diff --git a/Retroactiune.Core/Entities/Token.cs b/Retroactiune.Core/Entities/Token.cs
index 702d182..314be63 100644
--- a/Retroactiune.Core/Entities/Token.cs
+++ b/Retroactiune.Core/Entities/Token.cs
@@ -33,6 +33,16 @@ namespace Retroactiune.Core.Entities
 
         [JsonPropertyName("expiry_time")] public DateTime? ExpiryTime { get; set; }
 
+        public static bool operator ==(Token left, Token right)
+        {
+            return Equals(left, right);
+        }
+
+        public static bool operator !=(Token left, Token right)
+        {
+            return !Equals(left, right);
+        }
+        
         public override bool Equals(object obj)
         {
             if (!(obj is Token convertedObj))
@@ -50,13 +60,18 @@ namespace Retroactiune.Core.Entities
             return RuntimeHelpers.GetHashCode(this);
         }
 
+        public bool IsValid()
+        {
+            var hasExpired = ExpiryTime != null && ExpiryTime <= DateTime.UtcNow;
+            var isUsed = TimeUsed != null;
+            return !(hasExpired || isUsed);
+        }
+        
         public bool IsValid(FeedbackReceiver feedbackReceiver)
         {
             Guard.Against.Null(feedbackReceiver, nameof(feedbackReceiver));
-            var hasExpired = ExpiryTime != null && ExpiryTime <= DateTime.UtcNow;
             var differentFeedbackReceiver = !FeedbackReceiverId.Equals(feedbackReceiver.Id);
-            var isUsed = TimeUsed != null;
-            return !(hasExpired || differentFeedbackReceiver || isUsed);
+            return !differentFeedbackReceiver && IsValid();
         }
     }
 }
\ No newline at end of file
diff --git a/Retroactiune.Core/Services/FeedbacksListFilters.cs b/Retroactiune.Core/Services/FeedbacksListFilters.cs
index a0c4cde..3a46a9d 100644
--- a/Retroactiune.Core/Services/FeedbacksListFilters.cs
+++ b/Retroactiune.Core/Services/FeedbacksListFilters.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics.CodeAnalysis;
 
 namespace Retroactiune.Core.Services
 {
@@ -7,12 +8,11 @@ namespace Retroactiune.Core.Services
     /// </summary>
     public class FeedbacksListFilters
     {
-        
         /// <summary>
         /// FeedbackReceiverId the ID of the FeedbackReceiver.
         /// </summary>
         public string FeedbackReceiverId { get; set; }
-        
+
         /// <summary>
         /// CreatedAfter filters items that have been created after the given date.
         /// </summary>
@@ -27,5 +27,23 @@ namespace Retroactiune.Core.Services
         /// Rating filters for the rating.
         /// </summary>
         public uint Rating { get; set; }
+
+        public override bool Equals(object obj)
+        {
+            return obj != null && Equals((FeedbacksListFilters) obj);
+        }
+
+        private bool Equals(FeedbacksListFilters other)
+        {
+            return FeedbackReceiverId == other.FeedbackReceiverId &&
+                   Nullable.Equals(CreatedAfter, other.CreatedAfter) &&
+                   Nullable.Equals(CreatedBefore, other.CreatedBefore) && Rating == other.Rating;
+        }
+
+        [SuppressMessage("ReSharper", "NonReadonlyMemberInGetHashCode")]
+        public override int GetHashCode()
+        {
+            return HashCode.Combine(FeedbackReceiverId, CreatedAfter, CreatedBefore, Rating);
+        }
     }
 }
\ No newline at end of file
diff --git a/Retroactiune.UnitTests/Retroactiune.WebAPI/Controllers/TestFeedbackReceiverController.cs b/Retroactiune.UnitTests/Retroactiune.WebAPI/Controllers/TestFeedbackReceiverController.cs
index 0dc176f..e3fc00c 100644
--- a/Retroactiune.UnitTests/Retroactiune.WebAPI/Controllers/TestFeedbackReceiverController.cs
+++ b/Retroactiune.UnitTests/Retroactiune.WebAPI/Controllers/TestFeedbackReceiverController.cs
@@ -202,9 +202,6 @@ namespace Retroactiune.Tests.Retroactiune.WebAPI.Controllers
             mockService.Verify(s => s.FindAsync(filterArr, offset, limit), Times.Once);
         }
 
