diff --git a/auth_test.go b/auth_test.go
index 771d634..a2fd727 100644
--- a/auth_test.go
+++ b/auth_test.go
@@ -16,7 +16,7 @@ func TestAuth(t *testing.T) {
 	s := server.New()
 	defer s.Close()
 
-	_, _, err := s.CreateUser("user", []byte("password"))
+	_, _, err := s.CreateUser("user", []byte("pass"))
 	require.NoError(t, err)
 
 	m := proton.New(
@@ -26,14 +26,14 @@ func TestAuth(t *testing.T) {
 	defer m.Close()
 
 	// Create one session.
-	c1, auth1, err := m.NewClientWithLogin(context.Background(), "username", []byte("password"))
+	c1, auth1, err := m.NewClientWithLogin(context.Background(), "user", []byte("pass"))
 	require.NoError(t, err)
 
 	// Revoke all other sessions.
 	require.NoError(t, c1.AuthRevokeAll(context.Background()))
 
 	// Create another session.
-	c2, _, err := m.NewClientWithLogin(context.Background(), "username", []byte("password"))
+	c2, _, err := m.NewClientWithLogin(context.Background(), "user", []byte("pass"))
 	require.NoError(t, err)
 
 	// There should be two sessions.
@@ -61,7 +61,7 @@ func TestAuth_Refresh(t *testing.T) {
 	defer s.Close()
 
 	// Create a user on the server.
-	userID, _, err := s.CreateUser("user", []byte("password"))
+	userID, _, err := s.CreateUser("user", []byte("pass"))
 	require.NoError(t, err)
 
 	// The auth is valid for 4 seconds.
@@ -74,7 +74,7 @@ func TestAuth_Refresh(t *testing.T) {
 	defer m.Close()
 
 	// Create one session for the user.
-	c, auth, err := m.NewClientWithLogin(context.Background(), "username", []byte("password"))
+	c, auth, err := m.NewClientWithLogin(context.Background(), "user", []byte("pass"))
 	require.NoError(t, err)
 	require.Equal(t, userID, auth.UserID)
 
@@ -85,7 +85,7 @@ func TestAuth_Refresh(t *testing.T) {
 	{
 		user, err := c.GetUser(context.Background())
 		require.NoError(t, err)
-		require.Equal(t, "username", user.Name)
+		require.Equal(t, "user", user.Name)
 		require.Equal(t, userID, user.ID)
 	}
 
@@ -96,7 +96,7 @@ func TestAuth_Refresh(t *testing.T) {
 	{
 		user, err := c.GetUser(context.Background())
 		require.NoError(t, err)
-		require.Equal(t, "username", user.Name)
+		require.Equal(t, "user", user.Name)
 		require.Equal(t, userID, user.ID)
 	}
 }
@@ -106,7 +106,7 @@ func TestAuth_Refresh_Multi(t *testing.T) {
 	defer s.Close()
 
 	// Create a user on the server.
-	userID, _, err := s.CreateUser("user", []byte("password"))
+	userID, _, err := s.CreateUser("user", []byte("pass"))
 	require.NoError(t, err)
 
 	// The auth is valid for 4 seconds.
@@ -118,7 +118,7 @@ func TestAuth_Refresh_Multi(t *testing.T) {
 	)
 	defer m.Close()
 
-	c, auth, err := m.NewClientWithLogin(context.Background(), "username", []byte("password"))
+	c, auth, err := m.NewClientWithLogin(context.Background(), "user", []byte("pass"))
 	require.NoError(t, err)
 	require.Equal(t, userID, auth.UserID)
 
@@ -128,7 +128,7 @@ func TestAuth_Refresh_Multi(t *testing.T) {
 	parallel.Do(runtime.NumCPU(), 100, func(idx int) {
 		user, err := c.GetUser(context.Background())
 		require.NoError(t, err)
-		require.Equal(t, "username", user.Name)
+		require.Equal(t, "user", user.Name)
 		require.Equal(t, userID, user.ID)
 	})
 
@@ -139,7 +139,7 @@ func TestAuth_Refresh_Multi(t *testing.T) {
 	parallel.Do(runtime.NumCPU(), 100, func(idx int) {
 		user, err := c.GetUser(context.Background())
 		require.NoError(t, err)
-		require.Equal(t, "username", user.Name)
+		require.Equal(t, "user", user.Name)
 		require.Equal(t, userID, user.ID)
 	})
 }
@@ -149,7 +149,7 @@ func TestAuth_Refresh_Deauth(t *testing.T) {
 	defer s.Close()
 
 	// Create a user on the server.
-	userID, _, err := s.CreateUser("user", []byte("password"))
+	userID, _, err := s.CreateUser("user", []byte("pass"))
 	require.NoError(t, err)
 
 	m := proton.New(
@@ -159,7 +159,7 @@ func TestAuth_Refresh_Deauth(t *testing.T) {
 	defer m.Close()
 
 	// Create one session for the user.
-	c, auth, err := m.NewClientWithLogin(context.Background(), "username", []byte("password"))
+	c, auth, err := m.NewClientWithLogin(context.Background(), "user", []byte("pass"))
 	require.NoError(t, err)
 	require.Equal(t, userID, auth.UserID)
 
@@ -172,7 +172,7 @@ func TestAuth_Refresh_Deauth(t *testing.T) {
 	{
 		user, err := c.GetUser(context.Background())
 		require.NoError(t, err)
-		require.Equal(t, "username", user.Name)
+		require.Equal(t, "user", user.Name)
 		require.Equal(t, userID, user.ID)
 	}
 
