diff --git a/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala b/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala
index 79aef16..dc898f3 100644
--- a/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala
+++ b/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala
@@ -5,6 +5,7 @@
 import scala.scalajs.js
 import works.iterative.core.UserMessage
 import java.text.MessageFormat
+import scala.util.Try
 
 // TODO: support hierarchical json structure
 trait JsonMessageCatalogue extends MessageCatalogue:
@@ -16,4 +17,9 @@
 
   override def get(msg: UserMessage): Option[String] =
     assume(messages != null, "Message catalogue must not be null")
-    get(msg.id).map(_.format(msg.args: _*))
+    get(msg.id).map(m =>
+      Try(m.format(msg.args*)).fold(
+        t => s"error formatting [${msg.id.toString()}]: '$m': ${t.getMessage}",
+        identity
+      )
+    )

diff --git a/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala b/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala
index 79aef16..dc898f3 100644
--- a/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala
+++ b/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala
@@ -5,6 +5,7 @@
 import scala.scalajs.js
 import works.iterative.core.UserMessage
 import java.text.MessageFormat
+import scala.util.Try
 
 // TODO: support hierarchical json structure
 trait JsonMessageCatalogue extends MessageCatalogue:
@@ -16,4 +17,9 @@
 
   override def get(msg: UserMessage): Option[String] =
     assume(messages != null, "Message catalogue must not be null")
-    get(msg.id).map(_.format(msg.args: _*))
+    get(msg.id).map(m =>
+      Try(m.format(msg.args*)).fold(
+        t => s"error formatting [${msg.id.toString()}]: '$m': ${t.getMessage}",
+        identity
+      )
+    )
diff --git a/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormBuilderModule.scala b/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormBuilderModule.scala
index a7b1166..37d80f8 100644
--- a/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormBuilderModule.scala
+++ b/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormBuilderModule.scala
@@ -9,7 +9,9 @@
 trait InputField[A]:
   def render: ReactiveHtmlElement[html.Input]
 
-type Validated[A] = Validation[UserMessage, A]
+case class InvalidValue(name: String, message: String => UserMessage)
+
+type Validated[A] = Validation[InvalidValue, A]
 
 sealed trait Form[A]:
   def value: Validated[A]
@@ -17,7 +19,9 @@
 object Form:
   case class Input(name: String) extends Form[String]:
     override def value: Validated[String] =
-      Validation.fail(UserMessage("error.invalid.value"))
+      Validation.fail(
+        InvalidValue(name, UserMessage("error.value.required", _))
+      )
 
 trait FormBuilderModule:
   def formMessagesResolver: FormMessagesResolver
@@ -27,14 +31,26 @@
 
   case class HtmlFormBuilder[A](form: Form[A], submit: Observer[A]):
     def renderForm[A](form: Form[A]): HtmlElement = form match
-      case Form.Input(name) =>
+      case i @ Form.Input(name) =>
+        val userLabel = formMessagesResolver.label(name)
         formUIFactory.field(
-          formUIFactory.label(formMessagesResolver.label(name))()
+          formUIFactory.label(userLabel)()
         )(
           formUIFactory.input(
             name,
             placeholder = formMessagesResolver.placeholder(name)
-          )()
+          )(),
+          i.value.fold(
+            msgs =>
+              msgs
+                .map(msg =>
+                  formUIFactory.validationError(
+                    formMessagesResolver.message(msg.message(userLabel))
+                  )
+                )
+                .toList,
+            _ => List.empty[HtmlMod]
+          )
         )
 
     def build: HtmlElement =

diff --git a/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala b/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala
index 79aef16..dc898f3 100644
--- a/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala
+++ b/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala
@@ -5,6 +5,7 @@
 import scala.scalajs.js
 import works.iterative.core.UserMessage
 import java.text.MessageFormat
+import scala.util.Try
 
