diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 157317d2..6c1a9610 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -90,3 +90,36 @@ jobs:
           artifact-name: regression-test-results_musl_gcc
 
       # FIXME: We don't run invariance test on alpine yet because of difficulties with RDKit installation.
+
+
+  lint:
+    name: Code Quality
+    permissions:
+      # give only read-only access to the contents of the repository
+      # this is the only permission this job requires, so keep it to the least privilege
+      # i.e., not to issues, discussions, actions, etc.
+      contents: read
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
+        with:
+          persist-credentials: false
+
+      - name: Install Python
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
+        with:
+          python-version: "3.11"
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install ruff
+
+      # See documentation on ruff CI integration at
+      # https://docs.astral.sh/ruff/integrations/#github-actions
+      - name: Run Ruff format check
+        run: ruff format --check --output-format=github .
+
+      # Update output format to enable automatic inline annotations.
+      - name: Run Ruff check
+        run: ruff check --output-format=github .
diff --git a/INCHI-1-SRC/INCHI_API/demos/python_sample/mol2inchi.py b/INCHI-1-SRC/INCHI_API/demos/python_sample/mol2inchi.py
index ac350d7f..e2b1f0e3 100644
--- a/INCHI-1-SRC/INCHI_API/demos/python_sample/mol2inchi.py
+++ b/INCHI-1-SRC/INCHI_API/demos/python_sample/mol2inchi.py
@@ -1,108 +1,166 @@
+import gzip
 import os
 import sys
-import string
-import gzip
 from optparse import OptionParser
+
 from yapyinchi import *
+
+
 #
 #
 #
 ##############################################################################
 def show_record_results(rst, fout, flog):
     #
-    inchi_result, ikey_result, sinchi, slog, smessage, saux, sikey, sxtra1, sxtra2, ierr = rst
+    (
+        inchi_result,
+        ikey_result,
+        sinchi,
+        slog,
+        smessage,
+        saux,
+        sikey,
+        sxtra1,
+        sxtra2,
+        ierr,
+    ) = rst
     #
     if inchi_result != 0:
-        if (flog!=sys.stdout):
-            flog.write('\n  RECORD %-d\t' %  (num) )
-        if (inchi_result==1):
-            flog.write('Warning : ')
+        if flog != sys.stdout:
+            flog.write("\n  RECORD %-d\t" % (num))
+        if inchi_result == 1:
+            flog.write("Warning : ")
         else:
-            flog.write('InChI creation error (%-d) : ' % inchi_result)
-        flog.write('%-s' % smessage )
-    if inchi_result <=1 :
+            flog.write("InChI creation error (%-d) : " % inchi_result)
+        flog.write("%-s" % smessage)
+    if inchi_result <= 1:
         # no error or just warning
-        #print('%-s' % sinchi)
-        fout.write('%-s\n' % sinchi)
+        # print('%-s' % sinchi)
+        fout.write("%-s\n" % sinchi)
         # ... may compute InChIKey
-        if calc_key==1:
-            if ikey_result!=0:
-                if (fl!=sys.stdout):
-                    flog.write('RECORD %-d\t' %  (num) )
+        if calc_key == 1:
+            if ikey_result != 0:
+                if fl != sys.stdout:
+                    flog.write("RECORD %-d\t" % (num))
                 # special case: reversal of InChI failed
                 # InChIKey is computed, but the warning issued
-                if (ikey_result==11):
-                    flog.write('Warning: InChI reversal gets mismatching InChI string\n')
-                    fout.write('InChIKey=%-s\n' % sikey)
+                if ikey_result == 11:
+                    flog.write(
+                        "Warning: InChI reversal gets mismatching InChI string\n"
+                    )
+                    fout.write("InChIKey=%-s\n" % sikey)
                 else:
-                    flog.write('Key calculation error (%-d)\n' % ikey_result)
+                    flog.write("Key calculation error (%-d)\n" % ikey_result)
             else:
-                #print('InChIKey=%-s' % sikey )
-                fout.write('InChIKey=%-s\n' % sikey )
-                if (calc_xkey==1):
-                    print('XHash1=%-s' % sxtra1 )
-                    print('XHash1=%-s' % sxtra2 )
-                    fout.write('XHash1=%-s\n' % sxtra1 )
-                    fout.write('XHash2=%-s\n' % sxtra2 )
+                # print('InChIKey=%-s' % sikey )
+                fout.write("InChIKey=%-s\n" % sikey)
+                if calc_xkey == 1:
+                    print("XHash1=%-s" % sxtra1)
+                    print("XHash1=%-s" % sxtra2)
+                    fout.write("XHash1=%-s\n" % sxtra1)
+                    fout.write("XHash2=%-s\n" % sxtra2)
     if show_auxinfo:
-        fout.write('%-s\n' %  saux )
+        fout.write("%-s\n" % saux)
     return
 
 
 ##############################################################################
 def retire(code):
-    print ("Something went wrong...")
-    
-    if ( code==1 ):
-        print ("Invalid command line")
-    elif ( code==2 ):
+    print("Something went wrong...")
+
+    if code == 1:
+        print("Invalid command line")
+    elif code == 2:
         pass
-    elif( code==3 ):
-        print ("Unsupported platform")
-    elif( code==4 ):
-        print ("Could not access InChI library")
-    elif( code==5 ):
-        print ("Could not open input file")
-    elif( code==6 ):
-        print ("Could not open output file")
-    elif( code==7 ):
-        print ("Could not open log file")
+    elif code == 3:
+        print("Unsupported platform")
+    elif code == 4:
+        print("Could not access InChI library")
+    elif code == 5:
+        print("Could not open input file")
+    elif code == 6:
+        print("Could not open output file")
+    elif code == 7:
+        print("Could not open log file")
     else:
         pass
-    
-    sys.exit(code)
 
