diff --git a/src/core_ffi/py_ffi/CMakeLists.txt b/src/core_ffi/py_ffi/CMakeLists.txt
index 4d46608..c351ec8 100644
--- a/src/core_ffi/py_ffi/CMakeLists.txt
+++ b/src/core_ffi/py_ffi/CMakeLists.txt
@@ -11,12 +11,14 @@ pybind11_add_module(klotski_py
     binder/short_code.cc
     binder/group_union.cc
     binder/group.cc
+    binder/fast_cal.cc
 
     wrapper/short_code.cc
     wrapper/common_codec.cc
     wrapper/cases.cc
     wrapper/group_union.cc
     wrapper/group.cc
+    wrapper/fast_cal.cc
 )
 target_include_directories(klotski_py PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include)
 target_link_libraries(klotski_py PRIVATE klotski::core)
diff --git a/src/core_ffi/py_ffi/binder/fast_cal.cc b/src/core_ffi/py_ffi/binder/fast_cal.cc
new file mode 100644
index 0000000..b2d0397
--- /dev/null
+++ b/src/core_ffi/py_ffi/binder/fast_cal.cc
@@ -0,0 +1,12 @@
+#include <py_ffi/fast_cal.h>
+
+#include "binder.h"
+
+void bind_fast_cal(const py::module_ &m) {
+    py::class_<PyFastCal>(m, "FastCal")
+        .def(py::init<PyCommonCode>())
+        .def("solve", &PyFastCal::solve)
+        .def("exports", &PyFastCal::exports)
+        .def("build_all", &PyFastCal::build_all)
+        .def("backtrack", &PyFastCal::backtrack);
+}
diff --git a/src/core_ffi/py_ffi/include/binder.h b/src/core_ffi/py_ffi/include/binder.h
index ce6c315..237491e 100644
--- a/src/core_ffi/py_ffi/include/binder.h
+++ b/src/core_ffi/py_ffi/include/binder.h
@@ -10,6 +10,7 @@ namespace py = pybind11;
 #include "py_ffi/group.h"
 #include "py_ffi/short_code.h"
 #include "py_ffi/common_code.h"
+#include "py_ffi/fast_cal.h"
 
 using klotski::ffi::PyCases;
 using klotski::ffi::PyCasesIter;
@@ -17,6 +18,7 @@ using klotski::ffi::PyShortCode;
 using klotski::ffi::PyCommonCode;
 using klotski::ffi::PyGroupUnion;
 using klotski::ffi::PyGroup;
+using klotski::ffi::PyFastCal;
 
 void bind_cases(const py::module_ &m);
 void bind_short_code(const py::module_ &m);
@@ -24,3 +26,5 @@ void bind_common_code(const py::module_ &m);
 
 void bind_group_union(const py::module_ &m);
 void bind_group(const py::module_ &m);
+
+void bind_fast_cal(const py::module_ &m);
diff --git a/src/core_ffi/py_ffi/include/exception.h b/src/core_ffi/py_ffi/include/exception.h
index 0ba2169..616b61d 100644
--- a/src/core_ffi/py_ffi/include/exception.h
+++ b/src/core_ffi/py_ffi/include/exception.h
@@ -1,5 +1,3 @@
-/// Klotski Engine Python FFI by Dnomd343 @2024
-
 #pragma once
 
 #include <string>
diff --git a/src/core_ffi/py_ffi/include/py_ffi/fast_cal.h b/src/core_ffi/py_ffi/include/py_ffi/fast_cal.h
new file mode 100644
index 0000000..656a8a5
--- /dev/null
+++ b/src/core_ffi/py_ffi/include/py_ffi/fast_cal.h
@@ -0,0 +1,63 @@
+/// Klotski Engine Python FFI by Dnomd343 @2024
+
+#pragma once
+
+#include <fast_cal/fast_cal.h>
+
+#include "py_ffi/common_code.h"
+
+namespace klotski::ffi {
+
+using fast_cal::FastCal;
+
+class PyFastCal {
+public:
+    explicit PyFastCal(PyCommonCode code)
+        : fast_cal_(FastCal(std::bit_cast<CommonCode>(code).to_raw_code())) {}
+
+    // TODO: export solution path directly
+    std::optional<PyCommonCode> solve() {
+        auto tmp = fast_cal_.solve();
+        if (tmp.has_value()) {
+            return std::bit_cast<PyCommonCode>(tmp.value().to_common_code());
+        }
+        return std::nullopt;
+    }
+
+    // std::vector<PyCommonCode> solve_multi();
+
+    void build_all() {
+        fast_cal_.build_all();
+    }
+
+    [[nodiscard]] std::vector<PyCommonCode> backtrack(PyCommonCode code) const {
+        std::vector<PyCommonCode> path;
+        for (auto x : fast_cal_.backtrack(std::bit_cast<CommonCode>(code).to_raw_code())) {
+            path.emplace_back(std::bit_cast<PyCommonCode>(x.to_common_code()));
+        }
+        return path;
+    }
+
+    [[nodiscard]] std::vector<std::vector<PyCommonCode>> exports() const {
+        std::vector<std::vector<PyCommonCode>> result;
+
+        const auto data = fast_cal_.exports();
+        result.reserve(data.size());
+        for (const auto &layer_raw : data) {
+            std::vector<PyCommonCode> layer;
+            layer.reserve(layer_raw.size());
+            for (auto x : layer_raw) {
+                layer.emplace_back(std::bit_cast<PyCommonCode>(x.to_common_code()));
+            }
+            result.emplace_back(layer);
+        }
+
+        return result;
+    }
+
+private:
+    // TODO: add double call protect
+    FastCal fast_cal_;
+};
+
+} // namespace klotski::ffi
diff --git a/src/core_ffi/py_ffi/klotski.cc b/src/core_ffi/py_ffi/klotski.cc
index d33c2b1..6787c5d 100644
--- a/src/core_ffi/py_ffi/klotski.cc
+++ b/src/core_ffi/py_ffi/klotski.cc
@@ -12,16 +12,9 @@
 
 namespace py = pybind11;
 
-// using klotski::ffi::PyCases;
-// using klotski::ffi::PyShortCode;
-// using klotski::ffi::PyCommonCode;
-
 using klotski::ffi::PyExc_CodecError;
 using klotski::ffi::PyExc_GroupError;
 
-// using klotski::ffi::PyGroup;
-// using klotski::ffi::PyGroupUnion;
-
 #include "group/group.h"
 #include "all_cases/all_cases.h"
 
@@ -47,6 +40,7 @@ PYBIND11_MODULE(klotski, m) {
     bind_common_code(m);
     bind_group(m);
     bind_group_union(m);
+    bind_fast_cal(m);
 
     m.attr("__version__") = "version field";
 }
diff --git a/src/core_ffi/py_ffi/wrapper/fast_cal.cc b/src/core_ffi/py_ffi/wrapper/fast_cal.cc
new file mode 100644
index 0000000..30aaa4f
--- /dev/null
+++ b/src/core_ffi/py_ffi/wrapper/fast_cal.cc
@@ -0,0 +1 @@
+#include "py_ffi/fast_cal.h"