diff --git a/app/components/contribution-list/component.js b/app/components/contribution-list/component.js
index 444d813..24cf332 100644
--- a/app/components/contribution-list/component.js
+++ b/app/components/contribution-list/component.js
@@ -1,7 +1,7 @@
 import Component from '@ember/component';
-import { computed } from '@ember/object';
+import EmberObject, { computed, observer } from '@ember/object';
 import { sort } from '@ember/object/computed';
-import { isPresent } from '@ember/utils';
+import { isEmpty, isPresent } from '@ember/utils';
 import { inject as service } from '@ember/service';
 
 export default Component.extend({
@@ -12,6 +12,7 @@ export default Component.extend({
   classNames: ['contributions'],
 
   selectedContribution: null,
+  expandedGroup: null,
 
   showQuickFilter: false,
   hideSmallContributions: false,
@@ -33,23 +34,97 @@ export default Component.extend({
     return this.contributions.mapBy('kind').uniq();
   }),
 
-  contributionsFiltered: computed('contributions.[]', 'hideSmallContributions', 'contributorId', 'contributionKind', function() {
-    return this.contributions.filter(c => {
-      let included = true;
+  // Groups the contributions by their `groupId` (derived from `url`; see
+  // utils/contribution-grouping-key), then filters the groups: a group is
+  // included when any of its items matches the active filters, and when
+  // included all of its items render (grouped rows stay whole — filtering by
+  // a contributor does not collapse a group into a singleton). Preserves the
+  // input order so the controller's date-sort is retained. Manual
+  // contributions without a URL each form their own single-item group.
+  //
+  // Each group object exposes: groupId, items, contributors, contributorIds,
+  // amount (single contribution's, not a sum), kind, description, url, date,
+  // isGrouped, visibleContributors (capped at 3), extraContributorCount.
+  groupedContributions: computed('contributions.[]', 'hideSmallContributions', 'contributorId', 'contributionKind', function() {
+    const groupsMap = new Map();
+    const orderedGroups = [];
 
-      if (this.hideSmallContributions &&
-          c.amount <= 500) { included = false; }
-
-      if (isPresent(this.contributorId) &&
-          c.contributorId !== parseInt(this.contributorId)) { included = false; }
-
-      if (isPresent(this.contributionKind) &&
-          c.kind !== this.contributionKind) { included = false; }
-
-      return included;
+    this.contributions.forEach(c => {
+      const groupId = c.groupId;
+      if (isEmpty(groupId)) {
+        orderedGroups.push({ groupId: null, items: [c] });
+      } else if (groupsMap.has(groupId)) {
+        groupsMap.get(groupId).items.push(c);
+      } else {
+        const group = { groupId, items: [c] };
+        groupsMap.set(groupId, group);
+        orderedGroups.push(group);
+      }
     });
+
+    return orderedGroups
+      .filter(raw => raw.items.any(c => this.matchesFilters(c)))
+      .map(raw => {
+        const items = raw.items;
+        const first = items.firstObject;
+        const contributorIds = items.mapBy('contributorId').uniq();
+        const contributors = contributorIds
+          .map(id => this.contributors.findBy('id', id))
+          .filter(Boolean);
+
+        return EmberObject.create({
+          key: raw.groupId || `c-${first.id}`,
+          groupId: raw.groupId,
+          items,
+          contributors,
+          contributorIds,
+          amount: first ? first.amount : null,
+          kind: first ? first.kind : null,
+          description: first ? first.description : null,
+          url: first ? first.url : null,
+          date: first ? first.date : null,
+          isGrouped: items.length > 1,
+          visibleContributors: contributors.slice(0, 3),
+          extraContributorCount: Math.max(0, contributors.length - 3)
+        });
+      });
   }),
 
+  // Shared filter predicates for a single contribution. Used to decide group
+  // inclusion in `groupedContributions`. A group is shown when any of its
+  // items passes; "hide small contributions" thus keeps a group as long as
+  // any item is above the threshold.
+  matchesFilters (c) {
+    if (this.hideSmallContributions && c.amount <= 500) return false;
+    if (isPresent(this.contributorId) &&
+        c.contributorId !== parseInt(this.contributorId)) return false;
+    if (isPresent(this.contributionKind) &&
+        c.kind !== this.contributionKind) return false;
+    return true;
+  },
+
+  // Auto-expands the group containing the selected contribution so the
+  // selected child row is visible with the `selected` highlight.
+  autoExpandSelected: observer('selectedContributionId', function() {
+    this._autoExpandSelected();
+  }),
+
+  _autoExpandSelected () {
+    const selectedId = this.selectedContributionId;
+    if (!selectedId) return;
+    const group = this.groupedContributions.find(g =>
+      g.items.findBy('id', selectedId)
+    );
+    if (group && group.isGrouped && this.expandedGroup !== group.groupId) {
+      this.set('expandedGroup', group.groupId);
+    }
+  },
+
+  init () {
+    this._super(...arguments);
+    this._autoExpandSelected();
+  },
+
   actions: {
 
     veto (contributionId) {
@@ -62,6 +137,14 @@ export default Component.extend({
 
     openContributionDetails(contribution) {
       this.router.transitionTo('dashboard.contributions.show', contribution);
+    },
+
+    toggleGroup (group) {
+      if (this.expandedGroup === group.groupId) {
+        this.set('expandedGroup', null);
+      } else {
+        this.set('expandedGroup', group.groupId);
+      }
     }
 
   }
diff --git a/app/components/contribution-list/template.hbs b/app/components/contribution-list/template.hbs
index be603d0..4359668 100644
--- a/app/components/contribution-list/template.hbs
+++ b/app/components/contribution-list/template.hbs
@@ -30,27 +30,76 @@
 {{/if}}
 
