diff --git a/config.go b/config.go
index 90f4df8..55ab718 100644
--- a/config.go
+++ b/config.go
@@ -209,6 +209,12 @@ func (config Config) validateAcmeConfig() *Config {
 	acmeEmail := len(config.Connection.Downstream.Tls.Acme.Email) > 0
 
 	if acmeProvider || acmeDomain || acmeEmail {
+		if config.Connection.Downstream.Tls.Acme.GracePeriodDays == 0 {
+			config.Connection.Downstream.Tls.Acme.GracePeriodDays = 30
+		} else if config.Connection.Downstream.Tls.Acme.GracePeriodDays > 30 {
+			config.panic("ACME grace period must be between 1 and 30 days")
+		}
+
 		if len(config.Connection.Downstream.Tls.Cert) > 0 {
 			config.panic("cannot specify TLS cert with ACME configuration, it would be overridden.")
 		}
diff --git a/config_test.go b/config_test.go
index 726c774..261a35e 100644
--- a/config_test.go
+++ b/config_test.go
@@ -284,6 +284,112 @@ func TestValidateAcmeEmail(t *testing.T) {
 	config = config.validateAcmeConfig()
 }
 
+//TestValidateAcmeEmail
+func TestValidateAcmeGracePeriod30(t *testing.T) {
+	config := &Config{
+		Connection: Connection{
+			Downstream: Downstream{
+				Http: Http{Port: 80},
+				Tls: Tls{
+					Acme: Acme{
+						Domains:         []string{"adyntest.com"},
+						Provider:        "letsencrypt",
+						Email:           "noreply@example.org",
+						GracePeriodDays: 30,
+					},
+				},
+			},
+		},
+	}
+
+	config = config.validateAcmeConfig()
+
+	want := 30
+	got := config.Connection.Downstream.Tls.Acme.GracePeriodDays
+	if want != got {
+		t.Errorf("want grace period days %v, got %v", want, got)
+	}
+}
+
+func TestValidateAcmeGracePeriod15(t *testing.T) {
+	config := &Config{
+		Connection: Connection{
+			Downstream: Downstream{
+				Http: Http{Port: 80},
+				Tls: Tls{
+					Acme: Acme{
+						Domains:         []string{"adyntest.com"},
+						Provider:        "letsencrypt",
+						Email:           "noreply@example.org",
+						GracePeriodDays: 15,
+					},
+				},
+			},
+		},
+	}
+
+	config = config.validateAcmeConfig()
+
+	want := 15
+	got := config.Connection.Downstream.Tls.Acme.GracePeriodDays
+	if want != got {
+		t.Errorf("want grace period days %v, got %v", want, got)
+	}
+}
+
+func TestValidateDefaultAcmeGracePeriod(t *testing.T) {
+	config := &Config{
+		Connection: Connection{
+			Downstream: Downstream{
+				Http: Http{Port: 80},
+				Tls: Tls{
+					Acme: Acme{
+						Domains:  []string{"adyntest.com"},
+						Provider: "letsencrypt",
+						Email:    "noreply@example.org",
+					},
+				},
+			},
+		},
+	}
+
+	config = config.validateAcmeConfig()
+
+	want := 30
+	got := config.Connection.Downstream.Tls.Acme.GracePeriodDays
+	if want != got {
+		t.Errorf("want grace period days %v, got %v", want, got)
+	}
+}
+
+func TestValidateAcmeGracePeriodFailsGreater30(t *testing.T) {
+	defer func() {
+		if r := recover(); r == nil {
+			t.Errorf("config should have panicked with 31 days acme grace period")
+		} else {
+			t.Logf("normal config panic for 31 days acme grace period")
+		}
+	}()
+
+	config := &Config{
+		Connection: Connection{
+			Downstream: Downstream{
+				Http: Http{Port: 80},
+				Tls: Tls{
+					Acme: Acme{
+						Domains:         []string{"adyntest.com"},
+						Provider:        "letsencrypt",
+						Email:           "noreply@example.org",
+						GracePeriodDays: 31,
+					},
+				},
+			},
+		},
+	}
+
+	config = config.validateAcmeConfig()
+}
+
 //TestValidateAcmeDomainInvalidLeadingDotFails
 func TestValidateValidateAcmeDomainInvalidLeadingDotFails(t *testing.T) {
 	defer func() {
diff --git a/connection.go b/connection.go
index 4a3e241..1849f63 100644
--- a/connection.go
+++ b/connection.go
@@ -62,6 +62,9 @@ type Acme struct {
 
