diff --git a/jetstream/jetstream.go b/jetstream/jetstream.go
index e401cb926..36a44c810 100644
--- a/jetstream/jetstream.go
+++ b/jetstream/jetstream.go
@@ -435,7 +435,7 @@ func NewWithAPIPrefix(nc *nats.Conn, apiPrefix string, opts ...JetStreamOpt) (Je
 		}
 	}
 	if apiPrefix == "" {
-		return nil, fmt.Errorf("API prefix cannot be empty")
+		return nil, errors.New("API prefix cannot be empty")
 	}
 	if !strings.HasSuffix(apiPrefix, ".") {
 		jsOpts.apiPrefix = fmt.Sprintf("%s.", apiPrefix)
diff --git a/jetstream/jetstream_test.go b/jetstream/jetstream_test.go
index 58f906423..9d429ad33 100644
--- a/jetstream/jetstream_test.go
+++ b/jetstream/jetstream_test.go
@@ -430,13 +430,13 @@ func TestPullConsumer_checkPending(t *testing.T) {
 						}
 						ok <- struct{}{}
 					case <-time.After(1 * time.Second):
-						errs <- fmt.Errorf("Timeout")
+						errs <- errors.New("Timeout")
 						return
 					}
 				} else {
 					select {
 					case <-prChan:
-						errs <- fmt.Errorf("Unexpected pull request")
+						errs <- errors.New("Unexpected pull request")
 					case <-time.After(100 * time.Millisecond):
 						ok <- struct{}{}
 						return
diff --git a/jetstream/message.go b/jetstream/message.go
index 81e151268..095f13968 100644
--- a/jetstream/message.go
+++ b/jetstream/message.go
@@ -16,6 +16,7 @@ package jetstream
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"strconv"
 	"strings"
@@ -434,7 +435,7 @@ func parsePending(msg *nats.Msg) (int, int, error) {
 	if msgsLeftStr != "" {
 		msgsLeft, err = strconv.Atoi(msgsLeftStr)
 		if err != nil {
-			return 0, 0, fmt.Errorf("nats: invalid format of Nats-Pending-Messages")
+			return 0, 0, errors.New("nats: invalid format of Nats-Pending-Messages")
 		}
 	}
 	bytesLeftStr := msg.Header.Get("Nats-Pending-Bytes")
@@ -442,7 +443,7 @@ func parsePending(msg *nats.Msg) (int, int, error) {
 	if bytesLeftStr != "" {
 		bytesLeft, err = strconv.Atoi(bytesLeftStr)
 		if err != nil {
-			return 0, 0, fmt.Errorf("nats: invalid format of Nats-Pending-Bytes")
+			return 0, 0, errors.New("nats: invalid format of Nats-Pending-Bytes")
 		}
 	}
 	return msgsLeft, bytesLeft, nil
diff --git a/jetstream/ordered.go b/jetstream/ordered.go
index 199b8c383..0d7f952c3 100644
--- a/jetstream/ordered.go
+++ b/jetstream/ordered.go
@@ -747,7 +747,7 @@ func retryWithBackoff(f func(int) (bool, error), opts backoffOpts) error {
 	// if custom backoff is set, use it instead of other options
 	if len(opts.customBackoff) > 0 {
 		if opts.attempts != 0 {
-			return fmt.Errorf("cannot use custom backoff intervals when attempts are set")
+			return errors.New("cannot use custom backoff intervals when attempts are set")
 		}
 		for i, interval := range opts.customBackoff {
 			select {
@@ -774,7 +774,7 @@ func retryWithBackoff(f func(int) (bool, error), opts backoffOpts) error {
 		opts.maxInterval = 1 * time.Minute
 	}
 	if opts.attempts == 0 {
-		return fmt.Errorf("retry attempts have to be set when not using custom backoff intervals")
+		return errors.New("retry attempts have to be set when not using custom backoff intervals")
 	}
 	interval := opts.initialInterval
 	for i := 0; ; i++ {
diff --git a/jetstream/pull.go b/jetstream/pull.go
index 540282877..386968108 100644
--- a/jetstream/pull.go
+++ b/jetstream/pull.go
@@ -971,7 +971,7 @@ func parseMessagesOpts(ordered bool, opts ...PullMessagesOpt) (*consumeOpts, err
 
