diff --git a/src/config/toml_helper.c b/src/config/toml_helper.c
index 91f27c31..74f00047 100644
--- a/src/config/toml_helper.c
+++ b/src/config/toml_helper.c
@@ -444,7 +444,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 			if(val.ok)
 				conf_item->v.b = val.u.b;
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type bool", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a valid bool", conf_item->k);
 			break;
 		}
 		case CONF_ALL_DEBUG_BOOL:
@@ -453,7 +453,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 			if(val.ok)
 				set_all_debug(newconf, val.u.b);
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type bool", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a valid bool", conf_item->k);
 			break;
 		}
 		case CONF_INT:
@@ -462,7 +462,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 			if(val.ok)
 				conf_item->v.i = val.u.i;
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type integer", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a valid integer", conf_item->k);
 			break;
 		}
 		case CONF_UINT:
@@ -471,7 +471,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 			if(val.ok && val.u.i >= 0)
 				conf_item->v.ui = val.u.i;
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type unsigned integer", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a valid unsigned integer", conf_item->k);
 			break;
 		}
 		case CONF_UINT16:
@@ -480,7 +480,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 			if(val.ok && val.u.i >= 0 && val.u.i <= UINT16_MAX)
 				conf_item->v.ui = val.u.i;
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type unsigned integer (16 bit)", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a valid unsigned integer (16 bit)", conf_item->k);
 			break;
 		}
 		case CONF_LONG:
@@ -489,7 +489,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 			if(val.ok)
 				conf_item->v.l = val.u.i;
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type long", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a valid long integer", conf_item->k);
 			break;
 		}
 		case CONF_ULONG:
@@ -498,7 +498,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 			if(val.ok && val.u.i >= 0)
 				conf_item->v.ul = val.u.i;
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type unsigned long", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a valid unsigned long integer", conf_item->k);
 			break;
 		}
 		case CONF_DOUBLE:
@@ -507,7 +507,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 			if(val.ok)
 				conf_item->v.d = val.u.d;
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type double", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a valid double", conf_item->k);
 			break;
 		}
 		case CONF_STRING:
@@ -522,7 +522,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 				conf_item->t = CONF_STRING_ALLOCATED;
 			}
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type string", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a valid string", conf_item->k);
 			break;
 		}
 		case CONF_ENUM_PTR_TYPE:
@@ -538,7 +538,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 					log_warn("Config setting %s is invalid, allowed options are: %s", conf_item->k, conf_item->h);
 			}
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type string", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a valid string", conf_item->k);
 			break;
 		}
 		case CONF_ENUM_BUSY_TYPE:
@@ -554,7 +554,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 					log_warn("Config setting %s is invalid, allowed options are: %s", conf_item->k, conf_item->h);
 			}
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type string", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a valid string", conf_item->k);
 			break;
 		}
 		case CONF_ENUM_BLOCKING_MODE:
@@ -570,7 +570,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 					log_warn("Config setting %s is invalid, allowed options are: %s", conf_item->k, conf_item->h);
 			}
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type string", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a validstring", conf_item->k);
 			break;
 		}
 		case CONF_ENUM_REFRESH_HOSTNAMES:
@@ -586,7 +586,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 					log_warn("Config setting %s is invalid, allowed options are: %s", conf_item->k, conf_item->h);
 			}
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type string", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a valid string", conf_item->k);
 			break;
 		}
 		case CONF_ENUM_LISTENING_MODE:
@@ -602,7 +602,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 					log_warn("Config setting %s is invalid, allowed options are: %s", conf_item->k, conf_item->h);
 			}
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type string", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a valid string", conf_item->k);
 			break;
 		}
 		case CONF_ENUM_WEB_THEME:
@@ -618,7 +618,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 					log_warn("Config setting %s is invalid, allowed options are: %s", conf_item->k, conf_item->h);