 <ul class="item-list contribution-list {{if @loading 'loading'}}">
-  {{#each this.contributionsFiltered as |contribution|}}
-    <li role="button" data-contribution-id={{contribution.id}}
-        {{action "openContributionDetails" contribution}}
-        class="{{item-status contribution}}{{if (eq contribution.id @selectedContributionId) " selected"}}">
-      <p class="meta">
-        <span class="recipient"><UserAvatar @contributor={{contribution.contributor}} /></span>
-        <span class="category {{contribution.kind}}">({{contribution.kind}})</span>
-        <span class="title">{{contribution.description}}</span>
-      </p>
-      <p class="kredits-amount">
-        <span class="amount">{{contribution.amount}}</span><span class="symbol">₭S</span>
-      </p>
-      {{#unless contribution.vetoed}}
-        {{#unless (is-confirmed-contribution contribution)}}
-          <p class="voting">
-            {{input type="button" class="button small danger" value="veto"
-                    click=(action "veto" contribution.id)
-                    disabled=contribution.hasPendingChanges}}
+  {{#each this.groupedContributions key="key" as |group|}}
+    {{#if group.isGrouped}}
+      <li role="button" data-group-id={{group.groupId}}
+          {{action "toggleGroup" group}}
+          class="grouped {{if (eq this.expandedGroup group.groupId) "expanded"}}">
+        <p class="meta">
+          <span class="avatars">
+            {{#each group.visibleContributors as |contributor|}}
+              <UserAvatar @contributor={{contributor}} />
+            {{/each}}
+            {{#if group.extraContributorCount}}
+              <span class="avatar-overflow">+{{group.extraContributorCount}}</span>
+            {{/if}}
+          </span>
+          <span class="category {{group.kind}}">({{group.kind}})</span>
+          <span class="title">{{group.description}}</span>
+        </p>
+        <p class="kredits-amount">
+          <span class="amount">{{group.amount}}</span><span class="symbol">₭S</span>
+        </p>
+      </li>
+      {{#if (eq this.expandedGroup group.groupId)}}
+        {{#each group.items key="id" as |contribution|}}
+          <li role="button" data-contribution-id={{contribution.id}}
+              {{action "openContributionDetails" contribution}}
+              class="group-item {{item-status contribution}}{{if (eq contribution.id @selectedContributionId) " selected"}}">
+            <p class="meta">
+              <span class="recipient"><UserAvatar @contributor={{contribution.contributor}} /></span>
+              <span class="category {{contribution.kind}}">({{contribution.kind}})</span>
+              <span class="title">{{contribution.description}}</span>
+            </p>
+            <p class="kredits-amount">
+              <span class="amount">{{contribution.amount}}</span><span class="symbol">₭S</span>
+            </p>
+            {{#unless contribution.vetoed}}
+              {{#unless (is-confirmed-contribution contribution)}}
+                <p class="voting">
+                  {{input type="button" class="button small danger" value="veto"
+                          click=(action "veto" contribution.id)
+                          disabled=contribution.hasPendingChanges}}
+                </p>
+              {{/unless}}
+            {{/unless}}
+          </li>
+        {{/each}}
+      {{/if}}
+    {{else}}
+      {{#each group.items key="id" as |contribution|}}
+        <li role="button" data-contribution-id={{contribution.id}}
+            {{action "openContributionDetails" contribution}}
+            class="{{item-status contribution}}{{if (eq contribution.id @selectedContributionId) " selected"}}">
+          <p class="meta">
+            <span class="recipient"><UserAvatar @contributor={{contribution.contributor}} /></span>
+            <span class="category {{contribution.kind}}">({{contribution.kind}})</span>
+            <span class="title">{{contribution.description}}</span>
           </p>
-        {{/unless}}
-      {{/unless}}
-    </li>
+          <p class="kredits-amount">
+            <span class="amount">{{contribution.amount}}</span><span class="symbol">₭S</span>
+          </p>
+          {{#unless contribution.vetoed}}
+            {{#unless (is-confirmed-contribution contribution)}}
+              <p class="voting">
+                {{input type="button" class="button small danger" value="veto"
+                        click=(action "veto" contribution.id)
+                        disabled=contribution.hasPendingChanges}}
+              </p>
+            {{/unless}}
+          {{/unless}}
+        </li>
+      {{/each}}
+    {{/if}}
   {{/each}}
-</ul>
\ No newline at end of file
+</ul>
diff --git a/app/controllers/dashboard/contributions/show.js b/app/controllers/dashboard/contributions/show.js
index cd9a097..00e7d8f 100644
--- a/app/controllers/dashboard/contributions/show.js
+++ b/app/controllers/dashboard/contributions/show.js
@@ -1,12 +1,19 @@
 
 import Controller from '@ember/controller';
 import { computed } from '@ember/object';
+import { inject as service } from '@ember/service';
 import config from 'kredits-web/config/environment';
 
 export default Controller.extend({
 
+  kredits: service(),
+
   ipfsGatewayUrl: computed(function() {
     return config.ipfs.gatewayUrl;
+  }),
+
+  siblingContributions: computed('model.groupId', 'kredits.contributions.[]', function() {
+    return this.kredits.siblingContributions(this.model);
   })
 
 });
diff --git a/app/models/contribution.js b/app/models/contribution.js
index f57bbed..75bd7fe 100644
--- a/app/models/contribution.js
+++ b/app/models/contribution.js
@@ -2,6 +2,8 @@ import EmberObject, { computed } from '@ember/object';
 import { isEmpty, isPresent } from '@ember/utils';
 import moment from 'moment';
 
+import contributionGroupingKey from 'kredits-web/utils/contribution-grouping-key';
+
 export default EmberObject.extend({
   // Contract
   id: null,
@@ -44,6 +46,14 @@ export default EmberObject.extend({
     return isPresent(this.pendingTx);
   }),
 
+  // Stable key shared by all per-contributor contributions created for the
+  // same piece of work (derived from `url`, `description`, `date`, `amount`,
+  // and `kind`). Contributions without enough fields to derive a key return
+  // null and are treated as singletons (not grouped).
+  groupId: computed('url', 'description', 'date', 'amount', 'kind', function() {
+    return contributionGroupingKey(this);
+  }),
+
   serialize () {
     return JSON.stringify(this);
   }
diff --git a/app/services/kredits.js b/app/services/kredits.js
index 641af86..eaec074 100644
--- a/app/services/kredits.js
+++ b/app/services/kredits.js
@@ -227,6 +227,74 @@ export default Service.extend({
     return kreditsByContributor;
   }),
 