 // TODO: support hierarchical json structure
 trait JsonMessageCatalogue extends MessageCatalogue:
@@ -16,4 +17,9 @@
 
   override def get(msg: UserMessage): Option[String] =
     assume(messages != null, "Message catalogue must not be null")
-    get(msg.id).map(_.format(msg.args: _*))
+    get(msg.id).map(m =>
+      Try(m.format(msg.args*)).fold(
+        t => s"error formatting [${msg.id.toString()}]: '$m': ${t.getMessage}",
+        identity
+      )
+    )
diff --git a/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormBuilderModule.scala b/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormBuilderModule.scala
index a7b1166..37d80f8 100644
--- a/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormBuilderModule.scala
+++ b/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormBuilderModule.scala
@@ -9,7 +9,9 @@
 trait InputField[A]:
   def render: ReactiveHtmlElement[html.Input]
 
-type Validated[A] = Validation[UserMessage, A]
+case class InvalidValue(name: String, message: String => UserMessage)
+
+type Validated[A] = Validation[InvalidValue, A]
 
 sealed trait Form[A]:
   def value: Validated[A]
@@ -17,7 +19,9 @@
 object Form:
   case class Input(name: String) extends Form[String]:
     override def value: Validated[String] =
-      Validation.fail(UserMessage("error.invalid.value"))
+      Validation.fail(
+        InvalidValue(name, UserMessage("error.value.required", _))
+      )
 
 trait FormBuilderModule:
   def formMessagesResolver: FormMessagesResolver
@@ -27,14 +31,26 @@
 
   case class HtmlFormBuilder[A](form: Form[A], submit: Observer[A]):
     def renderForm[A](form: Form[A]): HtmlElement = form match
-      case Form.Input(name) =>
+      case i @ Form.Input(name) =>
+        val userLabel = formMessagesResolver.label(name)
         formUIFactory.field(
-          formUIFactory.label(formMessagesResolver.label(name))()
+          formUIFactory.label(userLabel)()
         )(
           formUIFactory.input(
             name,
             placeholder = formMessagesResolver.placeholder(name)
-          )()
+          )(),
+          i.value.fold(
+            msgs =>
+              msgs
+                .map(msg =>
+                  formUIFactory.validationError(
+                    formMessagesResolver.message(msg.message(userLabel))
+                  )
+                )
+                .toList,
+            _ => List.empty[HtmlMod]
+          )
         )
 
     def build: HtmlElement =
diff --git a/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormMessagesResolver.scala b/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormMessagesResolver.scala
index 58d0068..bd1ab7b 100644
--- a/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormMessagesResolver.scala
+++ b/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormMessagesResolver.scala
@@ -2,11 +2,13 @@
 
 import works.iterative.core.MessageCatalogue
 import works.iterative.ui.components.tailwind.ComponentContext
+import works.iterative.core.UserMessage
 
 trait FormMessagesResolver:
   def label(name: String): String
   def help(name: String): Option[String]
   def placeholder(name: String): Option[String]
+  def message(msg: UserMessage): String
 
 object FormMessagesResolver:
   given (using ctx: ComponentContext[_]): FormMessagesResolver =
@@ -17,6 +19,9 @@
 
 class MessageCatalogueFormMessagesResolver(using cat: MessageCatalogue)
     extends FormMessagesResolver:
-  def label(name: String): String = cat(name)
-  def help(name: String): Option[String] = cat.get(s"$name.help")
-  def placeholder(name: String): Option[String] = cat.get(s"$name.placeholder")
+  override def label(name: String): String = cat(name)
+  override def help(name: String): Option[String] = cat.get(s"$name.help")
+  override def placeholder(name: String): Option[String] =
+    cat.get(s"$name.placeholder")
+
+  override def message(msg: UserMessage): String = cat(msg)

diff --git a/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala b/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala
index 79aef16..dc898f3 100644
--- a/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala
+++ b/ui/js/src/main/scala/works/iterative/ui/JsonMessageCatalogue.scala
@@ -5,6 +5,7 @@
 import scala.scalajs.js
 import works.iterative.core.UserMessage
 import java.text.MessageFormat
+import scala.util.Try
 