 			}
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type string", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a valid string", conf_item->k);
 			break;
 		}
 		case CONF_ENUM_TEMP_UNIT:
@@ -634,7 +634,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 					log_warn("Config setting %s is invalid, allowed options are: %s", conf_item->k, conf_item->h);
 			}
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not of type string", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is not a valid string", conf_item->k);
 			break;
 		}
 		case CONF_ENUM_PRIVACY_LEVEL:
@@ -643,7 +643,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 			if(val.ok && val.u.i >= PRIVACY_SHOW_ALL && val.u.i <= PRIVACY_MAXIMUM)
 				conf_item->v.i = val.u.i;
 			else
-				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is invalid (not of type integer or outside allowed bounds)", conf_item->k);
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is invalid (not an integer or outside allowed bounds)", conf_item->k);
 			break;
 		}
 		case CONF_STRUCT_IN_ADDR:
@@ -654,8 +654,12 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 			{
 				if(inet_pton(AF_INET, val.u.s, &addr4))
 					memcpy(&conf_item->v.in_addr, &addr4, sizeof(addr4));
+				else
+					log_warn("Config %s is invalid (not of type IPv4 address)", conf_item->k);
 				free(val.u.s);
 			}
+			else
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is invalid (not a valid string of type IPv4 address)", conf_item->k);
 			break;
 		}
 		case CONF_STRUCT_IN6_ADDR:
@@ -666,8 +670,12 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 			{
 				if(inet_pton(AF_INET6, val.u.s, &addr6))
 					memcpy(&conf_item->v.in6_addr, &addr6, sizeof(addr6));
+				else
+					log_warn("Config %s is invalid (not of type IPv6 address)", conf_item->k);
 				free(val.u.s);
 			}
+			else
+				log_debug(DEBUG_CONFIG, "%s DOES NOT EXIST or is invalid (not a valid string of type IPv6 address)", conf_item->k);
 			break;
 		}
 		case CONF_JSON_STRING_ARRAY:
@@ -686,7 +694,7 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 					const toml_datum_t d = toml_string_at(array, i);
 					if(!d.ok)
 					{
-						log_debug(DEBUG_CONFIG, "%s is an invalid array (found at index %u)", conf_item->k, i);
+						log_warn("Config %s is an invalid array (found at index %u)", conf_item->k, i);
 						break;
 					}
 					// Only import non-empty entries
@@ -709,3 +717,244 @@ void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *t
 		}
 	}
 }
+
+#define FTLCONF_PREFIX "FTLCONF_"
+bool readEnvValue(struct conf_item *conf_item, struct config *newconf)
+{
+	// Allocate memory for config key + prefix (sizeof includes the trailing '\0')
+	const size_t envkey_size = strlen(conf_item->k) + sizeof(FTLCONF_PREFIX);
+	char *envkey = calloc(envkey_size, sizeof(char));
+
+	// Build env key to look for
+	strcpy(envkey, FTLCONF_PREFIX);
+	strcat(envkey, conf_item->k);
+
+	// Replace all "." by "_" as this is the convention used in v5.x and earlier
+	for(unsigned int i = 0; i < envkey_size - 1; i++)
+		if(envkey[i] == '.')
+			envkey[i] = '_';
+
+	// First check if a environmental variable with the given key exists
+	const char *envvar = getenv(envkey);
+
+	// Return early if this environment variable does not exist
+	if(envvar == NULL)
+	{
+		log_debug(DEBUG_CONFIG, "ENV %s is not set", envkey);
+		free(envkey);
+		return false;
+	}
+
+	log_debug(DEBUG_CONFIG, "ENV %s = \"%s\"", envkey, envvar);
+
+	switch(conf_item->t)
+	{
+		case CONF_BOOL:
+		{
+			if(strcasecmp(envkey, "true") == 0 || strcasecmp(envkey, "yes") == 0)
+				conf_item->v.b = true;
+			else if(strcasecmp(envkey, "false") == 0 || strcasecmp(envkey, "no") == 0)
+				conf_item->v.b = false;
+			else
+				log_warn("ENV %s is not of type bool", envkey);
+			break;
+		}
+		case CONF_ALL_DEBUG_BOOL:
+		{
+			if(strcasecmp(envkey, "true") == 0 || strcasecmp(envkey, "yes") == 0)
+				set_all_debug(newconf, true);
+			else if(strcasecmp(envkey, "false") == 0 || strcasecmp(envkey, "no") == 0)
+				set_all_debug(newconf, false);
+			else
+				log_warn("ENV %s is not of type bool", envkey);
+			break;
+		}
+		case CONF_INT:
+		{
+			int val = 0;
+			if(sscanf(envvar, "%i", &val) == 1)
+				conf_item->v.i = val;
+			else
+				log_warn("ENV %s is not of type integer", envkey);
+			break;
+		}
+		case CONF_UINT:
+		{
+			unsigned int val = 0;
+			if(sscanf(envvar, "%u", &val) == 1)
+				conf_item->v.ui = val;
+			else
+				log_warn("ENV %s is not of type unsigned integer", envkey);
+			break;
+		}
+		case CONF_UINT16:
+		{
+			unsigned int val = 0;
+			if(sscanf(envvar, "%u", &val) == 1 && val <= UINT16_MAX)
+				conf_item->v.ui = val;
+			else
+				log_warn("ENV %s is not of type unsigned integer (16 bit)", envkey);
+			break;
+		}
+		case CONF_LONG:
+		{
+			long val = 0;
+			if(sscanf(envvar, "%li", &val) == 1)
+				conf_item->v.l = val;
+			else
