diff --git a/.devcontainer.json b/.devcontainer.json
new file mode 100644
index 0000000..ff95e18
--- /dev/null
+++ b/.devcontainer.json
@@ -0,0 +1,24 @@
+{
+    "name": "inchi-gem",
+    "image": "ruby:3.3.10",
+    "features": {
+        "ghcr.io/devcontainers/features/common-utils:2": {
+            "installZsh": true,
+            "configureZshAsDefaultShell": true,
+            "installOhMyZsh": true,
+            "installOhMyZshConfig": true,
+            "upgradePackages": true,
+            "username": "automatic",
+            "userUid": "automatic",
+            "userGid": "automatic"
+        }
+    },
+    "customizations": {
+        "vscode": {
+            "extensions": [
+                "eamodio.gitlens"
+            ]
+        }
+    },
+    "postCreateCommand": "apt-get update && apt-get install cmake -y"
+}
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index 9cd31e4..2af8972 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,10 +4,9 @@ Gemfile.lock
 pkg/*
 
 # ignore build artifacts
-ext/inchi-gem/Makefile
-ext/inchi-gem/inchi/
-ext/inchi-gem/inchi.o
-ext/inchi-gem/inchi_wrap.*
+ext/inchi-gem/*
 
+!ext/inchi-gem/extconf.rb
+!ext/inchi-gem/inchi.c
 
 .tool-versions
diff --git a/ext/inchi-gem/extconf.rb b/ext/inchi-gem/extconf.rb
index 1a5ba93..0efa2b8 100644
--- a/ext/inchi-gem/extconf.rb
+++ b/ext/inchi-gem/extconf.rb
@@ -2,153 +2,28 @@
 require 'rbconfig'
 require 'mkmf'
 
-# current dir
 main_dir = File.expand_path(File.join(File.dirname(__FILE__)))
+inchi_src = File.join(main_dir, "inchi_src")
+libinchi_src = File.join(inchi_src, "INCHI-1-SRC/INCHI_API/libinchi/src")
+libinchi_build = File.join(inchi_src, "build")
+inchi_version = "d124ee52b4de0ed3d608d2a3d522b939f01f2549"
 
-# ext/inchi-gem/inchi
-inchi_src_dir = File.join(main_dir, "inchi")
-
-FileUtils.rm_rf inchi_src_dir
-
+### Download InChI source
+FileUtils.rm_rf inchi_src
 Dir.chdir main_dir
-puts "Downloading InChI sources"
-# ext/inchi-gem/inchi/
-system "git clone https://github.com/CamAnNguyen/inchi" or abort
-
-# ext/inchi-gem/inchi/INCHI_BASE/src -> inchi-gem/build/inchi/INCHI_API/libinchi/src
-FileUtils.cp_r("#{inchi_src_dir}/INCHI_BASE/src/.", "#{inchi_src_dir}/INCHI_API/libinchi/src")
-
-inc_dirs = '-I. -I./inchi/INCHI_API/libinchi/src'
+system("git clone --no-checkout --filter=tree:0 https://github.com/IUPAC-InChI/InChI.git #{inchi_src}") or abort
+Dir.chdir inchi_src
+system("git fetch --depth 1 origin #{inchi_version}") or abort
+system("git sparse-checkout set --no-cone /INCHI-1-SRC") or abort
+system("git checkout #{inchi_version}") or abort
 
-system("swig #{inc_dirs} -c++ -ruby inchi.i") or abort
+### Compile InChI
+system("cmake -B #{libinchi_build} -S #{libinchi_src}") or abort
+system("cmake --build #{libinchi_build}") or abort
 
-$INCFLAGS << inc_dirs
-$CFLAGS << " -DTARGET_API_LIB"
+### Configure Ruby extension
+find_library('inchi', "MakeINCHIFromMolfileText", File.join(libinchi_build, "lib"))
+find_header('inchi_api.h', File.join(inchi_src, "/INCHI-1-SRC/INCHI_BASE/src"))
 
-$srcs = [
-  'inchi.cpp',
-  'inchi_wrap.cxx',
-  './inchi/INCHI_API/libinchi/src/ichi_bns.c',
-  './inchi/INCHI_API/libinchi/src/ichi_io.c',
