diff --git a/ndradex/__init__.py b/ndradex/__init__.py
index 81f666a..071ee74 100644
--- a/ndradex/__init__.py
+++ b/ndradex/__init__.py
@@ -1,9 +1,8 @@
-__all__ = ["consts", "lamda", "nd", "radex", "run"]
+__all__ = ["lamda", "nd", "radex", "run"]
 __version__ = "0.3.1"
 
 
 # dependencies
-from . import consts
 from . import lamda
 from . import nd
 from . import radex
diff --git a/ndradex/consts.py b/ndradex/consts.py
deleted file mode 100644
index 92a312e..0000000
--- a/ndradex/consts.py
+++ /dev/null
@@ -1,86 +0,0 @@
-__all__ = [
-    # ndradex-related
-    "NDRADEX",
-    "NDRADEX_CONFIG",
-    "NDRADEX_DIR",
-    # radex-related
-    "RADEX_BIN",
-    "RADEX_VERSION",
-]
-
-
-# standard library
-from os import getenv
-from pathlib import Path
-from typing import Any, Optional, TypeVar, overload
-
-
-# dependencies
-from tomlkit import load
-
-
-# type hints
-T = TypeVar("T")
-
-
-# helper functions
-def ensure(toml: Path) -> Path:
-    """Create an empty TOML file if it does not exist."""
-    if not toml.exists():
-        toml.parent.mkdir(parents=True, exist_ok=True)
-        toml.touch()
-
-    return toml
-
-
-@overload
-def getval(toml: Path, keys: str, default: type[T]) -> Optional[T]: ...
-
-
-@overload
-def getval(toml: Path, keys: str, default: T) -> T: ...
-
-
-def getval(toml: Path, keys: str, default: Any) -> Any:
-    """Return the value of the keys in a TOML file."""
-    if isinstance(default, type):
-        type_, default_ = default, None
-    else:
-        type_, default_ = type(default), default
-
-    with open(toml) as file:
-        doc = load(file)
-
-    for key in keys.split("."):
-        if (doc := doc.get(key)) is None:
-            return default_
-
-    return type_(doc.unwrap())
-
-
-# ndradex-related
-NDRADEX = Path(__file__).parent
-"""Path of the ndRADEX package."""
-
-NDRADEX_CONFIG: Path
-"""Path of the ndRADEX config."""
-
-NDRADEX_DIR: Path
-"""Path of the ndRADEX directory."""
-
-if (env := getenv("NDRADEX_DIR")) is not None:
-    NDRADEX_DIR = Path(env)
-elif (env := getenv("XDG_CONFIG_HOME")) is not None:
-    NDRADEX_DIR = Path(env) / "ndradex"
-else:
-    NDRADEX_DIR = Path.home() / ".config" / "ndradex"
-
-NDRADEX_CONFIG = ensure(NDRADEX_DIR / "config.toml")
-
-
-# radex-related
-RADEX_BIN = getval(NDRADEX_CONFIG, "radex.bin", NDRADEX / "bin")
-"""Default path for the RADEX binaries."""
-
-RADEX_VERSION = "30nov2011"
-"""Supported version of the RADEX binaries."""
diff --git a/ndradex/radex.py b/ndradex/radex.py
index e223362..f052a62 100644
--- a/ndradex/radex.py
+++ b/ndradex/radex.py
@@ -1,4 +1,4 @@
-__all__ = ["build", "run", "runmap", "to_input"]
+__all__ = ["RADEX_BIN", "build", "run"]
 
 
 # standard library
@@ -14,10 +14,6 @@
 from typing import Any, Iterable, Iterator, Optional, Union
 
 
-# dependencies
-from .consts import NDRADEX, RADEX_BIN, RADEX_VERSION
-
-
 # type hints
 Input = tuple[str, ...]
 Output = list[tuple[str, ...]]
@@ -30,11 +26,13 @@
 # constants
 FC = getenv("FC", "gfortran")
 NAN = str(float("nan"))
-NDRADEX_BIN = NDRADEX / "bin"
+NDRADEX_BIN = Path(__file__).parent / "bin"
+RADEX_BIN = Path(getenv("RADEX_BIN", NDRADEX_BIN)).expanduser().resolve()
 RADEX_COLUMNS = 11
 RADEX_LOGFILE = devnull
 RADEX_MAXITER = 1_000_000
 RADEX_MINITER = 10
+RADEX_VERSION = "30nov2011"
 
 
 # module logger
@@ -55,7 +53,7 @@ def build(
     set to the package's bin (``/path/to/ndradex/bin``):
     Otherwise, no build is run even if ``force=True``.
 
-    Keyword Args:
+    Args:
         force: Whether to forcibly rebuild the binaries.
         logfile: Path of the RADEX log file.
         miniter: Minimum number of iterations.
@@ -72,7 +70,7 @@ def build(
     if force:
         sprun(
             args=["make", "clean"],
-            cwd=NDRADEX / "bin",
+            cwd=NDRADEX_BIN,
             stdout=PIPE,
             stderr=PIPE,
             check=True,
diff --git a/tests/test_radex.py b/tests/test_radex.py
index 9f21bdd..1955bb0 100644
--- a/tests/test_radex.py
+++ b/tests/test_radex.py
@@ -4,9 +4,8 @@
 
 
 # dependencies
-from ndradex.consts import RADEX_BIN
 from ndradex.lamda import query
-from ndradex.radex import run, runmap, to_input
+from ndradex.radex import RADEX_BIN, run, runmap, to_input
 
 
 # test data