 func (consumeOpts *consumeOpts) setDefaults(ordered bool) error {
 	if consumeOpts.MaxBytes != unset && consumeOpts.MaxMessages != unset {
-		return fmt.Errorf("only one of MaxMessages and MaxBytes can be specified")
+		return errors.New("only one of MaxMessages and MaxBytes can be specified")
 	}
 	if consumeOpts.MaxBytes != unset {
 		// when max_bytes is used, set batch size to a very large number
@@ -1007,7 +1007,7 @@ func (consumeOpts *consumeOpts) setDefaults(ordered bool) error {
 		}
 	}
 	if consumeOpts.Heartbeat > consumeOpts.Expires/2 {
-		return fmt.Errorf("the value of Heartbeat must be less than 50%% of expiry")
+		return errors.New("the value of Heartbeat must be less than 50%% of expiry")
 	}
 	return nil
 }
diff --git a/jetstream/stream.go b/jetstream/stream.go
index 4741a51c4..1cd9975dc 100644
--- a/jetstream/stream.go
+++ b/jetstream/stream.go
@@ -504,16 +504,16 @@ func convertDirectGetMsgResponseToMsg(name string, r *nats.Msg) (*RawStreamMsg,
 	// Check for headers that give us the required information to
 	// reconstruct the message.
 	if len(r.Header) == 0 {
-		return nil, fmt.Errorf("nats: response should have headers")
+		return nil, errors.New("nats: response should have headers")
 	}
 	stream := r.Header.Get(StreamHeader)
 	if stream == "" {
-		return nil, fmt.Errorf("nats: missing stream header")
+		return nil, errors.New("nats: missing stream header")
 	}
 
 	seqStr := r.Header.Get(SequenceHeader)
 	if seqStr == "" {
-		return nil, fmt.Errorf("nats: missing sequence header")
+		return nil, errors.New("nats: missing sequence header")
 	}
 	seq, err := strconv.ParseUint(seqStr, 10, 64)
 	if err != nil {
@@ -521,7 +521,7 @@ func convertDirectGetMsgResponseToMsg(name string, r *nats.Msg) (*RawStreamMsg,
 	}
 	timeStr := r.Header.Get(TimeStampHeaer)
 	if timeStr == "" {
-		return nil, fmt.Errorf("nats: missing timestamp header")
+		return nil, errors.New("nats: missing timestamp header")
 	}
 
