diff --git a/app.go b/app.go
index a39982f..a45ac26 100644
--- a/app.go
+++ b/app.go
@@ -3,6 +3,7 @@ package main
 import (
 	"github.com/urfave/cli/v2"
 	"gitnet.fr/deblan/expiration-check/checker"
+	"gitnet.fr/deblan/expiration-check/logger"
 	"gitnet.fr/deblan/expiration-check/render"
 )
 
@@ -33,6 +34,11 @@ func App() *cli.App {
 			Value:    "table",
 			Usage:    "output format: table, csv, tsv, html, json, markdown",
 		},
+		&cli.BoolFlag{
+			Name:     "verbose",
+			Aliases:  []string{"v"},
+			Required: false,
+		},
 	}
 
 	return &cli.App{
@@ -45,6 +51,8 @@ func App() *cli.App {
 				Usage:   "Checks certificate",
 				Flags:   flags,
 				Action: func(c *cli.Context) error {
+					logger.Get().SetVerbose(c.Bool("verbose"))
+
 					render.Render(
 						checker.CheckCertificates(c.StringSlice("domain")),
 						30, 14,
@@ -60,6 +68,8 @@ func App() *cli.App {
 				Aliases: []string{"d", "domains"},
 				Flags:   flags,
 				Action: func(c *cli.Context) error {
+					logger.Get().SetVerbose(c.Bool("verbose"))
+
 					render.Render(
 						checker.CheckDomains(c.StringSlice("domain")),
 						30, 14,
diff --git a/checker/certificates.go b/checker/certificates.go
index d0721c6..1ee3caf 100644
--- a/checker/certificates.go
+++ b/checker/certificates.go
@@ -6,6 +6,8 @@ import (
 	"math"
 	"strings"
 	"time"
+
+	"gitnet.fr/deblan/expiration-check/logger"
 )
 
 func FormatDomain(domain string) string {
@@ -26,13 +28,19 @@ func CheckCertificate(domain string) Domain {
 		date := conn.ConnectionState().PeerCertificates[0].NotAfter
 		daysLeft := date.Sub(now).Hours() / 24
 
-		return Domain{
+		d := Domain{
 			Name:     domain,
 			DaysLeft: math.Floor(daysLeft),
 			Date:     date.Format(time.DateTime),
 		}
+
+		logger.Get().Logf(`CheckCertificate: domain="%s" value="%+v"`, domain, d)
+
+		return d
 	}
 
+	logger.Get().Logf("CheckCertificate: domain=%s err=%s", domain, err)
+
 	return Domain{Name: domain, Failed: true}
 }
 
diff --git a/checker/domains.go b/checker/domains.go
index 119d229..1d975e2 100644
--- a/checker/domains.go
+++ b/checker/domains.go
@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/likexian/whois"
+	"gitnet.fr/deblan/expiration-check/logger"
 )
 
 type RdapResponseData struct {
@@ -64,15 +65,23 @@ func RdapCheck(domain, service string) Domain {
 			date, _ := time.Parse(time.RFC3339, event.EventDate)
 			daysLeft := date.Sub(now).Hours() / 24
 
-			return Domain{
+			d := Domain{
 				Name:     domain,
 				DaysLeft: math.Floor(daysLeft),
 				Date:     date.Format(time.DateTime),
 			}
+
+			logger.Get().Logf(`RdapCheck: domain="%s" value="%+v"`, domain, d)
+
+			return d
 		}
 	}
 
-	return Domain{Name: domain, Failed: true}
+	d := Domain{Name: domain, Failed: true}
+
+	logger.Get().Logf(`RdapCheck: domain="%s" value="%+v"`, domain, d)
+
+	return d
 }
 
 func WhoisCheck(domain string) Domain {
@@ -108,16 +117,22 @@ func WhoisCheck(domain string) Domain {
 				if err == nil {
 					daysLeft := date.Sub(now).Hours() / 24
 
-					return Domain{
+					d := Domain{
 						Name:     domain,
 						DaysLeft: math.Floor(daysLeft),
 						Date:     date.Format(time.DateTime),
 					}
+
+					logger.Get().Logf(`WhoisCheck: domain="%s" value="%+v"`, domain, d)
+
+					return d
 				}
 			}
 		}
 	}
 
+	logger.Get().Logf(`WhoisCheck: domain="%s" value="%+v"`, domain, domainFailed)
+
 	return domainFailed
 }
 
@@ -130,8 +145,12 @@ func CheckDomains(domains []string) []Domain {
 		service := services[tld]
 
 		if service != "" {
+			logger.Get().Logf(`CheckDomains: domain="%s" rdap=true whois=false`, domain)
+
 			values = append(values, RdapCheck(domain, service))
 		} else {
+			logger.Get().Logf(`CheckDomains: domain="%s" rdap=false whois=true`, domain)
+
 			values = append(values, WhoisCheck(domain))
 		}
 	}