diff --git a/src/app/components/add-expense/add-expense.component.html b/src/app/components/add-expense/add-expense.component.html
index bcfe018..afc5f76 100644
--- a/src/app/components/add-expense/add-expense.component.html
+++ b/src/app/components/add-expense/add-expense.component.html
@@ -20,10 +20,10 @@
 
         <mat-form-field appearance="outline">
           <mat-label>Category</mat-label>
-          <input type="text" matInput [matAutocomplete]="categoryAuto" [formField]="expenseForm.category">
-          <mat-autocomplete autoActiveFirstOption #categoryAuto="matAutocomplete">
+          <input type="text" matInput [matAutocomplete]="categoryAuto" [formField]="expenseForm.category" [value]="expenseForm.category()">
+          <mat-autocomplete [displayWith]="display" autoActiveFirstOption #categoryAuto="matAutocomplete">
             @for (category of categories(); track category.id) {
-              <mat-option [value]="category.name">{{ category.name }}</mat-option>
+              <mat-option [value]="category">{{ category.name }}</mat-option>
             }
           </mat-autocomplete>
         </mat-form-field>
@@ -31,9 +31,9 @@
         <mat-form-field appearance="outline">
           <mat-label>Merchant</mat-label>
           <input type="text" matInput [matAutocomplete]="merchantAuto" [formField]="expenseForm.merchant">
-          <mat-autocomplete autoActiveFirstOption #merchantAuto="matAutocomplete">
+          <mat-autocomplete [displayWith]="display" autoActiveFirstOption #merchantAuto="matAutocomplete">
             @for (merchant of merchants(); track merchant.id) {
-              <mat-option [value]="merchant.name">{{ merchant.name }}</mat-option>
+              <mat-option [value]="merchant">{{ merchant.name }}</mat-option>
             }
           </mat-autocomplete>
         </mat-form-field>
@@ -44,7 +44,7 @@
           <mat-label>Tags</mat-label>
           <mat-select disableRipple multiple [formField]="expenseForm.tags">
             @for (tag of tags(); track tag.id) {
-              <mat-option [value]="tag.name">{{ tag.name }}</mat-option>
+              <mat-option [value]="tag">{{ tag.name }}</mat-option>
             }
           </mat-select>
         </mat-form-field>
@@ -60,6 +60,12 @@
       <mat-card-actions>
         <button matButton="tonal" [disabled]="!enableSaveButton()" (click)="saveClick()">Save</button>
       </mat-card-actions>
+
+      @if (errorSaving()) {
+        <mat-error>
+          {{ errorSaving() }}
+        </mat-error>
+      }
     </mat-card-footer>
   </mat-card>
 </div>
diff --git a/src/app/components/add-expense/add-expense.component.ts b/src/app/components/add-expense/add-expense.component.ts
index 5931c7a..e3f0d4e 100644
--- a/src/app/components/add-expense/add-expense.component.ts
+++ b/src/app/components/add-expense/add-expense.component.ts
@@ -1,7 +1,7 @@
 import { Component, computed, signal } from '@angular/core';
-import { CategoryService } from '../../services/category.service';
-import { MerchantService } from '../../services/merchant.service';
-import { TagService } from '../../services/tag.service';
+import { Category, CategoryService } from '../../services/category.service';
+import { Merchant, MerchantService } from '../../services/merchant.service';
+import { Tag, TagService } from '../../services/tag.service';
 import { form, FormField, min, required } from '@angular/forms/signals';
 import { MatCardModule } from '@angular/material/card';
 import { MatInputModule } from '@angular/material/input';
@@ -11,20 +11,22 @@ import { MatAutocompleteModule } from '@angular/material/autocomplete';
 import { MatSelectModule } from '@angular/material/select';
 import { MatButtonModule } from '@angular/material/button';
 import { provideNativeDateAdapter } from '@angular/material/core';
+import { CreateExpense, ExpenseService } from '../../services/expense.service';
+import { DatePipe } from '@angular/common';
 
 interface ExpenseForm {
   date: Date;
   cents: number;
-  category: string;
-  merchant: string;
+  category: Category | string;
+  merchant: Merchant | string;
   note: string;
-  tags: string[];
+  tags: Tag[];
 }
 
