diff --git a/src/Api/Models/Request/Accounts/EmailRequestModel.cs b/src/Api/Models/Request/Accounts/EmailRequestModel.cs
index c9de5aeed..86c689d92 100644
--- a/src/Api/Models/Request/Accounts/EmailRequestModel.cs
+++ b/src/Api/Models/Request/Accounts/EmailRequestModel.cs
@@ -6,10 +6,13 @@ namespace Bit.Api.Models
     {
         [Required]
         [EmailAddress]
+        [StringLength(50)]
         public string NewEmail { get; set; }
         [Required]
+        [StringLength(300)]
         public string MasterPasswordHash { get; set; }
         [Required]
+        [StringLength(300)]
         public string NewMasterPasswordHash { get; set; }
         [Required]
         public string Token { get; set; }
diff --git a/src/Api/Models/Request/Accounts/EmailTokenRequestModel.cs b/src/Api/Models/Request/Accounts/EmailTokenRequestModel.cs
index 12a222864..3c8ff2754 100644
--- a/src/Api/Models/Request/Accounts/EmailTokenRequestModel.cs
+++ b/src/Api/Models/Request/Accounts/EmailTokenRequestModel.cs
@@ -6,8 +6,10 @@ namespace Bit.Api.Models
     {
         [Required]
         [EmailAddress]
+        [StringLength(50)]
         public string NewEmail { get; set; }
         [Required]
+        [StringLength(300)]
         public string MasterPasswordHash { get; set; }
     }
 }
diff --git a/src/Api/Models/Request/Accounts/PasswordHintRequestModel.cs b/src/Api/Models/Request/Accounts/PasswordHintRequestModel.cs
index d21051aa5..64261423d 100644
--- a/src/Api/Models/Request/Accounts/PasswordHintRequestModel.cs
+++ b/src/Api/Models/Request/Accounts/PasswordHintRequestModel.cs
@@ -6,6 +6,7 @@ namespace Bit.Api.Models
     {
         [Required]
         [EmailAddress]
+        [StringLength(50)]
         public string Email { get; set; }
     }
 }
diff --git a/src/Api/Models/Request/Accounts/PasswordRequestModel.cs b/src/Api/Models/Request/Accounts/PasswordRequestModel.cs
index c634e5663..886bf2ff6 100644
--- a/src/Api/Models/Request/Accounts/PasswordRequestModel.cs
+++ b/src/Api/Models/Request/Accounts/PasswordRequestModel.cs
@@ -5,8 +5,10 @@ namespace Bit.Api.Models
     public class PasswordRequestModel
     {
         [Required]
+        [StringLength(300)]
         public string MasterPasswordHash { get; set; }
         [Required]
+        [StringLength(300)]
         public string NewMasterPasswordHash { get; set; }
         [Required]
         public CipherRequestModel[] Ciphers { get; set; }
diff --git a/src/Api/Models/Request/Accounts/RegisterRequestModel.cs b/src/Api/Models/Request/Accounts/RegisterRequestModel.cs
index e1ebf02f9..be1efa2bd 100644
--- a/src/Api/Models/Request/Accounts/RegisterRequestModel.cs
+++ b/src/Api/Models/Request/Accounts/RegisterRequestModel.cs
@@ -8,12 +8,16 @@ namespace Bit.Api.Models
         [Required]
         public string Token { get; set; }
         [Required]
+        [StringLength(50)]
         public string Name { get; set; }
         [Required]
         [EmailAddress]
+        [StringLength(50)]
         public string Email { get; set; }
         [Required]
+        [StringLength(300)]
         public string MasterPasswordHash { get; set; }
+        [StringLength(50)]
         public string MasterPasswordHint { get; set; }
 