+    sys.exit(code)
 
 
 ##############################################################################
 def cl_parser():
-    parser = OptionParser(usage="""\
+    parser = OptionParser(
+        usage="""\
     Usage: %prog [options]
-    """)
-    parser.add_option('-i', '--input',
-                      type='string', action='store',
-                      help='name of input SD file (required)')
-    parser.add_option('-o', '--output',
-                      type='string', action='store',
-                      help='name of output file (default=inchi_out.txt)')
-    parser.add_option('-l', '--log',
-                      type='string', action='store',
-                      help='name of log file (errors/warnings; default=stdout)')
-    parser.add_option('-s', '--start_record',
-                      type='int', action='store',
-                      help='starting number of record to be converted')
-    parser.add_option('-e', '--end_record',
-                      type='int', action='store',
-                      help='number of the last record to be converted')
-    parser.add_option('-x', '--aux', dest='aux', 
-                    help='print auxilary info', default=False, action='store_true')
-    parser.add_option('-k', '--key', dest='key', 
-                    help='calculate InChIKey', default=False, action='store_true')
-    parser.add_option('-z', '--xtra', dest='xtra', 
-                    help='calculate extra hash complementing InChIKey', default=False, action='store_true')
-    parser.add_option('-p', '--inchi_options', 
-                      type='string', action='store',
-                      help='string with InChI options')
+    """
+    )
+    parser.add_option(
+        "-i",
+        "--input",
+        type="string",
+        action="store",
+        help="name of input SD file (required)",
+    )
+    parser.add_option(
+        "-o",
+        "--output",
+        type="string",
+        action="store",
+        help="name of output file (default=inchi_out.txt)",
+    )
+    parser.add_option(
+        "-l",
+        "--log",
+        type="string",
+        action="store",
+        help="name of log file (errors/warnings; default=stdout)",
+    )
+    parser.add_option(
+        "-s",
+        "--start_record",
+        type="int",
+        action="store",
+        help="starting number of record to be converted",
+    )
+    parser.add_option(
+        "-e",
+        "--end_record",
+        type="int",
+        action="store",
+        help="number of the last record to be converted",
+    )
+    parser.add_option(
+        "-x",
+        "--aux",
+        dest="aux",
+        help="print auxilary info",
+        default=False,
+        action="store_true",
+    )
+    parser.add_option(
+        "-k",
+        "--key",
+        dest="key",
+        help="calculate InChIKey",
+        default=False,
+        action="store_true",
+    )
+    parser.add_option(
+        "-z",
+        "--xtra",
+        dest="xtra",
+        help="calculate extra hash complementing InChIKey",
+        default=False,
+        action="store_true",
+    )
+    parser.add_option(
+        "-p",
+        "--inchi_options",
+        type="string",
+        action="store",
+        help="string with InChI options",
+    )
     opts, args = parser.parse_args()
     if not opts.input:
         parser.print_help()
@@ -112,20 +170,20 @@ def cl_parser():
     if opts.output:
         outname = opts.output
     else:
-        outname = "inchi_out.txt"    
+        outname = "inchi_out.txt"
     if opts.log:
         logname = opts.log
     else:
-        logname = "" 
+        logname = ""
 
     inchi_options = ""
     platform = what_platform()
-    if platform=='Windows':
+    if platform == "Windows":
         inchi_options = "/W60"
     else:
-        if platform=='Linux':
+        if platform == "Linux":
             inchi_options = "-W60"
- 
+
     if opts.inchi_options:
         inchi_options = inchi_options + opts.inchi_options
     if not opts.aux:
@@ -148,44 +206,55 @@ def cl_parser():
         endr = opts.end_record
     else:
         endr = -1
-    return [inname, outname, logname, inchi_options, show_auxinfo, calc_key, calc_xkey, startr, endr]
+    return [
+        inname,
+        outname,
+        logname,
+        inchi_options,
+        show_auxinfo,
+        calc_key,
+        calc_xkey,
+        startr,
+        endr,
+    ]
+
+
 ##############################################################################
-def open_files( inname, outname, logname ):
+def open_files(inname, outname, logname):
     try:
-        if  os.path.splitext(inname)[-1]==".gz":
+        if os.path.splitext(inname)[-1] == ".gz":
             f = gzip.open(inname)
         else:
             f = open(inname, "rb")
     except:
-        return ( None, 5 )            
+        return (None, 5)
     #
     try:
-        fout = open(outname, 'w')
+        fout = open(outname, "w")
     except:
-        return ( None, 6 )                        
+        return (None, 6)
     if not fout:
-        return ( None, 6 )                        
+        return (None, 6)
     #
     try:
-        if ( logname==""):
+        if logname == "":
             flog = sys.stderr
         else:
-            flog = open(logname, 'w')
+            flog = open(logname, "w")
     except:
-        return ( None, 7 )                                    
+        return (None, 7)
     if not flog:
-        return ( None, 7 )                        
-
-    return ( (f, fout, flog), 0)
+        return (None, 7)
 
+    return ((f, fout, flog), 0)
 
 
 ##############################################################################
 def banner():
-    print ("This Python demo program reads SD file and calls InChI library")
-    print ("(libinchi.dll/libinchi.so.1) function MakeINCHIFromMolfileText()")
-    print ("to generate InChI string (also generates InChIKey).")
-    print ("Note: the example is provided for illustrative purposes only.\n")
+    print("This Python demo program reads SD file and calls InChI library")
+    print("(libinchi.dll/libinchi.so.1) function MakeINCHIFromMolfileText()")
+    print("to generate InChI string (also generates InChIKey).")
+    print("Note: the example is provided for illustrative purposes only.\n")
 