 @Component({
   selector: 'app-add-expense',
   imports: [MatDatepickerModule, MatFormFieldModule, MatInputModule, MatCardModule, MatAutocompleteModule, MatSelectModule, MatButtonModule, FormField],
-  providers: [provideNativeDateAdapter()],
+  providers: [provideNativeDateAdapter(), DatePipe],
   templateUrl: './add-expense.component.html',
   styleUrl: './add-expense.component.scss',
 })
@@ -41,6 +43,8 @@ export class AddExpenseComponent {
 
     return dateValid && centsValid && categoryValid && merchantValid && noteValid;
   });
+  protected saving = signal(false);
+  protected errorSaving = signal('');
 
   private defaultFormState: ExpenseForm = {
     date: new Date(),
@@ -60,12 +64,40 @@ export class AddExpenseComponent {
 
   public constructor(private readonly categoryService: CategoryService,
                      private readonly merchantService: MerchantService,
-                     private readonly tagService: TagService) { }
+                     private readonly tagService: TagService,
+                     private readonly expenseService: ExpenseService,
+                     private readonly datePipe: DatePipe) { }
 
-  public saveClick(): void {
-    const saveExpense = this.expenseModel();
-    console.log(saveExpense);
-    this.expenseModel.set({ ...this.defaultFormState, date: saveExpense.date });
-    this.expenseForm().reset(this.expenseModel());
+  public async saveClick(): Promise<void> {
+    this.errorSaving.set('');
+    const saveExpenseModel = this.expenseModel();
+    const date = this.datePipe.transform(saveExpenseModel.date, 'yyyy-MM-dd')?.split('-') ?? [];
+    const expense: CreateExpense = {
+      year: date[0],
+      month: date[1],
+      day: date[2],
+      cents: saveExpenseModel.cents,
+      category: saveExpenseModel.category as Category,
+      merchant: saveExpenseModel.merchant ? saveExpenseModel.merchant as Merchant : undefined,
+      note: saveExpenseModel.note ? saveExpenseModel.note : undefined,
+      tags: saveExpenseModel.tags
+    };
+
+    this.saving.set(true);
+    try {
+      await this.expenseService.postExpense(expense);
+      this.expenseModel.set({ ...this.defaultFormState, date: saveExpenseModel.date });
+      this.expenseForm().reset(this.expenseModel());
+    }
+    catch (error) {
+      this.errorSaving.set(`Error saving expense: ${error}`)
+    }
+    finally {
+      this.saving.set(false);
+    }
+  }
+
+  public display(value: Merchant | Category | Tag) {
+    return value.name ?? null;
   }
 }
diff --git a/src/app/services/expense.service.ts b/src/app/services/expense.service.ts
index 993d225..2814357 100644
--- a/src/app/services/expense.service.ts
+++ b/src/app/services/expense.service.ts
@@ -19,6 +19,13 @@ export class ExpenseService {
   public async fetchExpenses(): Promise<void> {
     this.internalExpenses.set(await this.http.get(this.expensePath));
   }
+
+  public async postExpense(expense: CreateExpense): Promise<Expense> {
+    const createdExpense = await this.http.post<Expense>(this.expensePath, expense);
+    await this.fetchExpenses();
+
+    return createdExpense;
+  }
 }
 
 export interface Expense {
@@ -32,3 +39,14 @@ export interface Expense {
   merchant?: Merchant;
   tags: Tag[];
 }
+
+export interface CreateExpense {
+  year: string;
+  month: string;
+  day: string;
+  cents: number;
+  category: Category;
+  note?: string;
+  merchant?: Merchant;
+  tags: Tag[];
+}