diff --git a/docs/Project.toml b/docs/Project.toml
index 9c6785c..1038a18 100644
--- a/docs/Project.toml
+++ b/docs/Project.toml
@@ -24,5 +24,6 @@ AtomsBase = "0.5.2"
 DFTK = "0.7"
 Documenter = "~1.8"
 EmpiricalPotentials = "0.2.5"
+OptimizationNLopt = "0.3.9"
 PseudoPotentialData = "0.2"
 Unitful = "1.28.0"