 
 ##############################################################################
@@ -195,17 +264,19 @@ def clean_and_make_list_of_records(text):
         # Split string by '$$$$'
         content = text.split("$$$$")
         # Remove surplus empty record appearing after the last $4  (if any)
-        if ( len(content[-1])<2 ):    # \n
+        if len(content[-1]) < 2:  # \n
             content = content[:-1]
-    except: 
-        retire(97)    
+    except:
+        retire(97)
+
     # Clean up segments: remove surplus head linefeed in records 1-n start
     # ( it appears as we split at '$$$$' not '$$$$\n' )
     def del_head_lf(s):
         if s:
-            if s[0]=="\n":
+            if s[0] == "\n":
                 s = s[1:]
         return s
+
     content = [content[0]] + [del_head_lf(item) for item in content[1:]]
     return content
 
@@ -223,47 +294,70 @@ def del_head_lf(s):
 if not parameters:
     retire(1)
 
-inname, outname, logname, inchi_options, show_auxinfo, calc_key, calc_xkey, startr, endr = parameters    
+(
+    inname,
+    outname,
+    logname,
+    inchi_options,
+    show_auxinfo,
+    calc_key,
+    calc_xkey,
+    startr,
+    endr,
+) = parameters
 
 inchi_api = load_inchi_library("")
-if ( not inchi_api ):
-    retire(4)  
+if not inchi_api:
+    retire(4)
 
-print ("\nProcessing " + inname)
+print("\nProcessing " + inname)
 
-files, ierr = open_files( inname, outname, logname )
+files, ierr = open_files(inname, outname, logname)
 if not files:
     retire(ierr)
 
 f, fout, flog = files
 
 
-print ("\nReading, please wait..")
+print("\nReading, please wait..")
 text = f.read()
-print ("..done.")
-text = text.decode('utf-8')
+print("..done.")
+text = text.decode("utf-8")
 
 content = clean_and_make_list_of_records(text)
 
 num = nerr = 0
 for record in content:
     num = num + 1
-            
-    if (num<startr):
+
+    if num < startr:
         continue
-    if (endr>0):
-        if (num>endr):
+    if endr > 0:
+        if num > endr:
             break
-            
-    flog.write ( "\nRecord # %-ld (%-ld chars)" % (num, len(record)) )
-    #print ('{' + record + '}')
-            
-    results = inchify_molfile( record, inchi_options, show_auxinfo, calc_key, calc_xkey, inchi_api )
-            
-    show_record_results( results, fout, flog )
-    
-    inchi_result, ikey_result, sinchi, slog, smessage, saux, sikey, sxtra1, sxtra2, ierr = results
+
+    flog.write("\nRecord # %-ld (%-ld chars)" % (num, len(record)))
+    # print ('{' + record + '}')
+
+    results = inchify_molfile(
+        record, inchi_options, show_auxinfo, calc_key, calc_xkey, inchi_api
+    )
+
+    show_record_results(results, fout, flog)
+
+    (
+        inchi_result,
+        ikey_result,
+        sinchi,
+        slog,
+        smessage,
+        saux,
+        sikey,
+        sxtra1,
+        sxtra2,
+        ierr,
+    ) = results
     nerr = nerr + ierr
 