+				log_warn("ENV %s is not of type long", envkey);
+			break;
+		}
+		case CONF_ULONG:
+		{
+			unsigned long val = 0;
+			if(sscanf(envvar, "%lu", &val) == 1)
+				conf_item->v.ul = val;
+			else
+				log_warn("ENV %s is not of type unsigned long", envkey);
+			break;
+		}
+		case CONF_DOUBLE:
+		{
+			double val = 0;
+			if(sscanf(envvar, "%lf", &val) == 1)
+				conf_item->v.d = val;
+			else
+				log_warn("ENV %s is not of type double", envkey);
+			break;
+		}
+		case CONF_STRING:
+		case CONF_STRING_ALLOCATED:
+		{
+			if(conf_item->t == CONF_STRING_ALLOCATED)
+				free(conf_item->v.s);
+			conf_item->v.s = strdup(envvar);
+			conf_item->t = CONF_STRING_ALLOCATED;
+			break;
+		}
+		case CONF_ENUM_PTR_TYPE:
+		{
+			const int ptr_type = get_ptr_type_val(envvar);
+			if(ptr_type != -1)
+				conf_item->v.ptr_type = ptr_type;
+			else
+				log_warn("ENV %s is invalid, allowed options are: %s", envkey, conf_item->h);
+			break;
+		}
+		case CONF_ENUM_BUSY_TYPE:
+		{
+			const int busy_reply = get_busy_reply_val(envvar);
+			if(busy_reply != -1)
+				conf_item->v.busy_reply = busy_reply;
+			else
+				log_warn("ENV %s is invalid, allowed options are: %s", envkey, conf_item->h);
+			break;
+		}
+		case CONF_ENUM_BLOCKING_MODE:
+		{
+			const int blocking_mode = get_blocking_mode_val(envvar);
+			if(blocking_mode != -1)
+				conf_item->v.blocking_mode = blocking_mode;
+			else
+				log_warn("ENV %s is invalid, allowed options are: %s", envkey, conf_item->h);
+			break;
+		}
+		case CONF_ENUM_REFRESH_HOSTNAMES:
+		{
+			const int refresh_hostnames = get_refresh_hostnames_val(envvar);
+			if(refresh_hostnames != -1)
+				conf_item->v.refresh_hostnames = refresh_hostnames;
+			else
+				log_warn("ENV %s is invalid, allowed options are: %s", envkey, conf_item->h);
+			break;
+		}
+		case CONF_ENUM_LISTENING_MODE:
+		{
+			const int listeningMode = get_listeningMode_val(envvar);
+			if(listeningMode != -1)
+				conf_item->v.listeningMode = listeningMode;
+			else
+				log_warn("ENV %s is invalid, allowed options are: %s", envkey, conf_item->h);
+			break;
+		}
+		case CONF_ENUM_WEB_THEME:
+		{
+			const int web_theme = get_web_theme_val(envvar);
+			if(web_theme != -1)
+				conf_item->v.web_theme = web_theme;
+			else
+				log_warn("ENV %s is invalid, allowed options are: %s", envkey, conf_item->h);
+			break;
+		}
+		case CONF_ENUM_TEMP_UNIT:
+		{
+			const int temp_unit = get_temp_unit_val(envvar);
+			if(temp_unit != -1)
+				conf_item->v.temp_unit = temp_unit;
+			else
+				log_warn("ENV %s is invalid, allowed options are: %s", envkey, conf_item->h);
+			break;
+		}
+		case CONF_ENUM_PRIVACY_LEVEL:
+		{
+			int val = 0;
+			if(sscanf(envvar, "%i", &val) == 1 && val >= PRIVACY_SHOW_ALL && val <= PRIVACY_MAXIMUM)
+				conf_item->v.i = val;
+			else
+				log_warn("ENV %s is invalid (not of type integer or outside allowed bounds)", envkey);
+			break;
+		}
+		case CONF_STRUCT_IN_ADDR:
+		{
+			struct in_addr addr4 = { 0 };
+			if(inet_pton(AF_INET, envvar, &addr4))
+				memcpy(&conf_item->v.in_addr, &addr4, sizeof(addr4));
+			else
+				log_warn("ENV %s is invalid (not of type IPv4 address)", envkey);
+			break;
+		}
+		case CONF_STRUCT_IN6_ADDR:
+		{
+			struct in6_addr addr6 = { 0 };
+			if(inet_pton(AF_INET6, envvar, &addr6))
+				memcpy(&conf_item->v.in6_addr, &addr6, sizeof(addr6));
+			else
+				log_warn("ENV %s is invalid (not of type IPv6 address)", envkey);
+			break;
+		}
+		case CONF_JSON_STRING_ARRAY:
+		{
+			// Make a copy of envvar as strtok modified the input string
+			char *envvar_copy = strdup(envvar);
+			// Free previously allocated JSON array
+			cJSON_Delete(conf_item->v.json);
+			conf_item->v.json = cJSON_CreateArray();
+			// Parse envvar array and generate a JSON array
+			const char delim[] =",";
+			const char *elem = strtok(envvar_copy, delim);
+			while(elem != NULL)
+			{
+				// Only import non-empty entries
+				if(strlen(elem) > 0)
+				{
+					// Add string to our JSON array
+					cJSON *item = cJSON_CreateString(elem);
+					cJSON_AddItemToArray(conf_item->v.json, item);
+				}
+
+				// Search for the next element
+				elem = strtok(NULL, delim);
+			}
+			free(envvar_copy);
+			break;
+		}
+		case CONF_PASSWORD:
+		{
+			// This is ignored, it is only a pseudo-element with no real content
+		}
+	}
+
+	// Free allocated env var name
+	free(envkey);
+	return true;
+}
diff --git a/src/config/toml_helper.h b/src/config/toml_helper.h
index 2b0249fd..4a972f44 100644
--- a/src/config/toml_helper.h
+++ b/src/config/toml_helper.h
@@ -23,5 +23,6 @@ void print_comment(FILE *fp, const char *str, const char *intro, const unsigned
 void print_toml_allowed_values(cJSON *allowed_values, FILE *fp, const unsigned int width, const unsigned int indent);
 void writeTOMLvalue(FILE * fp, const int indent, const enum conf_type t, union conf_value *v);
 void readTOMLvalue(struct conf_item *conf_item, const char* key, toml_table_t *toml, struct config *newconf);
+bool readEnvValue(struct conf_item *conf_item, struct config *newconf);
 
