length < 13) tabs = "\t\t"
+    console.log("    ", `>> ${event}${tabs}(${params})`)
+  }
+}
diff --git a/utils/traceHeader.js b/utils/traceHeader.js
new file mode 100644
index 000000000..de350909d
--- /dev/null
+++ b/utils/traceHeader.js
@@ -0,0 +1,5 @@
+module.exports = function (header) {
+  console.log("")
+  console.log("  ", header)
+  console.log("  ", `${"-".repeat(header.length)}`)
+}
diff --git a/utils/traceTx.js b/utils/traceTx.js
new file mode 100644
index 000000000..b9053e216
--- /dev/null
+++ b/utils/traceTx.js
@@ -0,0 +1,9 @@
+module.exports = function (receipt, totalCost) {
+  console.log("  ", "> transaction hash:\t", receipt.transactionHash)
+  console.log("  ", "> block number:\t", receipt.blockNumber)
+  console.log("  ", "> gas used:\t\t", receipt.cumulativeGasUsed)
+  if (totalCost) {
+    console.log("  ", "> total cost:\t", totalCost, "ETH")
+  }
+  console.log()
+}