diff --git a/src/handlers/fileshdr/handlers.go b/src/handlers/fileshdr/handlers.go
index f90975f..820d1e3 100644
--- a/src/handlers/fileshdr/handlers.go
+++ b/src/handlers/fileshdr/handlers.go
@@ -147,7 +147,11 @@ func (h *FileHandlers) Create(c *gin.Context) {
 	locker.Exec(func() {
 		err = h.deps.Users().SetUsed(userIDInt, true, req.FileSize)
 		if err != nil {
-			c.JSON(q.ErrResp(c, 500, err))
+			if userstore.IsReachedLimitErr(err) {
+				c.JSON(q.ErrResp(c, 429, err))
+			} else {
+				c.JSON(q.ErrResp(c, 500, err))
+			}
 			return
 		}
 
@@ -206,7 +210,11 @@ func (h *FileHandlers) Delete(c *gin.Context) {
 
 		err = h.deps.Users().SetUsed(userIDInt, false, info.Size())
 		if err != nil {
-			c.JSON(q.ErrResp(c, 500, err))
+			if userstore.IsReachedLimitErr(err) {
+				c.JSON(q.ErrResp(c, 429, err))
+			} else {
+				c.JSON(q.ErrResp(c, 500, err))
+			}
 			return
 		}
 
@@ -702,7 +710,11 @@ func (h *FileHandlers) DelUploading(c *gin.Context) {
 
 		err = h.deps.Users().SetUsed(userIDInt, false, size)
 		if err != nil {
-			c.JSON(q.ErrResp(c, 500, err))
+			if userstore.IsReachedLimitErr(err) {
+				c.JSON(q.ErrResp(c, 429, err))
+			} else {
+				c.JSON(q.ErrResp(c, 500, err))
+			}
 			return
 		}
 
