diff --git a/datamodel/high/v3/link.go b/datamodel/high/v3/link.go
index d9f62b5..c44aa63 100644
--- a/datamodel/high/v3/link.go
+++ b/datamodel/high/v3/link.go
@@ -38,7 +38,7 @@ func NewLink(link *low.Link) *Link {
 	l.OperationRef = link.OperationRef.Value
 	l.OperationId = link.OperationId.Value
 	params := make(map[string]string)
-	for k, v := range link.Parameters.Value {
+	for k, v := range link.Parameters {
 		params[k.Value] = v.Value
 	}
 	l.Parameters = params
diff --git a/datamodel/low/v3/callback.go b/datamodel/low/v3/callback.go
index 1b76ea6..9e9cd41 100644
--- a/datamodel/low/v3/callback.go
+++ b/datamodel/low/v3/callback.go
@@ -4,9 +4,12 @@
 package v3
 
 import (
+	"crypto/sha256"
 	"github.com/pb33f/libopenapi/datamodel/low"
 	"github.com/pb33f/libopenapi/index"
 	"gopkg.in/yaml.v3"
+	"sort"
+	"strings"
 )
 
 // Callback represents a low-level Callback object for OpenAPI 3+.
@@ -59,3 +62,18 @@ func (cb *Callback) Build(root *yaml.Node, idx *index.SpecIndex) error {
 	}
 	return nil
 }
+
+// Hash will return a consistent SHA256 Hash of the Callback object
+func (cb *Callback) Hash() [32]byte {
+	var f []string
+	var keys []string
+	keys = make([]string, len(cb.Expression.Value))
+	z := 0
+	for k := range cb.Expression.Value {
+		keys[z] = low.GenerateHashString(cb.Expression.Value[k].Value)
+		z++
+	}
+	sort.Strings(keys)
+	f = append(f, keys...)
+	return sha256.Sum256([]byte(strings.Join(f, "|")))
+}
diff --git a/datamodel/low/v3/callback_test.go b/datamodel/low/v3/callback_test.go
index 15eaf2c..cba415a 100644
--- a/datamodel/low/v3/callback_test.go
+++ b/datamodel/low/v3/callback_test.go
@@ -111,3 +111,44 @@ func TestCallback_Build_Using_InlineRef(t *testing.T) {
 	assert.Equal(t, "this is something", exp.Value.Post.Value.RequestBody.Value.Description.Value)
 
 }
+
+func TestCallback_Hash(t *testing.T) {
+
+	yml := `x-seed: grow
+pizza:
+  description: cheesy
+burgers:
+  description: tasty!
+beer:
+  description: fantastic
+x-weed: loved`
+
+	var idxNode yaml.Node
+	_ = yaml.Unmarshal([]byte(yml), &idxNode)
+	idx := index.NewSpecIndex(&idxNode)
+
+	var n Callback
+	_ = low.BuildModel(idxNode.Content[0], &n)
+	_ = n.Build(idxNode.Content[0], idx)
+
+	yml2 := `burgers:
+  description: tasty!
+pizza:
+  description: cheesy
+x-weed: loved
+x-seed: grow
+beer:
+  description: fantastic
+`
+	var idxNode2 yaml.Node
+	_ = yaml.Unmarshal([]byte(yml2), &idxNode2)
+	idx2 := index.NewSpecIndex(&idxNode2)
+
+	var n2 Callback
+	_ = low.BuildModel(idxNode2.Content[0], &n2)
+	_ = n2.Build(idxNode2.Content[0], idx2)
+
+	// hash
+	assert.Equal(t, n.Hash(), n2.Hash())
+
+}
diff --git a/datamodel/low/v3/media_type_test.go b/datamodel/low/v3/media_type_test.go
index 5d157c2..c75b098 100644
--- a/datamodel/low/v3/media_type_test.go
+++ b/datamodel/low/v3/media_type_test.go
@@ -141,5 +141,4 @@ example: a thing`
 
