diff --git a/apps/proposal/contracts/Proposal.sol b/apps/proposal/contracts/Proposal.sol
index a0d808f..de89a51 100644
--- a/apps/proposal/contracts/Proposal.sol
+++ b/apps/proposal/contracts/Proposal.sol
@@ -4,13 +4,13 @@ import "@aragon/os/contracts/apps/AragonApp.sol";
 import "@aragon/os/contracts/kernel/IKernel.sol";
 
 interface IContributor {
-  function getContributorAddressById(uint256 contributorId) public view returns (address);
-  function getContributorIdByAddress(address contributorAccount) public view returns (uint256);
-  function exists(uint256 contributorId) public view returns (bool);
+  function getContributorAddressById(uint32 contributorId) public view returns (address);
+  function getContributorIdByAddress(address contributorAccount) public view returns (uint32);
+  function exists(uint32 contributorId) public view returns (bool);
 }
 
 interface IContribution {
-  function add(uint256 amount, address contributor, bytes32 hashDigest, uint8 hashFunction, uint8 hashSize) public;
+  function add(uint32 amount, uint32 contributorId, bytes32 hashDigest, uint8 hashFunction, uint8 hashSize) public;
 }
 
 contract Proposal is AragonApp {
@@ -25,26 +25,26 @@ contract Proposal is AragonApp {
 
   struct Proposal {
     address creatorAccount;
-    uint contributorId;
-    uint votesCount;
-    uint votesNeeded;
-    uint256 amount;
+    uint32 contributorId;
+    uint16 votesCount;
+    uint16 votesNeeded;
+    uint32 amount;
     bool executed;
     bytes32 hashDigest;
     uint8 hashFunction;
     uint8 hashSize;
-    uint256[] voterIds;
-    mapping (uint256 => bool) votes;
+    uint32[] voterIds;
+    mapping (uint32 => bool) votes;
     bool exists;
   }
 
-  mapping(uint256 => Proposal) public proposals;
-  uint256 public proposalsCount;
+  mapping(uint32 => Proposal) public proposals;
+  uint32 public proposalsCount;
 
-  event ProposalCreated(uint256 id, address creatorAccount, uint256 contributorId, uint256 amount);
+  event ProposalCreated(uint32 id, address creatorAccount, uint32 contributorId, uint32 amount);
 
-  event ProposalVoted(uint256 id, uint256 voterId, uint256 totalVotes);
-  event ProposalExecuted(uint256 id, uint256 contributorId, uint256 amount);
+  event ProposalVoted(uint32 id, uint32 voterId, uint16 totalVotes);
+  event ProposalExecuted(uint32 id, uint32 contributorId, uint32 amount);
 
   function initialize(bytes32[4] _appIds) public onlyInit {
     appIds = _appIds;
@@ -59,11 +59,11 @@ contract Proposal is AragonApp {
     return IKernel(kernel()).getApp(KERNEL_APP_ADDR_NAMESPACE, appIds[uint8(Apps.Contribution)]);
   }
 
-  function addProposal(uint contributorId, uint256 amount, bytes32 hashDigest, uint8 hashFunction, uint8 hashSize) public isInitialized auth(ADD_PROPOSAL_ROLE) {
+  function addProposal(uint32 contributorId, uint32 amount, bytes32 hashDigest, uint8 hashFunction, uint8 hashSize) public isInitialized auth(ADD_PROPOSAL_ROLE) {
     require(IContributor(getContributorContract()).exists(contributorId), 'CONTRIBUTOR_NOT_FOUND');
 
-    uint256 proposalId = proposalsCount + 1;
-    uint256 _votesNeeded = 1; //contributorsContract().coreContributorsCount() / 100 * 75;
+    uint32 proposalId = proposalsCount + 1;
+    uint16 _votesNeeded = 1; //contributorsContract().coreContributorsCount() / 100 * 75;
 
     Proposal storage p = proposals[proposalId];
     p.creatorAccount = msg.sender;
@@ -75,23 +75,23 @@ contract Proposal is AragonApp {
     p.votesCount =  0;
     p.votesNeeded = _votesNeeded;
     p.exists = true;
-   
+
     proposalsCount++;
     emit ProposalCreated(proposalId, msg.sender, p.contributorId, p.amount);
   }
 
