diff --git a/config/config.go b/config/config.go
index 4d412ec..4d18c64 100644
--- a/config/config.go
+++ b/config/config.go
@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
+	"github.com/muety/wakapi/utils"
 	"github.com/robfig/cron/v3"
 	"io/ioutil"
 	"net/http"
@@ -229,19 +230,19 @@ func (c *Config) GetMigrationFunc(dbDialect string) models.MigrationFunc {
 }
 
 func (c *appConfig) GetCustomLanguages() map[string]string {
-	return cloneStringMap(c.CustomLanguages, false)
+	return utils.CloneStringMap(c.CustomLanguages, false)
 }
 
 func (c *appConfig) GetLanguageColors() map[string]string {
-	return cloneStringMap(c.Colors["languages"], true)
+	return utils.CloneStringMap(c.Colors["languages"], true)
 }
 
 func (c *appConfig) GetEditorColors() map[string]string {
-	return cloneStringMap(c.Colors["editors"], true)
+	return utils.CloneStringMap(c.Colors["editors"], true)
 }
 
 func (c *appConfig) GetOSColors() map[string]string {
-	return cloneStringMap(c.Colors["operating_systems"], true)
+	return utils.CloneStringMap(c.Colors["operating_systems"], true)
 }
 
 func (c *appConfig) GetAggregationTimeCron() string {
@@ -261,14 +262,14 @@ func (c *appConfig) GetAggregationTimeCron() string {
 		return fmt.Sprintf("0 %d %d * * *", m, h)
 	}
 
-	return cronPadToSecondly(c.AggregationTime)
+	return utils.CronPadToSecondly(c.AggregationTime)
 }
 
 func (c *appConfig) GetWeeklyReportCron() string {
 	if strings.Contains(c.ReportTimeWeekly, ",") {
 		// old gocron format, e.g. "fri,18:00"
 		split := strings.Split(c.ReportTimeWeekly, ",")
-		weekday := parseWeekday(split[0])
+		weekday := utils.ParseWeekday(split[0])
 		timeParts := strings.Split(split[1], ":")
 
 		h, err := strconv.Atoi(timeParts[0])
@@ -284,7 +285,7 @@ func (c *appConfig) GetWeeklyReportCron() string {
 		return fmt.Sprintf("0 %d %d * * %d", m, h, weekday)
 	}
 
-	return cronPadToSecondly(c.ReportTimeWeekly)
+	return utils.CronPadToSecondly(c.ReportTimeWeekly)
 }
 
 func (c *appConfig) GetLeaderboardGenerationTimeCron() []string {
@@ -310,11 +311,11 @@ func (c *appConfig) GetLeaderboardGenerationTimeCron() []string {
 		}
 	} else {
 		parse = func(s string) string {
-			return cronPadToSecondly(s)
+			return utils.CronPadToSecondly(s)
 		}
 	}
 
-	for _, s := range strings.Split(c.LeaderboardGenerationTime, ";") {
+	for _, s := range utils.SplitMulti(c.LeaderboardGenerationTime, ",", ";") {
 		crons = append(crons, parse(strings.TrimSpace(s)))
 	}
 
@@ -393,43 +394,6 @@ func resolveDbDialect(dbType string) string {
 	return dbType
 }
 
-func findString(needle string, haystack []string, defaultVal string) string {
-	for _, s := range haystack {
-		if s == needle {
-			return s
-		}
-	}
-	return defaultVal
-}
-
-func parseWeekday(s string) time.Weekday {
-	switch strings.ToLower(s) {
-	case "mon", strings.ToLower(time.Monday.String()):
-		return time.Monday
-	case "tue", strings.ToLower(time.Tuesday.String()):
-		return time.Tuesday
-	case "wed", strings.ToLower(time.Wednesday.String()):
-		return time.Wednesday
-	case "thu", strings.ToLower(time.Thursday.String()):
-		return time.Thursday
-	case "fri", strings.ToLower(time.Friday.String()):
-		return time.Friday
-	case "sat", strings.ToLower(time.Saturday.String()):
-		return time.Saturday
-	case "sun", strings.ToLower(time.Sunday.String()):
-		return time.Sunday
-	}
-	return time.Monday
-}
-
-func cronPadToSecondly(expr string) string {
-	parts := strings.Split(expr, " ")
-	if len(parts) == 6 {
-		return expr
-	}
-	return "0 " + expr
-}
-
 func Set(config *Config) {
 	cfg = config
 }
@@ -489,7 +453,7 @@ func Load(version string) *Config {
 		logbuch.Warn("with sqlite, only a single connection is supported") // otherwise 'PRAGMA foreign_keys=ON' would somehow have to be set for every connection in the pool
 		config.Db.MaxConn = 1
 	}
-	if config.Mail.Provider != "" && findString(config.Mail.Provider, emailProviders, "") == "" {
+	if config.Mail.Provider != "" && utils.FindString(config.Mail.Provider, emailProviders, "") == "" {
 		logbuch.Fatal("unknown mail provider '%s'", config.Mail.Provider)
 	}
 	if _, err := time.ParseDuration(config.App.HeartbeatMaxAge); err != nil {
diff --git a/config/utils.go b/config/utils.go
deleted file mode 100644
index 942c66d..0000000
--- a/config/utils.go
+++ /dev/null
@@ -1,14 +0,0 @@
-package config
-
-import "strings"
-
-func cloneStringMap(m map[string]string, keysToLower bool) map[string]string {
-	m2 := make(map[string]string)
-	for k, v := range m {
-		if keysToLower {
-			k = strings.ToLower(k)
-		}
-		m2[k] = v
-	}
-	return m2
-}
diff --git a/utils/common.go b/helpers/date.go
similarity index 71%
rename from utils/common.go
rename to helpers/date.go
index 69f5b20..c099d40 100644
--- a/utils/common.go
+++ b/helpers/date.go
@@ -1,9 +1,8 @@
-package utils
+package helpers
 
 import (
-	"errors"
+	"fmt"
 	"github.com/muety/wakapi/config"
-	"regexp"
 	"time"
 )
 
@@ -41,22 +40,10 @@ func FormatDateHuman(date time.Time) string {
 	return date.Format("Mon, 02 Jan 2006")
 }
 
