diff --git a/backend/Controllers/EventsController.cs b/backend/Controllers/EventsController.cs
new file mode 100644
index 0000000..20c6072
--- /dev/null
+++ b/backend/Controllers/EventsController.cs
@@ -0,0 +1,242 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using RacePlannerApi.Data;
+using RacePlannerApi.DTOs;
+using RacePlannerApi.Models;
+
+namespace RacePlannerApi.Controllers;
+
+[ApiController]
+[Route("api/[controller]")]
+[Authorize]
+public class EventsController : ControllerBase
+{
+    private readonly RacePlannerDbContext _context;
+
+    public EventsController(RacePlannerDbContext context)
+    {
+        _context = context;
+    }
+
+    [HttpPost]
+    [Authorize(Roles = "Organizer")]
+    public async Task<ActionResult<EventDto>> CreateEvent(CreateEventRequest request)
+    {
+        var userId = GetCurrentUserId();
+        if (userId == null)
+        {
+            return Unauthorized();
+        }
+
+        var eventEntity = new Event
+        {
+            Name = request.Name,
+            Description = request.Description,
+            EventDate = request.EventDate,
+            Location = request.Location,
+            Category = request.Category,
+            Tags = request.Tags ?? new List<string>(),
+            MaxParticipants = request.MaxParticipants,
+            OrganizerId = userId.Value,
+            Status = EventStatus.Draft
+        };
+
+        _context.Events.Add(eventEntity);
+        await _context.SaveChangesAsync();
+
+        // Load organizer for response
+        await _context.Entry(eventEntity).Reference(e => e.Organizer).LoadAsync();
+
+        return CreatedAtAction(
+            nameof(GetEvent),
+            new { id = eventEntity.Id },
+            MapToEventDto(eventEntity));
+    }
+
+    [HttpGet]
+    [AllowAnonymous]
+    public async Task<ActionResult<IEnumerable<EventDto>>> GetEvents(
+        [FromQuery] EventFilterRequest? filter = null)
+    {
+        var query = _context.Events
+            .Include(e => e.Organizer)
+            .Include(e => e.Registrations)
+            .AsQueryable();
+
+        // Apply filters
+        if (filter?.Category != null)
+        {
+            query = query.Where(e => e.Category == filter.Category);
+        }
+
+        if (filter?.Tags != null && filter.Tags.Any())
+        {
+            query = query.Where(e => e.Tags.Any(t => filter.Tags.Contains(t)));
+        }
+
+        if (filter?.FromDate != null)
+        {
+            query = query.Where(e => e.EventDate >= filter.FromDate);
+        }
+
+        if (filter?.ToDate != null)
+        {
+            query = query.Where(e => e.EventDate <= filter.ToDate);
+        }
+
+        if (filter?.Status != null && Enum.TryParse<EventStatus>(filter.Status, out var status))
+        {
+            query = query.Where(e => e.Status == status);
+        }
+
+        if (filter?.OrganizerId != null)
+        {
+            query = query.Where(e => e.OrganizerId == filter.OrganizerId);
+        }
+
+        // Default to showing published events only for anonymous users
+        if (!User.Identity?.IsAuthenticated ?? true)
+        {
+            query = query.Where(e => e.Status == EventStatus.Published);
+        }
+
+        var events = await query
+            .OrderBy(e => e.EventDate)
+            .ToListAsync();
+
+        return Ok(events.Select(MapToEventDto));
+    }
+
+    [HttpGet("{id}")]
+    [AllowAnonymous]
+    public async Task<ActionResult<EventDto>> GetEvent(Guid id)
+    {
+        var eventEntity = await _context.Events
+            .Include(e => e.Organizer)
+            .Include(e => e.Registrations)
+            .FirstOrDefaultAsync(e => e.Id == id);
+
+        if (eventEntity == null)
+        {
+            return NotFound();
+        }
+
+        // Draft events only visible to organizers
+        if (eventEntity.Status == EventStatus.Draft)
+        {
+            var userId = GetCurrentUserId();
+            if (userId == null || eventEntity.OrganizerId != userId)
