diff --git a/nip46/dynamic-signer.go b/nip46/dynamic-signer.go
index cd26572..2d8eac8 100644
--- a/nip46/dynamic-signer.go
+++ b/nip46/dynamic-signer.go
@@ -42,6 +42,7 @@ func NewDynamicSigner(
 	onEventSigned func(event nostr.Event),
 ) DynamicSigner {
 	return DynamicSigner{
+		sessions:            make(map[nostr.PubKey]Session),
 		getHandlerSecretKey: getHandlerSecretKey,
 		getUserKeyer:        getUserKeyer,
 		authorizeSigning:    authorizeSigning,
@@ -51,6 +52,9 @@ func NewDynamicSigner(
 }
 
 func (p *DynamicSigner) GetSession(clientPubkey nostr.PubKey) (Session, bool) {
+	p.Lock()
+	defer p.Unlock()
+
 	session, exists := p.sessions[clientPubkey]
 	if exists {
 		return session, true
diff --git a/nip46/static-key-signer.go b/nip46/static-key-signer.go
index 265cac9..5d4b4e3 100644
--- a/nip46/static-key-signer.go
+++ b/nip46/static-key-signer.go
@@ -26,10 +26,14 @@ type StaticKeySigner struct {
 func NewStaticKeySigner(secretKey [32]byte) StaticKeySigner {
 	return StaticKeySigner{
 		secretKey: secretKey,
+		sessions:  make(map[nostr.PubKey]Session),
 	}
 }
 
 func (p *StaticKeySigner) GetSession(clientPubkey nostr.PubKey) (Session, bool) {
+	p.Lock()
+	defer p.Unlock()
+
 	session, ok := p.sessions[clientPubkey]
 	return session, ok
 }