diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5ad616c5..89bd7f69 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 - Added system and runtime overlay built time to REST API.
 - Support If-None-Match header in `PUT /api/nodes/{id}`
+- Added `PUT|DELETE /api/overlays/{name}/file?path={path}`
 - Added `DELETE /api/overlays/{name}/file?path={path}`
 
 ### Changed
diff --git a/internal/pkg/overlay/overlay.go b/internal/pkg/overlay/overlay.go
index e48427bd..ff418f5e 100644
--- a/internal/pkg/overlay/overlay.go
+++ b/internal/pkg/overlay/overlay.go
@@ -114,6 +114,25 @@ func (overlay Overlay) IsDistributionOverlay() bool {
 	return path.Dir(overlay.Path()) == config.Get().Paths.DistributionOverlaydir()
 }
 
+func (overlay Overlay) CreateOverlayFile(filePath string, content []byte, force bool) error {
+	wwlog.Info("Creating file %s in overlay %s, force: %v", filePath, overlay.Name(), force)
+	fullPath := overlay.File(filePath)
+	// create necessary parent directories
+	if err := os.MkdirAll(path.Dir(fullPath), 0o755); err != nil {
+		return fmt.Errorf("failed to create parent directories for %s: %w", fullPath, err)
+	}
+
+	// if the file already exists and force is false, return an error
+	if util.IsFile(fullPath) {
+		if force {
+			return os.WriteFile(fullPath, content, 0o644)
+		}
+		return fmt.Errorf("file %s already exists in overlay %s", filePath, overlay.Name())
+	}
+
+	return os.WriteFile(fullPath, content, 0o644)
+}
+
 // DeleteFile deletes a file or the entire overlay directory.
 // If the file belongs to a distribution overlay, it will be cloned to a site overlay
 // before deletion.
diff --git a/internal/pkg/overlay/overlay_test.go b/internal/pkg/overlay/overlay_test.go
index 6f8d44d8..ae7c8af0 100644
--- a/internal/pkg/overlay/overlay_test.go
+++ b/internal/pkg/overlay/overlay_test.go
@@ -20,7 +20,7 @@ import (
 )
 
 func Test_FindOverlays(t *testing.T) {
-	var tests = map[string]struct {
+	tests := map[string]struct {
 		distOverlays []string
 		siteOverlays []string
 		overlayList  []string
@@ -75,7 +75,7 @@ func Test_OverlayMethods(t *testing.T) {
 	env.WriteFile(path.Join(sitedir, "both/rootfs/testfile"), "the site version")
 	env.WriteFile(path.Join(distdir, "both/rootfs/testfile"), "the distribution version")
 
-	var tests = map[string]struct {
+	tests := map[string]struct {
 		name    string
 		path    string
 		rootfs  string
@@ -157,7 +157,7 @@ func Test_OverlayMethods(t *testing.T) {
 }
 
 func Test_BuildOverlayIndir(t *testing.T) {
-	var tests = map[string]struct {
+	tests := map[string]struct {
 		node            node.Node
 		overlays        []string
 		overlayFiles    map[string]string
@@ -336,7 +336,7 @@ Tags:map[]
 }
 