 	tm, err := time.Parse(time.RFC3339Nano, timeStr)
@@ -530,7 +530,7 @@ func convertDirectGetMsgResponseToMsg(name string, r *nats.Msg) (*RawStreamMsg,
 	}
 	subj := r.Header.Get(SubjectHeader)
 	if subj == "" {
-		return nil, fmt.Errorf("nats: missing subject header")
+		return nil, errors.New("nats: missing subject header")
 	}
 	return &RawStreamMsg{
 		Subject:  subj,
diff --git a/jetstream/stream_config.go b/jetstream/stream_config.go
index 6eb843278..304203bc5 100644
--- a/jetstream/stream_config.go
+++ b/jetstream/stream_config.go
@@ -15,6 +15,7 @@ package jetstream
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"strings"
 	"time"
@@ -584,7 +585,7 @@ func (alg StoreCompression) MarshalJSON() ([]byte, error) {
 	case NoCompression:
 		str = "none"
 	default:
-		return nil, fmt.Errorf("unknown compression algorithm")
+		return nil, errors.New("unknown compression algorithm")
 	}
 	return json.Marshal(str)
 }
@@ -600,7 +601,7 @@ func (alg *StoreCompression) UnmarshalJSON(b []byte) error {
 	case "none":
 		*alg = NoCompression
 	default:
-		return fmt.Errorf("unknown compression algorithm")
+		return errors.New("unknown compression algorithm")
 	}
 	return nil
 }
diff --git a/jetstream/test/kv_test.go b/jetstream/test/kv_test.go
index 010a7d5b3..50d2ffa69 100644
--- a/jetstream/test/kv_test.go
+++ b/jetstream/test/kv_test.go
@@ -1263,7 +1263,7 @@ func TestKeyValueMirrorCrossDomains(t *testing.T) {
 		checkFor(t, 10*time.Second, 10*time.Millisecond, func() error {
 			_, err := kv.Get(context.Background(), key)
 			if err == nil {
-				return fmt.Errorf("Expected key to be gone")
+				return errors.New("Expected key to be gone")
 			}
 			if !errors.Is(err, jetstream.ErrKeyNotFound) {
 				return err
diff --git a/jetstream/test/publish_test.go b/jetstream/test/publish_test.go
index 2233a16ce..2ab6de8f7 100644
--- a/jetstream/test/publish_test.go
+++ b/jetstream/test/publish_test.go
@@ -1383,7 +1383,7 @@ func TestPublishAsyncResetPendingOnReconnect(t *testing.T) {
 					errs <- fmt.Errorf("Expected error: %v or %v; got: %v", nats.ErrDisconnected, nats.ErrNoResponders, err)
 				}
 			case <-time.After(5 * time.Second):
-				errs <- fmt.Errorf("Did not receive completion signal")
+				errs <- errors.New("Did not receive completion signal")
 			}
 			wg.Done()
 		}(ack)
diff --git a/js.go b/js.go
index 0038afbc6..e024fae0a 100644
--- a/js.go
+++ b/js.go
@@ -547,7 +547,7 @@ func (js *js) PublishMsg(m *Msg, opts ...PubOpt) (*PubAck, error) {
 		o.ttl = js.opts.wait
 	}
 	if o.stallWait > 0 {
-		return nil, fmt.Errorf("nats: stall wait cannot be set to sync publish")
+		return nil, errors.New("nats: stall wait cannot be set to sync publish")
 	}
 
 	if o.id != _EMPTY_ {
@@ -1143,7 +1143,7 @@ func RetryAttempts(num int) PubOpt {
 func StallWait(ttl time.Duration) PubOpt {
 	return pubOptFn(func(opts *pubOpts) error {
 		if ttl <= 0 {
-			return fmt.Errorf("nats: stall wait should be more than 0")
+			return errors.New("nats: stall wait should be more than 0")
 		}
 		opts.stallWait = ttl
 		return nil
@@ -1501,11 +1501,11 @@ func processConsInfo(info *ConsumerInfo, userCfg *ConsumerConfig, isPullMode boo
 		// Prevent an user from attempting to create a queue subscription on
 		// a JS consumer that was not created with a deliver group.
 		if queue != _EMPTY_ {
-			return _EMPTY_, fmt.Errorf("cannot create a queue subscription for a consumer without a deliver group")
+			return _EMPTY_, errors.New("cannot create a queue subscription for a consumer without a deliver group")
 		} else if info.PushBound {
 			// Need to reject a non queue subscription to a non queue consumer
 			// if the consumer is already bound.
-			return _EMPTY_, fmt.Errorf("consumer is already bound to a subscription")
+			return _EMPTY_, errors.New("consumer is already bound to a subscription")
 		}
 	} else {
 		// If the JS consumer has a deliver group, we need to fail a non queue
@@ -1607,7 +1607,7 @@ func (js *js) subscribe(subj, queue string, cb MsgHandler, ch chan *Msg, isSync,
 
 	// If no stream name is specified, the subject cannot be empty.
 	if subj == _EMPTY_ && o.stream == _EMPTY_ {
-		return nil, fmt.Errorf("nats: subject required")
+		return nil, errors.New("nats: subject required")
 	}
 
