diff --git a/backend/app/Http/Controllers/ProposalController.php b/backend/app/Http/Controllers/ProposalController.php
index f5e1427..080dfd4 100644
--- a/backend/app/Http/Controllers/ProposalController.php
+++ b/backend/app/Http/Controllers/ProposalController.php
@@ -6,6 +6,7 @@
 use Illuminate\Http\Request;
 use App\Models\Track;
 use App\Models\Proposal;
+use App\Models\Opinion;
 
 class ProposalController extends Controller
 {
@@ -29,11 +30,43 @@ public function show(Proposal $proposal)
             abort(403);
         }
         $user = Auth::user();
-        $proposal->load('track','track.users', 'opinions');
+        $proposal->load('track', 'opinions','opinions.user', );
 
         if(!$proposal->track->users->contains($user->id)){
             abort(403);
         }
         return $proposal;
     }
+
+    public function upsertOpinion(Proposal $proposal, Request $request)
+    {
+        if (!Auth::check()){
+            abort(403);
+        }
+
+        $user = Auth::user();
+        $track = $proposal->track->load('users');
+        if(!$track->users->contains($user->id)){
+            abort(403);
+        }
+        $request->validate([
+            'vote' => 'required|numeric',
+            'comment' => 'required|string',
+        ]);
+        $opinion = Opinion::where('proposal_id', $proposal->id)->where('user_id', $user->id)->first();
+        if($opinion){
+            $opinion->vote = $request->vote;
+            $opinion->comment = $request->comment;
+            $opinion->save();
+            return $opinion;
+        }else{
+            $opinion = new Opinion();
+            $opinion->proposal_id = $proposal->id;
+            $opinion->user_id = $user->id;
+            $opinion->vote = $request->vote;
+            $opinion->comment = $request->comment;
+            $opinion->save();
+        }
+        return $opinion;
+    }
 }
diff --git a/backend/app/Models/Opinions.php b/backend/app/Models/Opinion.php
similarity index 68%
rename from backend/app/Models/Opinions.php
rename to backend/app/Models/Opinion.php
index a6278c7..60840ca 100644
--- a/backend/app/Models/Opinions.php
+++ b/backend/app/Models/Opinion.php
@@ -5,7 +5,7 @@
 use Illuminate\Database\Eloquent\Factories\HasFactory;
 use Illuminate\Database\Eloquent\Model;
 
-class Opinions extends Model
+class Opinion extends Model
 {
     use HasFactory;
 
@@ -13,4 +13,9 @@ public function proposal()
     {
         return $this->belongsTo(Proposal::class);
     }
+
+    public function user()
+    {
+        return $this->belongsTo(User::class);
+    }
 }
diff --git a/backend/app/Models/Proposal.php b/backend/app/Models/Proposal.php
index dae6658..5fefa41 100644
--- a/backend/app/Models/Proposal.php
+++ b/backend/app/Models/Proposal.php
@@ -14,7 +14,7 @@ class Proposal extends Model
 
     public function opinions(): HasMany
     {
-        return $this->hasMany(Opinions::class);
+        return $this->hasMany(Opinion::class);
     }
     public function track(): BelongsTo
     {
diff --git a/backend/app/Models/User.php b/backend/app/Models/User.php
index d03ba19..c98ebbe 100644
--- a/backend/app/Models/User.php
+++ b/backend/app/Models/User.php
@@ -69,4 +69,9 @@ public function tracks(): BelongsToMany
    {
        return $this->belongsToMany(Track::class, 'user_tracks');
    }
+
+   public function opinions(): BelongsToMany
+   {
+       return $this->belongsToMany(Opinion::class);
+   }
 }
diff --git a/backend/routes/api.php b/backend/routes/api.php
index fc5623c..9120768 100644
--- a/backend/routes/api.php
+++ b/backend/routes/api.php
@@ -30,6 +30,7 @@
 
 Route::post('proposals', [\App\Http\Controllers\ProposalController::class, 'create']);
 Route::get('proposal/{proposal}', [\App\Http\Controllers\ProposalController::class, 'show']);
+Route::post('proposal/{proposal}/opinion', [\App\Http\Controllers\ProposalController::class, 'upsertOpinion']);
 
 
 Route::get('user', [\App\Http\Controllers\UserController::class, 'me']);
diff --git a/frontend/src/components/OpinionForm.vue b/frontend/src/components/OpinionForm.vue
index 635f2e3..a908e3e 100644
--- a/frontend/src/components/OpinionForm.vue
+++ b/frontend/src/components/OpinionForm.vue
@@ -1,5 +1,6 @@
 <script setup>
 import { ref, onMounted } from "vue";
+import { client } from "../lib/api";
 import { useToast } from "primevue/usetoast";
 import { useRouter } from "vue-router";
 import { useForm } from "vee-validate";
@@ -39,8 +40,26 @@ const onSubmit = handleSubmit(async (values, actions) => {
       profile_id: currentUserId,
       proposal_id: proposalId,
     };
-    // TODO: Build API Call
-    router.go();
+    const response = await client.post(`proposal/${proposalId}/opinion`, {
+      vote: opinionForm.value.vote,
+      comment: opinionForm.value.comment,
+    });
+    if (response.status === 200 || response.status === 201) {
+      toast.add({
+        severity: "success",
+        summary: "Erfolgreich",
+        detail: "Deine Meinung wurde gespeichert",
+        life: 5000,
+      });
+      router.go();
+    } else {
+      toast.add({
+        severity: "warn",
+        summary: "Error",
+        detail: "Deine Meinung konnte nicht gespeichert werden",
+        life: 5000,
+      });
+    }
   } catch (error) {
     console.error(error);
     toast.add({
diff --git a/frontend/src/components/ProposalStatusForm.vue b/frontend/src/components/ProposalStatusForm.vue
index 2243b69..b0718d1 100644
--- a/frontend/src/components/ProposalStatusForm.vue
+++ b/frontend/src/components/ProposalStatusForm.vue
@@ -1,5 +1,6 @@
 <script setup>
 import { ref, onMounted } from "vue";
+import { client } from "../lib/api";
 import { useToast } from "primevue/usetoast";
 import { useRouter } from "vue-router";
 import { useForm } from "vee-validate";
diff --git a/frontend/src/views/orga/Proposal.vue b/frontend/src/views/orga/Proposal.vue
index f41cd67..fc68913 100644
--- a/frontend/src/views/orga/Proposal.vue
+++ b/frontend/src/views/orga/Proposal.vue
@@ -135,7 +135,7 @@ const fieldName = (name) => {
         <article v-for="opinion in proposal.opinions" v-if="proposal.opinions?.length > 0">
           <Card class="mt-1">
             <template #title>{{ opinion.special_vote || opinion.vote }}
-              {{ opinion.profiles.username }}
+              {{ opinion.user?.username }}
             </template>
             <template #content>{{ opinion.comment }}</template>
           </Card>