 func Test_BuildOverlay(t *testing.T) {
-	var tests = []struct {
+	tests := []struct {
 		description string
 		nodeName    string
 		context     string
@@ -377,7 +377,7 @@ func Test_BuildOverlay(t *testing.T) {
 			overlays:    []string{"o1"},
 			image:       "o1.img",
 			contents:    []string{"o1.txt"},
-			perms:       []int{0644},
+			perms:       []int{0o644},
 		},
 		{
 			description: "if multiple overlays are specified without a node, then the combined overlay is built directly in the overlay directory",
@@ -386,7 +386,7 @@ func Test_BuildOverlay(t *testing.T) {
 			overlays:    []string{"o1", "o2"},
 			image:       "o1-o2.img",
 			contents:    []string{"o1.txt", "o2.txt"},
-			perms:       []int{0644, 0644},
+			perms:       []int{0o644, 0o644},
 		},
 		{
 			description: "if a single node overlay is specified, then the overlay is built in a node overlay directory",
@@ -395,7 +395,7 @@ func Test_BuildOverlay(t *testing.T) {
 			overlays:    []string{"o1"},
 			image:       "node1/o1.img",
 			contents:    []string{"o1.txt"},
-			perms:       []int{0644},
+			perms:       []int{0o644},
 		},
 		{
 			description: "if multiple node overlays are specified, then the combined overlay is built in a node overlay directory",
@@ -404,7 +404,7 @@ func Test_BuildOverlay(t *testing.T) {
 			overlays:    []string{"o1", "o2"},
 			image:       "node1/o1-o2.img",
 			contents:    []string{"o1.txt", "o2.txt"},
-			perms:       []int{0644, 0644},
+			perms:       []int{0o644, 0o644},
 		},
 		{
 			description: "if no node system overlays are specified, then context pointed overlay is generated",
@@ -429,7 +429,7 @@ func Test_BuildOverlay(t *testing.T) {
 			overlays:    []string{"o1"},
 			image:       "node1/__SYSTEM__.img",
 			contents:    []string{"o1.txt"},
-			perms:       []int{0644},
+			perms:       []int{0o644},
 		},
 		{
 			description: "if a single node runtime overlay is specified, then a runtime overlay image is generated in a node overlay directory",
@@ -438,7 +438,7 @@ func Test_BuildOverlay(t *testing.T) {
 			overlays:    []string{"o1"},
 			image:       "node1/__RUNTIME__.img",
 			contents:    []string{"o1.txt"},
-			perms:       []int{0644},
+			perms:       []int{0o644},
 		},
 		{
 			description: "if multiple node system overlays are specified, then a system overlay image is generated with the contents of both overlays",
@@ -447,7 +447,7 @@ func Test_BuildOverlay(t *testing.T) {
 			overlays:    []string{"o1", "o2"},
 			image:       "node1/__SYSTEM__.img",
 			contents:    []string{"o1.txt", "o2.txt"},
-			perms:       []int{0644, 0644},
+			perms:       []int{0o644, 0o644},
 		},
 		{
 			description: "if multiple node runtime overlays are specified, then a runtime overlay image is generated with the contents of both overlays",
@@ -456,7 +456,7 @@ func Test_BuildOverlay(t *testing.T) {
 			overlays:    []string{"o1", "o2"},
 			image:       "node1/__RUNTIME__.img",
 			contents:    []string{"o1.txt", "o2.txt"},
-			perms:       []int{0644, 0644},
+			perms:       []int{0o644, 0o644},
 		},
 		{
 			description: "validating altered permissions are retained",
@@ -465,7 +465,7 @@ func Test_BuildOverlay(t *testing.T) {
 			overlays:    []string{"o3"},
 			image:       "node1/__RUNTIME__.img",
 			contents:    []string{"subdir", "subdir/o3.txt"},
-			perms:       []int{0700, 0600},
+			perms:       []int{0o700, 0o600},
 		},
 	}
 
@@ -473,12 +473,12 @@ func Test_BuildOverlay(t *testing.T) {
 	defer env.RemoveAll()
 
 	env.CreateFile("var/lib/warewulf/overlays/o1/rootfs/o1.txt")
-	env.Chmod("var/lib/warewulf/overlays/o1/rootfs/o1.txt", 0644)
+	env.Chmod("var/lib/warewulf/overlays/o1/rootfs/o1.txt", 0o644)
 	env.CreateFile("var/lib/warewulf/overlays/o2/rootfs/o2.txt")
-	env.Chmod("var/lib/warewulf/overlays/o2/rootfs/o2.txt", 0644)
+	env.Chmod("var/lib/warewulf/overlays/o2/rootfs/o2.txt", 0o644)
 	env.CreateFile("var/lib/warewulf/overlays/o3/rootfs/subdir/o3.txt.ww")
-	env.Chmod("var/lib/warewulf/overlays/o3/rootfs/subdir", 0700)
-	env.Chmod("var/lib/warewulf/overlays/o3/rootfs/subdir/o3.txt.ww", 0600)
+	env.Chmod("var/lib/warewulf/overlays/o3/rootfs/subdir", 0o700)
+	env.Chmod("var/lib/warewulf/overlays/o3/rootfs/subdir/o3.txt.ww", 0o600)
 