 #endif //CONFIG_WRITER_H
diff --git a/src/config/toml_reader.c b/src/config/toml_reader.c
index b6aadfea..f076022e 100644
--- a/src/config/toml_reader.c
+++ b/src/config/toml_reader.c
@@ -30,11 +30,10 @@ static void reportDebugFlags(void);
 bool readFTLtoml(struct config *conf, toml_table_t *toml, const bool verbose)
 {
 	// Parse lines in the config file if we did not receive a pointer to a TOML
-	// table (e.g. from an imported Teleporter file)
-	bool external = true;
-	if(toml == NULL)
+	// table from an imported Teleporter file
+	bool teleporter = (toml != NULL);
+	if(!teleporter)
 	{
-		external = false;
 		toml = parseTOML();
 		if(!toml)
 			return false;
@@ -42,13 +41,17 @@ bool readFTLtoml(struct config *conf, toml_table_t *toml, const bool verbose)
 
 	// Try to read debug config. This is done before the full config
 	// parsing to allow for debug output further down
-	toml_table_t *conf_debug = toml_table_in(toml, "debug");
-	if(conf_debug)
-		readTOMLvalue(&conf->debug.config, "config", conf_debug, conf);
+	// First try to read env variable, if this fails, read TOML
+	if(teleporter || !readEnvValue(&conf->debug.config, conf))
+	{
+		toml_table_t *conf_debug = toml_table_in(toml, "debug");
+		if(conf_debug)
+			readTOMLvalue(&conf->debug.config, "config", conf_debug, conf);
+	}
 	set_debug_flags(conf);
 