 // TODO: support hierarchical json structure
 trait JsonMessageCatalogue extends MessageCatalogue:
@@ -16,4 +17,9 @@
 
   override def get(msg: UserMessage): Option[String] =
     assume(messages != null, "Message catalogue must not be null")
-    get(msg.id).map(_.format(msg.args: _*))
+    get(msg.id).map(m =>
+      Try(m.format(msg.args*)).fold(
+        t => s"error formatting [${msg.id.toString()}]: '$m': ${t.getMessage}",
+        identity
+      )
+    )
diff --git a/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormBuilderModule.scala b/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormBuilderModule.scala
index a7b1166..37d80f8 100644
--- a/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormBuilderModule.scala
+++ b/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormBuilderModule.scala
@@ -9,7 +9,9 @@
 trait InputField[A]:
   def render: ReactiveHtmlElement[html.Input]
 
-type Validated[A] = Validation[UserMessage, A]
+case class InvalidValue(name: String, message: String => UserMessage)
+
+type Validated[A] = Validation[InvalidValue, A]
 
 sealed trait Form[A]:
   def value: Validated[A]
@@ -17,7 +19,9 @@
 object Form:
   case class Input(name: String) extends Form[String]:
     override def value: Validated[String] =
-      Validation.fail(UserMessage("error.invalid.value"))
+      Validation.fail(
+        InvalidValue(name, UserMessage("error.value.required", _))
+      )
 
 trait FormBuilderModule:
   def formMessagesResolver: FormMessagesResolver
@@ -27,14 +31,26 @@
 
   case class HtmlFormBuilder[A](form: Form[A], submit: Observer[A]):
     def renderForm[A](form: Form[A]): HtmlElement = form match
-      case Form.Input(name) =>
+      case i @ Form.Input(name) =>
+        val userLabel = formMessagesResolver.label(name)
         formUIFactory.field(
-          formUIFactory.label(formMessagesResolver.label(name))()
+          formUIFactory.label(userLabel)()
         )(
           formUIFactory.input(
             name,
             placeholder = formMessagesResolver.placeholder(name)
-          )()
+          )(),
+          i.value.fold(
+            msgs =>
+              msgs
+                .map(msg =>
+                  formUIFactory.validationError(
+                    formMessagesResolver.message(msg.message(userLabel))
+                  )
+                )
+                .toList,
+            _ => List.empty[HtmlMod]
+          )
         )
 
     def build: HtmlElement =
diff --git a/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormMessagesResolver.scala b/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormMessagesResolver.scala
index 58d0068..bd1ab7b 100644
--- a/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormMessagesResolver.scala
+++ b/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormMessagesResolver.scala
@@ -2,11 +2,13 @@
 
 import works.iterative.core.MessageCatalogue
 import works.iterative.ui.components.tailwind.ComponentContext
+import works.iterative.core.UserMessage
 
 trait FormMessagesResolver:
   def label(name: String): String
   def help(name: String): Option[String]
   def placeholder(name: String): Option[String]
+  def message(msg: UserMessage): String
 
 object FormMessagesResolver:
   given (using ctx: ComponentContext[_]): FormMessagesResolver =
@@ -17,6 +19,9 @@
 
 class MessageCatalogueFormMessagesResolver(using cat: MessageCatalogue)
     extends FormMessagesResolver:
-  def label(name: String): String = cat(name)
-  def help(name: String): Option[String] = cat.get(s"$name.help")
-  def placeholder(name: String): Option[String] = cat.get(s"$name.placeholder")
+  override def label(name: String): String = cat(name)
+  override def help(name: String): Option[String] = cat.get(s"$name.help")
+  override def placeholder(name: String): Option[String] =
+    cat.get(s"$name.placeholder")
+
+  override def message(msg: UserMessage): String = cat(msg)
diff --git a/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormUIFactory.scala b/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormUIFactory.scala
index 0fa941e..fd3d3e3 100644
--- a/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormUIFactory.scala
+++ b/ui/js/src/main/scala/works/iterative/ui/components/laminar/forms/FormUIFactory.scala
@@ -21,6 +21,8 @@
 
   def submit(label: HtmlMod): HtmlElement
 
+  def validationError(text: HtmlMod): HtmlElement
+
   def input(
       name: String,
       id: Option[String] = None,