 	for _, tt := range tests {
 		nodeInfo := node.NewNode(tt.nodeName)
@@ -508,7 +508,7 @@ func Test_BuildOverlay(t *testing.T) {
 }
 
 func Test_BuildAllOverlays(t *testing.T) {
-	var tests = []struct {
+	tests := []struct {
 		description     string
 		nodes           []string
 		systemOverlays  [][]string
@@ -585,8 +585,8 @@ func Test_BuildAllOverlays(t *testing.T) {
 	assert.NoError(t, overlayDirErr)
 	defer os.RemoveAll(overlayDir)
 	conf.Paths.WWOverlaydir = overlayDir
-	assert.NoError(t, os.Mkdir(path.Join(overlayDir, "o1"), 0700))
-	assert.NoError(t, os.Mkdir(path.Join(overlayDir, "o2"), 0700))
+	assert.NoError(t, os.Mkdir(path.Join(overlayDir, "o1"), 0o700))
+	assert.NoError(t, os.Mkdir(path.Join(overlayDir, "o2"), 0o700))
 
 	for _, tt := range tests {
 		t.Run(tt.description, func(t *testing.T) {
@@ -620,7 +620,7 @@ func Test_BuildAllOverlays(t *testing.T) {
 }
 
 func Test_BuildSpecificOverlays(t *testing.T) {
-	var tests = []struct {
+	tests := []struct {
 		description string
 		nodes       []string
 		overlays    []string
@@ -683,8 +683,8 @@ func Test_BuildSpecificOverlays(t *testing.T) {
 	assert.NoError(t, overlayDirErr)
 	defer os.RemoveAll(overlayDir)
 	conf.Paths.WWOverlaydir = overlayDir
-	assert.NoError(t, os.Mkdir(path.Join(overlayDir, "o1"), 0700))
-	assert.NoError(t, os.Mkdir(path.Join(overlayDir, "o2"), 0700))
+	assert.NoError(t, os.Mkdir(path.Join(overlayDir, "o1"), 0o700))
+	assert.NoError(t, os.Mkdir(path.Join(overlayDir, "o2"), 0o700))
 
 	for _, tt := range tests {
 		t.Run(tt.description, func(t *testing.T) {
@@ -711,6 +711,39 @@ func Test_BuildSpecificOverlays(t *testing.T) {
 	}
 }
 
+func Test_CreateOverlayFile(t *testing.T) {
+	tests := []struct {
+		name        string
+		overlayName string
+		filePath    string
+		content     []byte
+		force       bool
+	}{
+		{"create file", "test", "newfile.ww", []byte("new file"), false},
+		{"overwrite existing file", "test", "existingfile.ww", []byte("overwrite file"), true},
+	}
+
+	conf := warewulfconf.Get()
+	overlayDir, overlayDirErr := os.MkdirTemp(os.TempDir(), "ww-test-overlay-*")
+	assert.NoError(t, overlayDirErr)
+	defer os.RemoveAll(overlayDir)
+	conf.Paths.WWOverlaydir = overlayDir
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			newOverlay := GetSiteOverlay(tt.overlayName)
+			err := newOverlay.CreateOverlayFile(tt.filePath, tt.content, tt.force)
+			assert.NoError(t, err)
+
+			newFile := newOverlay.File(tt.filePath)
+			assert.FileExists(t, newFile)
+			readContent, err := os.ReadFile(newFile)
+			assert.NoError(t, err)
+			assert.Equal(t, tt.content, readContent)
+		})
+	}
+}
+
 func dirIsEmpty(t *testing.T, name string) bool {
 	f, err := os.Open(name)
 	if err != nil {
diff --git a/internal/pkg/util/util.go b/internal/pkg/util/util.go
index e2091a64..ca6615f5 100644
--- a/internal/pkg/util/util.go
+++ b/internal/pkg/util/util.go
@@ -36,7 +36,6 @@ func FirstError(errs ...error) (err error) {
 }
 
 func DirModTime(path string) (time.Time, error) {
-
 	var lastTime time.Time
 	err := filepath.Walk(path, func(path string, info os.FileInfo, err error) error {
 		if err != nil {
@@ -186,7 +185,8 @@ func FindFilterFiles(
 	path string,
 	includePattern []string,
 	ignorePattern []string,
-	ignore_xdev bool) (ofiles []string, err error) {
+	ignore_xdev bool,
+) (ofiles []string, err error) {
 	wwlog.Debug("Finding files: %s include: %s ignore: %s", path, includePattern, ignorePattern)
 
