diff --git a/carddav/carddav.go b/carddav/carddav.go
index d0870a0..5165837 100644
--- a/carddav/carddav.go
+++ b/carddav/carddav.go
@@ -11,7 +11,6 @@ import (
 	"strconv"
 	"strings"
 	"sync"
-	"time"
 
 	"github.com/emersion/go-vcard"
 	"github.com/emersion/go-webdav/carddav"
@@ -125,7 +124,7 @@ func (b *backend) toAddressObject(contact *protonmail.Contact, req *carddav.Addr
 
 	return &carddav.AddressObject{
 		Path:    formatAddressObjectPath(contact.ID),
-		ModTime: time.Unix(contact.ModifyTime, 0),
+		ModTime: contact.ModifyTime.Time(),
 		// TODO: stronger ETag
 		ETag: fmt.Sprintf("%x%x", contact.ModifyTime, contact.Size),
 		Card: card,
diff --git a/imap/mailbox.go b/imap/mailbox.go
index a319ded..84bf4f8 100644
--- a/imap/mailbox.go
+++ b/imap/mailbox.go
@@ -234,7 +234,7 @@ func (mbox *mailbox) fetchMessage(isUid bool, id uint32, items []imap.FetchItem)
 		case imap.FetchFlags:
 			fetched.Flags = mbox.fetchFlags(msg)
 		case imap.FetchInternalDate:
-			fetched.InternalDate = time.Unix(msg.Time, 0)
+			fetched.InternalDate = msg.Time.Time()
 		case imap.FetchRFC822Size:
 			fetched.Size = uint32(msg.Size)
 		case imap.FetchUid:
@@ -342,7 +342,7 @@ func (mbox *mailbox) SearchMessages(isUID bool, c *imap.SearchCriteria) ([]uint3
 			}
 		}
 
-		date := time.Unix(msg.Time, 0).Round(24 * time.Hour)
+		date := msg.Time.Time().Round(24 * time.Hour)
 		if !c.Since.IsZero() && !date.After(c.Since) {
 			return nil
 		}
diff --git a/imap/message.go b/imap/message.go
index 43f9e0e..caec096 100644
--- a/imap/message.go
+++ b/imap/message.go
@@ -7,7 +7,6 @@ import (
 	"io"
 	"log"
 	"strings"
-	"time"
 
 	"github.com/emersion/go-imap"
 	"github.com/emersion/go-message"
@@ -68,7 +67,7 @@ func imapAddressList(addresses []*protonmail.MessageAddress) []*imap.Address {
 
 func fetchEnvelope(msg *protonmail.Message) *imap.Envelope {
 	return &imap.Envelope{
-		Date:    time.Unix(msg.Time, 0),
+		Date:    msg.Time.Time(),
 		Subject: msg.Subject,
 		From:    []*imap.Address{imapAddress(msg.Sender)},
 		// TODO: Sender
@@ -212,7 +211,7 @@ func mailAddressList(addresses []*protonmail.MessageAddress) []*mail.Address {
 func messageHeader(msg *protonmail.Message) message.Header {
 	var h mail.Header
 	h.SetContentType("multipart/mixed", nil)
-	h.SetDate(time.Unix(msg.Time, 0))
+	h.SetDate(msg.Time.Time())
 	h.SetSubject(msg.Subject)
 	h.SetAddressList("From", []*mail.Address{mailAddress(msg.Sender)})
 	if len(msg.ReplyTos) > 0 {
diff --git a/protonmail/calendar.go b/protonmail/calendar.go
index 51788b5..62a3999 100644
--- a/protonmail/calendar.go
+++ b/protonmail/calendar.go
@@ -23,8 +23,8 @@ type CalendarEvent struct {
 	ID                string
 	CalendarID        string
 	CalendarKeyPacket string
-	CreateTime        int64
-	LastEditTime      int64
+	CreateTime        Timestamp
+	LastEditTime      Timestamp
 	Author            string
 	Permissions       CalendarEventPermissions
 	SharedKeyPacket   string
diff --git a/protonmail/contacts.go b/protonmail/contacts.go
index 96fcf86..2649aef 100644
--- a/protonmail/contacts.go
+++ b/protonmail/contacts.go
@@ -18,8 +18,8 @@ type Contact struct {
 	Name       string
 	UID        string
 	Size       int
-	CreateTime int64
-	ModifyTime int64
+	CreateTime Timestamp
+	ModifyTime Timestamp
 	LabelIDs   []string
 
 	// Not when using ListContacts
diff --git a/protonmail/events.go b/protonmail/events.go
index 0db5add..562b31f 100644
--- a/protonmail/events.go
+++ b/protonmail/events.go
@@ -53,7 +53,7 @@ type EventMessage struct {
 type EventMessageUpdate struct {
 	Unread       *int
 	Type         *MessageType
-	Time         int64
+	Time         Timestamp
 	IsReplied    *int
 	IsRepliedAll *int
 	IsForwarded  *int
diff --git a/protonmail/messages.go b/protonmail/messages.go
index f43b85d..08e3c3a 100644
--- a/protonmail/messages.go
+++ b/protonmail/messages.go
@@ -62,11 +62,11 @@ type Message struct {
 	Type           MessageType
 	Sender         *MessageAddress
 	ToList         []*MessageAddress
-	Time           int64
+	Time           Timestamp
 	Size           int64
 	NumAttachments int
 	IsEncrypted    MessageEncryption
-	ExpirationTime int64
+	ExpirationTime Timestamp
 	IsReplied      int
 	IsRepliedAll   int
 	IsForwarded    int
diff --git a/protonmail/protonmail.go b/protonmail/protonmail.go
index 3680955..4b35ebc 100644
--- a/protonmail/protonmail.go
+++ b/protonmail/protonmail.go
@@ -9,6 +9,7 @@ import (
 	"io/ioutil"
 	"net/http"
 	"strconv"
+	"time"
 
 	"golang.org/x/crypto/openpgp"
 
@@ -51,6 +52,12 @@ func (err *APIError) Error() string {
 	return fmt.Sprintf("[%v] %v", err.Code, err.Message)
 }
 
+type Timestamp int64
+
+func (t Timestamp) Time() time.Time {
+	return time.Unix(int64(t), 0)
+}
+
 // Client is a ProtonMail API client.
 type Client struct {
 	RootURL    string