+  // Groups contributions that were created together for the same
+  // issue/pull request (one contribution per contributor). The grouping key
+  // is the contribution's `url` (see utils/contribution-grouping-key).
+  // Manual contributions without a URL each form their own single-item group
+  // (they are never collapsed together, since `null` is not a real key).
+  //
+  // Each group is an EmberObject with: groupId, items, contributors,
+  // contributorIds, totalAmount, kind, description, url, date, isGrouped
+  // (true when more than one contribution shares the key).
+  contributionsGrouped: computed('contributions.[]', function() {
+    const groupsMap = new Map();
+    const singletons = [];
+
+    this.contributions.forEach(c => {
+      const groupId = c.groupId;
+      if (isEmpty(groupId)) {
+        singletons.push(c);
+      } else if (groupsMap.has(groupId)) {
+        groupsMap.get(groupId).items.push(c);
+      } else {
+        groupsMap.set(groupId, { groupId, items: [c] });
+      }
+    });
+
+    const groups = [
+      ...groupsMap.values(),
+      ...singletons.map(c => ({ groupId: null, items: [c] }))
+    ];
+
+    return groups.map(group => {
+      const items = group.items;
+      const first = items.firstObject;
+      const contributorIds = items.mapBy('contributorId').uniq();
+      const contributors = contributorIds
+        .map(id => this.contributors.findBy('id', id))
+        .filter(Boolean);
+      const totalAmount = items
+        .mapBy('amount')
+        .reduce((a, b) => a + (b || 0), 0);
+
+      return EmberObject.create({
+        groupId: group.groupId,
+        items,
+        contributors,
+        contributorIds,
+        totalAmount,
+        kind: first ? first.kind : null,
+        description: first ? first.description : null,
+        url: first ? first.url : null,
+        date: first ? first.date : null,
+        isGrouped: items.length > 1
+      });
+    });
+  }),
+
+  // Returns the other contributions that share a grouping key with the given
+  // contribution (i.e. the co-contributors' contributions). Returns an empty
+  // array when the contribution has no group (manual, no URL) or has no
+  // siblings.
+  siblingContributions (contribution) {
+    if (!contribution) return [];
+    const groupId = contribution.groupId;
+    if (isEmpty(groupId)) return [];
+    const group = this.contributionsGrouped.findBy('groupId', groupId);
+    if (!group) return [];
+    return group.items.filter(c => c !== contribution);
+  },
+
   contributionsUnconfirmed: computed('contributions.[]', 'currentBlock', function() {
     return this.contributions
                .filter(c => c.confirmedAt > this.currentBlock);
diff --git a/app/styles/_layout.scss b/app/styles/_layout.scss
index e65c4ee..bb0f120 100644
--- a/app/styles/_layout.scss
+++ b/app/styles/_layout.scss
@@ -97,7 +97,7 @@ main {
   }
 }
 
-@media (min-width: 550px) {
+@include media-min(small) {
   main {
     &#dashboard {
       grid-column-gap: 4rem;
@@ -107,10 +107,9 @@ main {
         "stats contributions";
 
       &.with-details {
-        grid-column-gap: 3rem;
-        grid-template-columns: 2fr 4fr 2fr;
+        grid-template-columns: 1fr;
         grid-template-areas:
-          "stats contributions details";
+          "details";
       }
     }
 
@@ -123,6 +122,23 @@ main {
   }
 }
 
+@include media-min(medium) {
+  main#dashboard.with-details {
+    grid-column-gap: 3rem;
+    grid-template-columns: 2fr 4fr 2fr;
+    grid-template-areas:
+      "stats contributions details";
+
+    #details {
+      position: sticky;
+      top: 2rem;
+      align-self: start;
+      max-height: calc(100vh - 4rem);
+      overflow-y: auto;
+    }
+  }
+}
+
 main section {
   margin-bottom: 5rem;
 
diff --git a/app/styles/components/_contribution-details.scss b/app/styles/components/_contribution-details.scss
index a2071a0..af086e5 100644
--- a/app/styles/components/_contribution-details.scss
+++ b/app/styles/components/_contribution-details.scss
@@ -49,6 +49,55 @@ section#contribution-details {
         text-decoration: underline;
       }
     }
+
+    .co-contributors {
+      margin-top: 2rem;
+      padding-top: 2rem;
+      border-top: 1px solid $item-border-color;
+
+      h4 {
+        font-size: 1.2rem;
+        margin-bottom: 1rem;
+        color: $body-text-color;
+      }
+
+      ul {
+        list-style: none;
+
+        li {
+          display: flex;
+          align-items: center;
+          padding: 0.5rem 0;
+          gap: 0.5rem;
+
+          .co-contributor {
+            display: inline-flex;
+            align-items: center;
+            text-decoration: none;
+            color: $body-text-color;
+            flex: 1;
+
+            .name {
+              margin-left: 0.5rem;
+            }
+
+            .amount {
+              margin-left: auto;
+              font-weight: 500;
+            }
+
+            .symbol {
+              font-size: 0.8rem;
+              padding-left: 0.2rem;
+            }
+
+            &:hover .name {
+              color: $primary-color;
+            }
+          }
+        }
+      }
+    }
   }
 
   .actions {
@@ -88,7 +137,7 @@ section#contribution-details {
 
 // On small screens, hide intro text, contributor and contributions list when
 // showing details
-@include media-max(small) {
+@include media-max(medium) {
   #dashboard.with-details {
     #contributions, #stats {
       display: none;
diff --git a/app/styles/components/_contribution-list.scss b/app/styles/components/_contribution-list.scss
index 2c6034d..c97e9a0 100644
--- a/app/styles/components/_contribution-list.scss
+++ b/app/styles/components/_contribution-list.scss
@@ -41,6 +41,69 @@ ul.contribution-list {
       opacity: 0.6;
     }
 
