diff --git a/services/web/pkg/service/v0/branding.go b/services/web/pkg/service/v0/branding.go
new file mode 100644
index 000000000..0201487ea
--- /dev/null
+++ b/services/web/pkg/service/v0/branding.go
@@ -0,0 +1,100 @@
+package svc
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+	"net/http"
+	"path/filepath"
+)
+
+var (
+	errInvalidThemeConfig = errors.New("invalid themes config")
+	_themesConfigPath     = filepath.FromSlash("themes/owncloud/theme.json")
+)
+
+// UploadLogo implements the endpoint to upload a custom logo for the oCIS instance.
+func (p Web) UploadLogo(w http.ResponseWriter, r *http.Request) {
+	file, fileHeader, err := r.FormFile("logo")
+	if err != nil {
+		if errors.Is(err, http.ErrMissingFile) {
+			w.WriteHeader(http.StatusBadRequest)
+		}
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	defer file.Close()
+
+	fp := filepath.Join("branding", filepath.Join("/", fileHeader.Filename))
+	err = p.storeAsset(fp, file)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	err = p.updateLogoThemeConfig(fp)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+}
+
+func (p Web) storeAsset(name string, asset io.Reader) error {
+	dst, err := p.fs.Create(name)
+	if err != nil {
+		return err
+	}
+	defer dst.Close()
+
+	_, err = io.Copy(dst, asset)
+	return err
+}
+
+func (p Web) updateLogoThemeConfig(logoPath string) error {
+	f, err := p.fs.Open(_themesConfigPath)
+	if err == nil {
+		defer f.Close()
+	}
+	var m map[string]interface{}
+	_ = json.NewDecoder(f).Decode(&m)
+
+	webCfg, ok := m["web"].(map[string]interface{})
+	if !ok {
+		return errInvalidThemeConfig
+	}
+
+	defaultCfg, ok := webCfg["default"].(map[string]interface{})
+	if !ok {
+		return errInvalidThemeConfig
+	}
+
+	logoCfg, ok := defaultCfg["logo"].(map[string]interface{})
+	if !ok {
+		return errInvalidThemeConfig
+	}
+
+	logoCfg["login"] = logoPath
+	logoCfg["topbar"] = logoPath
+
+	defaultDarkCfg, ok := webCfg["default-dark"].(map[string]interface{})
+	if !ok {
+		return errInvalidThemeConfig
+	}
+
+	logoDarkCfg, ok := defaultDarkCfg["logo"].(map[string]interface{})
+	if !ok {
+		return errInvalidThemeConfig
+	}
+
+	logoDarkCfg["login"] = logoPath
+	logoDarkCfg["topbar"] = logoPath
+
+	dst, err := p.fs.Create(_themesConfigPath)
+	if err != nil {
+		return err
+	}
+
+	return json.NewEncoder(dst).Encode(m)
+}
diff --git a/services/web/pkg/service/v0/service.go b/services/web/pkg/service/v0/service.go
index 8767304c8..ef151d2bb 100644
--- a/services/web/pkg/service/v0/service.go
+++ b/services/web/pkg/service/v0/service.go
@@ -2,13 +2,10 @@ package svc
 
 import (
 	"encoding/json"
-	"errors"
 	"fmt"
-	"io"
 	"net/http"
 	"net/url"
 	"os"
-	"path/filepath"
 	"strconv"
 	"strings"
 	"time"
@@ -164,50 +161,3 @@ func (p Web) Static(ttl int) http.HandlerFunc {
 		static.ServeHTTP(w, r)
 	}
 }
-
-// UploadLogo implements the endpoint to upload a custom logo for the oCIS instance.
-func (p Web) UploadLogo(w http.ResponseWriter, r *http.Request) {
-	file, fileHeader, err := r.FormFile("logo")
-	if err != nil {
-		if errors.Is(err, http.ErrMissingFile) {
-			w.WriteHeader(http.StatusBadRequest)
-		}
-		w.WriteHeader(http.StatusInternalServerError)
-		return
-	}
-	defer file.Close()
-
-	fp := filepath.Join("branding", filepath.Join("/", fileHeader.Filename))
-	dst, err := p.fs.Create(fp)
-	if err != nil {
-		w.WriteHeader(http.StatusInternalServerError)
-		return
-	}
-	defer dst.Close()
-
-	_, err = io.Copy(dst, file)
-	if err != nil {
-		w.WriteHeader(http.StatusInternalServerError)
-		return
-	}
-
-	f, err := p.fs.Open("themes/owncloud/theme.json")
-	if err == nil {
-		defer f.Close()
-	}
-	var m map[string]interface{}
-	_ = json.NewDecoder(f).Decode(&m)
-	logos := m["default"].(map[string]interface{})["logo"].(map[string]interface{})
-	logos["login"] = fp
-	logos["topbar"] = fp
-
-	dst, err = p.fs.Create("themes/owncloud/theme.json")
-	if err != nil {
-		w.WriteHeader(http.StatusInternalServerError)
-		return
-	}
-
-	_ = json.NewEncoder(dst).Encode(m)
-
-	w.WriteHeader(http.StatusOK)
-}