-  './inchi/INCHI_API/libinchi/src/ichican2.c',
-  './inchi/INCHI_API/libinchi/src/ichicano.c',
-  './inchi/INCHI_API/libinchi/src/ichicans.c',
-  './inchi/INCHI_API/libinchi/src/ichierr.c',
-  './inchi/INCHI_API/libinchi/src/ichiisot.c',
-  './inchi/INCHI_API/libinchi/src/ichilnct.c',
-  './inchi/INCHI_API/libinchi/src/ichimak2.c',
-  './inchi/INCHI_API/libinchi/src/ichimake.c',
-  './inchi/INCHI_API/libinchi/src/ichimap1.c',
-  './inchi/INCHI_API/libinchi/src/ichimap2.c',
-  './inchi/INCHI_API/libinchi/src/ichimap4.c',
-  './inchi/INCHI_API/libinchi/src/ichinorm.c',
-  './inchi/INCHI_API/libinchi/src/ichiparm.c',
-  './inchi/INCHI_API/libinchi/src/ichiprt1.c',
-  './inchi/INCHI_API/libinchi/src/ichiprt2.c',
-  './inchi/INCHI_API/libinchi/src/ichiprt3.c',
-  './inchi/INCHI_API/libinchi/src/ichiqueu.c',
-  './inchi/INCHI_API/libinchi/src/ichiread.c',
-  './inchi/INCHI_API/libinchi/src/ichiring.c',
-  './inchi/INCHI_API/libinchi/src/ichirvr1.c',
-  './inchi/INCHI_API/libinchi/src/ichirvr2.c',
-  './inchi/INCHI_API/libinchi/src/ichirvr3.c',
-  './inchi/INCHI_API/libinchi/src/ichirvr4.c',
-  './inchi/INCHI_API/libinchi/src/ichirvr5.c',
-  './inchi/INCHI_API/libinchi/src/ichirvr6.c',
-  './inchi/INCHI_API/libinchi/src/ichirvr7.c',
-  './inchi/INCHI_API/libinchi/src/ichisort.c',
-  './inchi/INCHI_API/libinchi/src/ichister.c',
-  './inchi/INCHI_API/libinchi/src/ichitaut.c',
-  './inchi/INCHI_API/libinchi/src/ikey_base26.c',
-  './inchi/INCHI_API/libinchi/src/ikey_dll.c',
-  './inchi/INCHI_API/libinchi/src/inchi_dll.c',
-  './inchi/INCHI_API/libinchi/src/inchi_dll_a.c',
-  './inchi/INCHI_API/libinchi/src/inchi_dll_a2.c',
-  './inchi/INCHI_API/libinchi/src/inchi_dll_b.c',
-  './inchi/INCHI_API/libinchi/src/inchi_dll_main.c',
-  './inchi/INCHI_API/libinchi/src/inchi_gui.c',
-  './inchi/INCHI_API/libinchi/src/mol2atom.c',
-  './inchi/INCHI_API/libinchi/src/mol_fmt1.c',
-  './inchi/INCHI_API/libinchi/src/mol_fmt2.c',
-  './inchi/INCHI_API/libinchi/src/mol_fmt3.c',
-  './inchi/INCHI_API/libinchi/src/mol_fmt4.c',
-  './inchi/INCHI_API/libinchi/src/readinch.c',
-  './inchi/INCHI_API/libinchi/src/runichi.c',
-  './inchi/INCHI_API/libinchi/src/runichi2.c',
-  './inchi/INCHI_API/libinchi/src/runichi3.c',
-  './inchi/INCHI_API/libinchi/src/runichi4.c',
-  './inchi/INCHI_API/libinchi/src/sha2.c',
-  './inchi/INCHI_API/libinchi/src/strutil.c',
-  './inchi/INCHI_API/libinchi/src/util.c',
-  './inchi/INCHI_API/libinchi/src/ixa/ixa_builder.c',
-  './inchi/INCHI_API/libinchi/src/ixa/ixa_inchikey_builder.c',
-  './inchi/INCHI_API/libinchi/src/ixa/ixa_mol.c',
-  './inchi/INCHI_API/libinchi/src/ixa/ixa_read_inchi.c',
-  './inchi/INCHI_API/libinchi/src/ixa/ixa_read_mol.c',
-  './inchi/INCHI_API/libinchi/src/ixa/ixa_status.c',
-]
-
-$objs = [
-  'inchi.o',
-  'inchi_wrap.o',
-  './inchi/INCHI_API/libinchi/src/ichi_bns.o',
-  './inchi/INCHI_API/libinchi/src/ichi_io.o',
-  './inchi/INCHI_API/libinchi/src/ichican2.o',
-  './inchi/INCHI_API/libinchi/src/ichicano.o',
-  './inchi/INCHI_API/libinchi/src/ichicans.o',
-  './inchi/INCHI_API/libinchi/src/ichierr.o',
-  './inchi/INCHI_API/libinchi/src/ichiisot.o',
-  './inchi/INCHI_API/libinchi/src/ichilnct.o',
