diff --git a/app/components/add-contribution/component.js b/app/components/add-contribution/component.js
index 96c4f48..5ae1d56 100644
--- a/app/components/add-contribution/component.js
+++ b/app/components/add-contribution/component.js
@@ -9,7 +9,15 @@ export default Component.extend({
   kredits: service(),
 
   attributes: null,
-  contributors: alias('kredits.contributorsSorted'),
+
+  contributors: computed('kredits.contributorsSorted.[]', function() {
+    return this.kredits.contributorsSorted.map(c => {
+      return {
+        id: c.id.toString(),
+        name: c.name
+      }
+    })
+  }),
 
   isValidContributor: notEmpty('contributorId'),
   isValidKind: notEmpty('kind'),
@@ -57,6 +65,8 @@ export default Component.extend({
 
       const attributes = this.getProperties(Object.keys(this.attributes));
 
+      attributes.contributorId = parseInt(this.contributorId);
+
       let dateInput = (attributes.date instanceof Array) ?
         attributes.date[0] : attributes.date;
 
diff --git a/app/components/add-contribution/template.hbs b/app/components/add-contribution/template.hbs
index 05ce592..3727c5d 100644
--- a/app/components/add-contribution/template.hbs
+++ b/app/components/add-contribution/template.hbs
@@ -4,7 +4,7 @@
     <p>
       <select required onchange={{action (mut this.contributorId) value="target.value"}}>
         <option value="" selected disabled hidden></option>
-        {{#each @contributors as |contributor|}}
+        {{#each this.contributors as |contributor|}}
           <option value={{contributor.id}} selected={{eq this.contributorId contributor.id}}>{{contributor.name}}</option>
         {{/each}}
       </select>
diff --git a/app/components/contribution-list/component.js b/app/components/contribution-list/component.js
index e297444..444d813 100644
--- a/app/components/contribution-list/component.js
+++ b/app/components/contribution-list/component.js
@@ -24,10 +24,9 @@ export default Component.extend({
   contributors: sort('kredits.contributors', 'contributorsSorting'),
 
   contributorsActive: computed('contributors.[]', 'contributions', function() {
-    const activeIds = new Set(this.contributions.mapBy('contributorId')
-                                                .map(id => id.toString()));
+    const activeIds = new Set(this.contributions.mapBy('contributorId'));
 
-    return this.contributors.filter(c => activeIds.has(c.id.toString()));
+    return this.contributors.filter(c => activeIds.has(c.id));
   }),
 
   contributionKinds: computed('contributions.[]', function() {
@@ -42,7 +41,7 @@ export default Component.extend({
           c.amount <= 500) { included = false; }
 
       if (isPresent(this.contributorId) &&
-          c.contributorId.toString() !== this.contributorId.toString()) { included = false; }
+          c.contributorId !== parseInt(this.contributorId)) { included = false; }
 
       if (isPresent(this.contributionKind) &&
           c.kind !== this.contributionKind) { included = false; }
diff --git a/app/models/contribution.js b/app/models/contribution.js
index 3fde117..f57bbed 100644
--- a/app/models/contribution.js
+++ b/app/models/contribution.js
@@ -3,7 +3,6 @@ import { isEmpty, isPresent } from '@ember/utils';
 import moment from 'moment';
 
 export default EmberObject.extend({
-
   // Contract
   id: null,
   contributorId: null,
@@ -48,5 +47,4 @@ export default EmberObject.extend({
   serialize () {
     return JSON.stringify(this);
   }
-
 });
diff --git a/app/models/contributor.js b/app/models/contributor.js
index 9485d0f..40f6448 100644
--- a/app/models/contributor.js
+++ b/app/models/contributor.js
@@ -22,5 +22,4 @@ export default EmberObject.extend({
   serialize () {
     return JSON.stringify(this);
   }
-
 });
diff --git a/app/routes/contributions/resubmit.js b/app/routes/contributions/resubmit.js
index 2de1d5a..c375323 100644
--- a/app/routes/contributions/resubmit.js
+++ b/app/routes/contributions/resubmit.js
@@ -6,19 +6,15 @@ export default Route.extend({
   kredits: service(),
 