-func Add(i, j int) int {
-	return i + j
-}
-
-func ParseUserAgent(ua string) (string, string, error) {
-	re := regexp.MustCompile(`(?iU)^wakatime\/(?:v?[\d+.]+|unset)\s\((\w+)-.*\)\s.+\s([^\/\s]+)-wakatime\/.+$`)
-	groups := re.FindAllStringSubmatch(ua, -1)
-	if len(groups) == 0 || len(groups[0]) != 3 {
-		return "", "", errors.New("failed to parse user agent string")
-	}
-	return groups[0][1], groups[0][2], nil
-}
-
-func SubSlice[T any](slice []T, from, to uint) []T {
-	if int(to) > len(slice) {
-		to = uint(len(slice))
-	}
-	return slice[from:int(to)]
+func FmtWakatimeDuration(d time.Duration) string {
+	d = d.Round(time.Minute)
+	h := d / time.Hour
+	d -= h * time.Hour
+	m := d / time.Minute
+	return fmt.Sprintf("%d hrs %d mins", h, m)
 }
diff --git a/helpers/helpers.go b/helpers/helpers.go
new file mode 100644
index 0000000..f6c2dbf
--- /dev/null
+++ b/helpers/helpers.go
@@ -0,0 +1,4 @@
+package helpers
+
+// helpers are different from utils in that they contain wakapi-specific utility functions
+// also, helpers may depend on the config package, while utils must be entirely static
diff --git a/helpers/http.go b/helpers/http.go
new file mode 100644
index 0000000..4318832
--- /dev/null
+++ b/helpers/http.go
@@ -0,0 +1,20 @@
+package helpers
+
+import (
+	"encoding/json"
+	"github.com/muety/wakapi/config"
+	"github.com/muety/wakapi/utils"
+	"net/http"
+)
+
+func ExtractCookieAuth(r *http.Request) (username *string, err error) {
+	return utils.ExtractCookieAuth(r, config.Get().Security.SecureCookie)
+}
+
+func RespondJSON(w http.ResponseWriter, r *http.Request, status int, object interface{}) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	if err := json.NewEncoder(w).Encode(object); err != nil {
+		config.Log().Request(r).Error("error while writing json response: %v", err)
+	}
+}
diff --git a/utils/summary.go b/helpers/summary.go
similarity index 86%
rename from utils/summary.go
rename to helpers/summary.go
index e2f62e9..842c6d2 100644
--- a/utils/summary.go
+++ b/helpers/summary.go
@@ -1,78 +1,13 @@
-package utils
+package helpers
 
 import (
 	"errors"
 	"github.com/muety/wakapi/models"
+	"github.com/muety/wakapi/utils"
 	"net/http"
 	"time"
 )
 
-func ParseInterval(interval string) (*models.IntervalKey, error) {
-	for _, i := range models.AllIntervals {
-		if i.HasAlias(interval) {
-			return i, nil
-		}
-	}
-	return nil, errors.New("not a valid interval")
-}
-
-func MustResolveIntervalRawTZ(interval string, tz *time.Location) (from, to time.Time) {
-	_, from, to = ResolveIntervalRawTZ(interval, tz)
-	return from, to
-}
-
-func ResolveIntervalRawTZ(interval string, tz *time.Location) (err error, from, to time.Time) {
-	parsed, err := ParseInterval(interval)
-	if err != nil {
-		return err, time.Time{}, time.Time{}
-	}
-	return ResolveIntervalTZ(parsed, tz)
-}
-
-func ResolveIntervalTZ(interval *models.IntervalKey, tz *time.Location) (err error, from, to time.Time) {
-	now := time.Now().In(tz)
-	to = now
-
-	switch interval {
-	case models.IntervalToday:
-		from = BeginOfToday(tz)
-	case models.IntervalYesterday:
-		from = BeginOfToday(tz).Add(-24 * time.Hour)
-		to = BeginOfToday(tz)
-	case models.IntervalThisWeek:
-		from = BeginOfThisWeek(tz)
-	case models.IntervalLastWeek:
-		from = BeginOfThisWeek(tz).AddDate(0, 0, -7)
-		to = BeginOfThisWeek(tz)
-	case models.IntervalThisMonth:
-		from = BeginOfThisMonth(tz)
-	case models.IntervalLastMonth:
-		from = BeginOfThisMonth(tz).AddDate(0, -1, 0)
-		to = BeginOfThisMonth(tz)
-	case models.IntervalThisYear:
-		from = BeginOfThisYear(tz)
-	case models.IntervalPast7Days:
-		from = now.AddDate(0, 0, -7)
-	case models.IntervalPast7DaysYesterday:
-		from = BeginOfToday(tz).AddDate(0, 0, -1).AddDate(0, 0, -7)
-		to = BeginOfToday(tz).AddDate(0, 0, -1)
-	case models.IntervalPast14Days:
-		from = now.AddDate(0, 0, -14)
-	case models.IntervalPast30Days:
-		from = now.AddDate(0, 0, -30)
-	case models.IntervalPast6Months:
-		from = now.AddDate(0, -6, 0)
-	case models.IntervalPast12Months:
-		from = now.AddDate(0, -12, 0)
-	case models.IntervalAny:
-		from = time.Time{}
-	default:
-		err = errors.New("invalid interval")
-	}
-
-	return err, from, to
-}
-
 func ParseSummaryParams(r *http.Request) (*models.SummaryParams, error) {
 	user := extractUser(r)
 	params := r.URL.Query()
@@ -144,3 +79,69 @@ func extractUser(r *http.Request) *models.User {
 	}
 	return nil
 }
+
+func ParseInterval(interval string) (*models.IntervalKey, error) {
+	for _, i := range models.AllIntervals {
+		if i.HasAlias(interval) {
+			return i, nil
+		}
+	}
+	return nil, errors.New("not a valid interval")
+}
+
+func MustResolveIntervalRawTZ(interval string, tz *time.Location) (from, to time.Time) {
+	_, from, to = ResolveIntervalRawTZ(interval, tz)
+	return from, to
+}
+
+func ResolveIntervalRawTZ(interval string, tz *time.Location) (err error, from, to time.Time) {
+	parsed, err := ParseInterval(interval)
+	if err != nil {
+		return err, time.Time{}, time.Time{}
+	}
+	return ResolveIntervalTZ(parsed, tz)
+}
+
+func ResolveIntervalTZ(interval *models.IntervalKey, tz *time.Location) (err error, from, to time.Time) {
+	now := time.Now().In(tz)
+	to = now
+
+	switch interval {
+	case models.IntervalToday:
+		from = utils.BeginOfToday(tz)
+	case models.IntervalYesterday:
+		from = utils.BeginOfToday(tz).Add(-24 * time.Hour)
+		to = utils.BeginOfToday(tz)
+	case models.IntervalThisWeek:
+		from = utils.BeginOfThisWeek(tz)
+	case models.IntervalLastWeek:
+		from = utils.BeginOfThisWeek(tz).AddDate(0, 0, -7)
+		to = utils.BeginOfThisWeek(tz)
+	case models.IntervalThisMonth:
+		from = utils.BeginOfThisMonth(tz)
+	case models.IntervalLastMonth:
+		from = utils.BeginOfThisMonth(tz).AddDate(0, -1, 0)
+		to = utils.BeginOfThisMonth(tz)
+	case models.IntervalThisYear:
+		from = utils.BeginOfThisYear(tz)
+	case models.IntervalPast7Days:
+		from = now.AddDate(0, 0, -7)
+	case models.IntervalPast7DaysYesterday:
+		from = utils.BeginOfToday(tz).AddDate(0, 0, -1).AddDate(0, 0, -7)
+		to = utils.BeginOfToday(tz).AddDate(0, 0, -1)
+	case models.IntervalPast14Days:
+		from = now.AddDate(0, 0, -14)
+	case models.IntervalPast30Days:
+		from = now.AddDate(0, 0, -30)
+	case models.IntervalPast6Months:
+		from = now.AddDate(0, -6, 0)
+	case models.IntervalPast12Months:
+		from = now.AddDate(0, -12, 0)
+	case models.IntervalAny:
+		from = time.Time{}
+	default:
+		err = errors.New("invalid interval")
+	}
+
+	return err, from, to
+}
diff --git a/middlewares/authenticate.go b/middlewares/authenticate.go
index 82417b4..3972b28 100644
--- a/middlewares/authenticate.go
+++ b/middlewares/authenticate.go
@@ -2,6 +2,7 @@ package middlewares
 
