diff --git a/.gitignore b/.gitignore
index a257dec6..c260c28b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,7 +7,8 @@ pihole-FTL
 # Versioning files (generated by Makefile)
 version*
 
-# CMake files
+# CMake files generated during compilation
+/cmake/
 /cmake-build-debug/
 /cmake-build-release/
 
diff --git a/src/api/socket.c b/src/api/socket.c
index d034db7d..a5fb901d 100644
--- a/src/api/socket.c
+++ b/src/api/socket.c
@@ -34,6 +34,29 @@ bool dualstack = false;
 bool ipv4telnet = false, ipv6telnet = false, sock_avail = false;
 bool istelnet[MAXCONNS];
 
+void saveport(int port)
+{
+	FILE *f;
+	// Open "w" for truncation/creating file
+	if((f = fopen(FTLfiles.port, "w")) == NULL)
+	{
+		// Opening failed (permissions, path does not exist, etc.)
+		logg("WARNING: Unable to write used port to file");
+		logg("         (API might not find the port)");
+	}
+	else if(port > 0)
+	{
+		// Save port to file
+		fprintf(f, "%i", port);
+		fclose(f);
+	}
+	else
+	{
+		// FTL is terminating: Leave file truncated
+		fclose(f);
+	}
+}
+
 static bool bind_to_telnet_port_IPv4(int *socketdescriptor)
 {
 	// IPv4 socket
diff --git a/src/api/socket.h b/src/api/socket.h
index 15d54231..630ba960 100644
--- a/src/api/socket.h
+++ b/src/api/socket.h
@@ -10,6 +10,7 @@
 #ifndef SOCKET_H
 #define SOCKET_H
 
+void saveport(int port);
 void close_telnet_socket(void);
 void close_unix_socket(bool unlink_file);
 void seom(const int sock);
diff --git a/src/config.c b/src/config.c
index f0355d3c..12a75d9b 100644
--- a/src/config.c
+++ b/src/config.c
@@ -15,6 +15,8 @@
 #include "log.h"
 // nice()
 #include <unistd.h>
+// saveport()
+#include "api/socket.h"
 
 ConfigStruct config;
 FTLFileNamesStruct FTLfiles = {
@@ -29,6 +31,7 @@ FTLFileNamesStruct FTLfiles = {
 	NULL,
 	NULL,
 	NULL,
+	NULL,
 	NULL
 };
 
@@ -300,6 +303,10 @@ void read_FTLconf(void)
 	// PIDFILE
 	getpath(fp, "PIDFILE", "/run/pihole-FTL.pid", &FTLfiles.pid);
 
+	// PORTFILE
+	getpath(fp, "PORTFILE", "/run/pihole-FTL.port", &FTLfiles.port);
+	saveport(config.port);
+
 	// SOCKETFILE
 	getpath(fp, "SOCKETFILE", "/run/pihole/FTL.sock", &FTLfiles.socketfile);
 
diff --git a/src/config.h b/src/config.h
index 503850f2..429d724b 100644
--- a/src/config.h
+++ b/src/config.h
@@ -50,6 +50,7 @@ typedef struct {
 	const char* snapConf;
 	char* log;
 	char* pid;
+	char* port;
 	char* socketfile;
 	char* FTL_db;
 	char* gravity_db;
diff --git a/src/main.c b/src/main.c
index 2fa4ea95..98d5a243 100644
--- a/src/main.c
+++ b/src/main.c
@@ -112,6 +112,9 @@ int main (int argc, char* argv[])
 	close_telnet_socket();
 	close_unix_socket(true);
 
+	// Empty API port file, port 0 = truncate file
+	saveport(0);
+
 	// Close gravity database connection
 	gravityDB_close();
 
diff --git a/test/run.sh b/test/run.sh
index bf64b9f5..32322aa1 100755
--- a/test/run.sh
+++ b/test/run.sh
@@ -11,8 +11,16 @@ if ! id -u pihole &> /dev/null; then
   useradd -m -s /usr/sbin/nologin pihole
 fi
 
+# Kill possibly running pihole-FTL process
+while pidof -s pihole-FTL > /dev/null; do
+  pid="$(pidof -s pihole-FTL)"
+  echo "Terminating running pihole-FTL process with PID ${pid}"
+  kill $pid
+  sleep 1
+done
+
 # Clean up possible old files from earlier test runs
-rm -f /etc/pihole/gravity.db /etc/pihole/pihole-FTL.db /var/log/pihole.log /var/log/pihole-FTL.log
+rm -f /etc/pihole/gravity.db /etc/pihole/pihole-FTL.db /var/log/pihole.log /var/log/pihole-FTL.log /dev/shm/FTL-*
 
 # Create necessary directories and files
 mkdir -p /etc/pihole /run/pihole /var/log
diff --git a/test/test_suite.bats b/test/test_suite.bats
index 82e1e15d..8fe60ab6 100644
--- a/test/test_suite.bats
+++ b/test/test_suite.bats
@@ -456,3 +456,9 @@
   printf "%s\n" "${lines[@]}"
   [[ ${lines[0]} == "2" ]]
 }
+
+@test "Port file exists and contains expected API port" {
+  run bash -c 'cat /run/pihole-FTL.port'
+  printf "%s\n" "${lines[@]}"
+  [[ ${lines[0]} == "4711" ]]
+}