diff --git a/internal/config/config.go b/internal/config/config.go
index 2a3a76f..3795d3b 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -81,7 +81,7 @@ func (c Config) Validate() error {
 		}
 	}
 
-	if c.Configs.Host.set {
+	if c.Configs.Master.set {
 		if err := c.Configs.Master.Validate(); err != nil {
 			return fmt.Errorf("configs.master: %w", err)
 		}
diff --git a/internal/config/host.go b/internal/config/host.go
index e3b3af5..9a302ef 100644
--- a/internal/config/host.go
+++ b/internal/config/host.go
@@ -30,19 +30,19 @@ func (c HostConfig) Validate() error {
 	}
 
 	if c.LocalAddress == "" {
-		return errors.New("missing local address")
+		return errors.New("missing local_address")
 	}
 
 	if c.InternalEntrypoint == "" {
-		return errors.New("missing internal entrypoint")
+		return errors.New("missing internal_entrypoint")
 	}
 
 	if c.ExternalEntrypoint == "" {
-		return errors.New("missing external entrypoint")
+		return errors.New("missing external_entrypoint")
 	}
 
 	if c.ListenAddress == "" {
-		return errors.New("missing listen address")
+		return errors.New("missing listen_address")
 	}
 
 	return nil
diff --git a/internal/roles/host/host.go b/internal/roles/host/host.go
index a97a80b..d82d0ee 100644
--- a/internal/roles/host/host.go
+++ b/internal/roles/host/host.go
@@ -23,6 +23,8 @@ type Role struct {
 
 	externalDomains []string // TODO: i don't like hardcoding external/internal logic here
 	internalDomains []string
+
+	lock sync.RWMutex
 }
 
 func New(state *app.State, config config.HostConfig) *Role {
@@ -56,6 +58,9 @@ func (r *Role) sendUpdate(domains []string, role types.Role) {
 }
 
 func (r *Role) OnTraefikUpdate(resp traefikResponse) {
+	r.lock.Lock()
+	defer r.lock.Unlock()
+
 	newInternal := resp.Domains(r.config.InternalEntrypoint)
 	newExternal := resp.Domains(r.config.ExternalEntrypoint)
 
@@ -73,6 +78,9 @@ func (r *Role) OnTraefikUpdate(resp traefikResponse) {
 }
 
 func (r *Role) Dns() (types.HostState, error) {
+	r.lock.RLock()
+	defer r.lock.RUnlock()
+
 	return types.HostState{
 		Domains:  r.internalDomains,
 		Address:  r.config.IpAddress,
@@ -81,6 +89,9 @@ func (r *Role) Dns() (types.HostState, error) {
 }
 
 func (r *Role) Nameserver() (types.HostState, error) {
+	r.lock.RLock()
+	defer r.lock.RUnlock()
+
 	return types.HostState{
 		Domains:  r.externalDomains,
 		Address:  r.config.IpAddress,
diff --git a/internal/roles/host/http.go b/internal/roles/host/http.go
deleted file mode 100644
index cd147b7..0000000
--- a/internal/roles/host/http.go
+++ /dev/null
@@ -1 +0,0 @@
-package host
diff --git a/internal/roles/master/observer.go b/internal/roles/master/observer.go
index fab3478..281aa39 100644
--- a/internal/roles/master/observer.go
+++ b/internal/roles/master/observer.go
@@ -39,6 +39,9 @@ func newObserver(
 }
 
 func (o *observer) pollNodes(ctx context.Context, onLeave func(types.Node) error) {
+	o.lock.Lock()
+	defer o.lock.Unlock()
+
 	nodes := o.state.Registry.Nodes()
 	toCheck := make([]types.Node, 0, len(nodes))
 	now := time.Now().UnixMilli()
diff --git a/internal/web/client/client.go b/internal/web/client/client.go
index 3396f6f..720ed9e 100644
--- a/internal/web/client/client.go
+++ b/internal/web/client/client.go
@@ -61,16 +61,16 @@ func (c *Client) Call(host string, path string, data any, out any) error {
 		return fmt.Errorf("http %d: %s", httpResponse.StatusCode, string(b))
 	}
 
+	var resp web.Response[json.RawMessage]
+	if err := json.NewDecoder(httpResponse.Body).Decode(&resp); err != nil {
+		return fmt.Errorf("decode response wrapper: %w", err)
+	}
+
+	if !resp.Ok {
+		return fmt.Errorf("error on the remote: %w", errors.New(resp.Err))
+	}
+
 	if out != nil {
-		var resp web.Response[json.RawMessage]
-		if err := json.NewDecoder(httpResponse.Body).Decode(&resp); err != nil {
-			return fmt.Errorf("decode response wrapper: %w", err)
-		}
-
-		if !resp.Ok {
-			return fmt.Errorf("error on the remote: %w", errors.New(resp.Err))
-		}
-
 		if err := json.Unmarshal(resp.Data, out); err != nil {
 			return fmt.Errorf("decode response body: %w", err)
 		}