-#print ( "\nProcessed %-ld records; had %-ld errors." % (num, nerr))
-flog.write ( "\nCOMPLETED\nProcessed %-ld records with %-ld errors\n" % (num, nerr))
+# print ( "\nProcessed %-ld records; had %-ld errors." % (num, nerr))
+flog.write("\nCOMPLETED\nProcessed %-ld records with %-ld errors\n" % (num, nerr))
diff --git a/INCHI-1-SRC/INCHI_API/demos/python_sample/yapyinchi.py b/INCHI-1-SRC/INCHI_API/demos/python_sample/yapyinchi.py
index 472b50b8..f4651b32 100644
--- a/INCHI-1-SRC/INCHI_API/demos/python_sample/yapyinchi.py
+++ b/INCHI-1-SRC/INCHI_API/demos/python_sample/yapyinchi.py
@@ -1,10 +1,11 @@
-'''
+"""
 Yet another Python (3) to InChI Software Library interface
-'''
-import os
+"""
+
 import sys
-import string
 from ctypes import *
+
+
 #
 #
 #
@@ -15,34 +16,36 @@
 #
 ##############################################################################
 def what_platform():
-    ''' Returns 'Windows' or 'Linux' '''
+    """Returns 'Windows' or 'Linux'"""
     opsys = sys.platform
-    if (opsys[:3]=='win'):
+    if opsys[:3] == "win":
         return "Windows"
-    elif (opsys[:5]=='linux'):
+    elif opsys[:5] == "linux":
         return "Linux"
     else:
         return "Unsupported"
+
+
 #
 #
 #
 def load_inchi_library(path):
     #
     platform = what_platform()
-    print ("Platform =",platform)
+    print("Platform =", platform)
     libname = ""
-    if (platform=="Windows"):
+    if platform == "Windows":
         libname = path + "libinchi.dll"
-    elif (platform=="Linux"):
-        libname = path + "libinchi.so.1" #"/usr/lib/libinchi.so.1"
+    elif platform == "Linux":
+        libname = path + "libinchi.so.1"  # "/usr/lib/libinchi.so.1"
     else:
         return None
     #
-    print (libname)
+    print(libname)
     try:
-        print ("Loading InChI Software library", libname)
+        print("Loading InChI Software library", libname)
         libinchi = cdll.LoadLibrary(libname)
-        print ("..loaded.")
+        print("..loaded.")
         makeinchi = libinchi.MakeINCHIFromMolfileText
         freeinchi = libinchi.FreeINCHI
         getikey = libinchi.GetINCHIKeyFromINCHI
@@ -57,6 +60,8 @@ def load_inchi_library(path):
         return None
     #
     return (makeinchi, freeinchi, getikey)
+
+
 #
 #
 #
@@ -67,10 +72,14 @@ def load_inchi_library(path):
 class inchi_Output(Structure):
     # zero-terminated C-strings allocated by GetINCHI()
     # to deallocate all of them call FreeINCHI() (see below)
-    _fields_ = [("szInChI", POINTER(c_char) ), 
-                ("szAuxInfo", POINTER(c_char) ), 
-                ("szMessage", POINTER(c_char) ), 
-                ("szLog", POINTER(c_char) ) ]  
+    _fields_ = [
+        ("szInChI", POINTER(c_char)),
+        ("szAuxInfo", POINTER(c_char)),
+        ("szMessage", POINTER(c_char)),
+        ("szLog", POINTER(c_char)),
+    ]
+
+
 #
 #
 #
@@ -78,34 +87,38 @@ class inchi_Output(Structure):
 #
 #
 #
-def calc_inchikey( sinchi, calc_xkey, inchi_api ):
+def calc_inchikey(sinchi, calc_xkey, inchi_api):
     #
     sikey = sxtra1 = sxtra2 = ""
     makeinchi, freeinchi, getikey = inchi_api
     #
-    c_sinchi = c_char_p(sinchi.encode('utf-8'))
+    c_sinchi = c_char_p(sinchi.encode("utf-8"))
     #
     # Fixed length buffers
     #
-    szIKey  = create_string_buffer(256) 
-    szXtra1 = create_string_buffer(256) 
-    szXtra2 = create_string_buffer(256) 
+    szIKey = create_string_buffer(256)
+    szXtra1 = create_string_buffer(256)
+    szXtra2 = create_string_buffer(256)
     #
     ikey_result = getikey(c_sinchi, calc_xkey, calc_xkey, szIKey, szXtra1, szXtra2)
-    if ikey_result==0 or ikey_result==11:   
-        # 11 is a special case: 
+    if ikey_result == 0 or ikey_result == 11:
+        # 11 is a special case:
         # reversal of InChI failed, InChIKey is computed with warning issued
-        sikey = cast( szIKey, c_char_p).value.decode("utf-8")
-    if (calc_xkey==1):
-        sxtra1 = cast( szXtra1, c_char_p).value.decode("utf-8")
-        sxtra2 = cast( szXtra2, c_char_p).value.decode("utf-8")
-    #
-    return ( ikey_result, sikey, sxtra1, sxtra2 )
+        sikey = cast(szIKey, c_char_p).value.decode("utf-8")
+    if calc_xkey == 1:
+        sxtra1 = cast(szXtra1, c_char_p).value.decode("utf-8")
+        sxtra2 = cast(szXtra2, c_char_p).value.decode("utf-8")
+    #
+    return (ikey_result, sikey, sxtra1, sxtra2)
+
+
 ##############################################################################
 #
 #
 #
-def inchify_molfile( molfile, inchi_options, show_auxinfo, calc_key, calc_xkey, inchi_api ):
+def inchify_molfile(
+    molfile, inchi_options, show_auxinfo, calc_key, calc_xkey, inchi_api
+):
     #
     makeinchi, freeinchi, getikey = inchi_api
     sinchi = slog = smessage = saux = sikey = sxtra1 = sxtra2 = ""
@@ -116,24 +129,24 @@ def inchify_molfile( molfile, inchi_options, show_auxinfo, calc_key, calc_xkey,
     #
     # Fixed length buffers
     #
-    szIKey  = create_string_buffer(256) 
-    szXtra1 = create_string_buffer(256) 
-    szXtra2 = create_string_buffer(256) 
+    szIKey = create_string_buffer(256)
+    szXtra1 = create_string_buffer(256)
+    szXtra2 = create_string_buffer(256)
     #
     # Variable lenght buffers (will be reallocated by libinchi)
     #
-    szInChI     = create_string_buffer(1) 
-    szAuxInfo   = create_string_buffer(1) 
-    szMessage   = create_string_buffer(1) 
-    szLog       = create_string_buffer(1) 
-    ioutput = inchi_Output( szInChI, szAuxInfo, szMessage, szLog )
+    szInChI = create_string_buffer(1)
+    szAuxInfo = create_string_buffer(1)
+    szMessage = create_string_buffer(1)
+    szLog = create_string_buffer(1)
+    ioutput = inchi_Output(szInChI, szAuxInfo, szMessage, szLog)
     #
-    #Make InChI
+    # Make InChI
     #
-    c_molfile = c_char_p(molfile.encode('utf-8'))
-    c_inchi_options = c_char_p(inchi_options.encode('utf-8'))
+    c_molfile = c_char_p(molfile.encode("utf-8"))
+    c_inchi_options = c_char_p(inchi_options.encode("utf-8"))
     #
-    inchi_result = makeinchi( c_molfile, c_inchi_options, byref(ioutput) )
+    inchi_result = makeinchi(c_molfile, c_inchi_options, byref(ioutput))
     #
     sinchi = cast(ioutput.szInChI, c_char_p).value.decode("utf-8")
     slog = cast(ioutput.szLog, c_char_p).value.decode("utf-8").strip()
@@ -145,41 +158,54 @@ def inchify_molfile( molfile, inchi_options, show_auxinfo, calc_key, calc_xkey,
         ierr = 1
     else:
         # no error or just warning ==> may compute InChIKey if requested
-        if calc_key==1:
-            ikey_result = getikey(ioutput.szInChI, calc_xkey, calc_xkey, szIKey, szXtra1, szXtra2)
-            if ikey_result==0 or ikey_result==11:   
-                # 11 is a special case: 
+        if calc_key == 1:
+            ikey_result = getikey(
+                ioutput.szInChI, calc_xkey, calc_xkey, szIKey, szXtra1, szXtra2
+            )
+            if ikey_result == 0 or ikey_result == 11:
+                # 11 is a special case:
                 # reversal of InChI failed, InChIKey is computed with warning issued
-                sikey = cast( szIKey, c_char_p).value.decode("utf-8")
-                if (calc_xkey==1):
-                    sxtra1 = cast( szXtra1, c_char_p).value.decode("utf-8")
-                    sxtra2 = cast( szXtra2, c_char_p).value.decode("utf-8")
+                sikey = cast(szIKey, c_char_p).value.decode("utf-8")
+                if calc_xkey == 1:
+                    sxtra1 = cast(szXtra1, c_char_p).value.decode("utf-8")
+                    sxtra2 = cast(szXtra2, c_char_p).value.decode("utf-8")
     #
     #
     #
-    # Deallocate memory reallocated by inchi dll 
+    # Deallocate memory reallocated by inchi dll
     #
     # Note the trick with None (Python's NULL) assignnment to pointers
-    # which have not been actually allocated (related strings are zero-length) 
-    # within C library libinchi. 
+    # which have not been actually allocated (related strings are zero-length)
+    # within C library libinchi.
     # We passed Python buffer_strings casted to char *, not real pointers
-    # so they could not be inited with NULL (as they would be in C)... 
-    # So if say szLog or szMessage were actually not used in libinchi.dll 
-    # and were not allocated, they should be massaged to become NULL at the end, 
+    # so they could not be inited with NULL (as they would be in C)...
+    # So if say szLog or szMessage were actually not used in libinchi.dll
+    # and were not allocated, they should be massaged to become NULL at the end,
     # in order to avoid unnecessary/illegal freeing upon call of freeinchi().
     #
     # -- all above is valid on no error.
     #
-    #print (ioutput.szInChI, ioutput.szAuxInfo, ioutput.szLog, ioutput.szMessage)
-    #print ( inchi_result, "{" + sinchi +"}, {" + slog +"}, {" + smessage +"}, {" + saux + "}" )
+    # print (ioutput.szInChI, ioutput.szAuxInfo, ioutput.szLog, ioutput.szMessage)
+    # print ( inchi_result, "{" + sinchi +"}, {" + slog +"}, {" + smessage +"}, {" + saux + "}" )
     #
     #
     #
-    if len(sinchi)==0:
-        ioutput.szInChI = None # Python's NULL
-    if len(slog)==0:
+    if len(sinchi) == 0:
+        ioutput.szInChI = None  # Python's NULL
+    if len(slog) == 0:
         ioutput.szLog = None
-    if len(smessage)==0:
-       ioutput.szMessage = None
+    if len(smessage) == 0:
+        ioutput.szMessage = None
     freeinchi(byref(ioutput))
-    return ( inchi_result, ikey_result, sinchi, slog, smessage, saux, sikey, sxtra1, sxtra2, ierr)
+    return (
+        inchi_result,
+        ikey_result,
+        sinchi,
+        slog,
+        smessage,
+        saux,
+        sikey,
+        sxtra1,
+        sxtra2,
+        ierr,
+    )
diff --git a/INCHI-1-TEST/src/sdf_pipeline/core.py b/INCHI-1-TEST/src/sdf_pipeline/core.py
index 871251d8..ca05bfde 100644
--- a/INCHI-1-TEST/src/sdf_pipeline/core.py
+++ b/INCHI-1-TEST/src/sdf_pipeline/core.py
@@ -1,8 +1,9 @@
 import multiprocessing
-from queue import Empty
-from typing import Callable, TYPE_CHECKING
 from collections.abc import Generator
 from pathlib import Path
+from queue import Empty
+from typing import TYPE_CHECKING, Callable
+
 from sdf_pipeline import logger, utils
 
