diff --git a/Blockchain.go b/Blockchain.go
index d9324a6..b74434e 100644
--- a/Blockchain.go
+++ b/Blockchain.go
@@ -26,6 +26,6 @@ func initUserBlockchain() {
 
 	if err != nil {
 		Filters.LogError("initUserBlockchain", "error: %s\n", err.Error())
-		os.Exit(1)
+		os.Exit(ExitBlockchainCorrupt)
 	}
 }
diff --git a/Config.go b/Config.go
index b935997..04dc480 100644
--- a/Config.go
+++ b/Config.go
@@ -16,7 +16,7 @@ import (
 )
 
 // Version is the current core library version
-const Version = "Alpha 4/05.11.2021"
+const Version = "Alpha 4/15.11.2021"
 
 var config struct {
 	LogFile string `yaml:"LogFile"` // Log file
diff --git a/Exit.go b/Exit.go
new file mode 100644
index 0000000..c3486be
--- /dev/null
+++ b/Exit.go
@@ -0,0 +1,23 @@
+/*
+File Name:  Exit.go
+Copyright:  2021 Peernet s.r.o.
+Author:     Peter Kleissner
+*/
+
+package core
+
+// Exit codes signal why the application exited. These are universal between clients developed by the Peernet organization.
+// Clients are encouraged to log additional details in a log file. 3rd party clients may define additional exit codes.
+const (
+	ExitSuccess            = 0          // This is actually never used.
+	ExitErrorConfigAccess  = 1          // Error accessing the config file.
+	ExitErrorConfigRead    = 2          // Error reading the config file.
+	ExitErrorConfigParse   = 3          // Error parsing the config file.
+	ExitErrorLogInit       = 4          // Error initializing log file.
+	ExitParamWebapiInvalid = 5          // Parameter for webapi is invalid.
+	ExitPrivateKeyCorrupt  = 6          // Private key is corrupt.
+	ExitPrivateKeyCreate   = 7          // Cannot create a new private key.
+	ExitBlockchainCorrupt  = 8          // Blockchain is corrupt.
+	ExitGraceful           = 9          // Graceful shutdown.
+	STATUS_CONTROL_C_EXIT  = 0xC000013A // The application terminated as a result of a CTRL+C. This is a Windows NTSTATUS value.
+)
diff --git a/Peer ID.go b/Peer ID.go
index 53540e7..3f0b099 100644
--- a/Peer ID.go	
+++ b/Peer ID.go	
@@ -42,7 +42,7 @@ func initPeerID() {
 		}
 
 		Filters.LogError("initPeerID", "private key in config is corrupted! Error: %s\n", err.Error())
-		os.Exit(1)
+		os.Exit(ExitPrivateKeyCorrupt)
 	}
 
 	// if the peer ID is empty, create a new user public-private key pair
@@ -50,7 +50,7 @@ func initPeerID() {
 	peerPrivateKey, peerPublicKey, err = Secp256k1NewPrivateKey()
 	if err != nil {
 		Filters.LogError("initPeerID", "generating public-private key pairs: %s\n", err.Error())
-		os.Exit(1)
+		os.Exit(ExitPrivateKeyCreate)
 	}
 	nodeID = protocol.PublicKey2NodeID(peerPublicKey)
 
diff --git a/README.md b/README.md
index 6131b4e..c686fee 100644
--- a/README.md
+++ b/README.md
@@ -21,7 +21,7 @@ import (
 func init() {
     if status, err := core.LoadConfig("Config.yaml"); err != nil {
         fmt.Printf("Error loading config file: %s", err.Error())
-        os.Exit(1)
+        os.Exit(core.ExitErrorConfigAccess)
     }
 
     core.InitLog()
diff --git a/webapi/API.go b/webapi/API.go
index b4ad608..549ffc9 100644
--- a/webapi/API.go
+++ b/webapi/API.go
@@ -10,10 +10,10 @@ import (
 	"crypto/tls"
 	"encoding/json"
 	"errors"
-	"log"
 	"net/http"
 	"time"
 
+	"github.com/PeernetOfficial/core"
 	"github.com/gorilla/mux"
 	"github.com/gorilla/websocket"
 )
@@ -73,13 +73,15 @@ func Start(ListenAddresses []string, UseSSL bool, CertificateFile, CertificateKe
 	Router.HandleFunc("/file/view", apiFileView).Methods("GET")
 
 	for _, listen := range ListenAddresses {
-		go startWebServer(listen, UseSSL, CertificateFile, CertificateKey, Router, "API", TimeoutRead, TimeoutWrite)
+		go startWebAPI(listen, UseSSL, CertificateFile, CertificateKey, Router, "API", TimeoutRead, TimeoutWrite)
 	}
 }
 
-// startWebServer starts a web-server with given parameters and logs the status. If may block forever and only returns if there is an error.
+// startWebAPI starts a web-server with given parameters and logs the status. If may block forever and only returns if there is an error.
 // The certificate file and key are only used if SSL is enabled. The read and write timeout may be 0 for no timeout.
-func startWebServer(WebListen string, UseSSL bool, CertificateFile, CertificateKey string, Handler http.Handler, Info string, ReadTimeout, WriteTimeout time.Duration) {
+func startWebAPI(WebListen string, UseSSL bool, CertificateFile, CertificateKey string, Handler http.Handler, Info string, ReadTimeout, WriteTimeout time.Duration) {
+	core.Filters.LogError("startWebAPI", "Start API at '%s'\n", WebListen)
+
 	tlsConfig := &tls.Config{MinVersion: tls.VersionTLS12} // for security reasons disable TLS 1.0/1.1
 
 	server := &http.Server{
@@ -94,12 +96,12 @@ func startWebServer(WebListen string, UseSSL bool, CertificateFile, CertificateK
 	if UseSSL {
 		// HTTPS
 		if err := server.ListenAndServeTLS(CertificateFile, CertificateKey); err != nil {
-			log.Printf("Error listening on '%s': %v\n", WebListen, err)
+			core.Filters.LogError("startWebAPI", "Error listening on '%s': %v\n", WebListen, err)
 		}
 	} else {
 		// HTTP
 		if err := server.ListenAndServe(); err != nil {
-			log.Printf("Error listening on '%s': %v\n", WebListen, err)
+			core.Filters.LogError("startWebAPI", "Error listening on '%s': %v\n", WebListen, err)
 		}
 	}
 }
@@ -110,7 +112,7 @@ func EncodeJSON(w http.ResponseWriter, r *http.Request, data interface{}) (err e
 
 	err = json.NewEncoder(w).Encode(data)
 	if err != nil {
-		log.Printf("Error writing data for route '%s': %v\n", r.URL.Path, err)
+		core.Filters.LogError("EncodeJSON", "Error writing data for route '%s': %v\n", r.URL.Path, err)
 	}
 
 	return err