diff --git a/lib/JSON/Validator/Schema/OpenAPIv3.pm b/lib/JSON/Validator/Schema/OpenAPIv3.pm
index 2044984f..3b9c9864 100644
--- a/lib/JSON/Validator/Schema/OpenAPIv3.pm
+++ b/lib/JSON/Validator/Schema/OpenAPIv3.pm
@@ -407,8 +407,19 @@ sub _validate_type_object_response {
 }
 
 sub _validate_type_string {
-  my $self = shift;
-  return $_[1]->{schema}{nullable} && !defined $_[0] ? () : $self->SUPER::_validate_type_string(@_);
+  my ($self, $val, $state) = @_;
+
+  return () if $state->{schema}{nullable} && !defined $val;
+
+  if (ref $val eq 'Mojo::Upload') {
+    return () if
+      defined $state->{schema}{format} &&
+      $state->{schema}{format} eq 'binary';
+
+    return E $state->{path}, [string => type => data_type $val];
+  }
+
+  return $self->SUPER::_validate_type_string($val, $state);
 }
 
 1;
diff --git a/lib/JSON/Validator/Util.pm b/lib/JSON/Validator/Util.pm
index cb79de76..a391c8e8 100644
--- a/lib/JSON/Validator/Util.pm
+++ b/lib/JSON/Validator/Util.pm
@@ -59,6 +59,7 @@ sub data_type {
   my $ref     = ref $_[0];
   my $blessed = blessed $_[0];
   return 'object'  if $ref eq 'HASH';
+  return 'file'    if $ref eq 'Mojo::Upload';
   return lc $ref   if $ref and !$blessed;
   return 'null'    if !defined $_[0];
   return 'boolean' if $blessed and ("$_[0]" eq "1" or !"$_[0]");
diff --git a/t/openapiv3-file.t b/t/openapiv3-file.t
new file mode 100644
index 00000000..7060f9ed
--- /dev/null
+++ b/t/openapiv3-file.t
@@ -0,0 +1,133 @@
+use Mojo::Base -strict;
+use JSON::Validator::Schema::OpenAPIv3;
+use Mojo::File;
+use Mojo::Upload;
+use Test::Deep;
+use Test::More;
+
+my $cwd    = Mojo::File->new(__FILE__)->dirname;
+my $schema = JSON::Validator::Schema::OpenAPIv3->new;
+my ($body, $p, @errors);
+
+subtest 'basic' => sub {
+  is $schema->specification, 'https://spec.openapis.org/oas/3.0/schema/2019-04-02', 'specification';
+  is_deeply $schema->coerce, {booleans => 1, numbers => 1, strings => 1}, 'default coercion';
+
+  $schema = JSON::Validator->new->schema('data://main/spec.yaml')->schema;
+  isa_ok $schema, 'JSON::Validator::Schema::OpenAPIv3';
+
+  @errors = @{JSON::Validator->new->schema({openapi => '3.0.0', paths => {}})->schema->errors};
+  is "@errors", '/info: Missing property.', 'invalid schema';
+
+  is_deeply(
+    $schema->routes->to_array,
+    [
+      {method => 'post', operation_id => 'submit',  path => '/submit'},
+      {method => 'post', operation_id => 'uploadFile',  path => '/upload'},
+    ],
+    'routes'
+  );
+};
+
+subtest 'validate_request - file string' => sub {
+  my $file = 'file contents\nmore content';
+
+  # Check required works
+  $body = {exists => 1,value => {image => $file } };
+  @errors = $schema->validate_request([post => '/upload'], {body => \&body});
+  is "@errors", "/body/file: Missing property.", 'detects missing file';
+
+  $body = {exists => 1,value => {file => $file } };
+  @errors = $schema->validate_request([post => '/upload'], {body => \&body});
+  is "@errors", "", 'valid file';
+  is_deeply $body, {
+    content_type => 'multipart/form-data',
+    exists => 1,
+    in => 'body',
+    name => 'body',
+    valid => 1,
+    value => {file => $file},
+  }, 'valid file';
+};
+
+subtest 'validate_request - file placeholder' => sub {
+  my $file = Mojo::Upload->new;
+
+  # Check required works
+  $body = {exists => 1,value => {image => $file } };
+  @errors = $schema->validate_request([post => '/upload'], {body => \&body});
+  is "@errors", "/body/file: Missing property.", 'detects missing file';
+
+  $body = {exists => 1,value => {file => $file } };
+  @errors = $schema->validate_request([post => '/upload'], {body => \&body});
+  is "@errors", "", 'valid file';
+  is_deeply $body, {
+    content_type => 'multipart/form-data',
+    exists => 1,
+    in => 'body',
+    name => 'body',
+    valid => 1,
+    value => {file => $file},
+  }, 'valid file';
+};
+
+subtest 'string in non-file string' => sub {
+
+  $body = {exists => 1,value => {name => 'some string' } };
+  @errors = $schema->validate_request([post => '/submit'], {body => \&body});
+  is "@errors", "", 'valid file';
+  is_deeply $body, {
+    content_type => 'multipart/form-data',
+    exists => 1,
+    value => {name => 'some string'},
+    in => 'body',
+    name => 'body',
+    valid => 1,
+  }, 'valid file';
+};
+
+subtest 'file placehodler in non-file string' => sub {
+  my $file = Mojo::Upload->new;
+  $body = {exists => 1,value => {name => $file } };
+  @errors = $schema->validate_request([post => '/submit'], {body => \&body});
+  is "@errors", "/body/name: Expected string - got file.", 'valid file';
+};
+
+done_testing;
+
+sub body {$body}
+
+__DATA__
+@@ spec.yaml
+openapi: 3.0.0
+info:
+  title: Test body
+  version: 0.8
+paths:
+  /submit:
+    post:
+      operationId: submit
+      requestBody:
+        content:
+          multipart/form-data:
+            schema:
+              type: object
+              required:
+                - name
+              properties:
+                name:
+                  type: string
+  /upload:
+    post:
+      operationId: uploadFile
+      requestBody:
+        content:
+          multipart/form-data:
+            schema:
+              type: object
+              required:
+                - file
+              properties:
+                file:
+                  type: string
+                  format: binary