-  './inchi/INCHI_API/libinchi/src/ichimak2.o',
-  './inchi/INCHI_API/libinchi/src/ichimake.o',
-  './inchi/INCHI_API/libinchi/src/ichimap1.o',
-  './inchi/INCHI_API/libinchi/src/ichimap2.o',
-  './inchi/INCHI_API/libinchi/src/ichimap4.o',
-  './inchi/INCHI_API/libinchi/src/ichinorm.o',
-  './inchi/INCHI_API/libinchi/src/ichiparm.o',
-  './inchi/INCHI_API/libinchi/src/ichiprt1.o',
-  './inchi/INCHI_API/libinchi/src/ichiprt2.o',
-  './inchi/INCHI_API/libinchi/src/ichiprt3.o',
-  './inchi/INCHI_API/libinchi/src/ichiqueu.o',
-  './inchi/INCHI_API/libinchi/src/ichiread.o',
-  './inchi/INCHI_API/libinchi/src/ichiring.o',
-  './inchi/INCHI_API/libinchi/src/ichirvr1.o',
-  './inchi/INCHI_API/libinchi/src/ichirvr2.o',
-  './inchi/INCHI_API/libinchi/src/ichirvr3.o',
-  './inchi/INCHI_API/libinchi/src/ichirvr4.o',
-  './inchi/INCHI_API/libinchi/src/ichirvr5.o',
-  './inchi/INCHI_API/libinchi/src/ichirvr6.o',
-  './inchi/INCHI_API/libinchi/src/ichirvr7.o',
-  './inchi/INCHI_API/libinchi/src/ichisort.o',
-  './inchi/INCHI_API/libinchi/src/ichister.o',
-  './inchi/INCHI_API/libinchi/src/ichitaut.o',
-  './inchi/INCHI_API/libinchi/src/ikey_base26.o',
-  './inchi/INCHI_API/libinchi/src/ikey_dll.o',
-  './inchi/INCHI_API/libinchi/src/inchi_dll.o',
-  './inchi/INCHI_API/libinchi/src/inchi_dll_a.o',
-  './inchi/INCHI_API/libinchi/src/inchi_dll_a2.o',
-  './inchi/INCHI_API/libinchi/src/inchi_dll_b.o',
-  './inchi/INCHI_API/libinchi/src/inchi_dll_main.o',
-  './inchi/INCHI_API/libinchi/src/inchi_gui.o',
-  './inchi/INCHI_API/libinchi/src/mol2atom.o',
-  './inchi/INCHI_API/libinchi/src/mol_fmt1.o',
-  './inchi/INCHI_API/libinchi/src/mol_fmt2.o',
-  './inchi/INCHI_API/libinchi/src/mol_fmt3.o',
-  './inchi/INCHI_API/libinchi/src/mol_fmt4.o',
-  './inchi/INCHI_API/libinchi/src/readinch.o',
-  './inchi/INCHI_API/libinchi/src/runichi.o',
-  './inchi/INCHI_API/libinchi/src/runichi2.o',
-  './inchi/INCHI_API/libinchi/src/runichi3.o',
-  './inchi/INCHI_API/libinchi/src/runichi4.o',
-  './inchi/INCHI_API/libinchi/src/sha2.o',
-  './inchi/INCHI_API/libinchi/src/strutil.o',
-  './inchi/INCHI_API/libinchi/src/util.o',
-  './inchi/INCHI_API/libinchi/src/ixa/ixa_builder.o',
-  './inchi/INCHI_API/libinchi/src/ixa/ixa_inchikey_builder.o',
-  './inchi/INCHI_API/libinchi/src/ixa/ixa_mol.o',
-  './inchi/INCHI_API/libinchi/src/ixa/ixa_read_inchi.o',
-  './inchi/INCHI_API/libinchi/src/ixa/ixa_read_mol.o',
-  './inchi/INCHI_API/libinchi/src/ixa/ixa_status.o',
-]
-
-create_makefile('inchi')
+Dir.chdir main_dir
+create_makefile("inchi")
diff --git a/ext/inchi-gem/inchi.c b/ext/inchi-gem/inchi.c
new file mode 100644
index 0000000..b1ca967
--- /dev/null
+++ b/ext/inchi-gem/inchi.c
@@ -0,0 +1,122 @@
+#include <ruby.h>
+#include <inchi_api.h>
+#include <string.h>
+
+
+typedef struct {
+    int    returnCode;
+    VALUE  message; 
+    VALUE  log;
+    VALUE  auxInfo;
+} rb_ExtraInchiReturnValues;
+
+static void
+rb_eirv_free(void *ptr)
+{
+    ruby_xfree(ptr);
+}
+
+static const rb_data_type_t rb_eirv_type = {
+    "ExtraInchiReturnValues",
+    {0, rb_eirv_free, 0},
+    0, 0,
+    RUBY_TYPED_FREE_IMMEDIATELY
+};
+
+static VALUE
+rb_eirv_alloc(VALUE klass)
+{
+    rb_ExtraInchiReturnValues *p;