 	// Preprocess patterns to remove leading (and trailing) /, as we are handling relative paths
@@ -347,7 +347,7 @@ Appending the lines to the given file
 */
 func AppendLines(fileName string, lines []string) error {
 	wwlog.Verbose("appending %v lines to %s", len(lines), fileName)
-	file, err := os.OpenFile(fileName, os.O_APPEND|os.O_WRONLY, 0644)
+	file, err := os.OpenFile(fileName, os.O_APPEND|os.O_WRONLY, 0o644)
 	if err != nil {
 		return fmt.Errorf("can't open file: %s: %w", fileName, err)
 	}
@@ -362,6 +362,21 @@ func AppendLines(fileName string, lines []string) error {
 	return nil
 }
 
+func OverwriteFile(fileName string, content []byte) error {
+	wwlog.Verbose("overwrite file %s", fileName)
+	file, err := os.OpenFile(fileName, os.O_RDWR|os.O_TRUNC, 0o644)
+	if err != nil {
+		return fmt.Errorf("failed to open file: %s, err: %w", fileName, err)
+	}
+	defer file.Close()
+
+	_, err = file.Write(content)
+	if err != nil {
+		return fmt.Errorf("while writing file: %s, err: %w", fileName, err)
+	}
+	return file.Sync()
+}
+
 /*
 ******************************************************************************
 
@@ -372,14 +387,15 @@ func CpioCreate(
 	ifiles []string,
 	ofile string,
 	format string,
-	cpio_args ...string) (err error) {
-
+	cpio_args ...string,
+) (err error) {
 	args := []string{
 		"--quiet",
 		"--create",
 		"--directory", rootdir,
 		"--format", format,
-		"--file=" + ofile}
+		"--file=" + ofile,
+	}
 
 	args = append(args, cpio_args...)
 
@@ -413,13 +429,12 @@ func CpioCreate(
 	Compress a file using gzip or pigz
 */
 func FileGz(
-	file string) (err error) {
-
+	file string,
+) (err error) {
 	file_gz := file + ".gz"
 
 	if IsFile(file_gz) {
 		err := os.Remove(file_gz)
-
 		if err != nil {
 			return fmt.Errorf("could not remove existing file: %s: %w", file_gz, err)
 		}
@@ -509,9 +524,9 @@ func BuildFsImage(
 	ignore []string,
 	ignore_xdev bool,
 	format string,
-	cpio_args ...string) (err error) {
-
-	err = os.MkdirAll(path.Dir(imagePath), 0755)
+	cpio_args ...string,
+) (err error) {
+	err = os.MkdirAll(path.Dir(imagePath), 0o755)
 	if err != nil {
 		return fmt.Errorf("failed to create image directory for %s: %s: %w", name, imagePath, err)
 	}
diff --git a/internal/pkg/util/util_test.go b/internal/pkg/util/util_test.go
index d93f7660..0f64186d 100644
--- a/internal/pkg/util/util_test.go
+++ b/internal/pkg/util/util_test.go
@@ -9,7 +9,7 @@ import (
 )
 
 func Test_FindFiles(t *testing.T) {
-	var tests = map[string]struct {
+	tests := map[string]struct {
 		createFiles []string
 		findFiles   []string
 	}{
@@ -43,7 +43,7 @@ func Test_FindFiles(t *testing.T) {
 }
 