diff --git a/dialer.go b/dialer.go
deleted file mode 100644
index 66c8eb1..0000000
--- a/dialer.go
+++ /dev/null
@@ -1,311 +0,0 @@
-package proton
-
-import (
-	"context"
-	"crypto/tls"
-	"errors"
-	"fmt"
-	"io"
-	"net"
-	"net/http"
-	"sync"
-)
-
-func InsecureTransport() *http.Transport {
-	return &http.Transport{
-		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
-	}
-}
-
-// NetCtl can be used to control whether a dialer can dial, and whether the resulting
-// connection can read or write.
-type NetCtl struct {
-	canDial   atomicBool
-	dialLimit atomicUint64
-
-	canRead   atomicBool
-	readLimit atomicUint64
-
-	canWrite   atomicBool
-	writeLimit atomicUint64
-
-	onDial  []func(net.Conn)
-	onRead  []func([]byte)
-	onWrite []func([]byte)
-
-	lock sync.Mutex
-}
-
-// NewNetCtl returns a new NetCtl with all fields set to true.
-func NewNetCtl() *NetCtl {
-	return &NetCtl{
-		canDial:  atomicBool{b32(true)},
-		canRead:  atomicBool{b32(true)},
-		canWrite: atomicBool{b32(true)},
-	}
-}
-
-// SetCanDial sets whether the dialer can dial.
-func (c *NetCtl) SetCanDial(canDial bool) {
-	c.canDial.Store(canDial)
-}
-
-// SetDialLimit sets the maximum number of times dialers using this controller can dial.
-func (c *NetCtl) SetDialLimit(limit uint64) {
-	c.dialLimit.Store(limit)
-}
-
-// SetCanRead sets whether the connection can read.
-func (c *NetCtl) SetCanRead(canRead bool) {
-	c.canRead.Store(canRead)
-}
-
-// SetReadLimit sets the maximum number of bytes that can be read.
-func (c *NetCtl) SetReadLimit(limit uint64) {
-	c.readLimit.Store(limit)
-}
-
-// SetCanWrite sets whether the connection can write.
-func (c *NetCtl) SetCanWrite(canWrite bool) {
-	c.canWrite.Store(canWrite)
-}
-
-// SetWriteLimit sets the maximum number of bytes that can be written.
-func (c *NetCtl) SetWriteLimit(limit uint64) {
-	c.writeLimit.Store(limit)
-}
-
-// OnDial adds a callback that is called with the created connection when a dial is successful.
-func (c *NetCtl) OnDial(f func(net.Conn)) {
-	c.lock.Lock()
-	defer c.lock.Unlock()
-
-	c.onDial = append(c.onDial, f)
-}
-
-// OnRead adds a callback that is called with the read bytes when a read is successful.
-func (c *NetCtl) OnRead(f func([]byte)) {
-	c.lock.Lock()
-	defer c.lock.Unlock()
-
-	c.onRead = append(c.onRead, f)
-}
-
-// OnWrite adds a callback that is called with the written bytes when a write is successful.
-func (c *NetCtl) OnWrite(f func([]byte)) {
-	c.lock.Lock()
-	defer c.lock.Unlock()
-
-	c.onWrite = append(c.onWrite, f)
-}
-
-// Disable is equivalent to disallowing dial, read and write.
-func (c *NetCtl) Disable() {
-	c.SetCanDial(false)
-	c.SetCanRead(false)
-	c.SetCanWrite(false)
-}
-
-// Enable is equivalent to allowing dial, read and write.
-func (c *NetCtl) Enable() {
-	c.SetCanDial(true)
-	c.SetCanRead(true)
-	c.SetCanWrite(true)
-}
-
-// Conn is a wrapper around net.Conn that can be used to control whether a connection can read or write.
-type Conn struct {
-	net.Conn
-
-	ctl *NetCtl
-
-	readLimiter  *readLimiter
-	writeLimiter *writeLimiter
-}
-
-// Read reads from the wrapped connection, but only if the controller allows it.
-func (c *Conn) Read(b []byte) (int, error) {
-	if !c.ctl.canRead.Load() {
-		return 0, errors.New("cannot read")
-	}
-
-	n, err := c.readLimiter.read(c.Conn, b)
-	if err != nil {
-		return n, err
-	}
-
-	for _, f := range c.ctl.onRead {
-		f(b[:n])
-	}
-
-	return n, err
-}
-
-// Write writes to the wrapped connection, but only if the controller allows it.
-func (c *Conn) Write(b []byte) (int, error) {
-	if !c.ctl.canWrite.Load() {
-		return 0, errors.New("cannot write")
-	}
-
-	n, err := c.writeLimiter.write(c.Conn, b)
-	if err != nil {
-		return n, err
-	}
-
-	for _, f := range c.ctl.onWrite {
-		f(b[:n])
-	}
-
-	return n, err
-}
-
-// Dialer performs network dialing, but only if the controller allows it.
-type Dialer struct {
-	ctl *NetCtl
-
-	netDialer *net.Dialer
-	tlsDialer *tls.Dialer
-	tlsConfig *tls.Config
-
-	readLimiter  *readLimiter
-	writeLimiter *writeLimiter
-
-	dialCount atomicUint64
-}
-
-// NewDialer returns a new dialer using the given net controller.
-// It optionally uses a provided tls config.
-func NewDialer(ctl *NetCtl, tlsConfig *tls.Config) *Dialer {
-	return &Dialer{
-		ctl: ctl,
-
-		netDialer: &net.Dialer{},
-		tlsDialer: &tls.Dialer{Config: tlsConfig},
-		tlsConfig: tlsConfig,
-
-		readLimiter:  newReadLimiter(ctl),
-		writeLimiter: newWriteLimiter(ctl),
-
-		dialCount: atomicUint64{0},
-	}
-}
-
-// DialContext dials a network connection, but only if the controller allows it.
-func (d *Dialer) DialContext(ctx context.Context, network, addr string) (net.Conn, error) {
-	return d.dialWithDialer(ctx, network, addr, d.netDialer)
-}
-
-// DialTLSContext dials a TLS network connection, but only if the controller allows it.
-func (d *Dialer) DialTLSContext(ctx context.Context, network, addr string) (net.Conn, error) {
-	return d.dialWithDialer(ctx, network, addr, d.tlsDialer)
-}
-
-// dialWithDialer dials a network connection using the given dialer, but only if the controller allows it.
-func (d *Dialer) dialWithDialer(ctx context.Context, network, addr string, dialer dialer) (net.Conn, error) {
-	if !d.ctl.canDial.Load() {
-		return nil, errors.New("cannot dial")
-	}
-
-	if limit := d.ctl.dialLimit.Load(); limit > 0 && d.dialCount.Load() >= limit {
-		return nil, errors.New("dial limit reached")
-	} else {
-		d.dialCount.Add(1)
-	}
-
-	conn, err := dialer.DialContext(ctx, network, addr)
-	if err != nil {
-		return nil, err
-	}
-
-	d.ctl.lock.Lock()
-	defer d.ctl.lock.Unlock()
-
-	for _, f := range d.ctl.onDial {
-		f(conn)
-	}
-
-	return &Conn{
-		Conn: conn,
-		ctl:  d.ctl,
-
-		readLimiter:  d.readLimiter,
-		writeLimiter: d.writeLimiter,
-	}, nil
-}
-
-// GetRoundTripper returns a new http.RoundTripper that uses the dialer.
-func (d *Dialer) GetRoundTripper() http.RoundTripper {
-	return &http.Transport{
-		DialContext:     d.DialContext,
-		DialTLSContext:  d.DialTLSContext,
-		TLSClientConfig: d.tlsConfig,
-	}
-}
-
-type dialer interface {
-	DialContext(ctx context.Context, network, addr string) (net.Conn, error)
-}
-
-type readLimiter struct {
-	ctl *NetCtl
-
-	count atomicUint64
-}
-
-// newReadLimiter returns a new io.Reader that reads from r, but only up to limit bytes.
-func newReadLimiter(ctl *NetCtl) *readLimiter {
-	return &readLimiter{
-		ctl: ctl,
-	}
-}
-
-func (limiter *readLimiter) read(r io.Reader, b []byte) (int, error) {
-	if limit := limiter.ctl.readLimit.Load(); limit > 0 && limiter.count.Load() >= limit {
-		return 0, fmt.Errorf("refusing to read: read limit reached")
-	}
-
-	n, err := r.Read(b)
-	if err != nil {
-		return n, err
-	}
-
-	if limit := limiter.ctl.readLimit.Load(); limit > 0 {
-		if new := limiter.count.Add(uint64(n)); new >= limit {
-			return 0, fmt.Errorf("read failed: read limit reached")
-		}
-	}
-
-	return n, err
-}
-
-type writeLimiter struct {
-	ctl *NetCtl
-
-	count atomicUint64
-}
-
-// newWriteLimiter returns a new io.Writer that writes to w, but only up to limit bytes.
-func newWriteLimiter(ctl *NetCtl) *writeLimiter {
-	return &writeLimiter{
-		ctl: ctl,
-	}
-}
-
-func (limiter *writeLimiter) write(w io.Writer, b []byte) (int, error) {
-	if limit := limiter.ctl.writeLimit.Load(); limit > 0 && limiter.count.Load() >= limit {
-		return 0, fmt.Errorf("refusing to write: write limit reached")
-	}
-
-	n, err := w.Write(b)
-	if err != nil {
-		return n, err
-	}
-
-	if limit := limiter.ctl.writeLimit.Load(); limit > 0 {
-		if new := limiter.count.Add(uint64(n)); new >= limit {
-			return 0, fmt.Errorf("write failed: write limit reached")
-		}
-	}
-
-	return n, err
-}
diff --git a/event_test.go b/event_test.go
index 3bf6e14..087f798 100644
--- a/event_test.go
+++ b/event_test.go
@@ -22,13 +22,13 @@ func TestEventStreamer(t *testing.T) {
 		proton.WithTransport(proton.InsecureTransport()),
 	)
 