+    VALUE obj = TypedData_Make_Struct(klass, rb_ExtraInchiReturnValues,
+                                      &rb_eirv_type, p);
+    p->returnCode = 0;
+    p->message    = Qnil;
+    p->log        = Qnil;
+    p->auxInfo    = Qnil;
+    return obj;
+}
+
+static void
+fix_option_symbols(const char *in, char *out)
+{
+    const char *s = in;
+    char *d = out;
+    while ((*d = *s)) {
+#ifdef _WIN32
+        if (*d == '-') *d = '/';
+#else
+        if (*d == '/') *d = '-';
+#endif
+        ++d; ++s;
+    }
+}
+
+static VALUE
+rb_molfile_to_inchi(int argc, VALUE *argv, VALUE self)
+{
+    VALUE rb_mol, rb_rv, rb_opts;
+    rb_scan_args(argc, argv, "21", &rb_mol, &rb_rv, &rb_opts);
+    if (NIL_P(rb_opts)) rb_opts = rb_str_new2("");
+
+    Check_Type(rb_mol,  T_STRING);
+    Check_Type(rb_opts, T_STRING);
+
+    rb_ExtraInchiReturnValues *rv;
+    TypedData_Get_Struct(rb_rv, rb_ExtraInchiReturnValues,
+                         &rb_eirv_type, rv);
+
+    const char *mol_text = RSTRING_PTR(rb_mol);
+    const char *opts_in  = RSTRING_LEN(rb_opts) ? RSTRING_PTR(rb_opts) : NULL;
+
+    char *opts_copy = NULL;
+    if (opts_in) {
+        opts_copy = ALLOCA_N(char, RSTRING_LEN(rb_opts) + 1);
+        fix_option_symbols(opts_in, opts_copy);
+    }
+
+    inchi_Output out;
+    memset(&out, 0, sizeof(out));
+
+    int ret = MakeINCHIFromMolfileText(mol_text, opts_copy, &out);
+
+    rv->returnCode = ret;
+    rv->message = (out.szMessage ? rb_str_new2(out.szMessage) : Qnil);
+    rv->log     = (out.szLog     ? rb_str_new2(out.szLog)     : Qnil);
+    rv->auxInfo = (out.szAuxInfo ? rb_str_new2(out.szAuxInfo) : Qnil);
+    VALUE result = out.szInChI ? rb_str_new2(out.szInChI) : rb_str_new2("");
+    FreeINCHI(&out);
+    return result;
+}
+
+static VALUE
+rb_inchi_to_inchi_key(VALUE self, VALUE rb_inchi)
+{
+    Check_Type(rb_inchi, T_STRING);
+    const char *inchi = RSTRING_PTR(rb_inchi);
+
+    char inchi_key[29], xtra1[65], xtra2[65];
+    int rc = GetINCHIKeyFromINCHI(inchi, 0, 0, inchi_key, xtra1, xtra2);
+
+    if (rc == INCHIKEY_OK)
+        return rb_str_new2(inchi_key);
+
+    return Qnil;
+}
+
+void
+Init_inchi(void)
+{
+    VALUE mInchi = rb_define_module("Inchi");
+
+    VALUE cRV = rb_define_class_under(mInchi, "ExtraInchiReturnValues", rb_cObject);
+    rb_define_alloc_func(cRV, rb_eirv_alloc);
+    rb_define_attr(cRV, "returnCode", 1, 1);
+    rb_define_attr(cRV, "message",    1, 1);
+    rb_define_attr(cRV, "log",        1, 1);
+    rb_define_attr(cRV, "auxInfo",    1, 1);
+
+    rb_define_module_function(mInchi, "molfileToInchi",
+                            rb_molfile_to_inchi, -1);
+    rb_define_module_function(mInchi, "InchiToInchiKey",
+                            rb_inchi_to_inchi_key, 1);
+}
diff --git a/ext/inchi-gem/inchi.cpp b/ext/inchi-gem/inchi.cpp
deleted file mode 100644
index 2da17e6..0000000
--- a/ext/inchi-gem/inchi.cpp
+++ /dev/null
@@ -1,109 +0,0 @@
-#include <string>
-#include <inchi_api.h>
-#include <cstring>
-#include <vector>
-#include <stack>
-#include <set>
-#include <queue>
-#include <algorithm>
-#include <iostream>
-
-#include "inchi.h"
-
-typedef std::pair<int, int> INT_PAIR;