 	// hash
 	assert.Equal(t, n.Hash(), n2.Hash())
-
 }
diff --git a/datamodel/low/v3/operation.go b/datamodel/low/v3/operation.go
index 8defb2f..d4edc96 100644
--- a/datamodel/low/v3/operation.go
+++ b/datamodel/low/v3/operation.go
@@ -182,16 +182,22 @@ func (o *Operation) Hash() [32]byte {
 	for k := range o.Parameters.Value {
 		keys[k] = low.GenerateHashString(o.Parameters.Value[k].Value)
 	}
-
 	sort.Strings(keys)
 	f = append(f, keys...)
+
+	keys = make([]string, len(o.Callbacks.Value))
+	z := 0
+	for k := range o.Callbacks.Value {
+		keys[z] = low.GenerateHashString(o.Callbacks.Value[k].Value)
+		z++
+	}
+	sort.Strings(keys)
+	f = append(f, keys...)
+
 	for k := range o.Extensions {
 		f = append(f, fmt.Sprintf("%s-%x", k.Value,
 			sha256.Sum256([]byte(fmt.Sprint(o.Extensions[k].Value)))))
 	}
-
-	// TODO: add callbacks in here.
-
 	return sha256.Sum256([]byte(strings.Join(f, "|")))
 }
 
@@ -200,15 +206,12 @@ func (o *Operation) Hash() [32]byte {
 func (o *Operation) GetTags() low.NodeReference[[]low.ValueReference[string]] {
 	return o.Tags
 }
-
 func (o *Operation) GetSummary() low.NodeReference[string] {
 	return o.Summary
 }
-
 func (o *Operation) GetDescription() low.NodeReference[string] {
 	return o.Description
 }
-
 func (o *Operation) GetExternalDocs() low.NodeReference[any] {
 	return low.NodeReference[any]{
 		ValueNode: o.ExternalDocs.ValueNode,
@@ -216,19 +219,15 @@ func (o *Operation) GetExternalDocs() low.NodeReference[any] {
 		Value:     o.ExternalDocs.Value,
 	}
 }
-
 func (o *Operation) GetOperationId() low.NodeReference[string] {
 	return o.OperationId
 }
-
 func (o *Operation) GetDeprecated() low.NodeReference[bool] {
 	return o.Deprecated
 }
-
 func (o *Operation) GetExtensions() map[low.KeyReference[string]]low.ValueReference[any] {
 	return o.Extensions
 }
-
 func (o *Operation) GetResponses() low.NodeReference[any] {
 	return low.NodeReference[any]{
 		ValueNode: o.Responses.ValueNode,
@@ -236,7 +235,6 @@ func (o *Operation) GetResponses() low.NodeReference[any] {
 		Value:     o.Responses.Value,
 	}
 }
-
 func (o *Operation) GetParameters() low.NodeReference[any] {
 	return low.NodeReference[any]{
 		ValueNode: o.Parameters.ValueNode,
@@ -244,7 +242,6 @@ func (o *Operation) GetParameters() low.NodeReference[any] {
 		Value:     o.Parameters.Value,
 	}
 }
-
 func (o *Operation) GetSecurity() low.NodeReference[any] {
 	return low.NodeReference[any]{
 		ValueNode: o.Security.ValueNode,
@@ -252,7 +249,6 @@ func (o *Operation) GetSecurity() low.NodeReference[any] {
 		Value:     o.Security.Value,
 	}
 }
-
 func (o *Operation) GetServers() low.NodeReference[any] {
 	return low.NodeReference[any]{
 		ValueNode: o.Servers.ValueNode,
@@ -260,7 +256,6 @@ func (o *Operation) GetServers() low.NodeReference[any] {
 		Value:     o.Servers.Value,
 	}
 }
-
-//func (o *Operation) GetCallbacks() low.NodeReference[[]low.ValueReference[any]] {
-//	return o.Produces
-//}
+func (o *Operation) GetCallbacks() low.NodeReference[map[low.KeyReference[string]]low.ValueReference[*Callback]] {
+	return o.Callbacks
+}
diff --git a/datamodel/low/v3/operation_test.go b/datamodel/low/v3/operation_test.go
index 8ae4ca0..4cc27e7 100644
--- a/datamodel/low/v3/operation_test.go
+++ b/datamodel/low/v3/operation_test.go
@@ -5,6 +5,7 @@ package v3
 