   model(params) {
-    const contribution = this.kredits.contributions.findBy('id', parseInt(params.id));
-    contribution.contributorId = contribution.contributorId.toString();
-
-    return contribution;
+    return this.kredits.contributions.findBy('id', parseInt(params.id));
   },
 
   setupController (controller, model) {
     this._super(controller, model);
 
     controller.set('attributes', model.getProperties([
-      'kind', 'amount', 'description', 'url', 'details'
+      'contributorId', 'kind', 'amount', 'description', 'url', 'details'
     ]));
-    controller.set('attributes.contributorId', model.contributorId.toString());
     controller.set('attributes.date', model.jsDate);
   }
 
diff --git a/app/services/kredits.js b/app/services/kredits.js
index 23a4b0f..cc55354 100644
--- a/app/services/kredits.js
+++ b/app/services/kredits.js
@@ -160,12 +160,12 @@ export default Service.extend({
   kreditsByContributor: computed('contributionsUnconfirmed.@each.vetoed', 'contributors.[]', function() {
     const contributionsUnconfirmed = this.contributionsUnconfirmed.filterBy('vetoed', false);
     const contributionsGrouped = groupBy(contributionsUnconfirmed, 'contributorId');
-    const contributorsWithUnconfirmed = contributionsGrouped.map(c => c.value.toString());
+    const contributorsWithUnconfirmed = contributionsGrouped.map(c => c.value);
     const contributorsWithOnlyConfirmed = this.contributors.reject(c => contributorsWithUnconfirmed.includes(c.id))
 
     const kreditsByContributor = contributionsGrouped.map(c => {
       const amountUnconfirmed = c.items.mapBy('amount').reduce((a, b) => a + b);
-      const contributor = this.contributors.findBy('id', c.value.toString());
+      const contributor = this.contributors.findBy('id', c.value);
 
       return EmberObject.create({
         contributor: contributor,
@@ -275,7 +275,7 @@ export default Service.extend({
       });
   },
 
-  loadContributorFromData(data) {
+  loadContributorFromData (data) {
     const contributor = Contributor.create(processContributorData(data));
     const loadedContributor = this.contributors.findBy('id', contributor.id);
     if (loadedContributor) { this.contributors.removeObject(loadedContributor); }
@@ -285,7 +285,7 @@ export default Service.extend({
 
   async cacheLoadedContributors () {
     for (const c of this.contributors) {
-      await this.browserCache.contributors.setItem(c.id, c.serialize());
+      await this.browserCache.contributors.setItem(c.id.toString(), c.serialize());
     }
     console.debug(`[kredits] Cached ${this.contributors.length} contributors in browser storage`);
     return Promise.resolve();
@@ -340,7 +340,7 @@ export default Service.extend({
 
   loadContributionFromData(data) {
     const contribution = Contribution.create(processContributionData(data));
-    contribution.set('contributor', this.contributors.findBy('id', data.contributorId.toString()));
+    contribution.set('contributor', this.contributors.findBy('id', data.contributorId));
     const loadedContribution = this.contributions.findBy('id', contribution.id);
     if (loadedContribution) { this.contributions.removeObject(loadedContribution); }
     this.contributions.pushObject(contribution);
@@ -349,7 +349,7 @@ export default Service.extend({
 
   async cacheLoadedContributions () {
     for (const c of this.contributions) {
-      await this.browserCache.contributions.setItem(c.id, c.serialize());
+      await this.browserCache.contributions.setItem(c.id.toString(), c.serialize());
     }
     console.debug(`[kredits] Cached ${this.contributions.length} contributions in browser storage`);
     return Promise.resolve();
@@ -575,7 +575,7 @@ export default Service.extend({
 
