diff --git a/agents/kamagent.go b/agents/kamagent.go
index a6abf417e..6201721a8 100644
--- a/agents/kamagent.go
+++ b/agents/kamagent.go
@@ -34,6 +34,13 @@ import (
 	"github.com/cgrates/rpcclient"
 )
 
+var (
+	kamAuthReqRegexp   = regexp.MustCompile(CGR_AUTH_REQUEST)
+	kamCallStartRegexp = regexp.MustCompile(CGR_CALL_START)
+	kamCallEndRegexp   = regexp.MustCompile(CGR_CALL_END)
+	kamDlgListRegexp   = regexp.MustCompile(CGR_DLG_LIST)
+)
+
 func NewKamailioAgent(kaCfg *config.KamAgentCfg,
 	sessionS rpcclient.RpcClientConnection, timezone string) (ka *KamailioAgent) {
 	ka = &KamailioAgent{
@@ -57,12 +64,10 @@ type KamailioAgent struct {
 func (self *KamailioAgent) Connect() error {
 	var err error
 	eventHandlers := map[*regexp.Regexp][]func([]byte, string){
-		regexp.MustCompile(CGR_AUTH_REQUEST): {
-			self.onCgrAuth},
-		regexp.MustCompile(CGR_CALL_START): {
-			self.onCallStart},
-		regexp.MustCompile(CGR_CALL_END): {self.onCallEnd},
-		regexp.MustCompile(CGR_DLG_LIST): {self.onDlgList},
+		kamAuthReqRegexp:   {self.onCgrAuth},
+		kamCallStartRegexp: {self.onCallStart},
+		kamCallEndRegexp:   {self.onCallEnd},
+		kamDlgListRegexp:   {self.onDlgList},
 	}
 	errChan := make(chan error)
 	for _, connCfg := range self.cfg.EvapiConns {
diff --git a/config/rsrparser.go b/config/rsrparser.go
index 70209a2cc..769c5df1e 100644
--- a/config/rsrparser.go
+++ b/config/rsrparser.go
@@ -26,6 +26,11 @@ import (
 	"github.com/cgrates/cgrates/utils"
 )
 
+var (
+	spltRgxp  = regexp.MustCompile(`:s\/`)
+	rulesRgxp = regexp.MustCompile(`(?:(.*[^\\])\/(.*[^\\])*\/){1,}`)
+)
+
 func NewRSRParsers(parsersRules string, allFiltersMatch bool, rsrSeparator string) (prsrs RSRParsers, err error) {
 	if parsersRules == "" {
 		return
@@ -167,11 +172,9 @@ func NewRSRParser(parserRules string, allFiltersMatch bool) (rsrParser *RSRParse
 		return
 	}
 	// dynamic content via attributeNames
-	spltRgxp := regexp.MustCompile(`:s\/`)
 	spltRules := spltRgxp.Split(parserRules, -1)
 	rsrParser.attrName = spltRules[0][1:] // in form ~hdr_name
 	if len(spltRules) > 1 {
-		rulesRgxp := regexp.MustCompile(`(?:(.*[^\\])\/(.*[^\\])*\/){1,}`)
 		for _, ruleStr := range spltRules[1:] { // :s/ already removed through split
 			allMatches := rulesRgxp.FindStringSubmatch(ruleStr)
 			if len(allMatches) != 3 {
diff --git a/utils/coreutils.go b/utils/coreutils.go
index 2d655075a..113226e8a 100644
--- a/utils/coreutils.go
+++ b/utils/coreutils.go
@@ -46,7 +46,24 @@ import (
 	"github.com/cgrates/rpcclient"
 )
 
-var startCGRateSTime time.Time
+var (
+	startCGRateSTime time.Time
+
+	rfc3339Rule                  = regexp.MustCompile(`^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.+$`)
+	sqlRule                      = regexp.MustCompile(`^\d{4}-\d{2}-\d{2}\s\d{2}:\d{2}:\d{2}$`)
+	utcFormat                    = regexp.MustCompile(`^\d{4}-\d{2}-\d{2}[T]\d{2}:\d{2}:\d{2}$`)
+	gotimeRule                   = regexp.MustCompile(`^\d{4}-\d{2}-\d{2}\s\d{2}:\d{2}:\d{2}\.?\d*\s[+,-]\d+\s\w+$`)
+	gotimeRule2                  = regexp.MustCompile(`^\d{4}-\d{2}-\d{2}\s\d{2}:\d{2}:\d{2}\.?\d*\s[+,-]\d+\s[+,-]\d+$`)
+	fsTimestamp                  = regexp.MustCompile(`^\d{16}$`)
+	astTimestamp                 = regexp.MustCompile(`^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d*[+,-]\d+$`)
+	unixTimestampRule            = regexp.MustCompile(`^\d{10}$`)
+	unixTimestampMilisecondsRule = regexp.MustCompile(`^\d{13}$`)
+	unixTimestampNanosecondsRule = regexp.MustCompile(`^\d{19}$`)
+	oneLineTimestampRule         = regexp.MustCompile(`^\d{14}$`)
+	oneSpaceTimestampRule        = regexp.MustCompile(`^\d{2}\.\d{2}.\d{4}\s{1}\d{2}:\d{2}:\d{2}$`)
+	eamonTimestampRule           = regexp.MustCompile(`^\d{2}/\d{2}/\d{4}\s{1}\d{2}:\d{2}:\d{2}$`)
+	broadsoftTimestampRule       = regexp.MustCompile(`^\d{14}\.\d{3}`)
+)
 