+    &.grouped {
+      grid-template-columns: auto 5rem;
+
+      .avatars {
+        display: inline-flex;
+        align-items: center;
+        vertical-align: middle;
+
+        img.avatar {
+          margin-right: 0;
+          margin-left: -0.6rem;
+          border: 2px solid $item-background-color;
+          box-sizing: content-box;
+          z-index: 1;
+          position: relative;
+
+          &:first-child {
+            margin-left: 0;
+            z-index: 3;
+          }
+
+          &:nth-child(2) {
+            z-index: 2;
+          }
+        }
+
+        .avatar-overflow {
+          display: inline-flex;
+          align-items: center;
+          justify-content: center;
+          width: 2rem;
+          height: 2rem;
+          margin-left: -0.6rem;
+          border-radius: 1rem;
+          background-color: #232323;
+          color: #fff;
+          font-size: 0.8rem;
+          font-weight: 500;
+          border: 2px solid $item-background-color;
+          box-sizing: content-box;
+          z-index: 0;
+          position: relative;
+        }
+      }
+
+      &.expanded {
+        border-bottom: none;
+      }
+    }
+
+    &.group-item {
+      padding-left: 2.8rem;
+      background-color: rgba(255,255,255,0.05);
+
+      &.selected {
+        background-color: $item-highlighted-background-color;
+      }
+
+      &:not(:last-child) {
+        border-bottom: 1px solid $item-border-color;
+      }
+    }
+
     p {
       align-self: center;
       margin: 0;
diff --git a/app/templates/dashboard/contributions/show.hbs b/app/templates/dashboard/contributions/show.hbs
index 52d6b3d..a6a56ed 100644
--- a/app/templates/dashboard/contributions/show.hbs
+++ b/app/templates/dashboard/contributions/show.hbs
@@ -32,6 +32,22 @@
         </a>
       </p>
     {{/if}}
+    {{#if this.siblingContributions.length}}
+      <div class="co-contributors">
+        <h4>Also contributed to this</h4>
+        <ul>
+          {{#each this.siblingContributions as |sibling|}}
+            <li>
+              <LinkTo @route="dashboard.contributions.show" @model={{sibling}} class="co-contributor">
+                <UserAvatar @contributor={{sibling.contributor}} />
+                <span class="name">{{sibling.contributor.name}}</span>
+                <span class="amount">{{sibling.amount}}</span><span class="symbol">₭S</span>
+              </LinkTo>
+            </li>
+          {{/each}}
+        </ul>
+      </div>
+    {{/if}}
     {{#if this.model.vetoed}}
       <div class="hint vetoed">
         <div class="icon">
diff --git a/app/utils/contribution-grouping-key.js b/app/utils/contribution-grouping-key.js
new file mode 100644
index 0000000..92763cc
--- /dev/null
+++ b/app/utils/contribution-grouping-key.js
@@ -0,0 +1,29 @@
+import ethers from 'ethers';
+import { isEmpty } from '@ember/utils';
+
+// Derives a stable grouping key for a contribution, so that contributions
+// created for the same issue/pull request (one per contributor) can be
+// linked together in the UI.
+//
+// The key is a 6-char keccak256 prefix of a combination of fields:
+// url (optional), description, date, amount, kind. When the URL is present
+// (bot contributions) it is included; when absent (manual contributions)
+// the remaining fields still produce a reliable key. All of description,
+// date, amount, and kind must be present — if any is missing, the
+// contribution is treated as a singleton (null key).
+
+export default function contributionGroupingKey (contribution) {
+  if (!contribution) return null;
+
+  const { url, description, date, amount, kind } = contribution;
+
+  if (isEmpty(description) || isEmpty(date) || isEmpty(amount) || isEmpty(kind)) {
+    return null;
+  }
+
+  const input = isEmpty(url)
+    ? `${description}|${date}|${amount}|${kind}`
+    : `${url}|${description}|${date}|${amount}|${kind}`;
+
+  return ethers.utils.id(input).slice(2, 8);
+}
diff --git a/package-lock.json b/package-lock.json
index 9258dda..96d88f3 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -61,7 +61,7 @@
         "web3-utils": "^1.7.3"
       },
       "engines": {
-        "node": ">= 14"
+        "node": ">= 22"
       }
     },
     "node_modules/@ampproject/remapping": {
@@ -5291,6 +5291,17 @@
         "url": "https://bevry.me/fund"
       }
     },
+    "node_modules/bindings": {
+      "version": "1.5.0",
+      "resolved": "https://registry.npmjs.org/bindings/-/bindings-1.5.0.tgz",
+      "integrity": "sha512-p2q/t/mhvuOj/UeLlV6566GD/guowlr0hHxClI0W9m7MWYkL1F0hLo+0Aexs9HSPCtR1SXQ0TD3MMKrXZajbiQ==",
+      "dev": true,
+      "license": "MIT",
+      "optional": true,
+      "dependencies": {
+        "file-uri-to-path": "1.0.0"
+      }
+    },
     "node_modules/bl": {
       "version": "4.1.0",
       "dev": true,
@@ -15167,6 +15178,14 @@
         "node": "^10.12.0 || >=12.0.0"
       }
     },
+    "node_modules/file-uri-to-path": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/file-uri-to-path/-/file-uri-to-path-1.0.0.tgz",
+      "integrity": "sha512-0Zt+s3L7Vf1biwWZ29aARiVYLx7iMGnEUl9x33fbB/j3jR81u/O2LbqK+Bm1CDSNDKVtJ/YjwY7TUd5SkeLQLw==",
+      "dev": true,
+      "license": "MIT",
+      "optional": true
+    },
     "node_modules/filesize": {
       "version": "6.4.0",
       "dev": true,
@@ -15738,6 +15757,21 @@
       "dev": true,
       "license": "ISC"
     },
+    "node_modules/fsevents": {
+      "version": "2.3.3",
+      "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.3.tgz",
+      "integrity": "sha512-5xoDfX+fL7faATnagmWPpbFtwh/R77WmMMqqHGS65C3vvB0YHrgF+B1YmZ3441tMj5n63k0212XNoJwzlhffQw==",
+      "dev": true,
+      "hasInstallScript": true,
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "darwin"
+      ],
+      "engines": {
+        "node": "^8.16.0 || ^10.6.0 || >=11.0.0"
+      }
+    },
     "node_modules/function-bind": {
       "version": "1.1.1",
       "dev": true,
@@ -18796,6 +18830,14 @@
       "dev": true,
       "license": "ISC"
     },
+    "node_modules/nan": {
+      "version": "2.28.0",
+      "resolved": "https://registry.npmjs.org/nan/-/nan-2.28.0.tgz",
+      "integrity": "sha512-fTsDz99OTq2sVePhGdp4qQhggZFtKr64ZNVyVajRKtMOkJxYekplBh577PiJB12v/D3s2E5cGtOI45LWp6rnLQ==",
+      "dev": true,
+      "license": "MIT",
+      "optional": true
+    },
     "node_modules/nanoid": {
       "version": "3.3.4",
       "dev": true,
@@ -23656,6 +23698,26 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/watchpack-chokidar2/node_modules/fsevents": {
+      "version": "1.2.13",
+      "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-1.2.13.tgz",
+      "integrity": "sha512-oWb1Z6mkHIskLzEJ/XWX0srkpkTQ7vaopMQkyaEIoq0fmtFVxOthb8cCxeT+p3ynTdkk/RZwbgG4brR5BeWECw==",
+      "deprecated": "Upgrade to fsevents v2 to mitigate potential security issues",
+      "dev": true,
+      "hasInstallScript": true,
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "darwin"
+      ],
+      "dependencies": {
+        "bindings": "^1.5.0",
+        "nan": "^2.12.1"
+      },
+      "engines": {
+        "node": ">= 4.0"
+      }
+    },
     "node_modules/watchpack-chokidar2/node_modules/glob-parent": {
       "version": "3.1.0",
       "dev": true,
@@ -27829,6 +27891,16 @@
       "version": "2.3.0",
       "dev": true
     },
+    "bindings": {
+      "version": "1.5.0",
+      "resolved": "https://registry.npmjs.org/bindings/-/bindings-1.5.0.tgz",
+      "integrity": "sha512-p2q/t/mhvuOj/UeLlV6566GD/guowlr0hHxClI0W9m7MWYkL1F0hLo+0Aexs9HSPCtR1SXQ0TD3MMKrXZajbiQ==",
+      "dev": true,
+      "optional": true,
+      "requires": {
+        "file-uri-to-path": "1.0.0"
+      }
+    },
     "bl": {
       "version": "4.1.0",
       "dev": true,
@@ -35048,6 +35120,13 @@
         "flat-cache": "^3.0.4"
       }
     },
+    "file-uri-to-path": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/file-uri-to-path/-/file-uri-to-path-1.0.0.tgz",
+      "integrity": "sha512-0Zt+s3L7Vf1biwWZ29aARiVYLx7iMGnEUl9x33fbB/j3jR81u/O2LbqK+Bm1CDSNDKVtJ/YjwY7TUd5SkeLQLw==",
+      "dev": true,
+      "optional": true
+    },
     "filesize": {
       "version": "6.4.0",
       "dev": true
@@ -35471,6 +35550,13 @@
       "version": "1.0.0",
       "dev": true
     },
+    "fsevents": {
+      "version": "2.3.3",
+      "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.3.tgz",
+      "integrity": "sha512-5xoDfX+fL7faATnagmWPpbFtwh/R77WmMMqqHGS65C3vvB0YHrgF+B1YmZ3441tMj5n63k0212XNoJwzlhffQw==",
+      "dev": true,
+      "optional": true
+    },
     "function-bind": {
       "version": "1.1.1",
       "dev": true
@@ -37591,6 +37677,13 @@
       "version": "0.0.8",
       "dev": true
     },
+    "nan": {
+      "version": "2.28.0",
+      "resolved": "https://registry.npmjs.org/nan/-/nan-2.28.0.tgz",
+      "integrity": "sha512-fTsDz99OTq2sVePhGdp4qQhggZFtKr64ZNVyVajRKtMOkJxYekplBh577PiJB12v/D3s2E5cGtOI45LWp6rnLQ==",
+      "dev": true,
+      "optional": true
+    },
     "nanoid": {
       "version": "3.3.4",
       "dev": true
@@ -40981,6 +41074,17 @@
             "to-regex-range": "^2.1.0"
           }
         },
+        "fsevents": {
+          "version": "1.2.13",
+          "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-1.2.13.tgz",
+          "integrity": "sha512-oWb1Z6mkHIskLzEJ/XWX0srkpkTQ7vaopMQkyaEIoq0fmtFVxOthb8cCxeT+p3ynTdkk/RZwbgG4brR5BeWECw==",
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "bindings": "^1.5.0",
+            "nan": "^2.12.1"
+          }
+        },
         "glob-parent": {
           "version": "3.1.0",
           "dev": true,
diff --git a/tests/fixtures/contributions.js b/tests/fixtures/contributions.js
index 5a809f0..8a22cac 100644
--- a/tests/fixtures/contributions.js
+++ b/tests/fixtures/contributions.js
@@ -5,15 +5,17 @@ import processContributionData from 'kredits-web/utils/process-contribution-data
 const items = [];
 