-typedef std::vector<INT_PAIR> INT_PAIR_VECT;
-
-void fixOptionSymbol(const char* in, char* out) {
-  unsigned int i;
-  for (i = 0; i < strlen(in); i++) {
-#ifdef _WIN32
-    if (in[i] == '-') {
-      out[i] = '/';
-
-#else
-    if (in[i] == '/') {
-      out[i] = '-';
-
-#endif
-    } else {
-      out[i] = in[i];
-    }
-  }
-  out[i] = '\0';
-}
-
-std::string molfileToInchi(const std::string& molBlock,
-  ExtraInchiReturnValues& rv, const char* options) {
-  // create output
-  inchi_Output output;
-  memset((void*)&output, 0, sizeof(output));
-  // call DLL
-  std::string inchi;
-  {
-    char* _options = nullptr;
-    if (options) {
-      _options = new char[strlen(options) + 1];
-      fixOptionSymbol(options, _options);
-      options = _options;
-    }
-
-    int retcode = MakeINCHIFromMolfileText(molBlock.c_str(), (char*)options, &output);
-
-    // generate output
-    rv.returnCode = retcode;
-    if (output.szInChI) {
-      inchi = std::string(output.szInChI);
-    }
-    if (output.szMessage) {
-      rv.messagePtr = std::string(output.szMessage);
-    }
-    if (output.szLog) {
-      rv.logPtr = std::string(output.szLog);
-    }
-    if (output.szAuxInfo) {
-      rv.auxInfoPtr = std::string(output.szAuxInfo);
-    }
-
-    // clean up
-    FreeINCHI(&output);
-    delete[] _options;
-  }
-
-  return inchi;
-}
-
-std::string InchiToInchiKey(const std::string& inchi) {
-  char inchiKey[29];
-  char xtra1[65], xtra2[65];
-  int ret = 0;
-
-  {
-    ret = GetINCHIKeyFromINCHI(inchi.c_str(), 0, 0, inchiKey, xtra1, xtra2);
-  }
-
-  std::string error;
-  switch (ret) {
-    case INCHIKEY_OK:
-      return std::string(inchiKey);
-    case INCHIKEY_UNKNOWN_ERROR:
-      error = "Unknown error";
-      break;
-    case INCHIKEY_EMPTY_INPUT:
-      error = "Empty input";
-      break;
-    case INCHIKEY_INVALID_INCHI_PREFIX:
-      error = "Invalid InChI prefix";
-      break;
-    case INCHIKEY_NOT_ENOUGH_MEMORY:
-      error = "Not enough memory";
-      break;
-    case INCHIKEY_INVALID_INCHI:
-      error = "Invalid input InChI string";
-      break;
-    case INCHIKEY_INVALID_STD_INCHI:
-      error = "Invalid standard InChI string";
-      break;
-  }
-
-  return std::string();
-}
diff --git a/ext/inchi-gem/inchi.h b/ext/inchi-gem/inchi.h
deleted file mode 100644
index bddede8..0000000
--- a/ext/inchi-gem/inchi.h
+++ /dev/null
@@ -1,21 +0,0 @@
-#ifndef INCHI_H_
-#define INCHI_H_
-
-#include <string>
-
-typedef std::vector<std::string> MolVect;
-
-struct ExtraInchiReturnValues {
-  int returnCode;
-  std::string messagePtr;
-  std::string logPtr;
-  std::string auxInfoPtr;  // not used for InchiToMol
-};
-
-/* options: space-delimited;
-   each is preceded by '/' or '-' depending on OS and compiler */
-std::string molfileToInchi(const std::string& mol,
-  ExtraInchiReturnValues& rv, const char* options = NULL);
-std::string InchiToInchiKey(const std::string& inchi);
-
-#endif /* INCHI_H_ */
diff --git a/ext/inchi-gem/inchi.i b/ext/inchi-gem/inchi.i
deleted file mode 100644
index 54be3a8..0000000
--- a/ext/inchi-gem/inchi.i
+++ /dev/null
@@ -1,9 +0,0 @@
-%module inchi
-
-%include stl.i
-
-%{
-#include "inchi.h"
-%}
-
-%include "inchi.h"