diff --git a/docker-compose.yml b/docker-compose.yml
index 831c8f9..acfc5c0 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -2,10 +2,11 @@ services:
     ip-info:
         build: .
         ports:
-            - "8080:8080"
+            - "28080:8080"
         restart: always
         volumes:
             - ./data:/app/data
         environment:
+            - GIN_MODE=release
             - GIN_TRUSTED_PROXY_IP=127.0.0.1
             - TZ=Asia/Ho_Chi_Minh
\ No newline at end of file
diff --git a/internal/data/ipdb.go b/internal/data/ipdb.go
index 1a63327..0742d5a 100644
--- a/internal/data/ipdb.go
+++ b/internal/data/ipdb.go
@@ -8,7 +8,8 @@ import (
 import reader "github.com/oschwald/maxminddb-golang"
 
 type IpDb struct {
-	r *reader.Reader
+	r  *reader.Reader
+	mu sync.RWMutex
 }
 
 var (
@@ -25,6 +26,9 @@ func Ins() *IpDb {
 }
 
 func (d *IpDb) Reload() error {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
 	if d.r != nil {
 		_ = d.r.Close()
 	}
@@ -37,3 +41,7 @@ func (d *IpDb) Reload() error {
 	d.r = r
 	return nil
 }
+
+func (d *IpDb) IsLoaded() bool {
+	return d.r != nil
+}
diff --git a/internal/services/api/handler_json.go b/internal/services/api/handler_json.go
index 9d4053e..8d976eb 100644
--- a/internal/services/api/handler_json.go
+++ b/internal/services/api/handler_json.go
@@ -9,6 +9,12 @@ import (
 
 func HandleJson(c *gin.Context) {
 	ip := c.ClientIP()
+	if !data.Ins().IsLoaded() {
+		log.Error().Msg("DB is not loaded")
+		c.String(http.StatusInternalServerError, "Try again later")
+		return
+	}
+
 	ipData, _, err := data.Ins().Query(ip)
 	if err != nil {
 		log.Err(err).Msg("Failed to query IP")
@@ -17,6 +23,8 @@ func HandleJson(c *gin.Context) {
 		})
 		return
 	}
+
 	ipData["ip"] = ip
 	c.JSON(http.StatusOK, ipData)
+
 }
diff --git a/internal/services/db_updater/downloader.go b/internal/services/db_updater/downloader.go
index a2b04a7..e14b31c 100644
--- a/internal/services/db_updater/downloader.go
+++ b/internal/services/db_updater/downloader.go
@@ -4,12 +4,11 @@ import (
 	"github.com/go-resty/resty/v2"
 	"github.com/rs/zerolog/log"
 	"net/http"
+	"os"
 	"path"
 	"thuanle.me/ip-info/configs"
 )
 
-var etags = map[string]string{}
-
 func download(url string) bool {
 	log.Info().Str("url", url).Msg("Downloading DB")
 	filename := configs.GeoDbFolder + path.Base(url)
@@ -17,7 +16,7 @@ func download(url string) bool {
 	client := resty.New()
 	resp, err := client.R().
 		SetOutput(filename).
-		SetHeader("If-None-Match", etags[url]).
+		SetHeader("If-None-Match", readETag(filename)).
 		Get(url)
 
 	if err != nil {
@@ -28,15 +27,31 @@ func download(url string) bool {
 	}
 
 	if resp.StatusCode() == http.StatusOK {
-		etags[url] = resp.Header().Get("Etag")
+		writeETag(filename, resp.Header().Get("Etag"))
 	} else {
 		//log.Printf("No update needed: %v", resp.Status())
 		return false
 	}
 
 	log.Info().
-		Str("Etag", etags[url]).
 		Str("filename", filename).
 		Msg("Downloaded DB")
 	return true
 }
+
+// readETag reads the ETag from the file
+func readETag(baseFile string) string {
+	data, err := os.ReadFile(baseFile + ".etag")
+	if err != nil {
+		return ""
+	}
+	return string(data)
+}
+
+// writeETag writes the ETag to the file
+func writeETag(baseFile, etag string) {
+	err := os.WriteFile(baseFile+".etag", []byte(etag), 0644)
+	if err != nil {
+		log.Err(err).Msg("Failed to write ETag")
+	}
+}