+            {
+                return NotFound();
+            }
+        }
+
+        return Ok(MapToEventDto(eventEntity));
+    }
+
+    [HttpPut("{id}")]
+    [Authorize(Roles = "Organizer")]
+    public async Task<ActionResult<EventDto>> UpdateEvent(Guid id, UpdateEventRequest request)
+    {
+        var userId = GetCurrentUserId();
+        if (userId == null)
+        {
+            return Unauthorized();
+        }
+
+        var eventEntity = await _context.Events
+            .Include(e => e.Organizer)
+            .FirstOrDefaultAsync(e => e.Id == id);
+
+        if (eventEntity == null)
+        {
+            return NotFound();
+        }
+
+        // Only organizer can update their event
+        if (eventEntity.OrganizerId != userId)
+        {
+            return Forbid();
+        }
+
+        // Update fields
+        if (request.Name != null) eventEntity.Name = request.Name;
+        if (request.Description != null) eventEntity.Description = request.Description;
+        if (request.EventDate != null) eventEntity.EventDate = request.EventDate.Value;
+        if (request.Location != null) eventEntity.Location = request.Location;
+        if (request.Status != null) eventEntity.Status = request.Status.Value;
+        if (request.Category != null) eventEntity.Category = request.Category;
+        if (request.Tags != null) eventEntity.Tags = request.Tags;
+        if (request.MaxParticipants != null) eventEntity.MaxParticipants = request.MaxParticipants;
+
+        eventEntity.UpdatedAt = DateTime.UtcNow;
+
+        await _context.SaveChangesAsync();
+
+        return Ok(MapToEventDto(eventEntity));
+    }
+
+    [HttpDelete("{id}")]
+    [Authorize(Roles = "Organizer")]
+    public async Task<IActionResult> DeleteEvent(Guid id)
+    {
+        var userId = GetCurrentUserId();
+        if (userId == null)
+        {
+            return Unauthorized();
+        }
+
+        var eventEntity = await _context.Events.FindAsync(id);
+
+        if (eventEntity == null)
+        {
+            return NotFound();
+        }
+
+        if (eventEntity.OrganizerId != userId)
+        {
+            return Forbid();
+        }
+
+        _context.Events.Remove(eventEntity);
+        await _context.SaveChangesAsync();
+
+        return NoContent();
+    }
+
+    private Guid? GetCurrentUserId()
+    {
+        var userIdClaim = User.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier)?.Value;
+        if (Guid.TryParse(userIdClaim, out var userId))
+        {
+            return userId;
+        }
+        return null;
+    }
+
+    private static EventDto MapToEventDto(Event eventEntity)
+    {
+        return new EventDto
+        {
+            Id = eventEntity.Id,
+            Name = eventEntity.Name,
+            Description = eventEntity.Description,
+            EventDate = eventEntity.EventDate,
+            Location = eventEntity.Location,
+            Status = eventEntity.Status.ToString(),
+            Category = eventEntity.Category,
+            Tags = eventEntity.Tags,
+            MaxParticipants = eventEntity.MaxParticipants,
+            CurrentRegistrations = eventEntity.Registrations?.Count ?? 0,
+            CreatedAt = eventEntity.CreatedAt,
+            UpdatedAt = eventEntity.UpdatedAt,
+            Organizer = new UserSummaryDto
+            {
+                Id = eventEntity.Organizer.Id,
+                Name = eventEntity.Organizer.Name,
+                Email = eventEntity.Organizer.Email
+            }
+        };
+    }
+}
\ No newline at end of file
diff --git a/backend/Controllers/PaymentsController.cs b/backend/Controllers/PaymentsController.cs
new file mode 100644
index 0000000..e6e8024
--- /dev/null
+++ b/backend/Controllers/PaymentsController.cs
@@ -0,0 +1,258 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using RacePlannerApi.Data;
+using RacePlannerApi.DTOs;
+using RacePlannerApi.Models;
+
+namespace RacePlannerApi.Controllers;
+
+[ApiController]
+[Route("api/[controller]")]
+[Authorize]