 	// Note that these may change based on the consumer info response we may get.
@@ -1629,7 +1629,7 @@ func (js *js) subscribe(subj, queue string, cb MsgHandler, ch chan *Msg, isSync,
 		// would subscribe to and server would send on.
 		if o.cfg.Heartbeat > 0 || o.cfg.FlowControl {
 			// Not making this a public ErrXXX in case we allow in the future.
-			return nil, fmt.Errorf("nats: queue subscription doesn't support idle heartbeat nor flow control")
+			return nil, errors.New("nats: queue subscription doesn't support idle heartbeat nor flow control")
 		}
 
 		// If this is a queue subscription and no consumer nor durable name was specified,
@@ -1667,31 +1667,31 @@ func (js *js) subscribe(subj, queue string, cb MsgHandler, ch chan *Msg, isSync,
 	if o.ordered {
 		// Make sure we are not durable.
 		if isDurable {
-			return nil, fmt.Errorf("nats: durable can not be set for an ordered consumer")
+			return nil, errors.New("nats: durable can not be set for an ordered consumer")
 		}
 		// Check ack policy.
 		if o.cfg.AckPolicy != ackPolicyNotSet {
-			return nil, fmt.Errorf("nats: ack policy can not be set for an ordered consumer")
+			return nil, errors.New("nats: ack policy can not be set for an ordered consumer")
 		}
 		// Check max deliver.
 		if o.cfg.MaxDeliver != 1 && o.cfg.MaxDeliver != 0 {
-			return nil, fmt.Errorf("nats: max deliver can not be set for an ordered consumer")
+			return nil, errors.New("nats: max deliver can not be set for an ordered consumer")
 		}
 		// No deliver subject, we pick our own.
 		if o.cfg.DeliverSubject != _EMPTY_ {
-			return nil, fmt.Errorf("nats: deliver subject can not be set for an ordered consumer")
+			return nil, errors.New("nats: deliver subject can not be set for an ordered consumer")
 		}
 		// Queue groups not allowed.
 		if queue != _EMPTY_ {
-			return nil, fmt.Errorf("nats: queues not be set for an ordered consumer")
+			return nil, errors.New("nats: queues not be set for an ordered consumer")
 		}
 		// Check for bound consumers.
 		if consumer != _EMPTY_ {
-			return nil, fmt.Errorf("nats: can not bind existing consumer for an ordered consumer")
+			return nil, errors.New("nats: can not bind existing consumer for an ordered consumer")
 		}
 		// Check for pull mode.
 		if isPullMode {
-			return nil, fmt.Errorf("nats: can not use pull mode for an ordered consumer")
+			return nil, errors.New("nats: can not use pull mode for an ordered consumer")
 		}
 		// Setup how we need it to be here.
 		o.cfg.FlowControl = true
@@ -2425,7 +2425,7 @@ func Description(description string) SubOpt {
 func Durable(consumer string) SubOpt {
 	return subOptFn(func(opts *subOpts) error {
 		if opts.cfg.Durable != _EMPTY_ {
-			return fmt.Errorf("nats: option Durable set more than once")
+			return errors.New("nats: option Durable set more than once")
 		}
 		if opts.consumer != _EMPTY_ && opts.consumer != consumer {
 			return fmt.Errorf("nats: duplicate consumer names (%s and %s)", opts.consumer, consumer)
@@ -3950,7 +3950,7 @@ func (alg StoreCompression) MarshalJSON() ([]byte, error) {
 	case NoCompression:
 		str = "none"
 	default:
-		return nil, fmt.Errorf("unknown compression algorithm")
+		return nil, errors.New("unknown compression algorithm")
 	}
 	return json.Marshal(str)
 }
@@ -3966,7 +3966,7 @@ func (alg *StoreCompression) UnmarshalJSON(b []byte) error {
 	case "none":
 		*alg = NoCompression
 	default:
-		return fmt.Errorf("unknown compression algorithm")
+		return errors.New("unknown compression algorithm")
 	}
 	return nil
 }
diff --git a/jsm.go b/jsm.go
index 682664730..2ae19c7a3 100644
--- a/jsm.go
+++ b/jsm.go
@@ -1330,11 +1330,11 @@ func convertDirectGetMsgResponseToMsg(name string, r *Msg) (*RawStreamMsg, error
 	// Check for headers that give us the required information to
 	// reconstruct the message.
 	if len(r.Header) == 0 {
-		return nil, fmt.Errorf("nats: response should have headers")
+		return nil, errors.New("nats: response should have headers")
 	}
 	stream := r.Header.Get(JSStream)
 	if stream == _EMPTY_ {
-		return nil, fmt.Errorf("nats: missing stream header")
+		return nil, errors.New("nats: missing stream header")
 	}
 
