diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index 622efad..e032f4b 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -34,6 +34,6 @@ jobs:
           fail_ci_if_error: true
 
       - name: Run linter
-        uses: golangci/golangci-lint-action@v3
+        uses: golangci/golangci-lint-action@v6
         with:
           version: latest 
\ No newline at end of file
diff --git a/cmd/rota/main.go b/cmd/rota/main.go
index 0e33166..258e3cd 100644
--- a/cmd/rota/main.go
+++ b/cmd/rota/main.go
@@ -25,6 +25,8 @@ const (
 	msgFailedToLoadProxies    = "failed to load proxies"
 	msgWatchingProxyFile      = "watching proxy file"
 	msgMissingProxyFile       = "missing proxy file"
+	msgFailedToCheckProxies   = "failed to check proxies"
+	msgFailedToServeApi       = "failed to serve api"
 	msgFailedToListen         = "failed to listen"
 	msgReceivedSignal         = "received signal, shutting down..."
 )
@@ -53,7 +55,11 @@ func main() {
 
 	if cfgManager.Check {
 		proxyChecker := proxy.NewProxyChecker(cfg, proxyServer)
-		proxyChecker.Check()
+		err = proxyChecker.Check()
+		if err != nil {
+			slog.Error(msgFailedToCheckProxies, "error", err)
+			os.Exit(1)
+		}
 		return
 	}
 
@@ -106,5 +112,9 @@ func runApi(cfg *config.Config) {
 	}
 
 	api := api.NewApi(cfg)
-	api.Serve()
+	err := api.Serve()
+	if err != nil {
+		slog.Error(msgFailedToServeApi, "error", err)
+		os.Exit(1)
+	}
 }
diff --git a/internal/api/api.go b/internal/api/api.go
index 6de0b57..c17ad2e 100644
--- a/internal/api/api.go
+++ b/internal/api/api.go
@@ -22,6 +22,7 @@ const (
 	msgMetricsRequested       = "metrics requested"
 	msgMethodNotAllowed       = "method not allowed"
 	msgFailedToCollectMetrics = "failed to collect metrics"
+	msgFailedToWriteMetrics   = "failed to write metrics"
 )
 
 type Api struct {
@@ -105,7 +106,12 @@ func (a *Api) handleMetrics(w http.ResponseWriter, r *http.Request) {
 	}
 
 	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(metrics)
+	err = json.NewEncoder(w).Encode(metrics)
+	if err != nil {
+		slog.Error(msgFailedToWriteMetrics, "error", err)
+		http.Error(w, msgFailedToWriteMetrics, http.StatusInternalServerError)
+		return
+	}
 }
 
 func collectMetrics() (*metrics, error) {
diff --git a/internal/proxy/check.go b/internal/proxy/check.go
index e83fb98..3d47e7f 100644
--- a/internal/proxy/check.go
+++ b/internal/proxy/check.go
@@ -22,6 +22,7 @@ const (
 	msgFailedToCreateRequest     = "failed to create request"
 	msgDeadProxy                 = "dead proxy"
 	msgAliveProxy                = "alive proxy"
+	msgFailedToWriteOutputFile   = "failed to write output file"
 )
 
 type ProxyChecker struct {
@@ -92,6 +93,9 @@ func (pl *ProxyChecker) checkProxy(proxy *Proxy, outputFile *os.File) {
 
 	slog.Info(msgAliveProxy, "proxy", proxy.Host)
 	if outputFile != nil {
-		outputFile.WriteString(proxy.Host + "\n")
+		_, err = outputFile.WriteString(proxy.Host + "\n")
+		if err != nil {
+			slog.Error(msgFailedToWriteOutputFile, "error", err)
+		}
 	}
 }