+public class PaymentsController : ControllerBase
+{
+    private readonly RacePlannerDbContext _context;
+
+    public PaymentsController(RacePlannerDbContext context)
+    {
+        _context = context;
+    }
+
+    [HttpPost]
+    [Authorize(Roles = "Organizer")]
+    public async Task<ActionResult<PaymentDto>> RecordPayment(CreatePaymentRequest request)
+    {
+        var userId = GetCurrentUserId();
+        if (userId == null)
+        {
+            return Unauthorized();
+        }
+
+        // Load registration with event
+        var registration = await _context.Registrations
+            .Include(r => r.Event)
+            .FirstOrDefaultAsync(r => r.Id == request.RegistrationId);
+
+        if (registration == null)
+        {
+            return NotFound(new { error = "Registration not found" });
+        }
+
+        // Verify user is organizer of the event
+        if (registration.Event.OrganizerId != userId.Value)
+        {
+            return Forbid();
+        }
+
+        // Check registration is not cancelled
+        if (registration.Status == RegistrationStatus.Cancelled)
+        {
+            return BadRequest(new { error = "Cannot record payment for cancelled registration" });
+        }
+
+        var payment = new Payment
+        {
+            RegistrationId = request.RegistrationId,
+            Amount = request.Amount,
+            Method = request.Method,
+            TransactionId = request.TransactionId,
+            Notes = request.Notes,
+            PaymentDate = request.PaymentDate ?? DateTime.UtcNow
+        };
+
+        _context.Payments.Add(payment);
+        await _context.SaveChangesAsync();
+
+        // Update registration status if fully paid (assuming a fixed fee amount would be known)
+        // For now, we'll just record the payment
+
+        return CreatedAtAction(
+            nameof(GetPayment),
+            new { id = payment.Id },
+            MapToPaymentDto(payment));
+    }
+
+    [HttpGet("{id}")]
+    [Authorize(Roles = "Organizer")]
+    public async Task<ActionResult<PaymentDto>> GetPayment(Guid id)
+    {
+        var userId = GetCurrentUserId();
+        if (userId == null)
+        {
+            return Unauthorized();
+        }
+
+        var payment = await _context.Payments
+            .Include(p => p.Registration)
+            .ThenInclude(r => r.Event)
+            .FirstOrDefaultAsync(p => p.Id == id);
+
+        if (payment == null)
+        {
+            return NotFound();
+        }
+
+        // Verify user is organizer
+        if (payment.Registration.Event.OrganizerId != userId.Value)
+        {
+            return Forbid();
+        }
+
+        return Ok(MapToPaymentDto(payment));
+    }
+
+    [HttpGet("registration/{registrationId}")]
+    [Authorize(Roles = "Organizer")]
+    public async Task<ActionResult<IEnumerable<PaymentDto>>> GetRegistrationPayments(Guid registrationId)
+    {
+        var userId = GetCurrentUserId();
+        if (userId == null)
+        {
+            return Unauthorized();
+        }
+
+        // Verify organizer has access to this registration
+        var registration = await _context.Registrations
+            .Include(r => r.Event)
+            .FirstOrDefaultAsync(r => r.Id == registrationId);
+
+        if (registration == null)
+        {
+            return NotFound();
+        }
+
+        if (registration.Event.OrganizerId != userId.Value)
+        {
+            return Forbid();
+        }
+
+        var payments = await _context.Payments
+            .Where(p => p.RegistrationId == registrationId)
+            .OrderByDescending(p => p.PaymentDate)
+            .ToListAsync();
+
+        return Ok(payments.Select(MapToPaymentDto));
+    }
+
+    [HttpGet("registration/{registrationId}/status")]
+    [Authorize]
+    public async Task<ActionResult<object>> GetPaymentStatus(Guid registrationId)
+    {
+        var userId = GetCurrentUserId();
+        if (userId == null)
+        {
+            return Unauthorized();