 	// Mirrors can now answer direct gets, so removing check for name equality.
@@ -1342,7 +1342,7 @@ func convertDirectGetMsgResponseToMsg(name string, r *Msg) (*RawStreamMsg, error
 
 	seqStr := r.Header.Get(JSSequence)
 	if seqStr == _EMPTY_ {
-		return nil, fmt.Errorf("nats: missing sequence header")
+		return nil, errors.New("nats: missing sequence header")
 	}
 	seq, err := strconv.ParseUint(seqStr, 10, 64)
 	if err != nil {
@@ -1350,7 +1350,7 @@ func convertDirectGetMsgResponseToMsg(name string, r *Msg) (*RawStreamMsg, error
 	}
 	timeStr := r.Header.Get(JSTimeStamp)
 	if timeStr == _EMPTY_ {
-		return nil, fmt.Errorf("nats: missing timestamp header")
+		return nil, errors.New("nats: missing timestamp header")
 	}
 	// Temporary code: the server in main branch is sending with format
 	// "2006-01-02 15:04:05.999999999 +0000 UTC", but will be changed
@@ -1365,7 +1365,7 @@ func convertDirectGetMsgResponseToMsg(name string, r *Msg) (*RawStreamMsg, error
 	}
 	subj := r.Header.Get(JSSubject)
 	if subj == _EMPTY_ {
-		return nil, fmt.Errorf("nats: missing subject header")
+		return nil, errors.New("nats: missing subject header")
 	}
 	return &RawStreamMsg{
 		Subject:  subj,
diff --git a/micro/test/service_test.go b/micro/test/service_test.go
index b9e004946..1dfafa072 100644
--- a/micro/test/service_test.go
+++ b/micro/test/service_test.go
@@ -504,7 +504,7 @@ func TestAddService(t *testing.T) {
 			}
 
 			if test.givenConfig.ErrorHandler != nil {
-				go nc.Opts.AsyncErrorCB(nc, &nats.Subscription{Subject: test.asyncErrorSubject}, fmt.Errorf("oops"))
+				go nc.Opts.AsyncErrorCB(nc, &nats.Subscription{Subject: test.asyncErrorSubject}, errors.New("oops"))
 				select {
 				case <-errService:
 				case <-time.After(1 * time.Second):
@@ -536,7 +536,7 @@ func TestAddService(t *testing.T) {
 				}
 			}
 			if test.natsErrorHandler != nil {
-				go nc.Opts.AsyncErrorCB(nc, &nats.Subscription{Subject: test.asyncErrorSubject}, fmt.Errorf("oops"))
+				go nc.Opts.AsyncErrorCB(nc, &nats.Subscription{Subject: test.asyncErrorSubject}, errors.New("oops"))
 				select {
 				case <-errService:
 					t.Fatalf("Expected to restore nats error handler")
@@ -634,7 +634,7 @@ func TestErrHandlerSubjectMatch(t *testing.T) {
 				}
 				defer svc.Stop()
 