 func Test_FindFilterFiles(t *testing.T) {
-	var tests = map[string]struct {
+	tests := map[string]struct {
 		createFiles []string
 		include     []string
 		exclude     []string
@@ -92,3 +92,19 @@ func Test_FindFilterFiles(t *testing.T) {
 		})
 	}
 }
+
+func Test_Overwrite(t *testing.T) {
+	t.Run("overwrite a file", func(t *testing.T) {
+		env := testenv.New(t)
+		defer env.RemoveAll()
+		env.CreateFile("file")
+		env.WriteFile("file", "hello world")
+
+		assert.Equal(t, "hello world", env.ReadFile("file"))
+
+		err := OverwriteFile(env.GetPath("file"), []byte("hello warewulf"))
+		assert.NoError(t, err)
+
+		assert.Equal(t, "hello warewulf", env.ReadFile("file"))
+	})
+}
diff --git a/internal/pkg/warewulfd/api/api.go b/internal/pkg/warewulfd/api/api.go
index d2a941ae..de515235 100644
--- a/internal/pkg/warewulfd/api/api.go
+++ b/internal/pkg/warewulfd/api/api.go
@@ -71,8 +71,10 @@ func Handler(auth *config.Authentication, allowedNets []net.IPNet) *web.Service
 			r.Method(http.MethodGet, "/{name}", nethttp.NewHandler(getOverlayByName()))
 			r.Method(http.MethodGet, "/{name}/file", nethttp.NewHandler(getOverlayFile()))
 			r.Method(http.MethodPut, "/{name}", nethttp.NewHandler(createOverlay()))
+			r.Method(http.MethodPut, "/{name}/file", nethttp.NewHandler(createOverlayFile()))
 			r.Method(http.MethodDelete, "/{name}", nethttp.NewHandler(deleteOverlay()))
 			r.Method(http.MethodDelete, "/{name}/file", nethttp.NewHandler(deleteOverlayFile()))
+			r.Method(http.MethodPut, "/{name}/file", nethttp.NewHandler(updateOverlayFile()))
 		})
 	})
 
diff --git a/internal/pkg/warewulfd/api/overlay.go b/internal/pkg/warewulfd/api/overlay.go
index 870d828b..a9fa497b 100644
--- a/internal/pkg/warewulfd/api/overlay.go
+++ b/internal/pkg/warewulfd/api/overlay.go
@@ -215,6 +215,39 @@ func createOverlay() usecase.Interactor {
 	return u
 }
 