+        }
+
+        var registration = await _context.Registrations
+            .Include(r => r.Event)
+            .Include(r => r.Payments)
+            .FirstOrDefaultAsync(r => r.Id == registrationId);
+
+        if (registration == null)
+        {
+            return NotFound();
+        }
+
+        // Participant can view their own, organizer can view any
+        var isOrganizer = registration.Event.OrganizerId == userId.Value;
+
+        if (registration.ParticipantId != userId.Value && !isOrganizer)
+        {
+            return Forbid();
+        }
+
+        var totalPaid = registration.Payments.Sum(p => p.Amount);
+        var status = totalPaid > 0 ? "paid" : "unpaid";
+
+        return Ok(new
+        {
+            RegistrationId = registrationId,
+            TotalPaid = totalPaid,
+            PaymentCount = registration.Payments.Count,
+            Status = status,
+            Payments = registration.Payments.Select(MapToPaymentDto)
+        });
+    }
+
+    [HttpGet("event/{eventId}/report")]
+    [Authorize(Roles = "Organizer")]
+    public async Task<ActionResult<PaymentReportDto>> GetPaymentReport(Guid eventId)
+    {
+        var userId = GetCurrentUserId();
+        if (userId == null)
+        {
+            return Unauthorized();
+        }
+
+        var eventEntity = await _context.Events
+            .FirstOrDefaultAsync(e => e.Id == eventId && e.OrganizerId == userId.Value);
+
+        if (eventEntity == null)
+        {
+            return NotFound();
+        }
+
+        var registrations = await _context.Registrations
+            .Include(r => r.Participant)
+            .Include(r => r.Payments)
+            .Where(r => r.EventId == eventId && r.Status != RegistrationStatus.Cancelled)
+            .ToListAsync();
+
+        var totalCollected = registrations.Sum(r => r.Payments.Sum(p => p.Amount));
+        var totalRegistrations = registrations.Count;
+        var paidRegistrations = registrations.Count(r => r.Payments.Any());
+        var unpaidRegistrations = registrations.Count(r => !r.Payments.Any());
+
+        var report = new PaymentReportDto
+        {
+            EventId = eventId,
+            EventName = eventEntity.Name,
+            TotalCollected = totalCollected,
+            TotalPending = 0, // Would require event fee structure
+            TotalOutstanding = 0, // Would require event fee structure
+            TotalRegistrations = totalRegistrations,
+            PaidRegistrations = paidRegistrations,
+            PartialRegistrations = 0, // Would require partial payment logic
+            UnpaidRegistrations = unpaidRegistrations,
+            Registrations = registrations.Select(r => new RegistrationPaymentDto
+            {
+                RegistrationId = r.Id,
+                ParticipantName = r.Participant.Name,
+                Status = r.Status.ToString(),
+                TotalPaid = r.Payments.Sum(p => p.Amount),
+                AmountDue = 0, // Would require event fee structure
+                PaymentStatus = r.Payments.Any() ? "paid" : "unpaid",
+                Payments = r.Payments.Select(MapToPaymentDto).ToList()
+            }).ToList()
+        };
+
+        return Ok(report);
+    }
+
+    private Guid? GetCurrentUserId()
+    {
+        var userIdClaim = User.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier)?.Value;
+        if (Guid.TryParse(userIdClaim, out var userId))
+        {
+            return userId;
+        }
+        return null;
+    }
+
+    private static PaymentDto MapToPaymentDto(Payment payment)
+    {
+        return new PaymentDto
+        {
+            Id = payment.Id,
+            RegistrationId = payment.RegistrationId,
+            Amount = payment.Amount,
+            Method = payment.Method.ToString(),
+            TransactionId = payment.TransactionId,
+            Notes = payment.Notes,
+            PaymentDate = payment.PaymentDate,
+            CreatedAt = payment.CreatedAt
+        };
+    }
+}
\ No newline at end of file