-	_, _, err := s.CreateUser("user", []byte("password"))
+	_, _, err := s.CreateUser("user", []byte("pass"))
 	require.NoError(t, err)
 
-	c, _, err := m.NewClientWithLogin(ctx, "username", []byte("password"))
+	c, _, err := m.NewClientWithLogin(ctx, "user", []byte("pass"))
 	require.NoError(t, err)
 
-	createTestMessages(t, c, "password", 10)
+	createTestMessages(t, c, "pass", 10)
 
 	latestEventID, err := c.GetLatestEventID(ctx)
 	require.NoError(t, err)
@@ -53,7 +53,7 @@ func TestEventStreamer(t *testing.T) {
 	c.Close()
 
 	// Create a new client and perform some actions with it to generate more events.
-	cc, _, err := m.NewClientWithLogin(ctx, "username", []byte("password"))
+	cc, _, err := m.NewClientWithLogin(ctx, "user", []byte("pass"))
 	require.NoError(t, err)
 	defer cc.Close()
 
diff --git a/manager_status_test.go b/manager_status_test.go
index 9184ef2..ac22a78 100644
--- a/manager_status_test.go
+++ b/manager_status_test.go
@@ -15,11 +15,11 @@ func TestStatus(t *testing.T) {
 	s := server.New()
 	defer s.Close()
 
-	netCtl := proton.NewNetCtl()
+	ctl := proton.NewNetCtl()
 
 	m := proton.New(
 		proton.WithHostURL(s.GetHostURL()),
-		proton.WithTransport(proton.NewDialer(netCtl, &tls.Config{InsecureSkipVerify: true}).GetRoundTripper()),
+		proton.WithTransport(ctl.NewRoundTripper(&tls.Config{InsecureSkipVerify: true})),
 	)
 
 	var (
@@ -39,7 +39,7 @@ func TestStatus(t *testing.T) {
 	require.Zero(t, called)
 
 	// Now we simulate a network failure.
-	netCtl.Disable()
+	ctl.Disable()
 
 	// This should fail.
 	require.Error(t, m.Ping(context.Background()))
@@ -49,7 +49,7 @@ func TestStatus(t *testing.T) {
 	require.Equal(t, proton.StatusDown, status)
 
 	// Now we simulate a network restoration.
-	netCtl.Enable()
+	ctl.Enable()
 
 	// This should succeed.
 	require.NoError(t, m.Ping(context.Background()))
@@ -63,11 +63,11 @@ func TestStatus_NoDial(t *testing.T) {
 	s := server.New()
 	defer s.Close()
 
-	netCtl := proton.NewNetCtl()
+	ctl := proton.NewNetCtl()
 
 	m := proton.New(
 		proton.WithHostURL(s.GetHostURL()),
-		proton.WithTransport(proton.NewDialer(netCtl, &tls.Config{InsecureSkipVerify: true}).GetRoundTripper()),
+		proton.WithTransport(ctl.NewRoundTripper(&tls.Config{InsecureSkipVerify: true})),
 	)
 
 	var (
@@ -81,7 +81,7 @@ func TestStatus_NoDial(t *testing.T) {
 	})
 
 	// Disable dialing.
-	netCtl.SetCanDial(false)
+	ctl.SetCanDial(false)
 
 	// This should fail.
 	require.Error(t, m.Ping(context.Background()))
@@ -95,11 +95,11 @@ func TestStatus_NoRead(t *testing.T) {
 	s := server.New()
 	defer s.Close()
 
-	netCtl := proton.NewNetCtl()
+	ctl := proton.NewNetCtl()
 
 	m := proton.New(
 		proton.WithHostURL(s.GetHostURL()),
-		proton.WithTransport(proton.NewDialer(netCtl, &tls.Config{InsecureSkipVerify: true}).GetRoundTripper()),
+		proton.WithTransport(ctl.NewRoundTripper(&tls.Config{InsecureSkipVerify: true})),
 	)
 
 	var (
@@ -113,7 +113,7 @@ func TestStatus_NoRead(t *testing.T) {
 	})
 
 	// Disable reading.
-	netCtl.SetCanRead(false)
+	ctl.SetCanRead(false)
 
 	// This should fail.
 	require.Error(t, m.Ping(context.Background()))
@@ -127,11 +127,11 @@ func TestStatus_NoWrite(t *testing.T) {
 	s := server.New()
 	defer s.Close()
 
-	netCtl := proton.NewNetCtl()
+	ctl := proton.NewNetCtl()
 
 	m := proton.New(
 		proton.WithHostURL(s.GetHostURL()),
-		proton.WithTransport(proton.NewDialer(netCtl, &tls.Config{InsecureSkipVerify: true}).GetRoundTripper()),
+		proton.WithTransport(ctl.NewRoundTripper(&tls.Config{InsecureSkipVerify: true})),
 	)
 
 	var (
@@ -145,7 +145,7 @@ func TestStatus_NoWrite(t *testing.T) {
 	})
 
 	// Disable writing.
-	netCtl.SetCanWrite(false)
+	ctl.SetCanWrite(false)
 
 	// This should fail.
 	require.Error(t, m.Ping(context.Background()))
@@ -162,17 +162,17 @@ func TestStatus_NoReadExistingConn(t *testing.T) {
 	_, _, err := s.CreateUser("user", []byte("pass"))
 	require.NoError(t, err)
 
-	netCtl := proton.NewNetCtl()
+	ctl := proton.NewNetCtl()
 
 	var dialed int
 
-	netCtl.OnDial(func(net.Conn) {
+	ctl.OnDial(func(net.Conn) {
 		dialed++
 	})
 
 	m := proton.New(
 		proton.WithHostURL(s.GetHostURL()),
-		proton.WithTransport(proton.NewDialer(netCtl, &tls.Config{InsecureSkipVerify: true}).GetRoundTripper()),
+		proton.WithTransport(ctl.NewRoundTripper(&tls.Config{InsecureSkipVerify: true})),
 	)
 
 	// This should succeed.
@@ -184,13 +184,10 @@ func TestStatus_NoReadExistingConn(t *testing.T) {
 	require.Equal(t, 1, dialed)
 
 	// Disable reading on the existing connection.
-	netCtl.SetCanRead(false)
+	ctl.SetCanRead(false)
 
