diff --git a/src/AccountTracking.Api/Data/AppDbContext.cs b/src/AccountTracking.Api/Data/AppDbContext.cs
new file mode 100644
index 0000000..18f7128
--- /dev/null
+++ b/src/AccountTracking.Api/Data/AppDbContext.cs
@@ -0,0 +1,31 @@
+using AccountTracking.Api.Models;
+using Microsoft.EntityFrameworkCore;
+
+namespace AccountTracking.Api.Data;
+
+public class AppDbContext : DbContext
+{
+    public AppDbContext(DbContextOptions<AppDbContext> options) : base(options) { }
+
+    public DbSet<Transaction> Transactions => Set<Transaction>();
+    public DbSet<ImportLog> ImportLogs => Set<ImportLog>();
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        // transaction_id: case-sensitive unique index using utf8mb4_bin
+        modelBuilder.Entity<Transaction>()
+            .HasIndex(t => t.TransactionId)
+            .IsUnique();
+
+        modelBuilder.Entity<Transaction>()
+            .Property(t => t.TransactionId)
+            .UseCollation("utf8mb4_bin");
+
+        // ImportedAt stored as UTC
+        modelBuilder.Entity<ImportLog>()
+            .Property(l => l.ImportedAt)
+            .HasConversion(
+                v => DateTime.SpecifyKind(v, DateTimeKind.Utc),
+                v => DateTime.SpecifyKind(v, DateTimeKind.Utc));
+    }
+}
diff --git a/src/AccountTracking.Api/Models/Dtos/CategorySpendingDto.cs b/src/AccountTracking.Api/Models/Dtos/CategorySpendingDto.cs
new file mode 100644
index 0000000..cf2e5e1
--- /dev/null
+++ b/src/AccountTracking.Api/Models/Dtos/CategorySpendingDto.cs
@@ -0,0 +1,2 @@
+namespace AccountTracking.Api.Models.Dtos;
+public record CategorySpendingDto(string Category, decimal Total);
diff --git a/src/AccountTracking.Api/Models/Dtos/CumulativeSpendingDto.cs b/src/AccountTracking.Api/Models/Dtos/CumulativeSpendingDto.cs
new file mode 100644
index 0000000..e3bc737
--- /dev/null
+++ b/src/AccountTracking.Api/Models/Dtos/CumulativeSpendingDto.cs
@@ -0,0 +1,2 @@
+namespace AccountTracking.Api.Models.Dtos;
+public record CumulativeSpendingDto(int Day, decimal CumulativeSpent);
diff --git a/src/AccountTracking.Api/Models/Dtos/ImportResult.cs b/src/AccountTracking.Api/Models/Dtos/ImportResult.cs
new file mode 100644
index 0000000..f2e8a2c
--- /dev/null
+++ b/src/AccountTracking.Api/Models/Dtos/ImportResult.cs
@@ -0,0 +1,3 @@
+namespace AccountTracking.Api.Models.Dtos;
+public record ImportResult(int RecordsImported, int RecordsSkipped);
+public record ErrorResult(string Error);
diff --git a/src/AccountTracking.Api/Models/Dtos/LoginRequest.cs b/src/AccountTracking.Api/Models/Dtos/LoginRequest.cs
new file mode 100644
index 0000000..ed6161d
--- /dev/null
+++ b/src/AccountTracking.Api/Models/Dtos/LoginRequest.cs
@@ -0,0 +1,2 @@
+namespace AccountTracking.Api.Models.Dtos;
+public record LoginRequest(string Username, string Password);
diff --git a/src/AccountTracking.Api/Models/Dtos/LoginResponse.cs b/src/AccountTracking.Api/Models/Dtos/LoginResponse.cs
new file mode 100644
index 0000000..150bedd
--- /dev/null
+++ b/src/AccountTracking.Api/Models/Dtos/LoginResponse.cs
@@ -0,0 +1,2 @@
+namespace AccountTracking.Api.Models.Dtos;
+public record LoginResponse(string Token, string ExpiresAt);
diff --git a/src/AccountTracking.Api/Models/Dtos/MonthlyBalanceDto.cs b/src/AccountTracking.Api/Models/Dtos/MonthlyBalanceDto.cs
new file mode 100644
index 0000000..b98f29e
--- /dev/null
+++ b/src/AccountTracking.Api/Models/Dtos/MonthlyBalanceDto.cs
@@ -0,0 +1,2 @@
+namespace AccountTracking.Api.Models.Dtos;
+public record MonthlyBalanceDto(int Month, decimal ClosingBalance);
diff --git a/src/AccountTracking.Api/Models/Dtos/SummaryDto.cs b/src/AccountTracking.Api/Models/Dtos/SummaryDto.cs
new file mode 100644
index 0000000..c84ac0e
--- /dev/null
+++ b/src/AccountTracking.Api/Models/Dtos/SummaryDto.cs
@@ -0,0 +1,2 @@
+namespace AccountTracking.Api.Models.Dtos;
+public record SummaryDto(decimal TotalSpent, decimal TotalIncome);
diff --git a/src/AccountTracking.Api/Models/Dtos/TransactionDto.cs b/src/AccountTracking.Api/Models/Dtos/TransactionDto.cs
new file mode 100644
index 0000000..2decbf3
--- /dev/null
+++ b/src/AccountTracking.Api/Models/Dtos/TransactionDto.cs