diff --git a/src/server/server_files_test.go b/src/server/server_files_test.go
index f36dba6..6b10f8e 100644
--- a/src/server/server_files_test.go
+++ b/src/server/server_files_test.go
@@ -25,7 +25,7 @@ func TestFileHandlers(t *testing.T) {
 			"captchaEnabled": false,
 			"uploadSpeedLimit": 409600,
 			"downloadSpeedLimit": 409600,
-			"spaceLimit": 1024,
+			"spaceLimit": 1000,
 			"limiterCapacity": 1000,
 			"limiterCyc": 1000
 		},
diff --git a/src/server/server_space_limit_test.go b/src/server/server_space_limit_test.go
new file mode 100644
index 0000000..48bf894
--- /dev/null
+++ b/src/server/server_space_limit_test.go
@@ -0,0 +1,138 @@
+package server
+
+import (
+	"fmt"
+	"os"
+	"testing"
+
+	"github.com/ihexxa/quickshare/src/client"
+	q "github.com/ihexxa/quickshare/src/handlers"
+	"github.com/ihexxa/quickshare/src/userstore"
+)
+
+func TestSpaceLimit(t *testing.T) {
+	addr := "http://127.0.0.1:8686"
+	root := "testData"
+	config := `{
+		"users": {
+			"enableAuth": true,
+			"minUserNameLen": 2,
+			"minPwdLen": 4,
+			"captchaEnabled": false,
+			"uploadSpeedLimit": 409600,
+			"downloadSpeedLimit": 409600,
+			"spaceLimit": 100,
+			"limiterCapacity": 1000,
+			"limiterCyc": 1000
+		},
+		"server": {
+			"debug": true
+		},
+		"fs": {
+			"root": "testData"
+		}
+	}`
+
+	adminName := "qs"
+	adminPwd := "quicksh@re"
+	os.Setenv("DEFAULTADMIN", adminName)
+	os.Setenv("DEFAULTADMINPWD", adminPwd)
+
+	os.RemoveAll(root)
+	err := os.MkdirAll(root, 0700)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(root)
+
+	srv := startTestServer(config)
+	defer srv.Shutdown()
+	// fs := srv.depsFS()
+	if !waitForReady(addr) {
+		t.Fatal("fail to start server")
+	}
+
+	usersCl := client.NewSingleUserClient(addr)
+	resp, _, errs := usersCl.Login(adminName, adminPwd)
+	if len(errs) > 0 {
+		t.Fatal(errs)
+	} else if resp.StatusCode != 200 {
+		t.Fatal(resp.StatusCode)
+	}
+	token := client.GetCookie(resp.Cookies(), q.TokenCookie)
+
+	userCount := 1
+	userPwd := "1234"
+	users := map[string]string{}
+	getUserName := func(id int) string {
+		return fmt.Sprintf("space_limit_user_%d", id)
+	}
+
+	for i := 0; i < userCount; i++ {
+		userName := getUserName(i)
+
+		resp, adResp, errs := usersCl.AddUser(userName, userPwd, userstore.UserRole, token)
+		if len(errs) > 0 {
+			t.Fatal(errs)
+		} else if resp.StatusCode != 200 {
+			t.Fatal("failed to add user")
+		}
+
+		users[userName] = adResp.ID
+	}
+
+	resp, _, errs = usersCl.Logout(token)
+	if len(errs) > 0 {
+		t.Fatal(errs)
+	} else if resp.StatusCode != 200 {
+		t.Fatal(resp.StatusCode)
+	}
+
+	t.Run("test space limitiong: Upload", func(t *testing.T) {
+		usersCl := client.NewSingleUserClient(addr)
+		resp, _, errs := usersCl.Login(getUserName(0), userPwd)
+		if len(errs) > 0 {
+			t.Fatal(errs)
+		} else if resp.StatusCode != 200 {
+			t.Fatal(resp.StatusCode)
+		}
+		token := client.GetCookie(resp.Cookies(), q.TokenCookie)
+
+		fileContent := ""
+		for i := 0; i < 10; i++ {
+			fileContent += "0"
+		}
+
+		for i := 0; i < 10; i++ {
+			ok := assertUploadOK(t, fmt.Sprintf("%s/spacelimit/f_%d", getUserName(0), 0), fileContent, addr, token)
+			if !ok {
+				t.Fatalf("space limit failed at %d", 0)
+			}
+
+			resp, selfResp, errs := usersCl.Self(token)
+			if len(errs) > 0 {
+				t.Fatal(errs)
+			} else if resp.StatusCode != 200 {
+				t.Fatal("failed to add user")
+			} else if selfResp.UsedSpace != int64((i+1)*10) {
+				t.Fatal("incorrect used space")
+			}
+		}
+
+		cl := client.NewFilesClient(addr, token)
+		filePath := fmt.Sprintf("%s/spacelimit/f_%d", getUserName(0), 11)
+		res, _, errs := cl.Create(filePath, 1)
+		if len(errs) > 0 {
+			t.Fatal(errs)
+		} else if res.StatusCode != 429 {
+			t.Fatal("(space limit): this request should be rejected")
+		}
+	})
+
+	resp, _, errs = usersCl.Logout(token)
+	if len(errs) > 0 {
+		t.Fatal(errs)
+	} else if resp.StatusCode != 200 {
+		t.Fatal(resp.StatusCode)
+	}
+}
diff --git a/src/userstore/user_store.go b/src/userstore/user_store.go
index 94acad8..8a11aa1 100644
--- a/src/userstore/user_store.go
+++ b/src/userstore/user_store.go
@@ -25,6 +25,14 @@ const (
 	defaultDownloadSpeedLimit = 50 * 1024 * 1024 // 50MB
 )
 
+var (
+	ErrReachedLimit = errors.New("reached space limit")
+)
+
+func IsReachedLimitErr(err error) bool {
+	return err == ErrReachedLimit
+}
+
 type Quota struct {
 	SpaceLimit         int64 `json:"spaceLimit,space"`
 	UploadSpeedLimit   int   `json:"uploadSpeedLimit"`
@@ -260,12 +268,7 @@ func (us *KVUserStore) SetUsed(id uint64, incr bool, capacity int64) error {
 	}
 
 	if incr && gotUser.UsedSpace+capacity > int64(gotUser.Quota.SpaceLimit) {
-		return fmt.Errorf(
-			"reached space limit (%d): file size(%d), used(%d)",
-			gotUser.Quota.SpaceLimit,
-			capacity,
-			gotUser.UsedSpace,
-		)
+		return ErrReachedLimit
 	}
 
 	if incr {