 import (
 	"github.com/pb33f/libopenapi/datamodel/low"
+	"github.com/pb33f/libopenapi/datamodel/low/base"
 	"github.com/pb33f/libopenapi/index"
 	"github.com/stretchr/testify/assert"
 	"gopkg.in/yaml.v3"
@@ -191,3 +192,97 @@ func TestOperation_Build_FailServers(t *testing.T) {
 	err = n.Build(idxNode.Content[0], idx)
 	assert.Error(t, err)
 }
+
+func TestOperation_Hash_n_Grab(t *testing.T) {
+
+	yml := `tags:
+  - nice
+  - rice
+summary: a thing
+description: another thing
+externalDocs:
+  url: https://pb33f.io/docs
+operationId: sleepyMornings
+parameters: 
+  - name: parammy
+    in: my head
+requestBody:
+  description: a thing
+responses:
+  "200":
+    description: ok
+callbacks: 
+  callMe:
+    something: blue
+deprecated: true
+security:
+  - lego:
+    dont: stand
+    or: eat
+servers:
+  - url: https://pb33f.io
+x-mint: sweet`
+
+	var idxNode yaml.Node
+	_ = yaml.Unmarshal([]byte(yml), &idxNode)
+	idx := index.NewSpecIndex(&idxNode)
+
+	var n Operation
+	_ = low.BuildModel(idxNode.Content[0], &n)
+	_ = n.Build(idxNode.Content[0], idx)
+
+	yml2 := `tags:
+  - nice
+  - rice
+summary: a thing
+description: another thing
+externalDocs:
+  url: https://pb33f.io/docs
+operationId: sleepyMornings
+parameters: 
+  - name: parammy
+    in: my head
+requestBody:
+  description: a thing
+responses:
+  "200":
+    description: ok
+callbacks: 
+  callMe:
+    something: blue
+deprecated: true
+security:
+  - lego:
+    dont: stand
+    or: eat
+servers:
+  - url: https://pb33f.io
+x-mint: sweet`
+
+	var idxNode2 yaml.Node
+	_ = yaml.Unmarshal([]byte(yml2), &idxNode2)
+	idx2 := index.NewSpecIndex(&idxNode2)
+
+	var n2 Operation
+	_ = low.BuildModel(idxNode2.Content[0], &n2)
+	_ = n2.Build(idxNode2.Content[0], idx2)
+
+	// hash
+	assert.Equal(t, n.Hash(), n2.Hash())
+
+	// n grab
+	assert.Len(t, n.GetTags().Value, 2)
+	assert.Equal(t, "a thing", n.GetSummary().Value)
+	assert.Equal(t, "another thing", n.GetDescription().Value)
+	assert.Equal(t, "https://pb33f.io/docs", n.GetExternalDocs().Value.(*base.ExternalDoc).URL.Value)
+	assert.Equal(t, "sleepyMornings", n.GetOperationId().Value)
+	assert.Len(t, n.GetParameters().Value, 1)
+	assert.Len(t, n.GetSecurity().Value, 1)
+	assert.True(t, n.GetDeprecated().Value)
+	assert.Len(t, n.GetExtensions(), 1)
+	assert.Len(t, n.GetServers().Value.([]low.ValueReference[*Server]), 1)
+	assert.Len(t, n.GetCallbacks().Value, 1)
+	assert.Len(t, n.GetResponses().Value.(*Responses).Codes, 1)
+	assert.Nil(t, n.FindSecurityRequirement("I do not exist"))
+
+}
diff --git a/what-changed/model/link.go b/what-changed/model/link.go
index 51a8312..d92d5f5 100644
--- a/what-changed/model/link.go
+++ b/what-changed/model/link.go
@@ -109,11 +109,11 @@ func CompareLinks(l, r *v3.Link) *LinkChanges {
 	// parameters
 	lValues := make(map[string]low.ValueReference[string])
 	rValues := make(map[string]low.ValueReference[string])
-	for i := range l.Parameters.Value {
-		lValues[i.Value] = l.Parameters.Value[i]
+	for i := range l.Parameters {
+		lValues[i.Value] = l.Parameters[i]
 	}
-	for i := range r.Parameters.Value {
-		rValues[i.Value] = r.Parameters.Value[i]
+	for i := range r.Parameters {
+		rValues[i.Value] = r.Parameters[i]
 	}
 	for k := range lValues {
 		if _, ok := rValues[k]; !ok {