   loadReimbursementFromData(data) {
     const obj = Reimbursement.create(processReimbursementData(data));
-    obj.set('contributor', this.contributors.findBy('id', data.recipientId.toString()));
+    obj.set('contributor', this.contributors.findBy('id', data.recipientId));
     this.removeObjectFromCollectionIfLoaded('reimbursements', obj.id);
     this.reimbursements.pushObject(obj);
     return obj;
@@ -589,7 +589,7 @@ export default Service.extend({
         console.debug('[kredits] add reimbursement response', data);
         const reimbursement = Reimbursement.create(attributes);
         reimbursement.setProperties({
-          contributor: this.contributors.findBy('id', attributes.recipientId.toString()),
+          contributor: this.contributors.findBy('id', attributes.recipientId),
           pendingTx: data,
           confirmedAt: this.currentBlock + 40320
         });
@@ -645,13 +645,15 @@ export default Service.extend({
     const contributorData = await this.kredits.Contributor.getById(contributorId);
     const newContributor = Contributor.create(contributorData);
 
-    const oldContributor = this.contributors.findBy('id', contributorId.toString());
+    // TODO check for actual differences in the contributor data first
+
+    const oldContributor = this.contributors.findBy('id', contributorId);
     if (oldContributor) {
-      console.debug('[kredits] old contributor', oldContributor);
+      // console.debug('[kredits] cached contributor', oldContributor);
       this.contributors.removeObject(oldContributor);
     }
 
-    console.debug('[kredits] new contributor', newContributor);
+    // console.debug('[kredits] incoming contributor data', newContributor);
     this.contributors.pushObject(newContributor);
   },
 
@@ -660,13 +662,13 @@ export default Service.extend({
 
     const pendingContribution = this.contributions.find(c => {
       return (c.id === null) &&
-             (c.contributorId.toString() === contributorId.toString()) &&
+             (c.contributorId === contributorId) &&
              (c.amount.toString() === amount.toString());
     });
 
     if (pendingContribution) {
       const attributes = await this.kredits.Contribution.getById(id);
-      attributes.contributor = this.contributors.findBy('id', attributes.contributorId.toString());
+      attributes.contributor = this.contributors.findBy('id', attributes.contributorId);
       const newContribution = Contribution.create(attributes);
       this.contributions.addObject(newContribution);
       this.contributions.removeObject(pendingContribution);
diff --git a/app/utils/process-contribution-data.js b/app/utils/process-contribution-data.js
index 0a3f18d..a12395e 100644
--- a/app/utils/process-contribution-data.js
+++ b/app/utils/process-contribution-data.js
@@ -8,9 +8,8 @@ export default function processContributionData(data) {
   }
 
   const otherProperties = [
-    'id', 'contributorId', 'amount', 'vetoed',
-    'ipfsHash', 'kind', 'description', 'details',
-    'url', 'date', 'time', 'pendingTx'
+    'id', 'contributorId', 'amount', 'vetoed', 'ipfsHash', 'kind',
+    'description', 'details', 'url', 'date', 'time', 'pendingTx'
   ];
 
   otherProperties.forEach(prop => {
diff --git a/app/utils/process-contributor-data.js b/app/utils/process-contributor-data.js
index 48074fb..47e6b66 100644
--- a/app/utils/process-contributor-data.js
+++ b/app/utils/process-contributor-data.js
@@ -1,13 +1,12 @@
 export default function processContributorData(data) {
   const processed = {
-    id: data.id.toString(),
     balance: data.balanceInt,
     totalKreditsEarned: data.totalKreditsEarned,
     contributionsCount: data.contributionsCount?.toNumber()
   }
 
   const otherProperties = [
-    'account', 'accounts', 'ipfsHash', 'isCore', 'kind', 'name', 'url',
+    'id', 'account', 'accounts', 'ipfsHash', 'isCore', 'kind', 'name', 'url',
     'github_username', 'github_uid', 'wiki_username', 'zoom_display_name'
   ];
 
diff --git a/tests/fixtures/contributions.js b/tests/fixtures/contributions.js
index 75a1270..5a809f0 100644
--- a/tests/fixtures/contributions.js
+++ b/tests/fixtures/contributions.js
@@ -18,7 +18,7 @@ const data = [
 
 data.forEach(attrs => {
   const c = Model.create(processContributionData(attrs));
-  c.set('contributor', contributors.findBy('id', attrs.contributorId.toString()));
+  c.set('contributor', contributors.findBy('id', attrs.contributorId));
   items.push(c);
 });
 