-        // Invalid token
-        // happy
-
         [Theory, AutoData]
         public async Task AddFeedback_No_FeedbackReceiver(FeedbackInDto requestBody)
         {
@@ -272,7 +269,7 @@ namespace Retroactiune.Tests.Retroactiune.WebAPI.Controllers
                         TimeUsed = DateTime.UtcNow
                     }
                 });
-            
+
             // Test
             var controller = new FeedbackReceiversController(feedbackReceiversService.Object, tokensService.Object,
                 feedbacksService.Object, mapper, null,
@@ -282,8 +279,8 @@ namespace Retroactiune.Tests.Retroactiune.WebAPI.Controllers
             // Assert
             Assert.IsType<BadRequestObjectResult>(result);
         }
-        
-        
+
+
         [Theory, AutoData]
         public async Task AddFeedback_Happy(FeedbackInDto requestBody)
         {
@@ -295,11 +292,15 @@ namespace Retroactiune.Tests.Retroactiune.WebAPI.Controllers
             var logger = new Mock<ILogger<FeedbackReceiversController>>();
 
             feedbackReceiversService
-                .Setup(i => i.FindAsync(It.IsAny<IEnumerable<string>>(), It.IsAny<int?>(), It.IsAny<int?>()))
-                .ReturnsAsync(new[] {new FeedbackReceiver
+                .Setup(i => i.FindAsync(It.IsAny<IEnumerable<string>>(),
+                    It.IsAny<int?>(), It.IsAny<int?>()))
+                .ReturnsAsync(new[]
                 {
-                    Id = "batman"
-                }});
+                    new FeedbackReceiver
+                    {
+                        Id = "batman"
+                    }
+                });
 
             tokensService.Setup(i => i.FindAsync(It.IsAny<TokenListFilters>()))
                 .ReturnsAsync(new[]
@@ -310,7 +311,7 @@ namespace Retroactiune.Tests.Retroactiune.WebAPI.Controllers
                         TimeUsed = null
                     }
                 });
-            
+
             // Test
             var controller = new FeedbackReceiversController(feedbackReceiversService.Object, tokensService.Object,
                 feedbacksService.Object, mapper, null, logger.Object);
@@ -318,6 +319,32 @@ namespace Retroactiune.Tests.Retroactiune.WebAPI.Controllers
 