         public User ToUser()
diff --git a/src/Api/Models/Request/Accounts/RegisterTokenRequestModel.cs b/src/Api/Models/Request/Accounts/RegisterTokenRequestModel.cs
index 9c79372cf..15b43d095 100644
--- a/src/Api/Models/Request/Accounts/RegisterTokenRequestModel.cs
+++ b/src/Api/Models/Request/Accounts/RegisterTokenRequestModel.cs
@@ -6,6 +6,7 @@ namespace Bit.Api.Models
     {
         [Required]
         [EmailAddress]
+        [StringLength(50)]
         public string Email { get; set; }
     }
 }
diff --git a/src/Api/Models/Request/Accounts/UpdateProfileRequestModel.cs b/src/Api/Models/Request/Accounts/UpdateProfileRequestModel.cs
index 504692a9f..f7cfee0e2 100644
--- a/src/Api/Models/Request/Accounts/UpdateProfileRequestModel.cs
+++ b/src/Api/Models/Request/Accounts/UpdateProfileRequestModel.cs
@@ -6,7 +6,9 @@ namespace Bit.Api.Models
     public class UpdateProfileRequestModel
     {
         [Required]
+        [StringLength(50)]
         public string Name { get; set; }
+        [StringLength(50)]
         public string MasterPasswordHint { get; set; }
         [Required]
         [RegularExpression("^[a-z]{2}-[A-Z]{2}$")]
diff --git a/src/Api/Models/Request/Accounts/UpdateTwoFactorRequestModel.cs b/src/Api/Models/Request/Accounts/UpdateTwoFactorRequestModel.cs
index 85593158f..b18b39814 100644
--- a/src/Api/Models/Request/Accounts/UpdateTwoFactorRequestModel.cs
+++ b/src/Api/Models/Request/Accounts/UpdateTwoFactorRequestModel.cs
@@ -9,6 +9,7 @@ namespace Bit.Api.Models
         public string MasterPasswordHash { get; set; }
         [Required]
         public bool? Enabled { get; set; }
+        [StringLength(50)]
         public string Token { get; set; }
 
         public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
diff --git a/src/Api/Models/Request/Auth/AuthTokenRequestModel.cs b/src/Api/Models/Request/Auth/AuthTokenRequestModel.cs
index c80d35898..1ccd66c31 100644
--- a/src/Api/Models/Request/Auth/AuthTokenRequestModel.cs
+++ b/src/Api/Models/Request/Auth/AuthTokenRequestModel.cs
@@ -6,6 +6,7 @@ namespace Bit.Api.Models
     {
         [Required]
         [EmailAddress]
+        [StringLength(50)]
         public string Email { get; set; }
         [Required]
         public string MasterPasswordHash { get; set; }
diff --git a/src/Api/Models/Request/Ciphers/CipherRequestModel.cs b/src/Api/Models/Request/Ciphers/CipherRequestModel.cs
index 0f0d0d295..15fee5e09 100644
--- a/src/Api/Models/Request/Ciphers/CipherRequestModel.cs
+++ b/src/Api/Models/Request/Ciphers/CipherRequestModel.cs
@@ -13,18 +13,25 @@ namespace Bit.Api.Models
         public CipherType Type { get; set; }
 
         [Required]
+        [StringLength(36)]
         public string Id { get; set; }
+        [StringLength(36)]
         public string FolderId { get; set; }
         [Required]
         [EncryptedString]
+        [StringLength(300)]
         public string Name { get; set; }
         [EncryptedString]
+        [StringLength(5000)]
         public string Uri { get; set; }
         [EncryptedString]
+        [StringLength(200)]
         public string Username { get; set; }
         [EncryptedString]
+        [StringLength(300)]
         public string Password { get; set; }
         [EncryptedString]
+        [StringLength(5000)]
         public string Notes { get; set; }
 
         public virtual Site ToSite(string userId = null)
diff --git a/src/Api/Models/Request/Folders/FolderRequestModel.cs b/src/Api/Models/Request/Folders/FolderRequestModel.cs
index 6dbb6b692..b1e3967ee 100644
--- a/src/Api/Models/Request/Folders/FolderRequestModel.cs
+++ b/src/Api/Models/Request/Folders/FolderRequestModel.cs
@@ -9,6 +9,7 @@ namespace Bit.Api.Models
     {
         [Required]
         [EncryptedString]
+        [StringLength(300)]
         public string Name { get; set; }
 
         public Folder ToFolder(string userId = null)
diff --git a/src/Api/Models/Request/Sites/SiteRequestModel.cs b/src/Api/Models/Request/Sites/SiteRequestModel.cs
index 7bfc2a93e..7579d0d97 100644
--- a/src/Api/Models/Request/Sites/SiteRequestModel.cs
+++ b/src/Api/Models/Request/Sites/SiteRequestModel.cs
@@ -7,19 +7,25 @@ namespace Bit.Api.Models
 {
     public class SiteRequestModel
     {
+        [StringLength(36)]
         public string FolderId { get; set; }
         [Required]
         [EncryptedString]
+        [StringLength(300)]
         public string Name { get; set; }
         [Required]
         [EncryptedString]
+        [StringLength(5000)]
         public string Uri { get; set; }
         [EncryptedString]
+        [StringLength(200)]
         public string Username { get; set; }
         [Required]
         [EncryptedString]
+        [StringLength(300)]
         public string Password { get; set; }
         [EncryptedString]
+        [StringLength(5000)]
         public string Notes { get; set; }
 
         public Site ToSite(string userId = null)