diff --git a/src/binding/python/openPMD.cpp b/src/binding/python/openPMD.cpp
index 1b0ca941c1..3ae13c5e3a 100644
--- a/src/binding/python/openPMD.cpp
+++ b/src/binding/python/openPMD.cpp
@@ -86,6 +86,7 @@ PYBIND11_MODULE(openpmd_api, m) {
     // feature variants
     m.attr("variants") = std::map<std::string, bool>{
         {"mpi", bool(openPMD_HAVE_MPI)},
+        {"json", bool(openPMD_HAVE_JSON)},
         {"hdf5", bool(openPMD_HAVE_HDF5)},
         {"adios1", bool(openPMD_HAVE_ADIOS1)},
         {"adios2", bool(openPMD_HAVE_ADIOS2)}