 import (
 	"fmt"
+	"github.com/muety/wakapi/helpers"
 	"net/http"
 	"strings"
 
@@ -121,7 +122,7 @@ func (m *AuthenticateMiddleware) tryGetUserByApiKeyQuery(r *http.Request) (*mode
 }
 
 func (m *AuthenticateMiddleware) tryGetUserByCookie(r *http.Request) (*models.User, error) {
-	username, err := utils.ExtractCookieAuth(r, m.config)
+	username, err := helpers.ExtractCookieAuth(r)
 	if err != nil {
 		return nil, err
 	}
diff --git a/models/compat/shields/v1/badge.go b/models/compat/shields/v1/badge.go
index 39f6dc1..6ef754d 100644
--- a/models/compat/shields/v1/badge.go
+++ b/models/compat/shields/v1/badge.go
@@ -1,8 +1,8 @@
 package v1
 
 import (
+	"github.com/muety/wakapi/helpers"
 	"github.com/muety/wakapi/models"
-	"github.com/muety/wakapi/utils"
 )
 
 // https://shields.io/endpoint
@@ -23,7 +23,7 @@ func NewBadgeDataFrom(summary *models.Summary) *BadgeData {
 	return &BadgeData{
 		SchemaVersion: 1,
 		Label:         defaultLabel,
-		Message:       utils.FmtWakatimeDuration(summary.TotalTime()),
+		Message:       helpers.FmtWakatimeDuration(summary.TotalTime()),
 		Color:         defaultColor,
 	}
 }
diff --git a/models/compat/wakatime/v1/all_time.go b/models/compat/wakatime/v1/all_time.go
index 8d200d4..55dc68f 100644
--- a/models/compat/wakatime/v1/all_time.go
+++ b/models/compat/wakatime/v1/all_time.go
@@ -1,8 +1,8 @@
 package v1
 
 import (
+	"github.com/muety/wakapi/helpers"
 	"github.com/muety/wakapi/models"
-	"github.com/muety/wakapi/utils"
 	"time"
 )
 
@@ -33,13 +33,13 @@ func NewAllTimeFrom(summary *models.Summary) *AllTimeViewModel {
 	return &AllTimeViewModel{
 		Data: &AllTimeData{
 			TotalSeconds: float32(total.Seconds()),
-			Text:         utils.FmtWakatimeDuration(total),
+			Text:         helpers.FmtWakatimeDuration(total),
 			IsUpToDate:   true,
 			Range: &AllTimeRange{
 				End:       summary.ToTime.T().Format(time.RFC3339),
-				EndDate:   utils.FormatDate(summary.ToTime.T()),
+				EndDate:   helpers.FormatDate(summary.ToTime.T()),
 				Start:     summary.FromTime.T().Format(time.RFC3339),
-				StartDate: utils.FormatDate(summary.FromTime.T()),
+				StartDate: helpers.FormatDate(summary.FromTime.T()),
 				Timezone:  tzName,
 			},
 		},
diff --git a/models/compat/wakatime/v1/summaries.go b/models/compat/wakatime/v1/summaries.go
index 7716e3a..cbbffa4 100644
--- a/models/compat/wakatime/v1/summaries.go
+++ b/models/compat/wakatime/v1/summaries.go
@@ -2,8 +2,8 @@ package v1
 
 import (
 	"fmt"
+	"github.com/muety/wakapi/helpers"
 	"github.com/muety/wakapi/models"
-	"github.com/muety/wakapi/utils"
 	"math"
 	"sync"
 	"time"
@@ -96,7 +96,7 @@ func NewSummariesFrom(summaries []*models.Summary) *SummariesViewModel {
 			Decimal: fmt.Sprintf("%.2f", totalHrs),
 			Digital: fmt.Sprintf("%d:%d", int(totalHrs), int(totalMins)),
 			Seconds: totalSecs,
-			Text:    utils.FmtWakatimeDuration(totalTime),
+			Text:    helpers.FmtWakatimeDuration(totalTime),
 		},
 	}
 }
@@ -119,7 +119,7 @@ func newDataFrom(s *models.Summary) *SummariesData {
 			Digital:      fmt.Sprintf("%d:%d", totalHrs, totalMins),
 			Hours:        totalHrs,
 			Minutes:      totalMins,
-			Text:         utils.FmtWakatimeDuration(total),
+			Text:         helpers.FmtWakatimeDuration(total),
 			TotalSeconds: total.Seconds(),
 		},
 		Range: &SummariesRange{
@@ -201,7 +201,7 @@ func convertEntry(e *models.SummaryItem, entityTotal time.Duration) *SummariesEn
 		Name:         e.Key,
 		Percent:      percentage,
 		Seconds:      secs,
-		Text:         utils.FmtWakatimeDuration(total),
+		Text:         helpers.FmtWakatimeDuration(total),
 		TotalSeconds: total.Seconds(),
 	}
 }
diff --git a/routes/api/diagnostics.go b/routes/api/diagnostics.go
index 219204d..5b3b8de 100644
--- a/routes/api/diagnostics.go
+++ b/routes/api/diagnostics.go
@@ -2,14 +2,13 @@ package api
 
 import (
 	"encoding/json"
+	"github.com/muety/wakapi/helpers"
 	"net/http"
 