-  function getProposal(uint proposalId) public view returns (uint256 id, address creatorAccount, uint256 contributorId, uint256 votesCount, uint256 votesNeeded, uint256 amount, bool executed, bytes32 hashDigest, uint8 hashFunction, uint8 hashSize, uint256[] voterIds, bool exists) {
+  function getProposal(uint32 proposalId) public view returns (uint32 id, address creatorAccount, uint32 contributorId, uint16 votesCount, uint16 votesNeeded, uint32 amount, bool executed, bytes32 hashDigest, uint8 hashFunction, uint8 hashSize, uint32[] voterIds, bool exists) {
     id = proposalId;
     Proposal storage p = proposals[id];
     return (
       id,
       p.creatorAccount,
-      p.contributorId, 
-      p.votesCount, 
+      p.contributorId,
+      p.votesCount,
       p.votesNeeded,
       p.amount,
-      p.executed, 
-      p.hashDigest, 
+      p.executed,
+      p.hashDigest,
       p.hashFunction,
       p.hashSize,
       p.voterIds,
@@ -99,10 +99,10 @@ contract Proposal is AragonApp {
     );
   }
 
-  function vote(uint256 proposalId) public isInitialized auth(VOTE_PROPOSAL_ROLE) {
+  function vote(uint32 proposalId) public isInitialized auth(VOTE_PROPOSAL_ROLE) {
     Proposal storage p = proposals[proposalId];
     require(!p.executed, 'ALREADY_EXECUTED');
-    uint256 voterId = IContributor(getContributorContract()).getContributorIdByAddress(msg.sender);
+    uint32 voterId = IContributor(getContributorContract()).getContributorIdByAddress(msg.sender);
     require(p.votes[voterId] != true, 'ALREADY_VOTED');
     p.voterIds.push(voterId);
     p.votes[voterId] = true;
@@ -114,20 +114,19 @@ contract Proposal is AragonApp {
     emit ProposalVoted(proposalId, voterId, p.votesCount);
   }
 
-  function batchVote(uint256[] _proposalIds) public isInitialized auth(VOTE_PROPOSAL_ROLE) {
-    for (uint256 i = 0; i < _proposalIds.length; i++) {
+  function batchVote(uint32[] _proposalIds) public isInitialized auth(VOTE_PROPOSAL_ROLE) {
+    for (uint32 i = 0; i < _proposalIds.length; i++) {
       vote(_proposalIds[i]);
     }
   }
 
-  function executeProposal(uint proposalId) private {
+  function executeProposal(uint32 proposalId) private {
     Proposal storage p = proposals[proposalId];
     require(!p.executed, 'ALREADY_EXECUTED');
     require(p.votesCount >= p.votesNeeded, 'MISSING_VOTES');
-    
+
     p.executed = true;
-    address contributorAccount = IContributor(getContributorContract()).getContributorAddressById(p.contributorId);
-    IContribution(getContributionContract()).add(p.amount, contributorAccount, p.hashDigest, p.hashFunction, p.hashSize);
+    IContribution(getContributionContract()).add(p.amount, p.contributorId, p.hashDigest, p.hashFunction, p.hashSize);
     emit ProposalExecuted(proposalId, p.contributorId, p.amount);
   }
 
diff --git a/lib/contracts/proposal.js b/lib/contracts/proposal.js
index cf7e363..896b72f 100644
--- a/lib/contracts/proposal.js
+++ b/lib/contracts/proposal.js
@@ -7,8 +7,7 @@ const Base = require('./base');
 class Proposal extends Base {
   all() {
     return this.functions.proposalsCount()
-      .then((count) => {
-        count = count.toNumber();
+      .then(count => {
         let proposals = [];
 
         for (let id = 1; id <= count; id++) {
@@ -20,10 +19,8 @@ class Proposal extends Base {
   }
 
   getById(id) {
-    id = ethers.utils.bigNumberify(id);
-
     return this.functions.getProposal(id)
-      .then((data) => {
+      .then(data => {
         return this.ipfs.catAndMerge(data, ContributionSerializer.deserialize);
       });
   }
diff --git a/scripts/list-proposals.js b/scripts/list-proposals.js
index 701ce83..2bbbedf 100644
--- a/scripts/list-proposals.js
+++ b/scripts/list-proposals.js
@@ -14,7 +14,6 @@ module.exports = async function(callback) {
 
   console.log(`Using Proposal at: ${kredits.Proposal.contract.address}`);
 
-
   const table = new Table({
     head: ['ID', 'Contributor ID', 'Amount', 'Votes', 'Executed?', 'Description']
   })