 const data = [
-  { id: 1, contributorId: 1, confirmedAt: 1000, claimed: false, vetoed: false, amount: 1500, kind: 'dev' },
-  { id: 2, contributorId: 1, confirmedAt: 1000, claimed: false, vetoed: false, amount: 5000, kind: 'ops' },
-  { id: 3, contributorId: 2, confirmedAt: 1000, claimed: false, vetoed: false, amount: 1500, kind: 'ops' },
-  { id: 4, contributorId: 2, confirmedAt: 1000, claimed: false, vetoed: false, amount: 1500, kind: 'docs' },
-  { id: 5, contributorId: 1, confirmedAt: 1000, claimed: false, vetoed: false, amount: 5000, kind: 'design' },
-  { id: 6, contributorId: 1, confirmedAt: 1000, claimed: false, vetoed: true, amount: 500, kind: 'dev' },
-  { id: 7, contributorId: 3, confirmedAt: 2000, claimed: false, vetoed: false, amount: 5000, kind: 'dev' },
-  { id: 8, contributorId: 1, confirmedAt: 2000, claimed: false, vetoed: false, amount: 1500, kind: 'community' },
-  { id: 9, contributorId: 3, confirmedAt: 2000, claimed: false, vetoed: true, amount: 1500, kind: 'docs' },
+  { id: 1, contributorId: 1, confirmedAt: 1000, claimed: false, vetoed: false, amount: 1500, kind: 'dev', url: 'https://github.com/67P/kredits-contracts/pull/196', description: 'Chore/dependency updates', date: '2020-05-27' },
+  { id: 2, contributorId: 1, confirmedAt: 1000, claimed: false, vetoed: false, amount: 5000, kind: 'ops', description: 'Server maintenance', date: '2020-05-27' },
+  { id: 3, contributorId: 2, confirmedAt: 1000, claimed: false, vetoed: false, amount: 1500, kind: 'dev', url: 'https://github.com/67P/kredits-contracts/pull/196', description: 'Chore/dependency updates', date: '2020-05-27' },
+  { id: 4, contributorId: 2, confirmedAt: 1000, claimed: false, vetoed: false, amount: 1500, kind: 'docs', description: 'API documentation', date: '2020-05-28' },
+  { id: 5, contributorId: 1, confirmedAt: 1000, claimed: false, vetoed: false, amount: 5000, kind: 'design', description: 'UI redesign', date: '2020-05-29' },
+  { id: 6, contributorId: 1, confirmedAt: 1000, claimed: false, vetoed: true, amount: 500, kind: 'dev', description: 'Minor fix', date: '2020-05-30' },
+  { id: 7, contributorId: 3, confirmedAt: 2000, claimed: false, vetoed: false, amount: 5000, kind: 'dev', url: 'https://gitea.kosmos.org/kredits/kredits-web/issues/231', description: 'Grouped contributions UI', date: '2020-06-01' },
+  { id: 8, contributorId: 1, confirmedAt: 2000, claimed: false, vetoed: false, amount: 5000, kind: 'dev', url: 'https://gitea.kosmos.org/kredits/kredits-web/issues/231', description: 'Grouped contributions UI', date: '2020-06-01' },
+  { id: 9, contributorId: 3, confirmedAt: 2000, claimed: false, vetoed: true, amount: 1500, kind: 'docs', description: 'Minor docs fix', date: '2020-06-02' },
+  { id: 10, contributorId: 2, confirmedAt: 2000, claimed: false, vetoed: false, amount: 1500, kind: 'dev', description: 'Pair programming session', date: '2020-06-03' },
+  { id: 11, contributorId: 3, confirmedAt: 2000, claimed: false, vetoed: false, amount: 1500, kind: 'dev', description: 'Pair programming session', date: '2020-06-03' },
 ];
 