 	"github.com/gorilla/mux"
 	conf "github.com/muety/wakapi/config"
-	"github.com/muety/wakapi/services"
-	"github.com/muety/wakapi/utils"
-
 	"github.com/muety/wakapi/models"
+	"github.com/muety/wakapi/services"
 )
 
 type DiagnosticsApiHandler struct {
@@ -55,5 +54,5 @@ func (h *DiagnosticsApiHandler) Post(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	utils.RespondJSON(w, r, http.StatusCreated, struct{}{})
+	helpers.RespondJSON(w, r, http.StatusCreated, struct{}{})
 }
diff --git a/routes/api/heartbeat.go b/routes/api/heartbeat.go
index 58574d8..c923d2c 100644
--- a/routes/api/heartbeat.go
+++ b/routes/api/heartbeat.go
@@ -1,6 +1,7 @@
 package api
 
 import (
+	"github.com/muety/wakapi/helpers"
 	"net/http"
 
 	"github.com/gorilla/mux"
@@ -120,7 +121,7 @@ func (h *HeartbeatApiHandler) Post(w http.ResponseWriter, r *http.Request) {
 
 	defer func() {}()
 
-	utils.RespondJSON(w, r, http.StatusCreated, constructSuccessResponse(len(heartbeats)))
+	helpers.RespondJSON(w, r, http.StatusCreated, constructSuccessResponse(len(heartbeats)))
 }
 
 // construct weird response format (see https://github.com/wakatime/wakatime/blob/2e636d389bf5da4e998e05d5285a96ce2c181e3d/wakatime/api.py#L288)
diff --git a/routes/api/metrics.go b/routes/api/metrics.go
index fcab86e..404c1bd 100644
--- a/routes/api/metrics.go
+++ b/routes/api/metrics.go
@@ -5,13 +5,13 @@ import (
 	"github.com/emvi/logbuch"
 	"github.com/gorilla/mux"
 	conf "github.com/muety/wakapi/config"
+	"github.com/muety/wakapi/helpers"
 	"github.com/muety/wakapi/middlewares"
 	"github.com/muety/wakapi/models"
 	v1 "github.com/muety/wakapi/models/compat/wakatime/v1"
 	mm "github.com/muety/wakapi/models/metrics"
 	"github.com/muety/wakapi/repositories"
 	"github.com/muety/wakapi/services"
-	"github.com/muety/wakapi/utils"
 	"net/http"
 	"runtime"
 	"sort"
@@ -129,7 +129,7 @@ func (h *MetricsHandler) getUserMetrics(user *models.User) (*mm.Metrics, error)
 		return nil, err
 	}
 
-	from, to := utils.MustResolveIntervalRawTZ("today", user.TZ())
+	from, to := helpers.MustResolveIntervalRawTZ("today", user.TZ())
 
 	summaryToday, err := h.summarySrvc.Aliased(from, to, user, h.summarySrvc.Retrieve, nil, false)
 	if err != nil {
diff --git a/routes/api/summary.go b/routes/api/summary.go
index ac013e8..a5926e8 100644
--- a/routes/api/summary.go
+++ b/routes/api/summary.go
@@ -1,6 +1,7 @@
 package api
 
 import (
+	"github.com/muety/wakapi/helpers"
 	routeutils "github.com/muety/wakapi/routes/utils"
 	"net/http"
 
@@ -8,7 +9,6 @@ import (
 	conf "github.com/muety/wakapi/config"
 	"github.com/muety/wakapi/middlewares"
 	"github.com/muety/wakapi/services"
-	"github.com/muety/wakapi/utils"
 )
 
 type SummaryApiHandler struct {
@@ -58,5 +58,5 @@ func (h *SummaryApiHandler) Get(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	utils.RespondJSON(w, r, http.StatusOK, summary)
+	helpers.RespondJSON(w, r, http.StatusOK, summary)
 }
diff --git a/routes/compat/shields/v1/badge.go b/routes/compat/shields/v1/badge.go
index 854d9d2..600cb4b 100644
--- a/routes/compat/shields/v1/badge.go
+++ b/routes/compat/shields/v1/badge.go
@@ -2,6 +2,7 @@ package v1
 
 import (
 	"fmt"
+	"github.com/muety/wakapi/helpers"
 	routeutils "github.com/muety/wakapi/routes/utils"
 	"net/http"
 	"time"
@@ -11,7 +12,6 @@ import (
 	"github.com/muety/wakapi/models"
 	v1 "github.com/muety/wakapi/models/compat/shields/v1"
 	"github.com/muety/wakapi/services"
-	"github.com/muety/wakapi/utils"
 	"github.com/patrickmn/go-cache"
 )
 
@@ -63,7 +63,7 @@ func (h *BadgeHandler) Get(w http.ResponseWriter, r *http.Request) {
 
 	cacheKey := fmt.Sprintf("%s_%v_%s", user.ID, *interval.Key, filters.Hash())
 	if cacheResult, ok := h.cache.Get(cacheKey); ok {
-		utils.RespondJSON(w, r, http.StatusOK, cacheResult.(*v1.BadgeData))
+		helpers.RespondJSON(w, r, http.StatusOK, cacheResult.(*v1.BadgeData))
 		return
 	}
 
@@ -83,11 +83,11 @@ func (h *BadgeHandler) Get(w http.ResponseWriter, r *http.Request) {
 
 	vm := v1.NewBadgeDataFrom(summary)
 	h.cache.SetDefault(cacheKey, vm)
-	utils.RespondJSON(w, r, http.StatusOK, vm)
+	helpers.RespondJSON(w, r, http.StatusOK, vm)
 }
 
 func (h *BadgeHandler) loadUserSummary(user *models.User, interval *models.IntervalKey, filters *models.Filters) (*models.Summary, error, int) {
-	err, from, to := utils.ResolveIntervalTZ(interval, user.TZ())
+	err, from, to := helpers.ResolveIntervalTZ(interval, user.TZ())
 	if err != nil {
 		return nil, err, http.StatusBadRequest
 	}
diff --git a/routes/compat/wakatime/v1/all_time.go b/routes/compat/wakatime/v1/all_time.go
index 8da804e..431eaec 100644
--- a/routes/compat/wakatime/v1/all_time.go
+++ b/routes/compat/wakatime/v1/all_time.go
@@ -3,12 +3,12 @@ package v1
 import (
 	"github.com/gorilla/mux"
 	conf "github.com/muety/wakapi/config"
+	"github.com/muety/wakapi/helpers"
 	"github.com/muety/wakapi/middlewares"
 	"github.com/muety/wakapi/models"
 	v1 "github.com/muety/wakapi/models/compat/wakatime/v1"
 	routeutils "github.com/muety/wakapi/routes/utils"
 	"github.com/muety/wakapi/services"
-	"github.com/muety/wakapi/utils"
 	"net/http"
 	"time"
 )
@@ -50,7 +50,7 @@ func (h *AllTimeHandler) Get(w http.ResponseWriter, r *http.Request) {
 		return // response was already sent by util function
 	}
 