-				go nc.Opts.AsyncErrorCB(nc, &nats.Subscription{Subject: test.errSubject}, fmt.Errorf("oops"))
+				go nc.Opts.AsyncErrorCB(nc, &nats.Subscription{Subject: test.errSubject}, errors.New("oops"))
 				if test.expectServiceErr {
 					select {
 					case <-errChan:
diff --git a/nats.go b/nats.go
index 10fa0f5b5..67277928e 100644
--- a/nats.go
+++ b/nats.go
@@ -1359,7 +1359,7 @@ func ProxyPath(path string) Option {
 func CustomInboxPrefix(p string) Option {
 	return func(o *Options) error {
 		if p == "" || strings.Contains(p, ">") || strings.Contains(p, "*") || strings.HasSuffix(p, ".") {
-			return fmt.Errorf("nats: invalid custom prefix")
+			return errors.New("nats: invalid custom prefix")
 		}
 		o.InboxPrefix = p
 		return nil
@@ -1814,7 +1814,7 @@ func (nc *Conn) addURLToPool(sURL string, implicit, saveTLSName bool) error {
 	if len(nc.srvPool) == 0 {
 		nc.ws = isWS
 	} else if isWS && !nc.ws || !isWS && nc.ws {
-		return fmt.Errorf("mixing of websocket and non websocket URLs is not allowed")
+		return errors.New("mixing of websocket and non websocket URLs is not allowed")
 	}
 
 	var tlsName string
@@ -5792,7 +5792,7 @@ func NkeyOptionFromSeed(seedFile string) (Option, error) {
 		return nil, err
 	}
 	if !nkeys.IsValidPublicUserKey(pub) {
-		return nil, fmt.Errorf("nats: Not a valid nkey user seed")
+		return nil, errors.New("nats: Not a valid nkey user seed")
 	}
 	sigCB := func(nonce []byte) ([]byte, error) {
 		return sigHandler(nonce, seedFile)
diff --git a/test/cluster_test.go b/test/cluster_test.go
index 8501e5da9..05fab49ef 100644
--- a/test/cluster_test.go
+++ b/test/cluster_test.go
@@ -682,7 +682,7 @@ func (d *checkPoolUpdatedDialer) Dial(network, address string) (net.Conn, error)
 		doReal = true
 	} else if d.final {
 		d.ra++
-		return nil, fmt.Errorf("On purpose")
+		return nil, errors.New("On purpose")
 	} else {
 		d.ra++
 		if d.ra == 15 {
@@ -698,7 +698,7 @@ func (d *checkPoolUpdatedDialer) Dial(network, address string) (net.Conn, error)
 		d.conn = c
 		return c, nil
 	}
-	return nil, fmt.Errorf("On purpose")
+	return nil, errors.New("On purpose")
 }
 
 func TestServerPoolUpdatedWhenRouteGoesAway(t *testing.T) {
diff --git a/test/conn_test.go b/test/conn_test.go
index c7713559c..1a4705092 100644
--- a/test/conn_test.go
+++ b/test/conn_test.go
@@ -277,7 +277,7 @@ func TestClientTLSConfig(t *testing.T) {
 		pool := x509.NewCertPool()
 		ok := pool.AppendCertsFromPEM(rootCAs)
 		if !ok {
-			return nil, fmt.Errorf("nats: failed to parse root certificate from")
+			return nil, errors.New("nats: failed to parse root certificate from")
 		}
 		return pool, nil
 	}
@@ -614,7 +614,7 @@ func TestErrOnConnectAndDeadlock(t *testing.T) {
 		nc, err := nats.Connect(natsURL)
 		if err == nil {
 			nc.Close()
-			errCh <- fmt.Errorf("expected bad INFO err, got none")
+			errCh <- errors.New("expected bad INFO err, got none")
 			return
 		}
 		errCh <- nil
@@ -1749,7 +1749,7 @@ type customDialer struct {
 
 func (cd *customDialer) Dial(network, address string) (net.Conn, error) {
 	cd.ch <- true
-	return nil, fmt.Errorf("on purpose")
+	return nil, errors.New("on purpose")
 }
 
 func TestUseCustomDialer(t *testing.T) {
diff --git a/test/drain_test.go b/test/drain_test.go
index c53305e17..da07c8967 100644
--- a/test/drain_test.go
+++ b/test/drain_test.go
@@ -14,6 +14,7 @@
 package test
 
 import (
+	"errors"
 	"fmt"
 	"sync"
 	"sync/atomic"
@@ -225,7 +226,7 @@ func TestDrainSlowSubscriber(t *testing.T) {
 		// Wait for it to become invalid. Once drained it is unsubscribed.
 		_, _, err := sub.Pending()
 		if err != nats.ErrBadSubscription {
-			return fmt.Errorf("Still valid")
+			return errors.New("Still valid")
 		}
 		r := int(atomic.LoadInt32(&received))
 		if r != total {
@@ -478,7 +479,7 @@ func TestDrainConnDuringReconnect(t *testing.T) {
 		if nc.IsReconnecting() {
 			return nil
 		}
-		return fmt.Errorf("Not reconnecting yet")
+		return errors.New("Not reconnecting yet")
 	})
 