@@ -0,0 +1,10 @@
+namespace AccountTracking.Api.Models.Dtos;
+public record TransactionDto(
+    int Id,
+    DateOnly BookingDate,
+    string? CounterPartyName,
+    string? Category,
+    decimal Amount,
+    decimal Balance,
+    string? Message
+);
diff --git a/src/AccountTracking.Api/Models/Dtos/TransactionListResponse.cs b/src/AccountTracking.Api/Models/Dtos/TransactionListResponse.cs
new file mode 100644
index 0000000..acffc75
--- /dev/null
+++ b/src/AccountTracking.Api/Models/Dtos/TransactionListResponse.cs
@@ -0,0 +1,7 @@
+namespace AccountTracking.Api.Models.Dtos;
+public record TransactionListResponse(
+    IEnumerable<TransactionDto> Items,
+    int TotalCount,
+    int Page,
+    int PageSize
+);
diff --git a/src/AccountTracking.Api/Models/ImportLog.cs b/src/AccountTracking.Api/Models/ImportLog.cs
new file mode 100644
index 0000000..33690fa
--- /dev/null
+++ b/src/AccountTracking.Api/Models/ImportLog.cs
@@ -0,0 +1,25 @@
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace AccountTracking.Api.Models;
+
+[Table("import_logs")]
+public class ImportLog
+{
+    [Key]
+    [Column("id")]
+    public int Id { get; set; }
+
+    [Column("imported_at")]
+    public DateTime ImportedAt { get; set; } = DateTime.UtcNow;
+
+    [Column("filename")]
+    [MaxLength(255)]
+    public string Filename { get; set; } = "";
+
+    [Column("records_imported")]
+    public int RecordsImported { get; set; }
+
+    [Column("records_skipped")]
+    public int RecordsSkipped { get; set; }
+}
diff --git a/src/AccountTracking.Api/Models/Transaction.cs b/src/AccountTracking.Api/Models/Transaction.cs
new file mode 100644
index 0000000..1758e7a
--- /dev/null
+++ b/src/AccountTracking.Api/Models/Transaction.cs
@@ -0,0 +1,71 @@
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+using Microsoft.EntityFrameworkCore;
+
+namespace AccountTracking.Api.Models;
+
+[Table("transactions")]
+public class Transaction
+{
+    [Key]
+    [Column("id")]
+    public int Id { get; set; }
+
+    [Column("account_number")]
+    [MaxLength(30)]
+    public string AccountNumber { get; set; } = "";
+
+    [Column("booking_date")]
+    public DateOnly BookingDate { get; set; }
+
+    [Column("amount")]
+    [Precision(15, 2)]
+    public decimal Amount { get; set; }
+
+    [Column("currency")]
+    [MaxLength(3)]
+    public string Currency { get; set; } = "CZK";
+
+    [Column("balance")]
+    [Precision(15, 2)]
+    public decimal Balance { get; set; }
+
+    [Column("counter_party_name")]
+    [MaxLength(255)]
+    public string? CounterPartyName { get; set; }
+
+    [Column("operation_description")]
+    [MaxLength(255)]
+    public string? OperationDescription { get; set; }
+
+    [Column("message")]
+    public string? Message { get; set; }
+
+    [Column("category")]
+    [MaxLength(100)]
+    public string? Category { get; set; }
+
+    [Column("variable_symbol")]
+    [MaxLength(30)]
+    public string? VariableSymbol { get; set; }
+
+    [Column("bank_note")]
+    [MaxLength(255)]
+    public string? BankNote { get; set; }
+
+    [Column("transaction_id")]
+    [MaxLength(512)]
+    public string TransactionId { get; set; } = "";
+
+    // Extra CSV columns stored but not used in UI
+    [Column("counter_bank_code")] [MaxLength(255)] public string? CounterBankCode { get; set; }
+    [Column("constant_symbol")] [MaxLength(255)] public string? ConstantSymbol { get; set; }
+    [Column("specific_symbol")] [MaxLength(255)] public string? SpecificSymbol { get; set; }
+    [Column("order_name")] [MaxLength(255)] public string? OrderName { get; set; }
+    [Column("exchange_rate")] [MaxLength(255)] public string? ExchangeRate { get; set; }
+    [Column("e2e_id")] [MaxLength(255)] public string? E2EId { get; set; }
+    [Column("payer_reference")] [MaxLength(255)] public string? PayerReference { get; set; }
+    [Column("original_payer")] [MaxLength(255)] public string? OriginalPayer { get; set; }
+    [Column("final_recipient")] [MaxLength(255)] public string? FinalRecipient { get; set; }
+    [Column("original_transaction")] [MaxLength(255)] public string? OriginalTransaction { get; set; }
+}