-	summary, err, status := h.loadUserSummary(user, utils.ParseSummaryFilters(r))
+	summary, err, status := h.loadUserSummary(user, helpers.ParseSummaryFilters(r))
 	if err != nil {
 		w.WriteHeader(status)
 		w.Write([]byte(err.Error()))
@@ -58,7 +58,7 @@ func (h *AllTimeHandler) Get(w http.ResponseWriter, r *http.Request) {
 	}
 
 	vm := v1.NewAllTimeFrom(summary)
-	utils.RespondJSON(w, r, http.StatusOK, vm)
+	helpers.RespondJSON(w, r, http.StatusOK, vm)
 }
 
 func (h *AllTimeHandler) loadUserSummary(user *models.User, filters *models.Filters) (*models.Summary, error, int) {
diff --git a/routes/compat/wakatime/v1/heartbeat.go b/routes/compat/wakatime/v1/heartbeat.go
index c21f797..1a30bad 100644
--- a/routes/compat/wakatime/v1/heartbeat.go
+++ b/routes/compat/wakatime/v1/heartbeat.go
@@ -2,6 +2,7 @@ package v1
 
 import (
 	"github.com/duke-git/lancet/v2/datetime"
+	"github.com/muety/wakapi/helpers"
 	"net/http"
 	"time"
 
@@ -11,7 +12,6 @@ import (
 	wakatime "github.com/muety/wakapi/models/compat/wakatime/v1"
 	routeutils "github.com/muety/wakapi/routes/utils"
 	"github.com/muety/wakapi/services"
-	"github.com/muety/wakapi/utils"
 )
 
 type HeartbeatsResult struct {
@@ -82,5 +82,5 @@ func (h *HeartbeatHandler) Get(w http.ResponseWriter, r *http.Request) {
 		End:      rangeTo.UTC().Format(time.RFC3339),
 		Timezone: timezone.String(),
 	}
-	utils.RespondJSON(w, r, http.StatusOK, res)
+	helpers.RespondJSON(w, r, http.StatusOK, res)
 }
diff --git a/routes/compat/wakatime/v1/projects.go b/routes/compat/wakatime/v1/projects.go
index 5e2ebb6..acdc12e 100644
--- a/routes/compat/wakatime/v1/projects.go
+++ b/routes/compat/wakatime/v1/projects.go
@@ -1,6 +1,7 @@
 package v1
 
 import (
+	"github.com/muety/wakapi/helpers"
 	"net/http"
 	"strings"
 
@@ -11,7 +12,6 @@ import (
 	v1 "github.com/muety/wakapi/models/compat/wakatime/v1"
 	routeutils "github.com/muety/wakapi/routes/utils"
 	"github.com/muety/wakapi/services"
-	"github.com/muety/wakapi/utils"
 )
 
 type ProjectsHandler struct {
@@ -70,5 +70,5 @@ func (h *ProjectsHandler) Get(w http.ResponseWriter, r *http.Request) {
 	}
 
 	vm := &v1.ProjectsViewModel{Data: projects}
-	utils.RespondJSON(w, r, http.StatusOK, vm)
+	helpers.RespondJSON(w, r, http.StatusOK, vm)
 }
diff --git a/routes/compat/wakatime/v1/stats.go b/routes/compat/wakatime/v1/stats.go
index b625eaa..fa03c1e 100644
--- a/routes/compat/wakatime/v1/stats.go
+++ b/routes/compat/wakatime/v1/stats.go
@@ -1,6 +1,7 @@
 package v1
 
 import (
+	"github.com/muety/wakapi/helpers"
 	"net/http"
 	"time"
 
@@ -10,7 +11,6 @@ import (
 	"github.com/muety/wakapi/models"
 	v1 "github.com/muety/wakapi/models/compat/wakatime/v1"
 	"github.com/muety/wakapi/services"
-	"github.com/muety/wakapi/utils"
 )
 
 type StatsHandler struct {
@@ -79,7 +79,7 @@ func (h *StatsHandler) Get(w http.ResponseWriter, r *http.Request) {
 		rangeParam = (*models.IntervalPast7Days)[0]
 	}
 
-	err, rangeFrom, rangeTo := utils.ResolveIntervalRawTZ(rangeParam, requestedUser.TZ())
+	err, rangeFrom, rangeTo := helpers.ResolveIntervalRawTZ(rangeParam, requestedUser.TZ())
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		w.Write([]byte("invalid range"))
@@ -94,7 +94,7 @@ func (h *StatsHandler) Get(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	summary, err, status := h.loadUserSummary(requestedUser, rangeFrom, rangeTo, utils.ParseSummaryFilters(r))
+	summary, err, status := h.loadUserSummary(requestedUser, rangeFrom, rangeTo, helpers.ParseSummaryFilters(r))
 	if err != nil {
 		w.WriteHeader(status)
 		w.Write([]byte(err.Error()))
@@ -120,7 +120,7 @@ func (h *StatsHandler) Get(w http.ResponseWriter, r *http.Request) {
 		stats.Data.Machines = nil
 	}
 
-	utils.RespondJSON(w, r, http.StatusOK, stats)
+	helpers.RespondJSON(w, r, http.StatusOK, stats)
 }
 
 func (h *StatsHandler) loadUserSummary(user *models.User, start, end time.Time, filters *models.Filters) (*models.Summary, error, int) {
diff --git a/routes/compat/wakatime/v1/statusbar.go b/routes/compat/wakatime/v1/statusbar.go
index 9fade55..a71a791 100644
--- a/routes/compat/wakatime/v1/statusbar.go
+++ b/routes/compat/wakatime/v1/statusbar.go
@@ -1,6 +1,7 @@
 package v1
 
 import (
+	"github.com/muety/wakapi/helpers"
 	"net/http"
 	"time"
 
@@ -11,7 +12,6 @@ import (
 	v1 "github.com/muety/wakapi/models/compat/wakatime/v1"
 	routeutils "github.com/muety/wakapi/routes/utils"
 	"github.com/muety/wakapi/services"
-	"github.com/muety/wakapi/utils"
 )
 
 type StatusBarViewModel struct {
@@ -65,7 +65,7 @@ func (h *StatusBarHandler) Get(w http.ResponseWriter, r *http.Request) {
 		rangeParam = (*models.IntervalToday)[0]
 	}
 