             // Assert
             Assert.IsType<OkResult>(result);
+            feedbacksService.Verify(i => i.AddFeedbackAsync(It.IsAny<Feedback>(),
+                It.IsAny<FeedbackReceiver>()));
+            tokensService.Verify(i => i.MarkTokenAsUsedAsync(It.IsAny<Token>()));
+        }
+
+        [Theory, AutoData]
+        public async Task GetFeedbacks_Happy(string guid, ListFeedbacksFiltersDto filters)
+        {
+            // Arrange
+            var mapper = TestUtils.GetMapper();
+            var feedbackReceiversService = new Mock<IFeedbackReceiversService>();
+            var tokensService = new Mock<ITokensService>();
+            var feedbacksService = new Mock<IFeedbacksService>();
+            var logger = new Mock<ILogger<FeedbackReceiversController>>();
+
+            // Test
+            var controller = new FeedbackReceiversController(feedbackReceiversService.Object, tokensService.Object,
+                feedbacksService.Object, mapper, null, logger.Object);
+            var result = await controller.GetFeedbacks(guid, filters);
+
+            // Assert
+            Assert.IsType<OkObjectResult>(result);
+
+            var listFilters = mapper.Map<FeedbacksListFilters>(filters);
+            listFilters.FeedbackReceiverId = guid;
+            feedbacksService.Verify(i => i.GetFeedbacksAsync(listFilters));
         }
     }
 }
\ No newline at end of file
diff --git a/Retroactiune.WebAPI/Controllers/FeedbackReceivers.FeedbacksController.cs b/Retroactiune.WebAPI/Controllers/FeedbackReceivers.FeedbacksController.cs
index 8281010..e9fd1c7 100644
--- a/Retroactiune.WebAPI/Controllers/FeedbackReceivers.FeedbacksController.cs
+++ b/Retroactiune.WebAPI/Controllers/FeedbackReceivers.FeedbacksController.cs
@@ -82,7 +82,7 @@ namespace Retroactiune.Controllers
         [ProducesResponseType(typeof(BasicResponse), StatusCodes.Status400BadRequest)]
         public async Task<IActionResult> GetFeedbacks(string guid, [FromQuery] ListFeedbacksFiltersDto filters)
         {
-            // TODO: Unit & Integration test.
+            // TODO: Integration test.
             var feedbacksListFilters = _mapper.Map<FeedbacksListFilters>(filters);
             feedbacksListFilters.FeedbackReceiverId = guid;
             var response = await _feedbacksService.GetFeedbacksAsync(feedbacksListFilters);
diff --git a/Retroactiune.WebAPI/Controllers/TokensController.cs b/Retroactiune.WebAPI/Controllers/TokensController.cs
index a50a5e7..23c4c72 100644
--- a/Retroactiune.WebAPI/Controllers/TokensController.cs
+++ b/Retroactiune.WebAPI/Controllers/TokensController.cs
@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
 using System.Linq;
 using System.Threading.Tasks;
@@ -145,5 +146,41 @@ namespace Retroactiune.Controllers
                 });
             }
         }
+
+        /// <summary>
+        /// Checks if a token is valid or not.
+        /// </summary>
+        /// <response code="200">The the result of the check.</response>
+        /// <response code="400">The request is invalid.</response>
+        [HttpGet("{guid}/check")]
+        [ProducesResponseType(typeof(CheckTokenDto), StatusCodes.Status200OK)]
+        [ProducesResponseType(StatusCodes.Status400BadRequest)]
+        public async Task<IActionResult> CheckToken(
+            [StringLength(24, ErrorMessage = "invalid guid, must be 24 characters", MinimumLength = 24)]
+            string guid
+        )
+        {
+            // TODO: Unit test.
+            var response = await _tokensService.FindAsync(new TokenListFilters
+            {
+                Ids = new[] {guid}
+            });
+            try
+            {
+                var token = response.ElementAt(0);
+                return Ok(new CheckTokenDto
+                {
+                    IsValid = token.IsValid()
+                });
+            }
+            catch (ArgumentOutOfRangeException)
+            {
+                _logger.LogWarning("Invalid token {Guid}", guid);
+                return Ok(new CheckTokenDto
+                {
+                    IsValid = true
+                });
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/Retroactiune.WebAPI/DataTransferObjects/CheckTokenDto.cs b/Retroactiune.WebAPI/DataTransferObjects/CheckTokenDto.cs
new file mode 100644
index 0000000..384b826
--- /dev/null
+++ b/Retroactiune.WebAPI/DataTransferObjects/CheckTokenDto.cs
@@ -0,0 +1,7 @@
+namespace Retroactiune.DataTransferObjects
+{
+    public class CheckTokenDto
+    {
+        public bool IsValid { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/Retroactiune.WebAPI/Startup.cs b/Retroactiune.WebAPI/Startup.cs
index 2a47f32..3adbfdf 100644
--- a/Retroactiune.WebAPI/Startup.cs
+++ b/Retroactiune.WebAPI/Startup.cs
@@ -21,6 +21,7 @@ namespace Retroactiune
     public class Startup
     {
         // TODO: External auth provider.
+        // TODO: Improve coverage.
         // TODO: UI? 
         public Startup(IConfiguration configuration)
         {