diff --git a/backend/Controllers/RegistrationsController.cs b/backend/Controllers/RegistrationsController.cs
new file mode 100644
index 0000000..4b227a7
--- /dev/null
+++ b/backend/Controllers/RegistrationsController.cs
@@ -0,0 +1,303 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using RacePlannerApi.Data;
+using RacePlannerApi.DTOs;
+using RacePlannerApi.Models;
+
+namespace RacePlannerApi.Controllers;
+
+[ApiController]
+[Route("api/[controller]")]
+[Authorize]
+public class RegistrationsController : ControllerBase
+{
+    private readonly RacePlannerDbContext _context;
+
+    public RegistrationsController(RacePlannerDbContext context)
+    {
+        _context = context;
+    }
+
+    [HttpPost]
+    public async Task<ActionResult<RegistrationDto>> CreateRegistration(CreateRegistrationRequest request)
+    {
+        var userId = GetCurrentUserId();
+        if (userId == null)
+        {
+            return Unauthorized();
+        }
+
+        // Check if event exists and is published
+        var eventEntity = await _context.Events
+            .FirstOrDefaultAsync(e => e.Id == request.EventId);
+
+        if (eventEntity == null)
+        {
+            return NotFound(new { error = "Event not found" });
+        }
+
+        if (eventEntity.Status != EventStatus.Published)
+        {
+            return BadRequest(new { error = "Event is not open for registration" });
+        }
+
+        // Check if already registered
+        var existingRegistration = await _context.Registrations
+            .FirstOrDefaultAsync(r => r.EventId == request.EventId && r.ParticipantId == userId.Value);
+
+        if (existingRegistration != null)
+        {
+            return Conflict(new { error = "Already registered for this event" });
+        }
+
+        // Check if event is full
+        if (eventEntity.MaxParticipants.HasValue)
+        {
+            var registrationCount = await _context.Registrations
+                .CountAsync(r => r.EventId == request.EventId && r.Status != RegistrationStatus.Cancelled);
+
+            if (registrationCount >= eventEntity.MaxParticipants.Value)
+            {
+                return BadRequest(new { error = "Event is full" });
+            }
+        }
+
+        var registration = new Registration
+        {
+            EventId = request.EventId,
+            ParticipantId = userId.Value,
+            Status = RegistrationStatus.Pending,
+            Category = request.Category,
+            EmergencyContact = request.EmergencyContact
+        };
+
+        _context.Registrations.Add(registration);
+        await _context.SaveChangesAsync();
+
+        // Load related data
+        await _context.Entry(registration)
+            .Reference(r => r.Event)
+            .LoadAsync();
+        await _context.Entry(registration)
+            .Reference(r => r.Participant)
+            .LoadAsync();
+        await _context.Entry(registration)
+            .Collection(r => r.Payments)
+            .LoadAsync();
+
+        return CreatedAtAction(
+            nameof(GetRegistration),
+            new { id = registration.Id },
+            MapToRegistrationDto(registration));
+    }
+
+    [HttpGet("{id}")]
+    public async Task<ActionResult<RegistrationDto>> GetRegistration(Guid id)
+    {
+        var userId = GetCurrentUserId();
+        if (userId == null)
+        {
+            return Unauthorized();
+        }
+
+        var registration = await _context.Registrations
+            .Include(r => r.Event)
+            .Include(r => r.Participant)
+            .Include(r => r.Payments)
+            .FirstOrDefaultAsync(r => r.Id == id);
+
+        if (registration == null)
+        {
+            return NotFound();
+        }
+
+        // Only participant or event organizer can view
+        var isOrganizer = await _context.Events
+            .AnyAsync(e => e.Id == registration.EventId && e.OrganizerId == userId.Value);
+
+        if (registration.ParticipantId != userId.Value && !isOrganizer)