-	err, rangeFrom, rangeTo := utils.ResolveIntervalRawTZ(rangeParam, user.TZ())
+	err, rangeFrom, rangeTo := helpers.ResolveIntervalRawTZ(rangeParam, user.TZ())
 	if err != nil {
 		w.WriteHeader(http.StatusBadRequest)
 		w.Write([]byte("invalid range"))
@@ -79,7 +79,7 @@ func (h *StatusBarHandler) Get(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	summariesView := v1.NewSummariesFrom([]*models.Summary{summary})
-	utils.RespondJSON(w, r, http.StatusOK, StatusBarViewModel{
+	helpers.RespondJSON(w, r, http.StatusOK, StatusBarViewModel{
 		CachedAt: time.Now(),
 		Data:     *summariesView.Data[0],
 	})
diff --git a/routes/compat/wakatime/v1/summaries.go b/routes/compat/wakatime/v1/summaries.go
index 62be34c..5a45b7b 100644
--- a/routes/compat/wakatime/v1/summaries.go
+++ b/routes/compat/wakatime/v1/summaries.go
@@ -3,6 +3,7 @@ package v1
 import (
 	"errors"
 	"github.com/duke-git/lancet/v2/datetime"
+	"github.com/muety/wakapi/helpers"
 	"net/http"
 	"strings"
 	"time"
@@ -76,7 +77,7 @@ func (h *SummariesHandler) Get(w http.ResponseWriter, r *http.Request) {
 	}
 
 	vm := v1.NewSummariesFrom(summaries)
-	utils.RespondJSON(w, r, http.StatusOK, vm)
+	helpers.RespondJSON(w, r, http.StatusOK, vm)
 }
 
 func (h *SummariesHandler) loadUserSummaries(r *http.Request) ([]*models.Summary, error, int) {
@@ -94,24 +95,24 @@ func (h *SummariesHandler) loadUserSummaries(r *http.Request) ([]*models.Summary
 	var start, end time.Time
 	if rangeParam != "" {
 		// range param takes precedence
-		if err, parsedFrom, parsedTo := utils.ResolveIntervalRawTZ(rangeParam, timezone); err == nil {
+		if err, parsedFrom, parsedTo := helpers.ResolveIntervalRawTZ(rangeParam, timezone); err == nil {
 			start, end = parsedFrom, parsedTo
 		} else {
 			return nil, errors.New("invalid 'range' parameter"), http.StatusBadRequest
 		}
-	} else if err, parsedFrom, parsedTo := utils.ResolveIntervalRawTZ(startParam, timezone); err == nil && startParam == endParam {
+	} else if err, parsedFrom, parsedTo := helpers.ResolveIntervalRawTZ(startParam, timezone); err == nil && startParam == endParam {
 		// also accept start param to be a range param
 		start, end = parsedFrom, parsedTo
 	} else {
 		// eventually, consider start and end params a date
 		var err error
 
-		start, err = utils.ParseDateTimeTZ(strings.Replace(startParam, " ", "+", 1), timezone)
+		start, err = helpers.ParseDateTimeTZ(strings.Replace(startParam, " ", "+", 1), timezone)
 		if err != nil {
 			return nil, errors.New("missing required 'start' parameter"), http.StatusBadRequest
 		}
 
-		end, err = utils.ParseDateTimeTZ(strings.Replace(endParam, " ", "+", 1), timezone)
+		end, err = helpers.ParseDateTimeTZ(strings.Replace(endParam, " ", "+", 1), timezone)
 		if err != nil {
 			return nil, errors.New("missing required 'end' parameter"), http.StatusBadRequest
 		}
@@ -133,7 +134,7 @@ func (h *SummariesHandler) loadUserSummaries(r *http.Request) ([]*models.Summary
 	summaries := make([]*models.Summary, len(intervals))
 
 	// filtering
-	filters := utils.ParseSummaryFilters(r)
+	filters := helpers.ParseSummaryFilters(r)
 
 	for i, interval := range intervals {
 		summary, err := h.summarySrvc.Aliased(interval[0], interval[1], user, h.summarySrvc.Retrieve, filters, end.After(time.Now()))
diff --git a/routes/compat/wakatime/v1/users.go b/routes/compat/wakatime/v1/users.go
index 72601bc..b1ae7ab 100644
--- a/routes/compat/wakatime/v1/users.go
+++ b/routes/compat/wakatime/v1/users.go
@@ -1,6 +1,7 @@
 package v1
 
 import (
+	"github.com/muety/wakapi/helpers"
 	"net/http"
 
 	"github.com/gorilla/mux"
@@ -9,7 +10,6 @@ import (
 	v1 "github.com/muety/wakapi/models/compat/wakatime/v1"
 	routeutils "github.com/muety/wakapi/routes/utils"
 	"github.com/muety/wakapi/services"
-	"github.com/muety/wakapi/utils"
 )
 
 type UsersHandler struct {
@@ -56,5 +56,5 @@ func (h *UsersHandler) Get(w http.ResponseWriter, r *http.Request) {
 		conf.Log().Request(r).Error("%v", err)
 	}
 
-	utils.RespondJSON(w, r, http.StatusOK, v1.UserViewModel{Data: user})
+	helpers.RespondJSON(w, r, http.StatusOK, v1.UserViewModel{Data: user})
 }
diff --git a/routes/routes.go b/routes/routes.go
index 1a8d508..7b281b0 100644
--- a/routes/routes.go
+++ b/routes/routes.go
@@ -2,6 +2,7 @@ package routes
 
 import (
 	"fmt"
+	"github.com/muety/wakapi/helpers"
 	"html/template"
 	"net/http"
 	"strings"
@@ -24,16 +25,16 @@ func Init() {
 func DefaultTemplateFuncs() template.FuncMap {
 	return template.FuncMap{
 		"json":           utils.Json,
-		"date":           utils.FormatDateHuman,
-		"datetime":       utils.FormatDateTimeHuman,
-		"simpledate":     utils.FormatDate,
-		"simpledatetime": utils.FormatDateTime,
-		"duration":       utils.FmtWakatimeDuration,
+		"date":           helpers.FormatDateHuman,
+		"datetime":       helpers.FormatDateTimeHuman,
+		"simpledate":     helpers.FormatDate,
+		"simpledatetime": helpers.FormatDateTime,
+		"duration":       helpers.FmtWakatimeDuration,
 		"floordate":      datetime.BeginOfDay,
 		"ceildate":       utils.CeilDate,
 		"title":          strings.Title,
 		"join":           strings.Join,
-		"add":            utils.Add,
+		"add":            add,
 		"capitalize":     utils.Capitalize,
 		"lower":          strings.ToLower,
 		"toRunes":        utils.ToRunes,
@@ -106,3 +107,7 @@ func loadTemplates() {
 func defaultErrorRedirectTarget() string {
 	return fmt.Sprintf("%s/?error=unauthorized", config.Get().Server.BasePath)
 }
+
+func add(i, j int) int {
+	return i + j
+}
diff --git a/routes/summary.go b/routes/summary.go
index 268da1d..709c4c7 100644
--- a/routes/summary.go
+++ b/routes/summary.go
@@ -3,6 +3,7 @@ package routes
 import (
 	"github.com/gorilla/mux"
 	conf "github.com/muety/wakapi/config"
+	"github.com/muety/wakapi/helpers"
 	"github.com/muety/wakapi/middlewares"
 	"github.com/muety/wakapi/models/view"
 	su "github.com/muety/wakapi/routes/utils"
@@ -47,7 +48,7 @@ func (h *SummaryHandler) GetIndex(w http.ResponseWriter, r *http.Request) {
 		r.URL.RawQuery = q.Encode()
 	}
 