 	// Email for registration.
 	Email string
+
+	// Number of days before certificate expiry that triggers first renewal attempt
+	GracePeriodDays int
 }
 
 // Upstream connection params for remote servers that are being proxied
diff --git a/integration/j8a4.yml b/integration/j8a4.yml
index 6642655..b779f95 100644
--- a/integration/j8a4.yml
+++ b/integration/j8a4.yml
@@ -15,6 +15,7 @@ connection:
         domains:
           - api.adyntest.com
           - adyntest.com
+        gracePeriodDays: 30
   upstream:
     socketTimeoutSeconds: 10
     readTimeoutSeconds: 30
diff --git a/proxyhandler_test.go b/proxyhandler_test.go
index 59400ec..c7a9807 100644
--- a/proxyhandler_test.go
+++ b/proxyhandler_test.go
@@ -659,7 +659,8 @@ func mockRuntime() *Runtime {
 					},
 					Tls: Tls{
 						Acme: Acme{
-							Domains: []string{"localhost"},
+							Domains:         []string{"localhost"},
+							GracePeriodDays: 30,
 						}},
 				},
 			},
diff --git a/tls.go b/tls.go
index eb40a60..7d17da8 100644
--- a/tls.go
+++ b/tls.go
@@ -46,7 +46,8 @@ type TlsLink struct {
 }
 
 func (t TlsLink) expiresTooCloseForComfort() bool {
-	return time.Duration(t.remainingValidity) <= Days30
+	gracePeriodDays := time.Hour * 24 * time.Duration(Runner.Connection.Downstream.Tls.Acme.GracePeriodDays)
+	return time.Duration(t.remainingValidity) <= gracePeriodDays
 }
 
 func (t TlsLink) expiryLongerThanLegalBrowserMaximum() bool {
diff --git a/tls_test.go b/tls_test.go
index 7dea096..1b10bf9 100644
--- a/tls_test.go
+++ b/tls_test.go
@@ -19,6 +19,7 @@ func TestPDurationAsString(t *testing.T) {
 }
 
 func TestTlsLinkRemainingValidity29DaysTooCloseForComfort(t *testing.T) {
+	Runner = mockRuntime()
 	t1 := TlsLink{remainingValidity: PDuration(time.Hour * 24 * 29)}
 	if !t1.expiresTooCloseForComfort() {
 		t.Errorf("did not fire too close for comfort, but 29 days is")
@@ -26,6 +27,7 @@ func TestTlsLinkRemainingValidity29DaysTooCloseForComfort(t *testing.T) {
 }
 
 func TestTlsLinkRemainingValidity31DaysNotTooCloseForComfort(t *testing.T) {
+	Runner = mockRuntime()
 	t1 := TlsLink{remainingValidity: PDuration(time.Hour * 24 * 31)}
 	if t1.expiresTooCloseForComfort() {
 		t.Errorf("did fire too close for comfort but 31 days is not")
@@ -33,6 +35,7 @@ func TestTlsLinkRemainingValidity31DaysNotTooCloseForComfort(t *testing.T) {
 }
 
 func TestTlsLinkTotalValidity397DaysWithinLegalBrowserPeriod(t *testing.T) {
+	Runner = mockRuntime()
 	t1 := TlsLink{
 		remainingValidity: PDuration(time.Hour * 24 * 397),
 		browserValidity:   PDuration(time.Hour * 24 * 398),
@@ -43,6 +46,7 @@ func TestTlsLinkTotalValidity397DaysWithinLegalBrowserPeriod(t *testing.T) {
 }
 
 func TestTlsLinkTotalValidity399DaysNotWithinLegalBrowserPeriod(t *testing.T) {
+	Runner = mockRuntime()
 	t1 := TlsLink{
 		remainingValidity: PDuration(time.Hour * 24 * 399),
 		browserValidity:   PDuration(time.Hour * 24 * 398),