+        {
+            return Forbid();
+        }
+
+        return Ok(MapToRegistrationDto(registration));
+    }
+
+    [HttpGet("my-registrations")]
+    public async Task<ActionResult<IEnumerable<RegistrationDto>>> GetMyRegistrations()
+    {
+        var userId = GetCurrentUserId();
+        if (userId == null)
+        {
+            return Unauthorized();
+        }
+
+        var registrations = await _context.Registrations
+            .Include(r => r.Event)
+            .Include(r => r.Participant)
+            .Include(r => r.Payments)
+            .Where(r => r.ParticipantId == userId.Value)
+            .OrderBy(r => r.Event.EventDate)
+            .ToListAsync();
+
+        return Ok(registrations.Select(MapToRegistrationDto));
+    }
+
+    [HttpGet("event/{eventId}")]
+    [Authorize(Roles = "Organizer")]
+    public async Task<ActionResult<IEnumerable<RegistrationDto>>> GetEventRegistrations(Guid eventId)
+    {
+        var userId = GetCurrentUserId();
+        if (userId == null)
+        {
+            return Unauthorized();
+        }
+
+        // Verify user is organizer of this event
+        var eventEntity = await _context.Events
+            .FirstOrDefaultAsync(e => e.Id == eventId && e.OrganizerId == userId.Value);
+
+        if (eventEntity == null)
+        {
+            return NotFound();
+        }
+
+        var registrations = await _context.Registrations
+            .Include(r => r.Event)
+            .Include(r => r.Participant)
+            .Include(r => r.Payments)
+            .Where(r => r.EventId == eventId)
+            .OrderBy(r => r.CreatedAt)
+            .ToListAsync();
+
+        return Ok(registrations.Select(MapToRegistrationDto));
+    }
+
+    [HttpPut("{id}")]
+    public async Task<ActionResult<RegistrationDto>> UpdateRegistration(Guid id, UpdateRegistrationRequest request)
+    {
+        var userId = GetCurrentUserId();
+        if (userId == null)
+        {
+            return Unauthorized();
+        }
+
+        var registration = await _context.Registrations
+            .Include(r => r.Event)
+            .FirstOrDefaultAsync(r => r.Id == id);
+
+        if (registration == null)
+        {
+            return NotFound();
+        }
+
+        // Participants can only update their own registrations
+        // Organizers can update any registration for their events
+        var isOrganizer = registration.Event.OrganizerId == userId.Value;
+
+        if (registration.ParticipantId != userId.Value && !isOrganizer)
+        {
+            return Forbid();
+        }
+
+        // Update fields
+        if (request.Status.HasValue && isOrganizer)
+        {
+            registration.Status = request.Status.Value;
+        }
+
+        if (request.Category != null)
+        {
+            registration.Category = request.Category;
+        }
+
+        if (request.EmergencyContact != null)
+        {
+            registration.EmergencyContact = request.EmergencyContact;
+        }
+
+        registration.UpdatedAt = DateTime.UtcNow;
+
+        await _context.SaveChangesAsync();
+
+        // Reload related data
+        await _context.Entry(registration)
+            .Reference(r => r.Participant)
+            .LoadAsync();
+        await _context.Entry(registration)
+            .Collection(r => r.Payments)
+            .LoadAsync();
+
+        return Ok(MapToRegistrationDto(registration));
+    }
+
+    [HttpPost("{id}/cancel")]
+    public async Task<ActionResult<RegistrationDto>> CancelRegistration(Guid id)
+    {
+        var userId = GetCurrentUserId();
+        if (userId == null)
+        {
+            return Unauthorized();
+        }
+
+        var registration = await _context.Registrations
+            .Include(r => r.Event)
+            .Include(r => r.Participant)
+            .Include(r => r.Payments)
+            .FirstOrDefaultAsync(r => r.Id == id);
+
+        if (registration == null)
+        {
+            return NotFound();
+        }
+