 	// This should fail because we won't be able to read the response.
 	require.Error(t, getErr(c.GetUser(context.Background())))
-
-	// We should still have dialed once; the connection should have been reused.
-	require.Equal(t, 1, dialed)
 }
 
 func TestStatus_NoWriteExistingConn(t *testing.T) {
@@ -200,17 +197,17 @@ func TestStatus_NoWriteExistingConn(t *testing.T) {
 	_, _, err := s.CreateUser("user", []byte("pass"))
 	require.NoError(t, err)
 
-	netCtl := proton.NewNetCtl()
+	ctl := proton.NewNetCtl()
 
 	var dialed int
 
-	netCtl.OnDial(func(net.Conn) {
+	ctl.OnDial(func(net.Conn) {
 		dialed++
 	})
 
 	m := proton.New(
 		proton.WithHostURL(s.GetHostURL()),
-		proton.WithTransport(proton.NewDialer(netCtl, &tls.Config{InsecureSkipVerify: true}).GetRoundTripper()),
+		proton.WithTransport(ctl.NewRoundTripper(&tls.Config{InsecureSkipVerify: true})),
 		proton.WithRetryCount(0),
 	)
 
@@ -223,7 +220,7 @@ func TestStatus_NoWriteExistingConn(t *testing.T) {
 	require.Equal(t, 1, dialed)
 
 	// Disable reading on the existing connection.
-	netCtl.SetCanWrite(false)
+	ctl.SetCanWrite(false)
 
 	// This should fail because we won't be able to write the request.
 	require.Error(t, c.LabelMessages(context.Background(), []string{"messageID"}, proton.TrashLabel))
@@ -240,7 +237,7 @@ func TestStatus_ContextCancel(t *testing.T) {
 
 	var called int
 
-	m.AddStatusObserver(func(val proton.Status) {
+	m.AddStatusObserver(func(proton.Status) {
 		called++
 	})
 
@@ -263,7 +260,7 @@ func TestStatus_ContextTimeout(t *testing.T) {
 
 	var called int
 
-	m.AddStatusObserver(func(val proton.Status) {
+	m.AddStatusObserver(func(proton.Status) {
 		called++
 	})
 
diff --git a/manager_test.go b/manager_test.go
index f599d51..269b8cd 100644
--- a/manager_test.go
+++ b/manager_test.go
@@ -4,16 +4,15 @@ import (
 	"context"
 	"crypto/tls"
 	"errors"
-	"fmt"
 	"net"
 	"net/http"
 	"net/http/httptest"
+	"strconv"
 	"testing"
 	"time"
 
 	"github.com/ProtonMail/go-proton-api"
 	"github.com/ProtonMail/go-proton-api/server"
-	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
@@ -21,17 +20,17 @@ func TestConnectionReuse(t *testing.T) {
 	s := server.New()
 	defer s.Close()
 
-	netCtl := proton.NewNetCtl()
+	ctl := proton.NewNetCtl()
 
 	var dialed int
 
-	netCtl.OnDial(func(net.Conn) {
+	ctl.OnDial(func(net.Conn) {
 		dialed++
 	})
 
 	m := proton.New(
 		proton.WithHostURL(s.GetHostURL()),
-		proton.WithTransport(proton.NewDialer(netCtl, &tls.Config{InsecureSkipVerify: true}).GetRoundTripper()),
+		proton.WithTransport(ctl.NewRoundTripper(&tls.Config{InsecureSkipVerify: true})),
 	)
 
 	// This should succeed; the resulting connection should be reused.
@@ -69,89 +68,70 @@ func TestAuthRefresh(t *testing.T) {
 }
 
 func TestHandleTooManyRequests(t *testing.T) {
-	var numCalls int
+	// Create a server with a rate limit of 1 request per second.
+	s := server.New(server.WithRateLimit(1, time.Second))
+	defer s.Close()
 
-	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		numCalls++
+	var calls []server.Call
 
-		if numCalls < 5 {
-			w.WriteHeader(http.StatusTooManyRequests)
-		} else {
-			w.WriteHeader(http.StatusOK)
-		}
-	}))
-	defer ts.Close()
+	// Watch the calls made.
+	s.AddCallWatcher(func(call server.Call) {
+		calls = append(calls, call)
+	})
 
 	m := proton.New(
-		proton.WithHostURL(ts.URL),
-		proton.WithRetryCount(5),
+		proton.WithHostURL(s.GetHostURL()),
+		proton.WithTransport(proton.InsecureTransport()),
 	)
+	defer m.Close()
 
-	// The call should succeed because the 5th retry should succeed (429s are retried).
-	c := m.NewClient("", "", "")
-	defer c.Close()
-
-	if _, err := c.GetAddresses(context.Background()); err != nil {
-		t.Fatal("got unexpected error", err)
+	// Make five calls; they should all succeed, but will be rate limited.
+	for i := 0; i < 5; i++ {
+		require.NoError(t, m.Ping(context.Background()))
 	}
 
-	// The server should be called 5 times.
-	// The first four calls should return 429 and the last call should return 200.
-	if numCalls != 5 {
-		t.Fatal("expected numCalls to be 5, instead got", numCalls)
+	// After each 429 response, we should wait at least the requested duration before making the next request.
+	for idx, call := range calls {
+		if call.Status == http.StatusTooManyRequests {
+			after, err := strconv.Atoi(call.ResponseHeader.Get("Retry-After"))
+			require.NoError(t, err)
+
+			// The next call should be made after the requested duration.
+			require.True(t, calls[idx+1].Time.After(call.Time.Add(time.Duration(after)*time.Second)))
+		}
 	}
 }
 
-func TestHandleTooManyRequestsRetryAfter(t *testing.T) {
-	getDelay := func(iCal int) time.Duration {
-		return time.Duration(5*1<<iCal) * time.Second
-	}
+func TestHandleTooManyRequests_Malformed(t *testing.T) {
+	var calls []time.Time
 
-	iRetry := -1
-	lastCall := time.Now()
-
-	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		currentCall := time.Now()
-
-		if iRetry >= 0 {
-			delay := getDelay(iRetry)
-			assert.False(t, currentCall.Before(
-				lastCall.Add(delay)),
-				"Delay was %v but expected to have %v",
-				currentCall.Sub(lastCall),
-				delay,
-			)
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		if len(calls) == 0 {
+			w.Header().Set("Retry-After", "malformed")
+			w.WriteHeader(http.StatusTooManyRequests)
 		}
 
-		iRetry++
-		lastCall = currentCall
-
-		// test defaul 10sec
-		if iRetry == 1 {
-			w.Header().Set("Retry-After", "something")
-		} else {
-			w.Header().Set("Retry-After", fmt.Sprintf("%.0f", getDelay(iRetry).Seconds()))
-		}
-		w.WriteHeader(http.StatusTooManyRequests)
+		calls = append(calls, time.Now())
 	}))
 	defer ts.Close()
 
-	m := proton.New(
-		proton.WithHostURL(ts.URL),
-		proton.WithRetryCount(3),
-	)
+	m := proton.New(proton.WithHostURL(ts.URL))
+	defer m.Close()
 
-	c := m.NewClient("", "", "")
-	defer c.Close()
+	require.NoError(t, m.Ping(context.Background()))
 