-	summaryParams, _ := utils.ParseSummaryParams(r)
+	summaryParams, _ := helpers.ParseSummaryParams(r)
 	summary, err, status := su.LoadUserSummary(h.summarySrvc, r)
 	if err != nil {
 		w.WriteHeader(status)
diff --git a/routes/utils/badge_utils.go b/routes/utils/badge_utils.go
index 327296b..5b012b6 100644
--- a/routes/utils/badge_utils.go
+++ b/routes/utils/badge_utils.go
@@ -2,8 +2,8 @@ package utils
 
 import (
 	"errors"
+	"github.com/muety/wakapi/helpers"
 	"github.com/muety/wakapi/models"
-	"github.com/muety/wakapi/utils"
 	"net/http"
 	"regexp"
 )
@@ -31,12 +31,12 @@ func GetBadgeParams(r *http.Request, requestedUser *models.User) (*models.KeyedI
 
 	var intervalKey = models.IntervalPast30Days
 	if groups := intervalReg.FindStringSubmatch(r.URL.Path); len(groups) > 1 {
-		if i, err := utils.ParseInterval(groups[1]); err == nil {
+		if i, err := helpers.ParseInterval(groups[1]); err == nil {
 			intervalKey = i
 		}
 	}
 
-	_, rangeFrom, rangeTo := utils.ResolveIntervalTZ(intervalKey, requestedUser.TZ())
+	_, rangeFrom, rangeTo := helpers.ResolveIntervalTZ(intervalKey, requestedUser.TZ())
 	interval := &models.KeyedInterval{
 		Interval: models.Interval{Start: rangeFrom, End: rangeTo},
 		Key:      intervalKey,
diff --git a/routes/utils/summary_utils.go b/routes/utils/summary_utils.go
index d07304c..dfee8bf 100644
--- a/routes/utils/summary_utils.go
+++ b/routes/utils/summary_utils.go
@@ -1,14 +1,14 @@
 package utils
 
 import (
+	"github.com/muety/wakapi/helpers"
 	"github.com/muety/wakapi/models"
 	"github.com/muety/wakapi/services"
-	"github.com/muety/wakapi/utils"
 	"net/http"
 )
 
 func LoadUserSummary(ss services.ISummaryService, r *http.Request) (*models.Summary, error, int) {
-	summaryParams, err := utils.ParseSummaryParams(r)
+	summaryParams, err := helpers.ParseSummaryParams(r)
 	if err != nil {
 		return nil, err, http.StatusBadRequest
 	}
diff --git a/services/leaderboard.go b/services/leaderboard.go
index 8bea809..a2e1015 100644
--- a/services/leaderboard.go
+++ b/services/leaderboard.go
@@ -5,9 +5,9 @@ import (
 	"github.com/leandro-lugaresi/hub"
 	"github.com/muety/artifex"
 	"github.com/muety/wakapi/config"
+	"github.com/muety/wakapi/helpers"
 	"github.com/muety/wakapi/models"
 	"github.com/muety/wakapi/repositories"
-	"github.com/muety/wakapi/utils"
 	"github.com/patrickmn/go-cache"
 	"reflect"
 	"strconv"
@@ -212,7 +212,7 @@ func (srv *LeaderboardService) GetAggregatedByIntervalAndUser(interval *models.I
 }
 
 func (srv *LeaderboardService) GenerateByUser(user *models.User, interval *models.IntervalKey) (*models.LeaderboardItem, error) {
-	err, from, to := utils.ResolveIntervalTZ(interval, user.TZ())
+	err, from, to := helpers.ResolveIntervalTZ(interval, user.TZ())
 	if err != nil {
 		return nil, err
 	}
@@ -231,7 +231,7 @@ func (srv *LeaderboardService) GenerateByUser(user *models.User, interval *model
 }
 
 func (srv *LeaderboardService) GenerateAggregatedByUser(user *models.User, interval *models.IntervalKey, by uint8) ([]*models.LeaderboardItem, error) {
-	err, from, to := utils.ResolveIntervalTZ(interval, user.TZ())
+	err, from, to := helpers.ResolveIntervalTZ(interval, user.TZ())
 	if err != nil {
 		return nil, err
 	}
diff --git a/services/mail/mail.go b/services/mail/mail.go
index 6f1c638..33c917c 100644
--- a/services/mail/mail.go
+++ b/services/mail/mail.go
@@ -3,6 +3,7 @@ package mail
 import (
 	"bytes"
 	"fmt"
+	"github.com/muety/wakapi/helpers"
 	"github.com/muety/wakapi/models"
 	"github.com/muety/wakapi/routes"
 	"github.com/muety/wakapi/services"
@@ -115,7 +116,7 @@ func (m *MailService) SendReport(recipient *models.User, report *models.Report)
 	mail := &models.Mail{
 		From:    models.MailAddress(m.config.Mail.Sender),
 		To:      models.MailAddresses([]models.MailAddress{models.MailAddress(recipient.Email)}),
-		Subject: fmt.Sprintf(subjectReport, utils.FormatDateHuman(time.Now().In(recipient.TZ()))),
+		Subject: fmt.Sprintf(subjectReport, helpers.FormatDateHuman(time.Now().In(recipient.TZ()))),
 	}
 	mail.WithHTML(tpl.String())
 	return m.sendingService.Send(mail)
diff --git a/utils/auth.go b/utils/auth.go
index ab96242..28ae791 100644
--- a/utils/auth.go
+++ b/utils/auth.go
@@ -3,7 +3,7 @@ package utils
 import (
 	"encoding/base64"
 	"errors"
-	"github.com/muety/wakapi/config"
+	"github.com/gorilla/securecookie"
 	"github.com/muety/wakapi/models"
 	"golang.org/x/crypto/bcrypt"
 	"net/http"
@@ -44,13 +44,13 @@ func ExtractBearerAuth(r *http.Request) (key string, err error) {
 	return string(keyBytes), err
 }
 
-func ExtractCookieAuth(r *http.Request, config *config.Config) (username *string, err error) {
+func ExtractCookieAuth(r *http.Request, secureCookie *securecookie.SecureCookie) (username *string, err error) {
 	cookie, err := r.Cookie(models.AuthCookieKey)
 	if err != nil {
 		return nil, errors.New("missing authentication")
 	}
 
