diff --git a/src/core/jit/context.rs b/src/core/jit/context.rs
index f52b34223b..757f5d9ff9 100644
--- a/src/core/jit/context.rs
+++ b/src/core/jit/context.rs
@@ -70,16 +70,9 @@ impl<'a, Input: Clone, Output> Context<'a, Input, Output> {
 
         for arg in field.args.iter() {
             let name = arg.name.as_str();
-            let value = arg
-                .value
-                .clone()
-                // TODO: default value resolution should happen in the InputResolver
-                .or_else(|| arg.default_value.clone());
+            let value = arg.value.clone();
             if let Some(value) = value {
                 arg_map.insert(Name::new(name), value);
-            } else if !arg.type_of.is_nullable() {
-                // TODO: throw error here
-                todo!()
             }
         }
         Some(arg_map)
diff --git a/src/core/jit/error.rs b/src/core/jit/error.rs
index 8689b61ca4..2183bcbeeb 100644
--- a/src/core/jit/error.rs
+++ b/src/core/jit/error.rs
@@ -20,6 +20,11 @@ pub enum BuildError {
 pub enum ResolveInputError {
     #[error("Variable `{0}` is not defined")]
     VariableIsNotFound(String),
+    #[error("Argument `{arg_name}` for field `{field_name}` is required")]
+    ArgumentIsRequired {
+        arg_name: String,
+        field_name: String,
+    },
 }
 
 #[derive(Error, Debug, Clone)]
diff --git a/src/core/jit/input_resolver.rs b/src/core/jit/input_resolver.rs
index 286070ed39..9c3bd20002 100644
--- a/src/core/jit/input_resolver.rs
+++ b/src/core/jit/input_resolver.rs
@@ -1,6 +1,6 @@
 use async_graphql_value::{ConstValue, Value};
 
-use super::{OperationPlan, ResolveInputError, Variables};
+use super::{Arg, Field, OperationPlan, ResolveInputError, Variables};
 
 /// Trait to represent conversion from some dynamic type (with variables)
 /// to the resolved variant based on the additional provided info.
@@ -15,6 +15,16 @@ pub trait InputResolvable {
     ) -> Result<Self::Output, ResolveInputError>;
 }
 
+pub trait OutputTrait {
+    fn is_null_value(&self) -> bool;
+}
+
+impl OutputTrait for ConstValue {
+    fn is_null_value(&self) -> bool {
+        self.eq(&ConstValue::Null)
+    }
+}
+
 impl InputResolvable for Value {
     type Output = ConstValue;
 
@@ -45,7 +55,7 @@ impl<Input> InputResolver<Input> {
 impl<Input, Output> InputResolver<Input>
 where
     Input: Clone,
-    Output: Clone,
+    Output: Clone + OutputTrait,
     Input: InputResolvable<Output = Output>,
 {
     pub fn resolve_input(
@@ -57,7 +67,42 @@ where
             .as_parent()
             .iter()
             .map(|field| field.clone().try_map(|value| value.resolve(variables)))
-            .collect::<Result<_, _>>()?;
+            .map(|field| match field {
+                Ok(field) => {
+                    let args = field
+                        .args
+                        .into_iter()
+                        .map(|arg| {
+                            // TODO: this should recursively check the InputType for field presence
+                            if arg
+                                .value
+                                .as_ref()
+                                .map(|val| val.is_null_value())
+                                .unwrap_or(true)
+                                && !arg.type_of.is_nullable()
+                            {
+                                let default_value = arg.default_value.clone();
+                                match default_value {
+                                    Some(value) => Ok(Arg { value: Some(value), ..arg }),
+                                    None => Err(ResolveInputError::ArgumentIsRequired {
+                                        arg_name: arg.name,
+                                        field_name: field.output_name.clone(),
+                                    }),
+                                }
+                            } else if arg.value.is_none() {
+                                let default_value = arg.default_value.clone();
+                                Ok(Arg { value: default_value, ..arg })
+                            } else {
+                                Ok(arg)
+                            }
+                        })
+                        .collect::<Result<_, _>>()?;
+
+                    Ok(Field { args, ..field })
+                }
+                Err(err) => Err(err),
+            })
+            .collect::<Result<Vec<_>, _>>()?;
 
         Ok(OperationPlan::new(
             new_fields,
diff --git a/tests/core/snapshots/graphql-conformance-001.md_5.snap b/tests/core/snapshots/graphql-conformance-001.md_5.snap
new file mode 100644
index 0000000000..92f6de675e
--- /dev/null
+++ b/tests/core/snapshots/graphql-conformance-001.md_5.snap
@@ -0,0 +1,18 @@
+---
+source: tests/core/spec.rs
+expression: response
+---
+{
+  "status": 200,
+  "headers": {
+    "content-type": "application/json"
+  },
+  "body": {
+    "data": null,
+    "errors": [
+      {
+        "message": "Build error: ResolveInputError: Argument `id` for field `user` is required"
+      }
+    ]
+  }
+}
diff --git a/tests/execution/graphql-conformance-001.md b/tests/execution/graphql-conformance-001.md
index c92262e53c..eaf8cbb478 100644
--- a/tests/execution/graphql-conformance-001.md
+++ b/tests/execution/graphql-conformance-001.md
@@ -114,16 +114,15 @@ type User {
         }
 
 # Negative: missing input
-# TODO: expect error that user.id input is missing
-# - method: POST
-#   url: http://localhost:8080/graphql
-#   body:
-#     query: |
-#       query {
-#         user {
-#           id
-#           name
-#           city
-#         }
-#       }
+- method: POST
+  url: http://localhost:8080/graphql
+  body:
+    query: |
+      query {
+        user {
+          id
+          name
+          city
+        }
+      }
 ```