-	_, err := c.GetAddresses(context.Background())
-	require.Error(t, err)
+	// The first call should fail because the Retry-After header is invalid.
+	// The second call should succeed.
+	require.Len(t, calls, 2)
+
+	// The second call should be made at least 10 seconds after the first call.
+	require.True(t, calls[1].After(calls[0].Add(10*time.Second)))
 }
 
 func TestHandleUnprocessableEntity(t *testing.T) {
 	var numCalls int
 
-	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 		numCalls++
 		w.WriteHeader(http.StatusUnprocessableEntity)
 	}))
@@ -180,7 +160,7 @@ func TestHandleUnprocessableEntity(t *testing.T) {
 func TestHandleDialFailure(t *testing.T) {
 	var numCalls int
 
-	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 		numCalls++
 		w.WriteHeader(http.StatusOK)
 	}))
@@ -210,7 +190,7 @@ func TestHandleDialFailure(t *testing.T) {
 func TestHandleTooManyDialFailures(t *testing.T) {
 	var numCalls int
 
-	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 		numCalls++
 		w.WriteHeader(http.StatusOK)
 	}))
@@ -242,7 +222,7 @@ func TestHandleTooManyDialFailures(t *testing.T) {
 func TestRetriesWithContextTimeout(t *testing.T) {
 	var numCalls int
 
-	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 		numCalls++
 
 		if numCalls < 5 {
@@ -276,7 +256,7 @@ func TestRetriesWithContextTimeout(t *testing.T) {
 }
 
 func TestReturnErrNoConnection(t *testing.T) {
-	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 		w.WriteHeader(http.StatusOK)
 	}))
 	defer ts.Close()
@@ -305,7 +285,7 @@ func TestStatusCallbacks(t *testing.T) {
 
 	m := proton.New(
 		proton.WithHostURL(s.GetHostURL()),
-		proton.WithTransport(proton.NewDialer(ctl, &tls.Config{InsecureSkipVerify: true}).GetRoundTripper()),
+		proton.WithTransport(ctl.NewRoundTripper(&tls.Config{InsecureSkipVerify: true})),
 	)
 