 if TYPE_CHECKING:
diff --git a/INCHI-1-TEST/src/sdf_pipeline/drivers.py b/INCHI-1-TEST/src/sdf_pipeline/drivers.py
index 80bd4172..3b4e9e6c 100644
--- a/INCHI-1-TEST/src/sdf_pipeline/drivers.py
+++ b/INCHI-1-TEST/src/sdf_pipeline/drivers.py
@@ -9,13 +9,15 @@
 
 """
 
-import sqlite3
 import json
-from typing import Callable, Any
+import sqlite3
+from datetime import datetime
 from functools import partial
 from pathlib import Path
-from datetime import datetime
+from typing import Any, Callable
+
 from pydantic import BaseModel, Field
+
 from sdf_pipeline import core, logger
 
 
@@ -51,18 +53,18 @@ def regression(
             number_of_consumer_processes=number_of_consumer_processes,
         ):
             molfile_id = consumer_result.molfile_id
-            assert (
-                molfile_id not in processed_molfile_ids
-            ), f"Molfile ID {molfile_id} has been processed multiple times."
+            assert molfile_id not in processed_molfile_ids, (
+                f"Molfile ID {molfile_id} has been processed multiple times."
+            )
             processed_molfile_ids.add(molfile_id)
 
             reference_query = reference_db.execute(
                 "SELECT result FROM results WHERE molfile_id = ?",
                 (molfile_id,),
             ).fetchone()
-            assert (
-                reference_query
-            ), f"Couldn't find molfile ID {molfile_id} in reference."
+            assert reference_query, (
+                f"Couldn't find molfile ID {molfile_id} in reference."
+            )
             reference_result = reference_query[0]
 
             current_result = json.dumps(consumer_result.result)
@@ -95,9 +97,9 @@ def regression(
             - processed_molfile_ids
         )
 