+func createOverlayFile() usecase.Interactor {
+	type createOverlayFileInput struct {
+		Name    string `path:"name" required:"true" description:"Name of overlay to create a file in"`
+		Path    string `query:"path" required:"true" description:"Path to file to create in an overlay"`
+		Force   bool   `query:"force" default:"false" description:"Whether to forcefully create an overlay file, default:'false'"`
+		Content string `json:"content" required:"true" description:"Content of the file to create"`
+	}
+
+	u := usecase.NewInteractor(func(ctx context.Context, input createOverlayFileInput, output *OverlayResponse) error {
+		wwlog.Debug("api.createOverlayFile(Name:%v, Path:%v, Force: %v)", input.Name, input.Path, input.Force)
+		if input.Path == "" {
+			return status.Wrap(fmt.Errorf("must specify a path"), status.InvalidArgument)
+		}
+		if input.Content == "" {
+			return status.Wrap(fmt.Errorf("content should not be empty"), status.InvalidArgument)
+		}
+		if relPath, err := url.QueryUnescape(input.Path); err != nil {
+			return fmt.Errorf("failed to decode path: %v: %w", input.Path, err)
+		} else {
+			newOverlay := overlay.GetOverlay(input.Name)
+			if err := newOverlay.CreateOverlayFile(relPath, []byte(input.Content), input.Force); err != nil {
+				return fmt.Errorf("unable to create overlay file %v: %v: %w", input.Name, relPath, err)
+			}
+			*output = *NewOverlayResponse(input.Name)
+			return nil
+		}
+	})
+	u.SetTitle("Create a file in an overlay")
+	u.SetDescription("Create a file in an overlay from the overlay name and file path.")
+	u.SetTags("Overlay")
+	return u
+}
+
 func deleteOverlay() usecase.Interactor {
 	type deleteOverlayInput struct {
 		Name  string `path:"name" required:"true" description:"Name of overlay to delete"`
@@ -288,3 +321,37 @@ func deleteOverlayFile() usecase.Interactor {
 	u.SetTags("Overlay")
 	return u
 }
+
+func updateOverlayFile() usecase.Interactor {
+	type updateOverlayInput struct {
+		Name    string `path:"name" required:"true" description:"Name of overlay to update"`
+		Path    string `query:"path" required:"true" description:"Path to file to get from an overlay"`
+		Content string `json:"content" required:"true" description:"New content"`
+	}
+
+	u := usecase.NewInteractor(func(ctx context.Context, input updateOverlayInput, output *OverlayResponse) error {
+		wwlog.Debug("api.updateOverlay(Name: %s)", input.Name)
+		if input.Path == "" {
+			return status.Wrap(fmt.Errorf("must specify a path"), status.InvalidArgument)
+		}
+		if input.Content == "" {
+			return status.Wrap(fmt.Errorf("new content should not be empty"), status.InvalidArgument)
+		}
+		*output = *NewOverlayResponse(input.Name)
+
+		if relPath, err := url.QueryUnescape(input.Path); err != nil {
+			return status.Wrap(fmt.Errorf("failed to decode path"), status.InvalidArgument)
+		} else {
+			overlay_ := overlay.GetOverlay(input.Name)
+			file := overlay_.File(relPath)
+			if err := util.OverwriteFile(file, []byte(input.Content)); err != nil {
+				return fmt.Errorf("failed to overwrite file: %s, err: %w", file, err)
+			}
+		}
+		return nil
+	})
+	u.SetTitle("Update an overlay")
+	u.SetDescription("Update an overlay")
+	u.SetTags("Overlay")
+	return u
+}
diff --git a/internal/pkg/warewulfd/api/overlay_test.go b/internal/pkg/warewulfd/api/overlay_test.go
index 08439209..62cb15c8 100644
--- a/internal/pkg/warewulfd/api/overlay_test.go
+++ b/internal/pkg/warewulfd/api/overlay_test.go
@@ -1,6 +1,7 @@
 package api
 
 import (
+	"bytes"
 	"io"
 	"net"
 	"net/http"
@@ -89,6 +90,46 @@ func TestOverlayAPI(t *testing.T) {
 		}`)
 	})
 
+	t.Run("update overlay file", func(t *testing.T) {
+		req, err := http.NewRequest(http.MethodPut, srv.URL+"/api/overlays/testoverlay/file?path=email.ww", bytes.NewReader([]byte("{\"content\":\"hello world\"}")))
+		assert.NoError(t, err)
+
+		// set request
+		resp, err := http.DefaultTransport.RoundTrip(req)
+		assert.NoError(t, err)
+
+		// validate the resp
+		body, err := io.ReadAll(resp.Body)
+		assert.NoError(t, err)
+		assert.NoError(t, resp.Body.Close())
+
+		assert.JSONEq(t, `{"files":["/email.ww"], "site":false}`, string(body))
+
+		// get again
+		req, err = http.NewRequest(http.MethodGet, srv.URL+"/api/overlays/testoverlay/file?path=email.ww", nil)
+		assert.NoError(t, err)
+
+		// send request
+		resp, err = http.DefaultTransport.RoundTrip(req)
+		assert.NoError(t, err)
+
+		// validate the resp
+		body, err = io.ReadAll(resp.Body)
+		assert.NoError(t, err)
+		assert.NoError(t, resp.Body.Close())
+
+		ja := jsonassert.New(t)
+		ja.Assert(string(body), `
+		{
+			"overlay": "testoverlay",
+			"path": "email.ww",
+			"contents": "hello world",
+			"perms": "<<PRESENCE>>",
+			"uid": "<<PRESENCE>>",
+			"gid": "<<PRESENCE>>"
+		}`)
+	})
+
 	t.Run("create an overlay", func(t *testing.T) {
 		req, err := http.NewRequest(http.MethodPut, srv.URL+"/api/overlays/test", nil)
 		assert.NoError(t, err)