 	statusCh := make(chan proton.Status, 1)
diff --git a/netctl.go b/netctl.go
new file mode 100644
index 0000000..ee8b3f1
--- /dev/null
+++ b/netctl.go
@@ -0,0 +1,398 @@
+package proton
+
+import (
+	"context"
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"sync"
+	"time"
+)
+
+// InsecureTransport returns an http.Transport with InsecureSkipVerify set to true.
+func InsecureTransport() *http.Transport {
+	return &http.Transport{
+		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
+	}
+}
+
+// ctl can be used to control whether a dialer can dial, and whether the resulting
+// connection can read or write.
+type NetCtl struct {
+	canDial   bool
+	dialLimit uint64
+	dialCount uint64
+	onDial    []func(net.Conn)
+	dlock     sync.RWMutex
+
+	canRead   bool
+	readLimit uint64
+	readCount uint64
+	readSpeed int
+	onRead    []func([]byte)
+	rlock     sync.RWMutex
+
+	canWrite   bool
+	writeLimit uint64
+	writeCount uint64
+	writeSpeed int
+	onWrite    []func([]byte)
+	wlock      sync.RWMutex
+
+	conns []net.Conn
+}
+
+// NewNetCtl returns a new ctl with all fields set to true.
+func NewNetCtl() *NetCtl {
+	return &NetCtl{
+		canDial:  true,
+		canRead:  true,
+		canWrite: true,
+	}
+}
+
+// SetCanDial sets whether the dialer can dial.
+func (c *NetCtl) SetCanDial(canDial bool) {
+	c.dlock.Lock()
+	defer c.dlock.Unlock()
+
+	c.canDial = canDial
+}
+
+// SetDialLimit sets the maximum number of times dialers using this controller can dial.
+func (c *NetCtl) SetDialLimit(limit uint64) {
+	c.dlock.Lock()
+	defer c.dlock.Unlock()
+
+	c.dialLimit = limit
+}
+
+// SetCanRead sets whether the connection can read.
+func (c *NetCtl) SetCanRead(canRead bool) {
+	c.dlock.Lock()
+	defer c.dlock.Unlock()
+
+	for _, conn := range c.conns {
+		conn.Close()
+	}
+
+	c.rlock.Lock()
+	defer c.rlock.Unlock()
+
+	c.canRead = canRead
+}
+
+// SetReadLimit sets the maximum number of bytes that can be read.
+func (c *NetCtl) SetReadLimit(limit uint64) {
+	c.dlock.Lock()
+	defer c.dlock.Unlock()
+
+	for _, conn := range c.conns {
+		conn.Close()
+	}
+
+	c.rlock.Lock()
+	defer c.rlock.Unlock()
+
+	c.readLimit = limit
+	c.readCount = 0
+}
+
+// SetReadSpeed sets the maximum number of bytes that can be read per second.
+func (c *NetCtl) SetReadSpeed(speed int) {
+	c.dlock.Lock()
+	defer c.dlock.Unlock()
+
+	for _, conn := range c.conns {
+		conn.Close()
+	}
+
+	c.rlock.Lock()
+	defer c.rlock.Unlock()
+
+	c.readSpeed = speed
+}
+
+// SetCanWrite sets whether the connection can write.
+func (c *NetCtl) SetCanWrite(canWrite bool) {
+	c.dlock.Lock()
+	defer c.dlock.Unlock()
+
+	for _, conn := range c.conns {
+		conn.Close()
+	}
+
+	c.wlock.Lock()
+	defer c.wlock.Unlock()
+
+	c.canWrite = canWrite
+}
+
+// SetWriteLimit sets the maximum number of bytes that can be written.
+func (c *NetCtl) SetWriteLimit(limit uint64) {
+	c.dlock.Lock()
+	defer c.dlock.Unlock()
+
+	for _, conn := range c.conns {
+		conn.Close()
+	}
+
+	c.wlock.Lock()
+	defer c.wlock.Unlock()
+
+	c.writeLimit = limit
+	c.writeCount = 0
+}
+
+// SetWriteSpeed sets the maximum number of bytes that can be written per second.
+func (c *NetCtl) SetWriteSpeed(speed int) {
+	c.dlock.Lock()
+	defer c.dlock.Unlock()
+
+	for _, conn := range c.conns {
+		conn.Close()
+	}
+
+	c.wlock.Lock()
+	defer c.wlock.Unlock()
+
+	c.writeSpeed = speed
+}
+
+// OnDial adds a callback that is called with the created connection when a dial is successful.
+func (c *NetCtl) OnDial(f func(net.Conn)) {
+	c.dlock.Lock()
+	defer c.dlock.Unlock()
+
+	c.onDial = append(c.onDial, f)
+}
+
+// OnRead adds a callback that is called with the read bytes when a read is successful.
+func (c *NetCtl) OnRead(fn func([]byte)) {
+	c.rlock.Lock()
+	defer c.rlock.Unlock()
+
+	c.onRead = append(c.onRead, fn)
+}
+
+// OnWrite adds a callback that is called with the written bytes when a write is successful.
+func (c *NetCtl) OnWrite(fn func([]byte)) {
+	c.wlock.Lock()
+	defer c.wlock.Unlock()
+
+	c.onWrite = append(c.onWrite, fn)
+}
+
+// Disable is equivalent to disallowing dial, read and write.
+func (c *NetCtl) Disable() {
+	c.SetCanDial(false)
+	c.SetCanRead(false)
+	c.SetCanWrite(false)
+}
+
+// Enable is equivalent to allowing dial, read and write.
+func (c *NetCtl) Enable() {
+	c.SetCanDial(true)
+	c.SetCanRead(true)
+	c.SetCanWrite(true)
+}
+
+// NewDialer returns a new dialer controlled by the ctl.
+func (c *NetCtl) NewRoundTripper(tlsConfig *tls.Config) http.RoundTripper {
+	return &http.Transport{
+		DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
+			return c.dial(ctx, &net.Dialer{}, network, addr)
+		},
+		DialTLSContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
+			return c.dial(ctx, &tls.Dialer{Config: tlsConfig}, network, addr)
+		},
+		TLSClientConfig: tlsConfig,
+	}
+}
+
+// ctxDialer implements DialContext.
+type ctxDialer interface {
+	DialContext(ctx context.Context, network, addr string) (net.Conn, error)
+}
+
+// dial dials using d, but only if the controller allows it.
+func (c *NetCtl) dial(ctx context.Context, dialer ctxDialer, network, addr string) (net.Conn, error) {
+	c.dlock.Lock()
+	defer c.dlock.Unlock()
+
+	if !c.canDial {
+		return nil, errors.New("dial failed (not allowed)")
+	}
+
+	if c.dialLimit > 0 && c.dialCount >= c.dialLimit {
+		return nil, errors.New("dial failed (limit reached)")
+	}
+
+	conn, err := dialer.DialContext(ctx, network, addr)
+	if err != nil {
+		return nil, err
+	}
+
+	c.dialCount++
+
+	for _, fn := range c.onDial {
+		fn(conn)
+	}
+
+	c.conns = append(c.conns, conn)
+
+	return newConn(conn, c), nil
+}
+
+// read reads from r, but only if the controller allows it.
+func (c *NetCtl) read(r io.Reader, b []byte) (int, error) {
+	c.rlock.Lock()
+	defer c.rlock.Unlock()
+
+	if !c.canRead {
+		return 0, errors.New("read failed (not allowed)")
+	}
+
+	if c.readLimit > 0 && c.readCount >= c.readLimit {
+		return 0, errors.New("read failed (limit reached)")
+	}
+
+	var rem uint64
+
+	if c.readLimit > 0 && c.readLimit-c.readCount < uint64(len(b)) {
+		rem = c.readLimit - c.readCount
+	} else {
+		rem = uint64(len(b))
+	}
+
+	c.rlock.Unlock()
+	n, err := newSlowReader(r, c.readSpeed).Read(b[:rem])
+	c.rlock.Lock()
+
+	c.readCount += uint64(n)
+
+	for _, fn := range c.onRead {
+		fn(b[:n])
+	}
+
+	return n, err
+}
+
+// write writes to w, but only if the controller allows it.
+func (c *NetCtl) write(w io.Writer, b []byte) (int, error) {
+	c.wlock.Lock()
+	defer c.wlock.Unlock()
+
+	if !c.canWrite {
+		return 0, errors.New("write failed (not allowed)")
+	}
+
+	if c.writeLimit > 0 && c.writeCount >= c.writeLimit {
+		return 0, errors.New("write failed (limit exceeded)")
+	}
+
+	var rem uint64
+
+	if c.writeLimit > 0 && c.writeLimit-c.writeCount < uint64(len(b)) {
+		rem = c.writeLimit - c.writeCount
+	} else {
+		rem = uint64(len(b))
+	}
+
+	c.wlock.Unlock()
+	n, err := newSlowWriter(w, c.writeSpeed).Write(b[:rem])
+	c.wlock.Lock()
+
+	c.writeCount += uint64(n)
+
+	for _, fn := range c.onWrite {
+		fn(b[:n])
+	}
+
+	if uint64(n) < rem {
+		return n, fmt.Errorf("write incomplete (limit reached)")
+	}
+
+	return n, err
+}
+
+// conn is a wrapper around net.conn that can be used to control whether a connection can read or write.
+type conn struct {
+	net.Conn
+
+	ctl *NetCtl
+}
+
+func newConn(c net.Conn, ctl *NetCtl) *conn {
+	return &conn{
+		Conn: c,
+		ctl:  ctl,
+	}
+}
+
+// Read reads from the wrapped connection, but only if the controller allows it.
+func (c *conn) Read(b []byte) (int, error) {
+	return c.ctl.read(c.Conn, b)
+}
+
+// Write writes to the wrapped connection, but only if the controller allows it.
+func (c *conn) Write(b []byte) (int, error) {
+	return c.ctl.write(c.Conn, b)
+}
+
+// slowReader is an io.Reader that reads at a fixed rate.
+type slowReader struct {
+	r io.Reader
+
+	// bytesPerSec is the number of bytes to read per second.
+	bytesPerSec int
+}
+
+func newSlowReader(r io.Reader, bytesPerSec int) *slowReader {
+	return &slowReader{
+		r:           r,
+		bytesPerSec: bytesPerSec,
+	}
+}
+
+func (r *slowReader) Read(b []byte) (int, error) {
+	start := time.Now()
+
+	n, err := r.r.Read(b)
+
+	if r.bytesPerSec > 0 {
+		time.Sleep(time.Until(start.Add(time.Duration(n*r.bytesPerSec) * time.Second)))
+	}
+
+	return n, err
+}
+
+// slowWriter is an io.Writer that writes at a fixed rate.
+type slowWriter struct {
+	w io.Writer
+
+	// bytesPerSec is the number of bytes to write per second.
+	bytesPerSec int
+}
+
+func newSlowWriter(w io.Writer, bytesPerSec int) *slowWriter {
+	return &slowWriter{
+		w:           w,
+		bytesPerSec: bytesPerSec,
+	}
+}
+
+func (w *slowWriter) Write(b []byte) (int, error) {
+	start := time.Now()
+
+	n, err := w.w.Write(b)
+
+	if w.bytesPerSec > 0 {
+		time.Sleep(time.Until(start.Add(time.Duration(n*w.bytesPerSec) * time.Second)))
+	}
+
+	return n, err
+}
diff --git a/dialer_test.go b/netctl_test.go
similarity index 81%
rename from dialer_test.go
rename to netctl_test.go
index 6ef32c2..ee9f01f 100644
--- a/dialer_test.go
+++ b/netctl_test.go
@@ -14,7 +14,7 @@ import (
 func TestNetCtl_ReadLimit(t *testing.T) {
 	// Create a test http server that writes 100 bytes.
 	// Including the header, this is 217 bytes (100 bytes + 117 bytes).
-	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
 		if _, err := w.Write(make([]byte, 100)); err != nil {
 			t.Fatal(err)
 		}
@@ -22,16 +22,16 @@ func TestNetCtl_ReadLimit(t *testing.T) {
 	defer ts.Close()
 
 	// Create a new net controller.
-	netCtl := proton.NewNetCtl()
+	ctl := proton.NewNetCtl()
+
+	// Set the read limit to 300 bytes -- the first request should succeed, the second should fail.
+	ctl.SetReadLimit(300)
 
 	// Create a new http client with the dialer.
 	client := &http.Client{
-		Transport: proton.NewDialer(netCtl, &tls.Config{InsecureSkipVerify: true}).GetRoundTripper(),
+		Transport: ctl.NewRoundTripper(&tls.Config{InsecureSkipVerify: true}),
 	}
 