 	log_debug(DEBUG_CONFIG, "Reading %s TOML config file: full config",
-	          external ? "external" : "default");
+	          teleporter ? "teleporter" : "default");
 
 	// Read all known config items
 	for(unsigned int i = 0; i < CONFIG_ELEMENTS; i++)
@@ -56,6 +59,12 @@ bool readFTLtoml(struct config *conf, toml_table_t *toml, const bool verbose)
 		// Get pointer to memory location of this conf_item
 		struct conf_item *conf_item = get_conf_item(conf, i);
 
+		// First try to read this config option from an environment variable
+		// Skip reading environment variables when importing from Teleporter
+		// If this succeeds, skip searching the TOML file for this config item
+		if(!teleporter && readEnvValue(conf_item, conf))
+			continue;
+
 		// Get config path depth
 		unsigned int level = config_path_depth(conf_item->p);
 
diff --git a/test/run.sh b/test/run.sh
index e2563e82..e237b3fd 100755
--- a/test/run.sh
+++ b/test/run.sh
@@ -69,6 +69,7 @@ OLDUMASK=$(umask)
 umask 0022
 
 # Start FTL
+export FTLCONF_misc_nice="-11"
 if ! su pihole -s /bin/sh -c /home/pihole/pihole-FTL; then
   echo "pihole-FTL failed to start"
   exit 1
diff --git a/test/test_suite.bats b/test/test_suite.bats
index 6401306e..6dfbab63 100644
--- a/test/test_suite.bats
+++ b/test/test_suite.bats
@@ -1185,7 +1185,7 @@
   [[ ${lines[0]} == "0" ]]
 }
 
-@test "No config errors in pihole.toml" {
+@test "No missing config items in pihole.toml" {
   run bash -c 'grep "DEBUG_CONFIG: " /var/log/pihole/FTL.log'
   printf "%s\n" "${lines[@]}"
   run bash -c 'grep "DEBUG_CONFIG: " /var/log/pihole/FTL.log | grep -c "DOES NOT EXIST"'
@@ -1251,6 +1251,13 @@
   [[ "${lines[0]}" == "192.168.1.7" ]]
 }
 
+@test "Environmental variable is favored over config file" {
+  # The config file has -10 but we set FTLCONF_misc_nice="-11"
+  run bash -c 'grep -c "nice = -11" /etc/pihole/pihole.toml'
+  printf "%s\n" "${lines[@]}"
+  [[ ${lines[0]} == "1" ]]
+}
+
 @test "API domain search: Non-existing domain returns expected JSON" {
   run bash -c 'curl -s 127.0.0.1/api/search/non.existent'
   printf "%s\n" "${lines[@]}"