+        // Only participant or event organizer can cancel
+        var isOrganizer = registration.Event.OrganizerId == userId.Value;
+
+        if (registration.ParticipantId != userId.Value && !isOrganizer)
+        {
+            return Forbid();
+        }
+
+        registration.Status = RegistrationStatus.Cancelled;
+        registration.UpdatedAt = DateTime.UtcNow;
+
+        await _context.SaveChangesAsync();
+
+        return Ok(MapToRegistrationDto(registration));
+    }
+
+    private Guid? GetCurrentUserId()
+    {
+        var userIdClaim = User.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier)?.Value;
+        if (Guid.TryParse(userIdClaim, out var userId))
+        {
+            return userId;
+        }
+        return null;
+    }
+
+    private static RegistrationDto MapToRegistrationDto(Registration registration)
+    {
+        var totalPaid = registration.Payments?.Sum(p => p.Amount) ?? 0;
+
+        return new RegistrationDto
+        {
+            Id = registration.Id,
+            EventId = registration.EventId,
+            EventName = registration.Event?.Name ?? string.Empty,
+            EventDate = registration.Event?.EventDate ?? DateTime.MinValue,
+            ParticipantId = registration.ParticipantId,
+            ParticipantName = registration.Participant?.Name ?? string.Empty,
+            ParticipantEmail = registration.Participant?.Email ?? string.Empty,
+            Status = registration.Status.ToString(),
+            Category = registration.Category,
+            EmergencyContact = registration.EmergencyContact,
+            CreatedAt = registration.CreatedAt,
+            UpdatedAt = registration.UpdatedAt,
+            TotalPaid = totalPaid,
+            AmountDue = 0 // Will be calculated based on event fee if needed
+        };
+    }
+}
\ No newline at end of file
diff --git a/backend/DTOs/EventDtos.cs b/backend/DTOs/EventDtos.cs
new file mode 100644
index 0000000..c82b9c6
--- /dev/null
+++ b/backend/DTOs/EventDtos.cs
@@ -0,0 +1,85 @@
+using System.ComponentModel.DataAnnotations;
+using RacePlannerApi.Models;
+
+namespace RacePlannerApi.DTOs;
+
+public class CreateEventRequest
+{
+    [Required]
+    [MaxLength(200)]
+    public string Name { get; set; } = string.Empty;
+
+    [MaxLength(2000)]
+    public string Description { get; set; } = string.Empty;
+
+    [Required]
+    public DateTime EventDate { get; set; }
+
+    [Required]
+    [MaxLength(500)]
+    public string Location { get; set; } = string.Empty;
+
+    [MaxLength(100)]
+    public string? Category { get; set; }
+
+    public List<string> Tags { get; set; } = new();
+
+    public int? MaxParticipants { get; set; }
+}
+
+public class UpdateEventRequest
+{
+    [MaxLength(200)]
+    public string? Name { get; set; }
+
+    [MaxLength(2000)]
+    public string? Description { get; set; }
+
+    public DateTime? EventDate { get; set; }
+
+    [MaxLength(500)]
+    public string? Location { get; set; }
+
+    public EventStatus? Status { get; set; }
+
+    [MaxLength(100)]
+    public string? Category { get; set; }
+
+    public List<string>? Tags { get; set; }
+
+    public int? MaxParticipants { get; set; }
+}
+
+public class EventDto
+{
+    public Guid Id { get; set; }
+    public string Name { get; set; } = string.Empty;
+    public string Description { get; set; } = string.Empty;
+    public DateTime EventDate { get; set; }
+    public string Location { get; set; } = string.Empty;
+    public string Status { get; set; } = string.Empty;
+    public string? Category { get; set; }
+    public List<string> Tags { get; set; } = new();
+    public int? MaxParticipants { get; set; }
+    public int CurrentRegistrations { get; set; }
+    public DateTime CreatedAt { get; set; }
+    public DateTime UpdatedAt { get; set; }
+    public UserSummaryDto Organizer { get; set; } = null!;
+}
+
+public class EventFilterRequest
+{
+    public string? Category { get; set; }
+    public List<string>? Tags { get; set; }
+    public DateTime? FromDate { get; set; }