-        assert (
-            not unprocessed_molfile_ids
-        ), f"Reference contains molfile IDs that haven't been processed: {unprocessed_molfile_ids}."
+        assert not unprocessed_molfile_ids, (
+            f"Reference contains molfile IDs that haven't been processed: {unprocessed_molfile_ids}."
+        )
 
     reference_db.close()
 
diff --git a/INCHI-1-TEST/src/sdf_pipeline/utils.py b/INCHI-1-TEST/src/sdf_pipeline/utils.py
index 8a0c586a..c4df69af 100644
--- a/INCHI-1-TEST/src/sdf_pipeline/utils.py
+++ b/INCHI-1-TEST/src/sdf_pipeline/utils.py
@@ -1,12 +1,11 @@
 import gzip
 import random
 from pathlib import Path
-from typing import Generator, Callable
+from typing import Callable, Generator
 
 try:
     # Optional import of RDKit.
-    from rdkit import Chem
-    from rdkit import RDLogger
+    from rdkit import Chem, RDLogger
 
     # Suppress RDKit console output.
     RDLogger.DisableLog("rdApp.*")
diff --git a/INCHI-1-TEST/tests/test_executable/conftest.py b/INCHI-1-TEST/tests/test_executable/conftest.py
index 42288203..473c9a7a 100644
--- a/INCHI-1-TEST/tests/test_executable/conftest.py
+++ b/INCHI-1-TEST/tests/test_executable/conftest.py
@@ -1,9 +1,10 @@
-import pytest
 import subprocess
+from dataclasses import dataclass
+from pathlib import Path
 from sys import platform
 from typing import Callable
-from pathlib import Path
-from dataclasses import dataclass
+
+import pytest
 
 
 def pytest_addoption(parser):
diff --git a/INCHI-1-TEST/tests/test_executable/test_alex_clark_structures.py b/INCHI-1-TEST/tests/test_executable/test_alex_clark_structures.py
index bdefa1b6..722983b5 100644
--- a/INCHI-1-TEST/tests/test_executable/test_alex_clark_structures.py
+++ b/INCHI-1-TEST/tests/test_executable/test_alex_clark_structures.py
@@ -1,8 +1,9 @@
-import pytest
+import tempfile
 from pathlib import Path
+
+import pytest
 from helpers import parse_inchi_from_executable_output
 from sdf_pipeline.utils import read_records_from_gzipped_sdf
-import tempfile
 
 
 @pytest.fixture
diff --git a/INCHI-1-TEST/tests/test_executable/test_io.py b/INCHI-1-TEST/tests/test_executable/test_io.py
index dd38d1ed..74d741fa 100644
--- a/INCHI-1-TEST/tests/test_executable/test_io.py
+++ b/INCHI-1-TEST/tests/test_executable/test_io.py
@@ -1,10 +1,10 @@
 import re
-import pytest
 from pathlib import Path
+
+import pytest
 from helpers import parse_inchi_from_executable_output
 from sdf_pipeline.utils import select_records_from_gzipped_sdf
 
-
 ID_PATTERN = re.compile(r"> <ID>\n(.*?)\n\$\$\$\$", re.DOTALL)
 
 
diff --git a/INCHI-1-TEST/tests/test_executable/test_organometallics_ccdc.py b/INCHI-1-TEST/tests/test_executable/test_organometallics_ccdc.py
index c96119ca..b98a28d6 100644
--- a/INCHI-1-TEST/tests/test_executable/test_organometallics_ccdc.py
+++ b/INCHI-1-TEST/tests/test_executable/test_organometallics_ccdc.py
@@ -1,8 +1,9 @@
-import pytest
+import tempfile
 from pathlib import Path
+
+import pytest
 from helpers import parse_inchi_from_executable_output
 from sdf_pipeline.utils import read_records_from_gzipped_sdf
-import tempfile
 
 
 @pytest.fixture
diff --git a/INCHI-1-TEST/tests/test_executable/test_organometallics_pubchem.py b/INCHI-1-TEST/tests/test_executable/test_organometallics_pubchem.py
index d29d07c3..1802fe0a 100644
--- a/INCHI-1-TEST/tests/test_executable/test_organometallics_pubchem.py
+++ b/INCHI-1-TEST/tests/test_executable/test_organometallics_pubchem.py
@@ -1,8 +1,9 @@
-import pytest
+import tempfile
 from pathlib import Path
+
+import pytest
 from helpers import parse_inchi_from_executable_output
 from sdf_pipeline.utils import read_records_from_gzipped_sdf
-import tempfile
 
 
 @pytest.fixture
diff --git a/INCHI-1-TEST/tests/test_library/config/config_ci.py b/INCHI-1-TEST/tests/test_library/config/config_ci.py
index 31d4cde7..651ba0db 100644
--- a/INCHI-1-TEST/tests/test_library/config/config_ci.py
+++ b/INCHI-1-TEST/tests/test_library/config/config_ci.py
@@ -1,5 +1,6 @@
 import re
 from pathlib import Path
+
 from inchi_tests.config_models import DataConfig
 
 
diff --git a/INCHI-1-TEST/tests/test_library/config/config_pubchem_compound.py b/INCHI-1-TEST/tests/test_library/config/config_pubchem_compound.py
index cdd43596..700a15ca 100644
--- a/INCHI-1-TEST/tests/test_library/config/config_pubchem_compound.py
+++ b/INCHI-1-TEST/tests/test_library/config/config_pubchem_compound.py
@@ -1,4 +1,5 @@
 from pathlib import Path
+
 from inchi_tests.config_models import DataConfig
 from inchi_tests.utils import get_molfile_id_pubchem
 