-	// Set the read limit to 300 bytes -- the first request should succeed, the second should fail.
-	netCtl.SetReadLimit(300)
-
 	// This should succeed.
 	if resp, err := client.Get(ts.URL); err != nil {
 		t.Fatal(err)
@@ -47,7 +47,7 @@ func TestNetCtl_ReadLimit(t *testing.T) {
 
 func TestNetCtl_WriteLimit(t *testing.T) {
 	// Create a test http server that reads the given body.
-	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	ts := httptest.NewServer(http.HandlerFunc(func(_ http.ResponseWriter, r *http.Request) {
 		if _, err := io.ReadAll(r.Body); err != nil {
 			t.Fatal(err)
 		}
@@ -55,16 +55,16 @@ func TestNetCtl_WriteLimit(t *testing.T) {
 	defer ts.Close()
 
 	// Create a new net controller.
-	netCtl := proton.NewNetCtl()
+	ctl := proton.NewNetCtl()
+
+	// Set the read limit to 300 bytes -- the first request should succeed, the second should fail.
+	ctl.SetWriteLimit(300)
 
 	// Create a new http client with the dialer.
 	client := &http.Client{
-		Transport: proton.NewDialer(netCtl, &tls.Config{InsecureSkipVerify: true}).GetRoundTripper(),
+		Transport: ctl.NewRoundTripper(&tls.Config{InsecureSkipVerify: true}),
 	}
 
-	// Set the read limit to 300 bytes -- the first request should succeed, the second should fail.
-	netCtl.SetWriteLimit(300)
-
 	// This should succeed.
 	if resp, err := client.Post(ts.URL, "application/octet-stream", bytes.NewReader(make([]byte, 100))); err != nil {
 		t.Fatal(err)
diff --git a/response.go b/response.go
index 4017fa5..d344b67 100644
--- a/response.go
+++ b/response.go
@@ -62,37 +62,31 @@ func updateTime(_ *resty.Client, res *resty.Response) error {
 	return nil
 }
 
+// nolint:gosec
 func catchRetryAfter(_ *resty.Client, res *resty.Response) (time.Duration, error) {
-	if res.StatusCode() == http.StatusTooManyRequests {
-		if after := res.Header().Get("Retry-After"); after != "" {
-			l := logrus.WithFields(logrus.Fields{
-				"pkg":        "go-proton-api",
-				"statusCode": res.StatusCode(),
-				"url":        res.Request.URL,
-				"verb":       res.Request.Method,
-			})
-
-			seconds, err := strconv.Atoi(after)
-			if err != nil {
-				l.WithField("after", after).WithError(err).Warning(
-					"Cannot convert Retry-After to a number, continue with default 10 second cooldown.",
-				)
-				seconds = 10
-			}
-
-			// To avoid spikes when all clients retry at the same time, we add some random wait.
-			seconds += rand.Intn(10) //nolint:gosec // It is OK to use weak random number generator here.
-			l = l.WithField("delay", seconds)
-
-			// Maximum retry time in client is is one minute. But
-			// here wait times can be longer e.g. high API load
-			l.Warn("Delay the retry after http response")
-			return time.Duration(seconds) * time.Second, nil
-		}
+	// 0 and no error means default behaviour which is exponential backoff with jitter.
+	if res.StatusCode() != http.StatusTooManyRequests {
+		return 0, nil
 	}
 
-	// 0 and no error means default behaviour which is exponential backoff with jitter.
-	return 0, nil
+	// Parse the Retry-After header, or fallback to 10 seconds.
+	after, err := strconv.Atoi(res.Header().Get("Retry-After"))
+	if err != nil {
+		after = 10
+	}
+
+	// Add some jitter to the delay.
+	after += rand.Intn(10)
+
+	logrus.WithFields(logrus.Fields{
+		"pkg":    "go-proton-api",
+		"status": res.StatusCode(),
+		"url":    res.Request.URL,
+		"method": res.Request.Method,
+		"after":  after,
+	}).Warn("Too many requests, retrying after delay")
+
+	return time.Duration(after) * time.Second, nil
 }
 
 func catchTooManyRequests(res *resty.Response, _ error) bool {
diff --git a/server/backend/crypto_fast.go b/server/backend/crypto_fast.go
new file mode 100644
index 0000000..9e020a5
--- /dev/null
+++ b/server/backend/crypto_fast.go
@@ -0,0 +1,25 @@
+package backend
+
+import "github.com/ProtonMail/gopenpgp/v2/crypto"
+
+var preCompKey *crypto.Key
+
+func init() {
+	key, err := crypto.GenerateKey("name", "email", "rsa", 1024)
+	if err != nil {
+		panic(err)
+	}
+
+	preCompKey = key
+}
+
+// FastGenerateKey is a fast version of GenerateKey that uses a pre-computed key.
+// This is useful for testing but is incredibly insecure.
+func FastGenerateKey(_, _ string, passphrase []byte, _ string, _ int) (string, error) {
+	encKey, err := preCompKey.Lock(passphrase)
+	if err != nil {
+		return "", err
+	}
+
+	return encKey.Armor()
+}
diff --git a/server/call.go b/server/call.go
index 9bd78bc..45eff9f 100644
--- a/server/call.go
+++ b/server/call.go
@@ -3,6 +3,7 @@ package server
 import (
 	"net/http"
 	"net/url"
+	"time"
 )
 
 type Call struct {
@@ -10,6 +11,9 @@ type Call struct {
 	Method string
 	Status int
 
+	Time     time.Time
+	Duration time.Duration
+
 	RequestHeader http.Header
 	RequestBody   []byte
 
diff --git a/server/init_test.go b/server/init_test.go
index 79b446c..c885b17 100644
--- a/server/init_test.go
+++ b/server/init_test.go
@@ -1,22 +1,7 @@
 package server
 
-import (
-	"github.com/ProtonMail/go-proton-api/server/backend"
-	"github.com/ProtonMail/gopenpgp/v2/crypto"
-)
+import "github.com/ProtonMail/go-proton-api/server/backend"
 
 func init() {
-	key, err := crypto.GenerateKey("name", "email", "rsa", 1024)
-	if err != nil {
-		panic(err)
-	}
-
-	backend.GenerateKey = func(_, _ string, passphrase []byte, _ string, _ int) (string, error) {
-		encKey, err := key.Lock(passphrase)
-		if err != nil {
-			return "", err
-		}
-
-		return encKey.Armor()
-	}
+	backend.GenerateKey = backend.FastGenerateKey
 }
diff --git a/server/rate_limit.go b/server/rate_limit.go
new file mode 100644
index 0000000..29bb59e
--- /dev/null
+++ b/server/rate_limit.go
@@ -0,0 +1,51 @@
+package server
+
+import (
+	"sync"
+	"time"
+)
+
+// rateLimiter is a rate limiter for the server.
+// If more than limit requests are made in the time window, the server will return 429.
+type rateLimiter struct {
+	// limit is the rate limit to apply to the server.
+	limit int
+
+	// window is the window in which to apply the rate limit.
+	window time.Duration
+
+	// nextReset is the time at which the rate limit will reset.
+	nextReset time.Time
+
+	// count is the number of calls made to the server.
+	count int
+
+	// countLock is a mutex for the callCount.
+	countLock sync.Mutex
+}
+
+func newRateLimiter(limit int, window time.Duration) *rateLimiter {
+	return &rateLimiter{
+		limit:  limit,
+		window: window,
+	}
+}
+
+// exceeded checks the rate limit and returns how long to wait before the next request.
+func (r *rateLimiter) exceeded() time.Duration {
+	r.countLock.Lock()
+	defer r.countLock.Unlock()
+
+	if time.Now().After(r.nextReset) {
+		r.count = 0
+		r.nextReset = time.Now().Add(r.window)
+	}
+
+	r.count++
+
+	if r.count > r.limit {
+		return time.Until(r.nextReset)
+	}
+
+	return 0
+}
diff --git a/server/router.go b/server/router.go
index c83cadb..9a61ff3 100644
--- a/server/router.go
+++ b/server/router.go
@@ -7,6 +7,7 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"strconv"
 	"strings"
 	"time"
 
