diff --git a/pkg/storage/inmemory/inmemory.go b/pkg/storage/inmemory/inmemory.go
index 9b0b9606c..1ac6674dc 100644
--- a/pkg/storage/inmemory/inmemory.go
+++ b/pkg/storage/inmemory/inmemory.go
@@ -49,7 +49,7 @@ type DB struct {
 
 	lastVersion uint64
 
-	mu         sync.Mutex
+	mu         sync.RWMutex
 	byID       *btree.BTree
 	byVersion  *btree.BTree
 	deletedIDs []string
@@ -100,6 +100,9 @@ func (db *DB) Close() error {
 
 // Delete marks a record as deleted.
 func (db *DB) Delete(_ context.Context, id string) error {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+
 	defer db.onchange.Broadcast()
 	db.replaceOrInsert(id, func(record *databroker.Record) {
 		record.DeletedAt = ptypes.TimestampNow()
@@ -110,6 +113,9 @@ func (db *DB) Delete(_ context.Context, id string) error {
 
 // Get gets a record from the db.
 func (db *DB) Get(_ context.Context, id string) (*databroker.Record, error) {
+	db.mu.RLock()
+	defer db.mu.RUnlock()
+
 	record, ok := db.byID.Get(byIDRecord{Record: &databroker.Record{Id: id}}).(byIDRecord)
 	if !ok {
 		return nil, errors.New("not found")
@@ -119,6 +125,9 @@ func (db *DB) Get(_ context.Context, id string) (*databroker.Record, error) {
 
 // GetAll gets all the records in the db.
 func (db *DB) GetAll(_ context.Context) ([]*databroker.Record, error) {
+	db.mu.RLock()
+	defer db.mu.RUnlock()
+
 	var records []*databroker.Record
 	db.byID.Ascend(func(item btree.Item) bool {
 		records = append(records, item.(byIDRecord).Record)
@@ -129,6 +138,9 @@ func (db *DB) GetAll(_ context.Context) ([]*databroker.Record, error) {
 
 // List lists all the changes since the given version.
 func (db *DB) List(_ context.Context, sinceVersion string) ([]*databroker.Record, error) {
+	db.mu.RLock()
+	defer db.mu.RUnlock()
+
 	var records []*databroker.Record
 	db.byVersion.AscendGreaterOrEqual(byVersionRecord{Record: &databroker.Record{Version: sinceVersion}}, func(i btree.Item) bool {
 		record := i.(byVersionRecord)
@@ -142,6 +154,9 @@ func (db *DB) List(_ context.Context, sinceVersion string) ([]*databroker.Record
 
 // Put replaces or inserts a record in the db.
 func (db *DB) Put(_ context.Context, id string, data *anypb.Any) error {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+
 	defer db.onchange.Broadcast()
 	db.replaceOrInsert(id, func(record *databroker.Record) {
 		record.Data = data
@@ -165,9 +180,6 @@ func (db *DB) Watch(ctx context.Context) <-chan struct{} {
 }
 
 func (db *DB) replaceOrInsert(id string, f func(record *databroker.Record)) {
-	db.mu.Lock()
-	defer db.mu.Unlock()
-
 	record, ok := db.byID.Get(byIDRecord{Record: &databroker.Record{Id: id}}).(byIDRecord)
 	if ok {
 		db.byVersion.Delete(byVersionRecord(record))
diff --git a/pkg/storage/inmemory/inmemory_test.go b/pkg/storage/inmemory/inmemory_test.go
index d79b5f9a6..9605e6a89 100644
--- a/pkg/storage/inmemory/inmemory_test.go
+++ b/pkg/storage/inmemory/inmemory_test.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"golang.org/x/sync/errgroup"
 	"google.golang.org/protobuf/types/known/anypb"
 )
 
@@ -85,3 +86,23 @@ func TestDB(t *testing.T) {
 		assert.Nil(t, record)
 	})
 }
+
+func TestConcurrency(t *testing.T) {
+	ctx := context.Background()
+	db := NewDB("example", 2)
+
+	eg, ctx := errgroup.WithContext(ctx)
+	eg.Go(func() error {
+		for i := 0; i < 1000; i++ {
+			_, _ = db.List(ctx, "")
+		}
+		return nil
+	})
+	eg.Go(func() error {
+		for i := 0; i < 1000; i++ {
+			db.Put(ctx, fmt.Sprint(i), new(anypb.Any))
+		}
+		return nil
+	})
+	eg.Wait()
+}