diff --git a/INCHI-1-TEST/tests/test_library/config/config_pubchem_compound3d.py b/INCHI-1-TEST/tests/test_library/config/config_pubchem_compound3d.py
index b90cbf3f..d4c436c6 100644
--- a/INCHI-1-TEST/tests/test_library/config/config_pubchem_compound3d.py
+++ b/INCHI-1-TEST/tests/test_library/config/config_pubchem_compound3d.py
@@ -1,4 +1,5 @@
 from pathlib import Path
+
 from inchi_tests.config_models import DataConfig
 from inchi_tests.utils import get_molfile_id_pubchem
 
diff --git a/INCHI-1-TEST/tests/test_library/config/config_pubchem_substance.py b/INCHI-1-TEST/tests/test_library/config/config_pubchem_substance.py
index 01d5dd88..487b84e8 100644
--- a/INCHI-1-TEST/tests/test_library/config/config_pubchem_substance.py
+++ b/INCHI-1-TEST/tests/test_library/config/config_pubchem_substance.py
@@ -1,4 +1,5 @@
 from pathlib import Path
+
 from inchi_tests.config_models import DataConfig
 from inchi_tests.utils import get_molfile_id_pubchem
 
diff --git a/INCHI-1-TEST/tests/test_library/data/pubchem/download.py b/INCHI-1-TEST/tests/test_library/data/pubchem/download.py
index 1466afbe..cedee016 100644
--- a/INCHI-1-TEST/tests/test_library/data/pubchem/download.py
+++ b/INCHI-1-TEST/tests/test_library/data/pubchem/download.py
@@ -1,7 +1,7 @@
-import subprocess
 import shlex
-from .utils import get_dataset_arg, DOWNLOAD_PATHS, PUBCHEM_DIR
+import subprocess
 
+from .utils import DOWNLOAD_PATHS, PUBCHEM_DIR, get_dataset_arg
 
 if __name__ == "__main__":
     dataset = get_dataset_arg()
diff --git a/INCHI-1-TEST/tests/test_library/data/pubchem/utils.py b/INCHI-1-TEST/tests/test_library/data/pubchem/utils.py
index 4f358c10..9a56c6d5 100644
--- a/INCHI-1-TEST/tests/test_library/data/pubchem/utils.py
+++ b/INCHI-1-TEST/tests/test_library/data/pubchem/utils.py
@@ -1,7 +1,6 @@
 import argparse
 from pathlib import Path
 
-
 DATASETS = ["compound", "compound3d", "substance"]
 DOWNLOAD_PATHS = {
     "compound": "Compound/CURRENT-Full",
diff --git a/INCHI-1-TEST/tests/test_library/data/pubchem/validate.py b/INCHI-1-TEST/tests/test_library/data/pubchem/validate.py
index 0831be2d..cad69b20 100644
--- a/INCHI-1-TEST/tests/test_library/data/pubchem/validate.py
+++ b/INCHI-1-TEST/tests/test_library/data/pubchem/validate.py
@@ -1,7 +1,8 @@
 import hashlib
+
 from inchi_tests.utils import get_progress
-from .utils import get_dataset_arg, PUBCHEM_DIR
 
+from .utils import PUBCHEM_DIR, get_dataset_arg
 
 if __name__ == "__main__":
     dataset = get_dataset_arg()
diff --git a/INCHI-1-TEST/tests/test_library/inchi_tests/config_models.py b/INCHI-1-TEST/tests/test_library/inchi_tests/config_models.py
index e1ff0d36..36b76e64 100644
--- a/INCHI-1-TEST/tests/test_library/inchi_tests/config_models.py
+++ b/INCHI-1-TEST/tests/test_library/inchi_tests/config_models.py
@@ -1,5 +1,6 @@
 from typing import Callable
-from pydantic import BaseModel, FilePath, DirectoryPath
+
+from pydantic import BaseModel, DirectoryPath, FilePath
 
 
 class DataConfig(BaseModel):
diff --git a/INCHI-1-TEST/tests/test_library/inchi_tests/consumers.py b/INCHI-1-TEST/tests/test_library/inchi_tests/consumers.py
index b57b2259..aa369d30 100644
--- a/INCHI-1-TEST/tests/test_library/inchi_tests/consumers.py
+++ b/INCHI-1-TEST/tests/test_library/inchi_tests/consumers.py
@@ -1,8 +1,10 @@
 import ctypes
 import random
 from typing import Callable
+
 from sdf_pipeline import drivers, utils
-from inchi_tests.inchi_api import make_inchi_from_molfile_text, get_inchi_key_from_inchi
+
+from inchi_tests.inchi_api import get_inchi_key_from_inchi, make_inchi_from_molfile_text
 
 
 def regression_consumer(
diff --git a/INCHI-1-TEST/tests/test_library/inchi_tests/inchi_api.py b/INCHI-1-TEST/tests/test_library/inchi_tests/inchi_api.py
index 52b0d170..1bfdfe45 100644
--- a/INCHI-1-TEST/tests/test_library/inchi_tests/inchi_api.py
+++ b/INCHI-1-TEST/tests/test_library/inchi_tests/inchi_api.py
@@ -1,4 +1,5 @@
 """`INCHI-1-SRC/INCHI_API/demos/python_sample` stripped to the essentials."""
+
 import ctypes
 
 
diff --git a/INCHI-1-TEST/tests/test_library/inchi_tests/parse_log.py b/INCHI-1-TEST/tests/test_library/inchi_tests/parse_log.py
index 643bb4e9..1e75acdb 100644
--- a/INCHI-1-TEST/tests/test_library/inchi_tests/parse_log.py
+++ b/INCHI-1-TEST/tests/test_library/inchi_tests/parse_log.py
@@ -1,11 +1,13 @@
+import importlib
 import json
 import sys
-import importlib
-from pathlib import Path
-from difflib import SequenceMatcher
 from collections import defaultdict
+from difflib import SequenceMatcher
+from pathlib import Path
 from typing import Callable, Final, TextIO
+
 from sdf_pipeline.utils import select_records_from_gzipped_sdf
+
 from inchi_tests.utils import get_config_args
 