 data.forEach(attrs => {
diff --git a/tests/integration/components/contribution-list/component-test.js b/tests/integration/components/contribution-list/component-test.js
index b7f87ba..febf8e6 100644
--- a/tests/integration/components/contribution-list/component-test.js
+++ b/tests/integration/components/contribution-list/component-test.js
@@ -8,11 +8,17 @@ import contributions from '../../../fixtures/contributions';
 module('Integration | Component | contribution-list', function(hooks) {
   setupRenderingTest(hooks);
 
-  test('it renders all contributions', async function(assert) {
+  test('it renders all contributions with grouped rows collapsed', async function(assert) {
+    let kredits = this.owner.lookup('service:kredits');
+    kredits.set('contributors', contributors);
+
     this.set('fixtures', contributions);
     await render(hbs`{{contribution-list contributions=fixtures}}`);
 
-    assert.equal(this.element.querySelectorAll('li').length, 9);
+    // 11 contributions: 3 groups ({1,3}, {7,8}, {10,11}) + 5 singletons = 8 rows
+    assert.equal(this.element.querySelectorAll('li').length, 8, '8 top-level rows when collapsed');
+    assert.equal(this.element.querySelectorAll('li.grouped').length, 3, '3 grouped headers');
+    assert.equal(this.element.querySelectorAll('li.group-item').length, 0, 'no expanded sub-items');
   });
 
   test('it renders filtered contributions', async function(assert) {
@@ -23,12 +29,86 @@ module('Integration | Component | contribution-list', function(hooks) {
     await render(hbs`{{contribution-list contributions=fixtures showQuickFilter=true}}`);
 
     await fillIn('.filter-contributor select', '1');
+    // Contributor 1 is in ids 1, 2, 5, 6, 8. Grouped rows stay whole: id 1's
+    // group (with id 3) and id 8's group (with id 7) show as grouped rows
+    // because id 1 / id 8 match; ids 2, 5, 6 are singletons. 5 top-level rows.
     assert.equal(this.element.querySelectorAll('li').length, 5, 'select contributor');
 
     await click('.filter-contribution-size input');
+    // Hide small (<=500): drops id 6 only. Grouped rows stay (matching items
+    // are 1500/5000). 4 top-level rows.
     assert.equal(this.element.querySelectorAll('li').length, 4, 'hide small contributions');
 
     await fillIn('.filter-contribution-kind select', 'dev');
-    assert.equal(this.element.querySelectorAll('li').length, 1, 'select kind');
+    // Kind dev (still filtered to contributor 1, hide small on): only groups
+    // where a single item passes all three filters survive. Group {1,3}: id 1
+    // is contributor 1 + dev → included. Group {7,8}: id 8 is contributor 1 +
+    // dev → included. Singletons id 2 (ops), id 5 (design) → excluded. 2 rows.
+    assert.equal(this.element.querySelectorAll('li').length, 2, 'select kind');
+  });
+
+  test('filtering by contributor keeps grouped rows whole', async function(assert) {
+    let kredits = this.owner.lookup('service:kredits');
+    kredits.set('contributors', contributors);
+
+    this.set('fixtures', contributions);
+    await render(hbs`{{contribution-list contributions=fixtures showQuickFilter=true}}`);
+
+    await fillIn('.filter-contributor select', '1');
+
+    // The first row is the group containing id 1 (contributor 1) and id 3
+    // (contributor 2) — it stays grouped, not collapsed to a singleton.
+    const firstRow = this.element.querySelector('li');
+    assert.ok(firstRow.classList.contains('grouped'), 'first row is still grouped');
+    assert.equal(firstRow.querySelectorAll('.avatars img').length, 2, 'shows both contributors avatars');
+  });
+
+  test('grouped row expands on click to reveal sub-items', async function(assert) {
+    let kredits = this.owner.lookup('service:kredits');
+    kredits.set('contributors', contributors);
+
+    this.set('fixtures', contributions);
+    await render(hbs`{{contribution-list contributions=fixtures}}`);
+
+    assert.equal(this.element.querySelectorAll('li.group-item').length, 0, 'no sub-items when collapsed');
+
+    await click('.grouped:first-child');
+
+    assert.equal(this.element.querySelectorAll('li.group-item').length, 2, '2 sub-items when expanded');
+    assert.ok(this.element.querySelector('.grouped').classList.contains('expanded'), 'header has expanded class');
+
+    await click('.grouped:first-child');
+    assert.equal(this.element.querySelectorAll('li.group-item').length, 0, 'sub-items hidden when collapsed');
+  });
+
+  test('grouped row shows stacked avatars and single amount', async function(assert) {
+    let kredits = this.owner.lookup('service:kredits');
+    kredits.set('contributors', contributors);
+
+    this.set('fixtures', contributions);
+    await render(hbs`{{contribution-list contributions=fixtures}}`);
+
+    const firstGroup = this.element.querySelector('.grouped');
+    // Group ids 1+3 → 2 contributors → 2 avatars, no overflow
+    assert.equal(firstGroup.querySelectorAll('.avatars img').length, 2, '2 avatar images');
+    assert.equal(firstGroup.querySelectorAll('.avatar-overflow').length, 0, 'no overflow bubble for 2 contributors');
+    // Single amount (first item's amount = 1500, not the sum)
+    assert.equal(firstGroup.querySelector('.amount').textContent.trim(), '1500', 'shows single contribution amount');
+  });
+
+  test('auto-expands when selectedContributionId is a group child', async function(assert) {
+    let kredits = this.owner.lookup('service:kredits');
+    kredits.set('contributors', contributors);
+
+    this.set('fixtures', contributions);
+    this.set('selectedId', 3);
+
+    await render(hbs`{{contribution-list contributions=fixtures selectedContributionId=selectedId}}`);
+
+    assert.equal(this.element.querySelectorAll('li.group-item').length, 2, 'group auto-expanded');
+
+    const selectedChild = this.element.querySelector('.group-item.selected');
+    assert.ok(selectedChild, 'selected child has selected class');
+    assert.equal(selectedChild.dataset.contributionId, '3', 'correct child is selected');
   });
 });
diff --git a/tests/unit/controllers/dashboard/contributions/show-test.js b/tests/unit/controllers/dashboard/contributions/show-test.js
new file mode 100644
index 0000000..724af21
--- /dev/null
+++ b/tests/unit/controllers/dashboard/contributions/show-test.js
@@ -0,0 +1,34 @@
+import { module, test } from 'qunit';
+import { setupTest } from 'ember-qunit';
+import contributors from '../../../../fixtures/contributors';
+import contributions from '../../../../fixtures/contributions';
+
+module('Unit | Controller | dashboard/contributions/show', function(hooks) {
+  setupTest(hooks);
+
+  test('#siblingContributions returns co-contributor contributions for a grouped contribution', function(assert) {
+    let kredits = this.owner.lookup('service:kredits');
+    kredits.set('contributors', contributors);
+    kredits.set('contributions', contributions);
+
+    let controller = this.owner.lookup('controller:dashboard.contributions.show');
+    // id=1 shares a url with id=3
+    controller.set('model', contributions.findBy('id', 1));
+
+    const siblings = controller.siblingContributions;
+    assert.equal(siblings.length, 1, 'one sibling');
+    assert.equal(siblings[0].id, 3, 'sibling is contribution 3');
+  });
+
+  test('#siblingContributions returns empty for a manual contribution without url', function(assert) {
+    let kredits = this.owner.lookup('service:kredits');
+    kredits.set('contributors', contributors);
+    kredits.set('contributions', contributions);
+
+    let controller = this.owner.lookup('controller:dashboard.contributions.show');
+    // id=2 has no url
+    controller.set('model', contributions.findBy('id', 2));
+
+    assert.deepEqual(controller.siblingContributions, [], 'no siblings for manual contribution');
+  });
+});
diff --git a/tests/unit/services/kredits-test.js b/tests/unit/services/kredits-test.js
index 16b5ca4..276b888 100644
--- a/tests/unit/services/kredits-test.js
+++ b/tests/unit/services/kredits-test.js
@@ -23,7 +23,7 @@ module('Unit | Service | kredits', function(hooks) {
     service.set('currentBlock', 1023);
 