+    public DateTime? ToDate { get; set; }
+    public string? Status { get; set; }
+    public Guid? OrganizerId { get; set; }
+}
+
+public class UserSummaryDto
+{
+    public Guid Id { get; set; }
+    public string Name { get; set; } = string.Empty;
+    public string Email { get; set; } = string.Empty;
+}
\ No newline at end of file
diff --git a/backend/DTOs/PaymentDtos.cs b/backend/DTOs/PaymentDtos.cs
new file mode 100644
index 0000000..d974ca9
--- /dev/null
+++ b/backend/DTOs/PaymentDtos.cs
@@ -0,0 +1,62 @@
+using System.ComponentModel.DataAnnotations;
+using RacePlannerApi.Models;
+
+namespace RacePlannerApi.DTOs;
+
+public class CreatePaymentRequest
+{
+    [Required]
+    public Guid RegistrationId { get; set; }
+
+    [Required]
+    [Range(0.01, double.MaxValue)]
+    public decimal Amount { get; set; }
+
+    [Required]
+    public PaymentMethod Method { get; set; }
+
+    [MaxLength(100)]
+    public string? TransactionId { get; set; }
+
+    [MaxLength(500)]
+    public string? Notes { get; set; }
+
+    public DateTime? PaymentDate { get; set; }
+}
+
+public class PaymentDto
+{
+    public Guid Id { get; set; }
+    public Guid RegistrationId { get; set; }
+    public decimal Amount { get; set; }
+    public string Method { get; set; } = string.Empty;
+    public string? TransactionId { get; set; }
+    public string? Notes { get; set; }
+    public DateTime PaymentDate { get; set; }
+    public DateTime CreatedAt { get; set; }
+}
+
+public class PaymentReportDto
+{
+    public Guid EventId { get; set; }
+    public string EventName { get; set; } = string.Empty;
+    public decimal TotalCollected { get; set; }
+    public decimal TotalPending { get; set; }
+    public decimal TotalOutstanding { get; set; }
+    public int TotalRegistrations { get; set; }
+    public int PaidRegistrations { get; set; }
+    public int PartialRegistrations { get; set; }
+    public int UnpaidRegistrations { get; set; }
+    public List<RegistrationPaymentDto> Registrations { get; set; } = new();
+}
+
+public class RegistrationPaymentDto
+{
+    public Guid RegistrationId { get; set; }
+    public string ParticipantName { get; set; } = string.Empty;
+    public string Status { get; set; } = string.Empty;
+    public decimal TotalPaid { get; set; }
+    public decimal AmountDue { get; set; }
+    public string PaymentStatus { get; set; } = string.Empty;
+    public List<PaymentDto> Payments { get; set; } = new();
+}
\ No newline at end of file
diff --git a/backend/DTOs/RegistrationDtos.cs b/backend/DTOs/RegistrationDtos.cs
new file mode 100644
index 0000000..a75fd16
--- /dev/null
+++ b/backend/DTOs/RegistrationDtos.cs
@@ -0,0 +1,45 @@
+using System.ComponentModel.DataAnnotations;
+using RacePlannerApi.Models;
+
+namespace RacePlannerApi.DTOs;
+
+public class CreateRegistrationRequest
+{
+    [Required]
+    public Guid EventId { get; set; }
+
+    [MaxLength(100)]
+    public string? Category { get; set; }
+
+    [MaxLength(200)]
+    public string? EmergencyContact { get; set; }
+}
+
+public class UpdateRegistrationRequest
+{
+    public RegistrationStatus? Status { get; set; }
+
+    [MaxLength(100)]
+    public string? Category { get; set; }
+
+    [MaxLength(200)]
+    public string? EmergencyContact { get; set; }
+}
+
+public class RegistrationDto
+{
+    public Guid Id { get; set; }
+    public Guid EventId { get; set; }
+    public string EventName { get; set; } = string.Empty;
+    public DateTime EventDate { get; set; }
+    public Guid ParticipantId { get; set; }
+    public string ParticipantName { get; set; } = string.Empty;
+    public string ParticipantEmail { get; set; } = string.Empty;
+    public string Status { get; set; } = string.Empty;
+    public string? Category { get; set; }
+    public string? EmergencyContact { get; set; }
+    public DateTime CreatedAt { get; set; }
+    public DateTime? UpdatedAt { get; set; }
+    public decimal TotalPaid { get; set; }
+    public decimal AmountDue { get; set; }
+}
\ No newline at end of file