@@ -20,6 +21,7 @@ func initRouter(s *Server) {
 	s.r.Use(
 		s.requireValidAppVersion(),
 		s.setSessionCookie(),
+		s.applyRateLimit(),
 	)
 
 	if core := s.r.Group("/core/v4"); core != nil {
@@ -171,8 +173,23 @@ func (s *Server) setSessionCookie() gin.HandlerFunc {
 	}
 }
 
+func (s *Server) applyRateLimit() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		if s.rateLimit == nil {
+			return
+		}
+
+		if wait := s.rateLimit.exceeded(); wait > 0 {
+			c.Header("Retry-After", strconv.Itoa(int(wait.Seconds())))
+			c.AbortWithStatus(http.StatusTooManyRequests)
+		}
+	}
+}
+
 func (s *Server) logCalls() gin.HandlerFunc {
 	return func(c *gin.Context) {
+		start := time.Now()
+
 		req, err := io.ReadAll(c.Request.Body)
 		if err != nil {
 			panic(err)
@@ -199,6 +216,9 @@ func (s *Server) logCalls() gin.HandlerFunc {
 					Method: c.Request.Method,
 					Status: c.Writer.Status(),
 
+					Time:     start,
+					Duration: time.Since(start),
+
 					RequestHeader: c.Request.Header,
 					RequestBody:   req,
 
diff --git a/server/server.go b/server/server.go
index b6ac468..3e797c8 100644
--- a/server/server.go
+++ b/server/server.go
@@ -47,6 +47,9 @@ type Server struct {
 
 	// offline is whether to pretend the server is offline and return 5xx errors.
 	offline bool
+
+	// rateLimit is the rate limiter for the server.
+	rateLimit *rateLimiter
 }
 
 func New(opts ...Option) *Server {
@@ -69,7 +72,7 @@ func (s *Server) GetProxyURL() string {
 	return s.s.URL + "/proxy"
 }
 
-// GetDomain returns the domain of the server.
+// GetDomain returns the domain of the server (e.g. "proton.local").
 func (s *Server) GetDomain() string {
 	return s.domain
 }
diff --git a/server/server_builder.go b/server/server_builder.go
index 2d28a18..fda65cd 100644
--- a/server/server_builder.go
+++ b/server/server_builder.go
@@ -12,11 +12,12 @@ import (
 )
 
 type serverBuilder struct {
-	withTLS bool
-	domain  string
-	logger  io.Writer
-	origin  string
-	cacher  AuthCacher
+	withTLS     bool
+	domain      string
+	logger      io.Writer
+	origin      string
+	cacher      AuthCacher
+	rateLimiter *rateLimiter
 }
 
 func newServerBuilder() *serverBuilder {
@@ -46,6 +47,7 @@ func (builder *serverBuilder) build() *Server {
 		domain:      builder.domain,
 		proxyOrigin: builder.origin,
 		authCacher:  builder.cacher,
+		rateLimit:   builder.rateLimiter,
 	}
 
 	if builder.withTLS {
@@ -143,3 +145,19 @@ type withAuthCache struct {
 func (opt withAuthCache) config(builder *serverBuilder) {
 	builder.cacher = opt.cacher
 }
+
+func WithRateLimit(limit int, window time.Duration) Option {
+	return &withRateLimit{
+		limit:  limit,
+		window: window,
+	}
+}
+
+type withRateLimit struct {
+	limit  int
+	window time.Duration
+}
+
+func (opt withRateLimit) config(builder *serverBuilder) {
+	builder.rateLimiter = newRateLimiter(opt.limit, opt.window)
+}
diff --git a/server/server_test.go b/server/server_test.go
index 237eca3..0f2350c 100644
--- a/server/server_test.go
+++ b/server/server_test.go
@@ -77,7 +77,7 @@ func TestServer_Ping(t *testing.T) {
 
 		m := proton.New(
 			proton.WithHostURL(s.GetHostURL()),
-			proton.WithTransport(proton.NewDialer(ctl, &tls.Config{InsecureSkipVerify: true}).GetRoundTripper()),
+			proton.WithTransport(ctl.NewRoundTripper(&tls.Config{InsecureSkipVerify: true})),
 		)
 
 		var status proton.Status
@@ -1313,7 +1313,7 @@ func TestServer_Messages_Fetch(t *testing.T) {
 
 				mm := proton.New(
 					proton.WithHostURL(s.GetHostURL()),
-					proton.WithTransport(proton.NewDialer(ctl, &tls.Config{InsecureSkipVerify: true}).GetRoundTripper()),
+					proton.WithTransport(ctl.NewRoundTripper(&tls.Config{InsecureSkipVerify: true})),
 				)
 				defer mm.Close()
 
@@ -1355,7 +1355,7 @@ func TestServer_Messages_Status(t *testing.T) {
 
 				mm := proton.New(
 					proton.WithHostURL(s.GetHostURL()),
-					proton.WithTransport(proton.NewDialer(ctl, &tls.Config{InsecureSkipVerify: true}).GetRoundTripper()),
+					proton.WithTransport(ctl.NewRoundTripper(&tls.Config{InsecureSkipVerify: true})),
 				)
 				defer mm.Close()
 
diff --git a/unlock.go b/unlock.go
index 731bb87..faa6842 100644
--- a/unlock.go
+++ b/unlock.go
@@ -12,6 +12,8 @@ func Unlock(user User, addresses []Address, saltedKeyPass []byte) (*crypto.KeyRi
 	userKR, err := user.Keys.Unlock(saltedKeyPass, nil)
 	if err != nil {
 		return nil, nil, fmt.Errorf("failed to unlock user keys: %w", err)
+	} else if userKR.CountDecryptionEntities() == 0 {
+		return nil, nil, fmt.Errorf("failed to unlock any user keys")
 	}
 
 	addrKRs := make(map[string]*crypto.KeyRing)
@@ -19,9 +21,13 @@ func Unlock(user User, addresses []Address, saltedKeyPass []byte) (*crypto.KeyRi
 	for idx, addrKR := range parallel.Map(runtime.NumCPU(), addresses, func(addr Address) *crypto.KeyRing {
 		return addr.Keys.TryUnlock(saltedKeyPass, userKR)
 	}) {
-		if addrKR != nil {
-			addrKRs[addresses[idx].ID] = addrKR
+		if addrKR.CountDecryptionEntities() == 0 {
+			continue
+		} else if addrKR == nil {
+			continue
 		}
+
+		addrKRs[addresses[idx].ID] = addrKR
 	}
 
 	if len(addrKRs) == 0 {