     const items = service.contributionsUnconfirmed;
-    assert.equal(items.length, 3);
+    assert.equal(items.length, 5);
   });
 
   test('#kreditsByContributor', function(assert) {
@@ -38,18 +38,18 @@ module('Unit | Service | kredits', function(hooks) {
 
     const c1 = kreditsByContributor.find(k => k.contributor.id == 1);
     assert.equal(c1.amountConfirmed, 11500, 'correct amount confirmed');
-    assert.equal(c1.amountUnconfirmed, 1500, 'correct amount unconfirmed');
-    assert.equal(c1.amountTotal, 13000, 'correct amount total');
+    assert.equal(c1.amountUnconfirmed, 5000, 'correct amount unconfirmed');
+    assert.equal(c1.amountTotal, 16500, 'correct amount total');
 
     const c2 = kreditsByContributor.find(k => k.contributor.id == 2);
     assert.equal(c2.amountConfirmed, 3000, 'correct amount confirmed');
-    assert.equal(c2.amountUnconfirmed, 0, 'correct amount unconfirmed');
-    assert.equal(c2.amountTotal, 3000, 'correct amount total');
+    assert.equal(c2.amountUnconfirmed, 1500, 'correct amount unconfirmed');
+    assert.equal(c2.amountTotal, 4500, 'correct amount total');
 
     const c3 = kreditsByContributor.find(k => k.contributor.id == 3);
     assert.equal(c3.amountConfirmed, 0, 'correct amount confirmed');
-    assert.equal(c3.amountUnconfirmed, 5000, 'correct amount unconfirmed');
-    assert.equal(c3.amountTotal, 5000, 'correct amount total');
+    assert.equal(c3.amountUnconfirmed, 6500, 'correct amount unconfirmed');
+    assert.equal(c3.amountTotal, 6500, 'correct amount total');
   });
 
   test('#contributorsSorted', function(assert) {
@@ -60,6 +60,82 @@ module('Unit | Service | kredits', function(hooks) {
     assert.equal(service.contributorsSorted[1].name, 'Manuel', 'sorts by name');
   });
 