 func init() {
 	startCGRateSTime = time.Now()
@@ -177,20 +194,6 @@ func ParseTimeDetectLayout(tmStr string, timezone string) (time.Time, error) {
 	if err != nil {
 		return nilTime, err
 	}
-	rfc3339Rule := regexp.MustCompile(`^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.+$`)
-	sqlRule := regexp.MustCompile(`^\d{4}-\d{2}-\d{2}\s\d{2}:\d{2}:\d{2}$`)
-	utcFormat := regexp.MustCompile(`^\d{4}-\d{2}-\d{2}[T]\d{2}:\d{2}:\d{2}$`)
-	gotimeRule := regexp.MustCompile(`^\d{4}-\d{2}-\d{2}\s\d{2}:\d{2}:\d{2}\.?\d*\s[+,-]\d+\s\w+$`)
-	gotimeRule2 := regexp.MustCompile(`^\d{4}-\d{2}-\d{2}\s\d{2}:\d{2}:\d{2}\.?\d*\s[+,-]\d+\s[+,-]\d+$`)
-	fsTimestamp := regexp.MustCompile(`^\d{16}$`)
-	astTimestamp := regexp.MustCompile(`^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d*[+,-]\d+$`)
-	unixTimestampRule := regexp.MustCompile(`^\d{10}$`)
-	unixTimestampMilisecondsRule := regexp.MustCompile(`^\d{13}$`)
-	unixTimestampNanosecondsRule := regexp.MustCompile(`^\d{19}$`)
-	oneLineTimestampRule := regexp.MustCompile(`^\d{14}$`)
-	oneSpaceTimestampRule := regexp.MustCompile(`^\d{2}\.\d{2}.\d{4}\s{1}\d{2}:\d{2}:\d{2}$`)
-	eamonTimestampRule := regexp.MustCompile(`^\d{2}/\d{2}/\d{4}\s{1}\d{2}:\d{2}:\d{2}$`)
-	broadsoftTimestampRule := regexp.MustCompile(`^\d{14}\.\d{3}`)
 	switch {
 	case tmStr == UNLIMITED || tmStr == "":
 	// leave it at zero
diff --git a/utils/rsrfield.go b/utils/rsrfield.go
index 6ecc3070f..117677519 100644
--- a/utils/rsrfield.go
+++ b/utils/rsrfield.go
@@ -24,6 +24,11 @@ import (
 	"strings"
 )
 
+var (
+	spltRgxp  = regexp.MustCompile(`:s\/`)
+	rulesRgxp = regexp.MustCompile(`(?:(.+[^\\])\/(.*[^\\])*\/){1,}`)
+)
+
 func NewRSRField(fldStr string) (fld *RSRField, err error) {
 	if len(fldStr) == 0 {
 		return nil, nil
@@ -85,14 +90,12 @@ func NewRSRField(fldStr string) (fld *RSRField, err error) {
 		rsrField.filters = filters
 		return rsrField, nil
 	}
-	spltRgxp := regexp.MustCompile(`:s\/`)
 	spltRules := spltRgxp.Split(fldStr, -1)
 	if len(spltRules) < 2 {
 		return nil, fmt.Errorf("Invalid Split of Search&Replace field rule. %s", fldStr)
 	}
 	rsrField.Id = spltRules[0][1:]
-	rsrField.filters = filters // Original id in form ~hdr_name
-	rulesRgxp := regexp.MustCompile(`(?:(.+[^\\])\/(.*[^\\])*\/){1,}`)
+	rsrField.filters = filters              // Original id in form ~hdr_name
 	for _, ruleStr := range spltRules[1:] { // :s/ already removed through split
 		allMatches := rulesRgxp.FindStringSubmatch(ruleStr)
 		if len(allMatches) != 3 {