-	if err := config.Security.SecureCookie.Decode(models.AuthCookieKey, cookie.Value, &username); err != nil {
+	if err := secureCookie.Decode(models.AuthCookieKey, cookie.Value, &username); err != nil {
 		return nil, errors.New("cookie is invalid")
 	}
 
diff --git a/utils/collection.go b/utils/collection.go
new file mode 100644
index 0000000..b079e4a
--- /dev/null
+++ b/utils/collection.go
@@ -0,0 +1,21 @@
+package utils
+
+import "strings"
+
+func SubSlice[T any](slice []T, from, to uint) []T {
+	if int(to) > len(slice) {
+		to = uint(len(slice))
+	}
+	return slice[from:int(to)]
+}
+
+func CloneStringMap(m map[string]string, keysToLower bool) map[string]string {
+	m2 := make(map[string]string)
+	for k, v := range m {
+		if keysToLower {
+			k = strings.ToLower(k)
+		}
+		m2[k] = v
+	}
+	return m2
+}
diff --git a/utils/common_test.go b/utils/collection_test.go
similarity index 100%
rename from utils/common_test.go
rename to utils/collection_test.go
diff --git a/utils/date.go b/utils/date.go
index 4a0a64e..2fc1717 100644
--- a/utils/date.go
+++ b/utils/date.go
@@ -1,8 +1,8 @@
 package utils
 
 import (
-	"fmt"
 	"github.com/duke-git/lancet/v2/datetime"
+	"strings"
 	"time"
 )
 
@@ -47,16 +47,28 @@ func SplitRangeByDays(from time.Time, to time.Time) [][]time.Time {
 	return intervals
 }
 
-func FmtWakatimeDuration(d time.Duration) string {
-	d = d.Round(time.Minute)
-	h := d / time.Hour
-	d -= h * time.Hour
-	m := d / time.Minute
-	return fmt.Sprintf("%d hrs %d mins", h, m)
-}
-
 // LocalTZOffset returns the time difference between server local time and UTC
 func LocalTZOffset() time.Duration {
 	_, offset := time.Now().Zone()
 	return time.Duration(offset * int(time.Second))
 }
+
+func ParseWeekday(s string) time.Weekday {
+	switch strings.ToLower(s) {
+	case "mon", strings.ToLower(time.Monday.String()):
+		return time.Monday
+	case "tue", strings.ToLower(time.Tuesday.String()):
+		return time.Tuesday
+	case "wed", strings.ToLower(time.Wednesday.String()):
+		return time.Wednesday
+	case "thu", strings.ToLower(time.Thursday.String()):
+		return time.Thursday
+	case "fri", strings.ToLower(time.Friday.String()):
+		return time.Friday
+	case "sat", strings.ToLower(time.Saturday.String()):
+		return time.Saturday
+	case "sun", strings.ToLower(time.Sunday.String()):
+		return time.Sunday
+	}
+	return time.Monday
+}
diff --git a/utils/date_test.go b/utils/date_test.go
index 02d85db..a5d676c 100644
--- a/utils/date_test.go
+++ b/utils/date_test.go
@@ -2,7 +2,6 @@ package utils
 
 import (
 	"github.com/duke-git/lancet/v2/datetime"
-	"github.com/muety/wakapi/config"
 	"github.com/stretchr/testify/assert"
 	"testing"
 	"time"
@@ -23,8 +22,8 @@ func init() {
 }
 
 func TestDate_SplitRangeByDays(t *testing.T) {
-	df1, _ := time.Parse(config.SimpleDateTimeFormat, "2021-04-25 20:25:00")
-	dt1, _ := time.Parse(config.SimpleDateTimeFormat, "2021-04-28 06:45:00")
+	df1, _ := time.Parse("2006-01-02 15:04:05", "2021-04-25 20:25:00")
+	dt1, _ := time.Parse("2006-01-02 15:04:05", "2021-04-28 06:45:00")
 	df2 := df1
 	dt2 := datetime.EndOfDay(df1)
 	df3 := df1
diff --git a/utils/http.go b/utils/http.go
index faebb7e..5ee9b29 100644
--- a/utils/http.go
+++ b/utils/http.go
@@ -1,8 +1,7 @@
 package utils
 
 import (
-	"encoding/json"
-	"github.com/muety/wakapi/config"
+	"errors"
 	"github.com/muety/wakapi/models"
 	"net/http"
 	"regexp"
@@ -23,14 +22,6 @@ func init() {
 	cacheMaxAgeRe = regexp.MustCompile(cacheMaxAgePattern)
 }
 
-func RespondJSON(w http.ResponseWriter, r *http.Request, status int, object interface{}) {
-	w.Header().Set("Content-Type", "application/json")
-	w.WriteHeader(status)
-	if err := json.NewEncoder(w).Encode(object); err != nil {
-		config.Log().Request(r).Error("error while writing json response: %v", err)
-	}
-}
-
 func IsNoCache(r *http.Request, cacheTtl time.Duration) bool {
 	cacheControl := r.Header.Get("cache-control")
 	if strings.Contains(cacheControl, "no-cache") {
@@ -67,3 +58,12 @@ func ParsePageParamsWithDefault(r *http.Request, page, size int) *models.PagePar
 	}
 	return pageParams
 }
+
+func ParseUserAgent(ua string) (string, string, error) {
+	re := regexp.MustCompile(`(?iU)^wakatime\/(?:v?[\d+.]+|unset)\s\((\w+)-.*\)\s.+\s([^\/\s]+)-wakatime\/.+$`)
+	groups := re.FindAllStringSubmatch(ua, -1)
+	if len(groups) == 0 || len(groups[0]) != 3 {
+		return "", "", errors.New("failed to parse user agent string")
+	}
+	return groups[0][1], groups[0][2], nil
+}
diff --git a/utils/strings.go b/utils/strings.go
index 3175d79..ef78ffc 100644
--- a/utils/strings.go
+++ b/utils/strings.go
@@ -8,3 +8,23 @@ import (
 func Capitalize(s string) string {
 	return fmt.Sprintf("%s%s", strings.ToUpper(s[:1]), s[1:])
 }
+
+func SplitMulti(s string, delimiters ...string) []string {
+	return strings.FieldsFunc(s, func(r rune) bool {
+		for _, d := range delimiters {
+			if string(r) == d {
+				return true
+			}
+		}
+		return false
+	})
+}
+
+func FindString(needle string, haystack []string, defaultVal string) string {
+	for _, s := range haystack {
+		if s == needle {
+			return s
+		}
+	}
+	return defaultVal
+}