+  test('#contributionsGrouped groups contributions sharing a url', function(assert) {
+    let service = this.owner.lookup('service:kredits');
+    service.set('contributors', contributors);
+    service.set('contributions', contributions);
+
+    const grouped = service.contributionsGrouped;
+
+    // 11 contributions: 3 groups ({1,3}, {7,8}, {10,11}) + 5 singletons
+    assert.equal(grouped.length, 8, 'produces one group per unique key plus singletons');
+
+    const ghGroup = grouped.findBy('groupId', contributions.findBy('id', 1).groupId);
+    assert.ok(ghGroup, 'github url group exists');
+    assert.ok(ghGroup.isGrouped, 'github group is flagged as grouped');
+    assert.equal(ghGroup.items.length, 2, 'github group has two contributions');
+    assert.deepEqual(ghGroup.contributorIds, [1, 2], 'github group lists both contributor ids');
+    assert.equal(ghGroup.contributors.length, 2, 'github group resolves both contributors');
+    assert.equal(ghGroup.totalAmount, 3000, 'github group sums amounts (1500 + 1500)');
+    assert.equal(ghGroup.kind, 'dev', 'github group takes kind from first item');
+    assert.equal(ghGroup.url, 'https://github.com/67P/kredits-contracts/pull/196');
+
+    const giteaGroup = grouped.findBy('groupId', contributions.findBy('id', 7).groupId);
+    assert.ok(giteaGroup, 'gitea url group exists');
+    assert.ok(giteaGroup.isGrouped, 'gitea group is flagged as grouped');
+    assert.deepEqual(giteaGroup.contributorIds, [3, 1], 'gitea group lists both contributor ids');
+    assert.equal(giteaGroup.totalAmount, 10000, 'gitea group sums amounts (5000 + 5000)');
+
+    const manualGroup = grouped.findBy('groupId', contributions.findBy('id', 10).groupId);
+    assert.ok(manualGroup, 'manual (no-url) group exists');
+    assert.ok(manualGroup.isGrouped, 'manual group is flagged as grouped');
+    assert.deepEqual(manualGroup.contributorIds, [2, 3], 'manual group lists both contributor ids');
+    assert.equal(manualGroup.totalAmount, 3000, 'manual group sums amounts (1500 + 1500)');
+  });
+
+  test('#contributionsGrouped treats contributions without enough fields as singletons', function(assert) {
+    let service = this.owner.lookup('service:kredits');
+    service.set('contributors', contributors);
+    service.set('contributions', contributions);
+
+    const grouped = service.contributionsGrouped;
+    const singletons = grouped.filterBy('isGrouped', false);
+
+    // 5 singletons: ids 2, 4, 5, 6, 9 (each has unique description/date/amount/kind)
+    assert.equal(singletons.length, 5, 'one singleton group per non-grouped contribution');
+    singletons.forEach(g => {
+      assert.equal(g.items.length, 1, 'singleton group has exactly one item');
+    });
+  });
+
+  test('#siblingContributions returns co-contributor contributions for the same url', function(assert) {
+    let service = this.owner.lookup('service:kredits');
+    service.set('contributors', contributors);
+    service.set('contributions', contributions);
+
+    const c1 = contributions.findBy('id', 1);
+    const siblings = service.siblingContributions(c1);
+    assert.equal(siblings.length, 1, 'contribution 1 has one sibling');
+    assert.equal(siblings[0].id, 3, 'the sibling is contribution 3');
+  });
+
+  test('#siblingContributions returns empty for contributions without siblings', function(assert) {
+    let service = this.owner.lookup('service:kredits');
+    service.set('contributors', contributors);
+    service.set('contributions', contributions);
+
+    const c2 = contributions.findBy('id', 2);
+    assert.deepEqual(service.siblingContributions(c2), [], 'no siblings for unique contribution');
+  });
+
+  test('#siblingContributions returns empty for null contribution', function(assert) {
+    let service = this.owner.lookup('service:kredits');
+    service.set('contributors', contributors);
+    service.set('contributions', contributions);
+
+    assert.deepEqual(service.siblingContributions(null), [], 'no siblings for null');
+  });
+
   test('#kreditsByContributor ignores unconfirmed contributions for contributors that are not loaded', function(assert) {
     let service = this.owner.lookup('service:kredits');
     service.set('contributors', contributors);
diff --git a/tests/unit/utils/contribution-grouping-key-test.js b/tests/unit/utils/contribution-grouping-key-test.js
new file mode 100644
index 0000000..45e649e
--- /dev/null
+++ b/tests/unit/utils/contribution-grouping-key-test.js
@@ -0,0 +1,99 @@
+import { module, test } from 'qunit';
+import EmberObject from '@ember/object';
+import contributionGroupingKey from 'kredits-web/utils/contribution-grouping-key';
+
+function makeContribution (attrs) {
+  return EmberObject.create(attrs);
+}
+
+const baseAttrs = {
+  url: 'https://github.com/67P/kredits-contracts/pull/196',
+  description: 'Chore/dependency updates',
+  date: '2020-05-27',
+  amount: 1500,
+  kind: 'dev'
+};
+
+module('Unit | Utils | contribution-grouping-key', function() {
+
+  test('returns a 6-char hex string when all fields are present', function(assert) {
+    const c = makeContribution(baseAttrs);
+    const key = contributionGroupingKey(c);
+    assert.equal(key.length, 6, '6 chars');
+    assert.ok(/^[0-9a-f]{6}$/.test(key), 'is lowercase hex: ' + key);
+  });
+
+  test('returns the same key for identical contributions with url', function(assert) {
+    const a = makeContribution(baseAttrs);
+    const b = makeContribution(baseAttrs);
+    assert.equal(contributionGroupingKey(a), contributionGroupingKey(b));
+  });
+
+  test('returns the same key for identical contributions without url', function(assert) {
+    const attrs = { ...baseAttrs, url: null };
+    const a = makeContribution(attrs);
+    const b = makeContribution(attrs);
+    assert.equal(contributionGroupingKey(a), contributionGroupingKey(b));
+  });
+
+  test('returns different keys when url differs', function(assert) {
+    const a = makeContribution(baseAttrs);
+    const b = makeContribution({ ...baseAttrs, url: 'https://github.com/67P/kredits-contracts/pull/197' });
+    assert.notEqual(contributionGroupingKey(a), contributionGroupingKey(b));
+  });
+
+  test('returns different keys when amount differs', function(assert) {
+    const a = makeContribution(baseAttrs);
+    const b = makeContribution({ ...baseAttrs, amount: 5000 });
+    assert.notEqual(contributionGroupingKey(a), contributionGroupingKey(b));
+  });
+
+  test('returns different keys when kind differs', function(assert) {
+    const a = makeContribution(baseAttrs);
+    const b = makeContribution({ ...baseAttrs, kind: 'ops' });
+    assert.notEqual(contributionGroupingKey(a), contributionGroupingKey(b));
+  });
+
+  test('returns different keys when description differs', function(assert) {
+    const a = makeContribution(baseAttrs);
+    const b = makeContribution({ ...baseAttrs, description: 'Something else' });
+    assert.notEqual(contributionGroupingKey(a), contributionGroupingKey(b));
+  });
+
+  test('returns different keys when date differs', function(assert) {
+    const a = makeContribution(baseAttrs);
+    const b = makeContribution({ ...baseAttrs, date: '2020-05-28' });
+    assert.notEqual(contributionGroupingKey(a), contributionGroupingKey(b));
+  });
+
+  test('returns different keys for url vs no-url with otherwise identical fields', function(assert) {
+    const withUrl = makeContribution(baseAttrs);
+    const withoutUrl = makeContribution({ ...baseAttrs, url: null });
+    assert.notEqual(contributionGroupingKey(withUrl), contributionGroupingKey(withoutUrl));
+  });
+
+  test('returns null when description is missing', function(assert) {
+    const c = makeContribution({ ...baseAttrs, description: null });
+    assert.equal(contributionGroupingKey(c), null);
+  });
+
+  test('returns null when date is missing', function(assert) {
+    const c = makeContribution({ ...baseAttrs, date: null });
+    assert.equal(contributionGroupingKey(c), null);
+  });
+
+  test('returns null when amount is missing', function(assert) {
+    const c = makeContribution({ ...baseAttrs, amount: null });
+    assert.equal(contributionGroupingKey(c), null);
+  });
+
+  test('returns null when kind is missing', function(assert) {
+    const c = makeContribution({ ...baseAttrs, kind: null });
+    assert.equal(contributionGroupingKey(c), null);
+  });
+
+  test('returns null when contribution is null/undefined', function(assert) {
+    assert.equal(contributionGroupingKey(null), null);
+    assert.equal(contributionGroupingKey(undefined), null);
+  });
+});