diff --git a/datamodel/low/extraction_functions_test.go b/datamodel/low/extraction_functions_test.go
index 6a75386..3403f60 100644
--- a/datamodel/low/extraction_functions_test.go
+++ b/datamodel/low/extraction_functions_test.go
@@ -7,7 +7,9 @@ import (
 	"context"
 	"crypto/sha256"
 	"fmt"
+	"golang.org/x/sync/syncmap"
 	"net/url"
+	"os"
 	"strings"
 	"testing"
 
@@ -1889,3 +1891,72 @@ func TestLocateRefNode_NoExplode_HTTP(t *testing.T) {
 	assert.NotNil(t, e)
 	assert.NotNil(t, c)
 }
+
+func TestLocateRefNode_NoExplode_NoSpecPath(t *testing.T) {
+
+	no := yaml.Node{
+		Kind: yaml.MappingNode,
+		Content: []*yaml.Node{
+			{
+				Kind:  yaml.ScalarNode,
+				Value: "$ref",
+			},
+			{
+				Kind:  yaml.ScalarNode,
+				Value: "components/schemas/thing.yaml",
+			},
+		},
+	}
+
+	cf := index.CreateClosedAPIIndexConfig()
+	u, _ := url.Parse("http://smilfghfhfhfhfhes.com/bikes")
+	cf.BaseURL = u
+	idx := index.NewSpecIndexWithConfig(&no, cf)
+	ctx := context.WithValue(context.Background(), index.CurrentPathKey, "no.yaml")
+	n, i, e, c := LocateRefNodeWithContext(ctx, &no, idx)
+	assert.Nil(t, n)
+	assert.NotNil(t, i)
+	assert.NotNil(t, e)
+	assert.NotNil(t, c)
+}
+
+func TestLocateRefNode_DoARealLookup(t *testing.T) {
+
+	no := yaml.Node{
+		Kind: yaml.MappingNode,
+		Content: []*yaml.Node{
+			{
+				Kind:  yaml.ScalarNode,
+				Value: "$ref",
+			},
+			{
+				Kind:  yaml.ScalarNode,
+				Value: "/root.yaml#/components/schemas/Burger",
+			},
+		},
+	}
+
+	b, err := os.ReadFile("../../test_specs/burgershop.openapi.yaml")
+	if err != nil {
+		t.Fatal(err)
+	}
+	var rootNode yaml.Node
+	_ = yaml.Unmarshal(b, &rootNode)
+
+	cf := index.CreateClosedAPIIndexConfig()
+	u, _ := url.Parse("http://smilfghfhfhfhfhes.com/bikes")
+	cf.BaseURL = u
+	idx := index.NewSpecIndexWithConfig(&rootNode, cf)
+
+	// fake cache to a lookup for a file that does not exist will work.
+	fakeCache := new(syncmap.Map)
+	fakeCache.Store("/root.yaml#/components/schemas/Burger", &index.Reference{Node: &no})
+	idx.SetCache(fakeCache)
+
+	ctx := context.WithValue(context.Background(), index.CurrentPathKey, "/root.yaml#/components/schemas/Burger")
+	n, i, e, c := LocateRefNodeWithContext(ctx, &no, idx)
+	assert.NotNil(t, n)
+	assert.NotNil(t, i)
+	assert.Nil(t, e)
+	assert.NotNil(t, c)
+}
diff --git a/index/index_model.go b/index/index_model.go
index 291c33b..459a36d 100644
--- a/index/index_model.go
+++ b/index/index_model.go
@@ -270,7 +270,7 @@ type SpecIndex struct {
 	componentIndexChan                  chan bool
 	polyComponentIndexChan              chan bool
 	resolver                            *Resolver
-	cache                               syncmap.Map
+	cache                               *syncmap.Map
 	built                               bool
 	uri                                 []string
 	logger                              *slog.Logger
@@ -286,6 +286,14 @@ func (index *SpecIndex) GetConfig() *SpecIndexConfig {
 	return index.config
 }
 
+func (index *SpecIndex) SetCache(sync *syncmap.Map) {
+	index.cache = sync
+}
+
+func (index *SpecIndex) GetCache() *syncmap.Map {
+	return index.cache
+}
+
 // ExternalLookupFunction is for lookup functions that take a JSONSchema reference and tries to find that node in the
 // URI based document. Decides if the reference is local, remote or in a file.
 type ExternalLookupFunction func(id string) (foundNode *yaml.Node, rootNode *yaml.Node, lookupError error)
diff --git a/index/spec_index.go b/index/spec_index.go
index 021313c..730d4f0 100644
--- a/index/spec_index.go
+++ b/index/spec_index.go
@@ -15,6 +15,7 @@ package index
 import (
 	"context"
 	"fmt"
+	"golang.org/x/sync/syncmap"
 	"log/slog"
 	"os"
 	"sort"
@@ -76,6 +77,8 @@ func createNewIndex(rootNode *yaml.Node, index *SpecIndex, avoidBuildOut bool) *
 		return index
 	}
 
+	index.cache = new(syncmap.Map)
+
 	// boot index.
 	results := index.ExtractRefs(index.root.Content[0], index.root, []string{}, 0, false, "")
 
diff --git a/index/spec_index_test.go b/index/spec_index_test.go
index b04cd02..3d9c896 100644
--- a/index/spec_index_test.go
+++ b/index/spec_index_test.go
@@ -7,6 +7,7 @@ import (
 	"bytes"
 	"fmt"
 	"github.com/pb33f/libopenapi/utils"
+	"golang.org/x/sync/syncmap"
 	"log"
 	"log/slog"
 	"net/http"
@@ -22,6 +23,41 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
+func TestSpecIndex_GetCache(t *testing.T) {
+
+	petstore, _ := os.ReadFile("../test_specs/petstorev3.json")
+	var rootNode yaml.Node
+	_ = yaml.Unmarshal(petstore, &rootNode)
+
+	index := NewSpecIndexWithConfig(&rootNode, CreateOpenAPIIndexConfig())
+
+	extCache := index.GetCache()
+	assert.NotNil(t, extCache)
+	extCache.Store("test", "test")
+	loaded, ok := extCache.Load("test")
+	assert.Equal(t, "test", loaded)
+	assert.True(t, ok)
+
+	// create a new cache
+	newCache := new(syncmap.Map)
+	index.SetCache(newCache)
+
+	// check that the cache has been set.
+	assert.Equal(t, newCache, index.GetCache())
+
+	// add an item to the new cache and check it exists
+	newCache.Store("test2", "test2")
+	loaded, ok = newCache.Load("test2")
+	assert.Equal(t, "test2", loaded)
+	assert.True(t, ok)
+
+	// now check that the new item in the new cache does not exist in the old cache.
+	loaded, ok = extCache.Load("test2")
+	assert.Nil(t, loaded)
+	assert.False(t, ok)
+
+}
+
 func TestSpecIndex_ExtractRefsStripe(t *testing.T) {
 	stripe, _ := os.ReadFile("../test_specs/stripe.yaml")
 	var rootNode yaml.Node