 	// This should work correctly.
diff --git a/test/js_test.go b/test/js_test.go
index d748a3613..db791eb50 100644
--- a/test/js_test.go
+++ b/test/js_test.go
@@ -9426,7 +9426,7 @@ func TestJetStreamClusterStreamLeaderChangeClientErr(t *testing.T) {
 						return err
 					}
 					if si.Cluster.Leader == "" {
-						return fmt.Errorf("No leader yet")
+						return errors.New("No leader yet")
 					}
 					return nil
 				})
diff --git a/test/kv_test.go b/test/kv_test.go
index a1b5ca45d..768895845 100644
--- a/test/kv_test.go
+++ b/test/kv_test.go
@@ -1113,7 +1113,7 @@ func TestKeyValueMirrorCrossDomains(t *testing.T) {
 		checkFor(t, 10*time.Second, 10*time.Millisecond, func() error {
 			_, err := kv.Get(key)
 			if err == nil {
-				return fmt.Errorf("Expected key to be gone")
+				return errors.New("Expected key to be gone")
 			}
 			if !errors.Is(err, nats.ErrKeyNotFound) {
 				return err
diff --git a/test/sub_test.go b/test/sub_test.go
index 1961e23d8..a27e14256 100644
--- a/test/sub_test.go
+++ b/test/sub_test.go
@@ -1319,10 +1319,10 @@ func TestSetPendingLimits(t *testing.T) {
 	// Check for invalid values
 	invalid := func() error {
 		if err := sub.SetPendingLimits(0, 1); err == nil {
-			return fmt.Errorf("Setting limit with 0 should fail")
+			return errors.New("Setting limit with 0 should fail")
 		}
 		if err := sub.SetPendingLimits(1, 0); err == nil {
-			return fmt.Errorf("Setting limit with 0 should fail")
+			return errors.New("Setting limit with 0 should fail")
 		}
 		return nil
 	}
diff --git a/test/ws_test.go b/test/ws_test.go
index 15707d8b3..ee13b336f 100644
--- a/test/ws_test.go
+++ b/test/ws_test.go
@@ -17,6 +17,7 @@ import (
 	"bytes"
 	"crypto/tls"
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"math/rand"
 	"net"
@@ -524,7 +525,7 @@ func TestWSStress(t *testing.T) {
 					return
 				}
 				if !bytes.Equal(m.Data[4:4+ps], mainPayload[:ps]) {
-					pushErr(fmt.Errorf("invalid content"))
+					pushErr(errors.New("invalid content"))
 					return
 				}
 				if atomic.AddInt64(&count, 1) == totalRecv {
diff --git a/ws.go b/ws.go
index 8cd6c52e5..fbc568845 100644
--- a/ws.go
+++ b/ws.go
@@ -622,7 +622,7 @@ func (nc *Conn) wsInitHandshake(u *url.URL) error {
 			!strings.EqualFold(resp.Header.Get("Connection"), "upgrade") ||
 			resp.Header.Get("Sec-Websocket-Accept") != wsAcceptKey(wsKey)) {
 
-		err = fmt.Errorf("invalid websocket connection")
+		err = errors.New("invalid websocket connection")
 	}
 	// Check compression extension...
 	if err == nil && compress {
@@ -634,7 +634,7 @@ func (nc *Conn) wsInitHandshake(u *url.URL) error {
 		if !srvCompress {
 			compress = false
 		} else if !noCtxTakeover {
-			err = fmt.Errorf("compression negotiation error")
+			err = errors.New("compression negotiation error")
 		}
 	}
 	if resp != nil {