 
diff --git a/INCHI-1-TEST/tests/test_library/inchi_tests/run_tests.py b/INCHI-1-TEST/tests/test_library/inchi_tests/run_tests.py
index 36420681..fedeb6a2 100644
--- a/INCHI-1-TEST/tests/test_library/inchi_tests/run_tests.py
+++ b/INCHI-1-TEST/tests/test_library/inchi_tests/run_tests.py
@@ -1,14 +1,16 @@
-import os
+import importlib
 import logging
 import multiprocessing
+import os
 import sys
-import importlib
-from functools import partial
 from datetime import datetime
+from functools import partial
 from pathlib import Path
+
 from sdf_pipeline import drivers
-from inchi_tests.utils import get_current_time, get_progress, get_config_args
-from inchi_tests.consumers import regression_consumer, invariance_consumer
+
+from inchi_tests.consumers import invariance_consumer, regression_consumer
+from inchi_tests.utils import get_config_args, get_current_time, get_progress
 
 
 def main(test, inchi_lib_path, data_config) -> None:
diff --git a/INCHI-1-TEST/tests/test_library/test_multithreading.py b/INCHI-1-TEST/tests/test_library/test_multithreading.py
index 0c96ded7..09648a66 100644
--- a/INCHI-1-TEST/tests/test_library/test_multithreading.py
+++ b/INCHI-1-TEST/tests/test_library/test_multithreading.py
@@ -6,13 +6,13 @@
 and 11 means "SIGSEGV", i.e., segfault, see wikipedia.org/wiki/Signal_(IPC)#POSIX_signals.
 """
 
-import threading
 import ctypes
+import threading
 from pathlib import Path
+
 from inchi_tests.inchi_api import make_inchi_from_molfile_text
 from sdf_pipeline.utils import read_records_from_gzipped_sdf
 
-
 SDF_PATH = Path("INCHI-1-TEST/tests/test_library/data/ci/inchi.sdf.gz")
 INCHI_LIB_PATH = (
     "CMake_build/full_build/INCHI-1-SRC/INCHI_API/libinchi/src/lib/libinchi.so"
diff --git a/INCHI-1-TEST/tests/test_meta/consumers.py b/INCHI-1-TEST/tests/test_meta/consumers.py
index 51cd28a2..dffbe22a 100644
--- a/INCHI-1-TEST/tests/test_meta/consumers.py
+++ b/INCHI-1-TEST/tests/test_meta/consumers.py
@@ -1,5 +1,6 @@
 import ctypes
 from typing import Callable
+
 from sdf_pipeline import drivers
 
 
diff --git a/INCHI-1-TEST/tests/test_meta/test_drivers.py b/INCHI-1-TEST/tests/test_meta/test_drivers.py
index d85860e7..3b847920 100644
--- a/INCHI-1-TEST/tests/test_meta/test_drivers.py
+++ b/INCHI-1-TEST/tests/test_meta/test_drivers.py
@@ -1,19 +1,19 @@
-import pytest
+import json
+import logging
 import re
 import sqlite3
-import logging
-import json
+from functools import partial, reduce
 from operator import add
-from functools import reduce
 from pathlib import Path
-from functools import partial
-from sdf_pipeline import drivers, core
+
+import pytest
 from consumers import (
-    regression_consumer,
     invariance_consumer,
     raising_consumer,
+    regression_consumer,
     segfaulting_consumer,
 )
+from sdf_pipeline import core, drivers
 
 
 def _get_mcule_id(molfile: str) -> str:
diff --git a/INCHI-1-TEST/tests/test_meta/test_performance.py b/INCHI-1-TEST/tests/test_meta/test_performance.py
index 4b25b12e..8238ae9c 100644
--- a/INCHI-1-TEST/tests/test_meta/test_performance.py
+++ b/INCHI-1-TEST/tests/test_meta/test_performance.py
@@ -1,9 +1,10 @@
-import pytest
 import timeit
-from pathlib import Path
 from functools import partial
-from sdf_pipeline import drivers, core
+from pathlib import Path
+
+import pytest
 from consumers import busy_consumer, regression_consumer
+from sdf_pipeline import core, drivers
 
 
 def _get_pubchem_id(molfile: str) -> str:
diff --git a/INCHI-1-TEST/tests/test_meta/test_permutation.py b/INCHI-1-TEST/tests/test_meta/test_permutation.py
index 922b9ce9..213d5fb4 100644
--- a/INCHI-1-TEST/tests/test_meta/test_permutation.py
+++ b/INCHI-1-TEST/tests/test_meta/test_permutation.py
@@ -1,7 +1,8 @@
-import pytest
 import random
-from sdf_pipeline.utils import permute_molblock
+
+import pytest
 from rdkit import Chem
+from sdf_pipeline.utils import permute_molblock
 
 molblocks = [
     """
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 00000000..0af6896d
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,17 @@
+# this root-level pyproject.toml will cascade to all
+# python code in each section of the project
+
+[tool.ruff]
+extend-include = ["*.ipynb"]
+
+[tool.ruff.lint]
+# See https://docs.astral.sh/ruff/rules
+extend-select = [
+    "F", # pyflakes
+    "I", # isort
+]
+ignore = [
+    "F403",  # FIXME ignore issues with star imports
+    "F405",  # FIXME ignore issues with star imports
+    "E722",  # FIXME do not use bare excepts
+]