diff --git a/tests/fixtures/contributors.js b/tests/fixtures/contributors.js
index ebe261e..2ddb787 100644
--- a/tests/fixtures/contributors.js
+++ b/tests/fixtures/contributors.js
@@ -4,9 +4,9 @@ import processContributorData from 'kredits-web/utils/process-contributor-data';
 const contributors = [];
 
 const data = [
-  { id: '1', name: 'Bumi', totalKreditsEarned: 11500, github_uid: 318 },
-  { id: '2', name: 'Râu Cao', totalKreditsEarned: 3000, github_uid: 842 },
-  { id: '3', name: 'Manuel', totalKreditsEarned: 0, github_uid: 54812 }
+  { id: 1, name: 'Bumi', totalKreditsEarned: 11500, github_uid: 318 },
+  { id: 2, name: 'Râu Cao', totalKreditsEarned: 3000, github_uid: 842 },
+  { id: 3, name: 'Manuel', totalKreditsEarned: 0, github_uid: 54812 }
 ];
 
 data.forEach(attrs => {
diff --git a/tests/integration/components/contribution-list/component-test.js b/tests/integration/components/contribution-list/component-test.js
index 995ad69..9892cf2 100644
--- a/tests/integration/components/contribution-list/component-test.js
+++ b/tests/integration/components/contribution-list/component-test.js
@@ -16,8 +16,10 @@ module('Integration | Component | contribution-list', function(hooks) {
   });
 
   test('it renders filtered contributions', async function(assert) {
-    let service = this.owner.lookup('service:kredits');
-    service.set('contributors', contributors);
+    let kredits = this.owner.lookup('service:kredits');
+    kredits.set('contributors', contributors);
+
+    debugger;
 
     this.set('fixtures', contributions);
     await render(hbs`{{contribution-list contributions=fixtures showQuickFilter=true}}`);
diff --git a/tests/integration/components/user-avatar/component-test.js b/tests/integration/components/user-avatar/component-test.js
index 1275f21..674f263 100644
--- a/tests/integration/components/user-avatar/component-test.js
+++ b/tests/integration/components/user-avatar/component-test.js
@@ -8,14 +8,14 @@ module('Integration | Component | user-avatar', function(hooks) {
   setupRenderingTest(hooks);
 
   test('it renders', async function(assert) {
-    this.set('bumi', contributors.findBy('id', '1'));
+    this.set('bumi', contributors.findBy('id', 1));
     await render(hbs`{{user-avatar contributor=bumi}}`);
 
     assert.dom(this.element).hasText('');
   });
 
   test('default image source URL', async function(assert) {
-    this.set('bumi', contributors.findBy('id', '1'));
+    this.set('bumi', contributors.findBy('id', 1));
     await render(hbs`{{user-avatar contributor=bumi}}`);
 
     assert.equal(this.element.querySelector('img').src,
@@ -23,7 +23,7 @@ module('Integration | Component | user-avatar', function(hooks) {
   });
 
   test('size-specific image source URLs', async function(assert) {
-    this.set('bumi', contributors.findBy('id', '1'));
+    this.set('bumi', contributors.findBy('id', 1));
     this.set('size', 'medium');
 
     await render(hbs`{{user-avatar contributor=bumi size=size}}`);
diff --git a/tests/unit/utils/process-contributor-data-test.js b/tests/unit/utils/process-contributor-data-test.js
index f81a58d..f164316 100644
--- a/tests/unit/utils/process-contributor-data-test.js
+++ b/tests/unit/utils/process-contributor-data-test.js
@@ -8,7 +8,7 @@ module('Unit | Utility | process-contributor-data', function() {
 
   test('formats the data correctly', function(assert) {
     // TODO use integers everywhere for IDs
-    assert.ok(typeof result.id === 'string');
+    assert.ok(typeof result.id === 'number');
     assert.ok(typeof result.balance === 'number');
     assert.ok(typeof result.totalKreditsEarned === 'number');
     assert.ok(typeof result.contributionsCount === 'number');