diff --git a/client.go b/client.go
index 3ecf86f..04643c9 100644
--- a/client.go
+++ b/client.go
@@ -165,6 +165,9 @@ func (c *Client) HTTPClient() *http.Client {
 //
 //	s := client.String()
 func (c *Client) String() string {
+	if c == nil {
+		return "forge.Client{<nil>}"
+	}
 	tokenState := "unset"
 	if c.HasToken() {
 		tokenState = "set"
diff --git a/forge.go b/forge.go
index fab6e2e..3c3a976 100644
--- a/forge.go
+++ b/forge.go
@@ -117,6 +117,12 @@ func (f *Forge) HasToken() bool { return f.client.HasToken() }
 //
 //	s := f.String()
 func (f *Forge) String() string {
+	if f == nil {
+		return "forge.Forge{<nil>}"
+	}
+	if f.client == nil {
+		return "forge.Forge{client=<nil>}"
+	}
 	return "forge.Forge{" + f.client.String() + "}"
 }
 
diff --git a/resource.go b/resource.go
index d2f34f1..712a610 100644
--- a/resource.go
+++ b/resource.go
@@ -27,6 +27,9 @@ type Resource[T any, C any, U any] struct {
 //
 //	s := res.String()
 func (r *Resource[T, C, U]) String() string {
+	if r == nil {
+		return "forge.Resource{<nil>}"
+	}
 	return core.Concat(
 		"forge.Resource{path=",
 		strconv.Quote(r.path),
diff --git a/stringer_nil_test.go b/stringer_nil_test.go
new file mode 100644
index 0000000..8295a68
--- /dev/null
+++ b/stringer_nil_test.go
@@ -0,0 +1,48 @@
+package forge
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestClient_String_NilSafe(t *testing.T) {
+	var c *Client
+	want := "forge.Client{<nil>}"
+	if got := c.String(); got != want {
+		t.Fatalf("got String()=%q, want %q", got, want)
+	}
+	if got := fmt.Sprint(c); got != want {
+		t.Fatalf("got fmt.Sprint=%q, want %q", got, want)
+	}
+	if got := fmt.Sprintf("%#v", c); got != want {
+		t.Fatalf("got GoString=%q, want %q", got, want)
+	}
+}
+
+func TestForge_String_NilSafe(t *testing.T) {
+	var f *Forge
+	want := "forge.Forge{<nil>}"
+	if got := f.String(); got != want {
+		t.Fatalf("got String()=%q, want %q", got, want)
+	}
+	if got := fmt.Sprint(f); got != want {
+		t.Fatalf("got fmt.Sprint=%q, want %q", got, want)
+	}
+	if got := fmt.Sprintf("%#v", f); got != want {
+		t.Fatalf("got GoString=%q, want %q", got, want)
+	}
+}
+
+func TestResource_String_NilSafe(t *testing.T) {
+	var r *Resource[int, struct{}, struct{}]
+	want := "forge.Resource{<nil>}"
+	if got := r.String(); got != want {
+		t.Fatalf("got String()=%q, want %q", got, want)
+	}
+	if got := fmt.Sprint(r); got != want {
+		t.Fatalf("got fmt.Sprint=%q, want %q", got, want)
+	}
+	if got := fmt.Sprintf("%#v", r); got != want {
+		t.Fatalf("got GoString=%q, want %q", got, want)
+	}
+}