diff --git a/docs/conf.py b/docs/conf.py
index 45953ec..a431ebd 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -31,7 +31,7 @@
 
 # -- Options for HTML output -------------------------------------------
 html_title = "parselglossy Documentation"
-html_short_title = "parselglossy {}".format(version)
+html_short_title = f"parselglossy {version}"
 html_show_sourcelink = False
 html_sidebars = {
     "**": ["logo-text.html", "globaltoc.html", "localtoc.html", "searchbox.html"]
diff --git a/parselglossy/documentation.py b/parselglossy/documentation.py
index 0c1a9ba..7a0b669 100644
--- a/parselglossy/documentation.py
+++ b/parselglossy/documentation.py
@@ -58,8 +58,8 @@ def documentation_generator(
         " Editing by hand is not recommended.\n"
     )
 
-    header_fmt = (
-        "{comment:s}\n{markup:s}\n{header:s}\n{markup:s}\n\n"
+    header = (
+        f"{comment:s}\n{'=' * len(header):s}\n{header:s}\n{'=' * len(header):s}\n\n"
         "- Keywords without a default value are **required**.\n"
         "- Default values are either explicit or computed from the value of other keywords in the input.\n"  # noqa: E501
         "- Sections where all keywords have a default value can be omitted.\n"
@@ -68,40 +68,30 @@ def documentation_generator(
 
     docs = _rec_documentation_generator(template=template)
 
-    documentation = (
-        header_fmt.format(comment=comment, markup=("=" * len(header)), header=header)
-        + docs
-    )
+    documentation = header + docs
 
     return documentation
 
 
 def _document_keyword(keyword: JSONDict) -> str:
-    kw_fmt = """
- :{0:s}: {1:s}
+    docstring = keyword["docstring"].replace("\n", " ")
+    doc = f"""
+ :{keyword['name']:s}: {docstring:s}
 
-  **Type** ``{2:s}``
+  **Type** ``{keyword['type']:s}``
 """
 
-    doc = kw_fmt.format(
-        keyword["name"], keyword["docstring"].replace("\n", " "), keyword["type"]
-    )
-
     if "default" in keyword.keys():
-        doc += """
-  **Default** ``{}``
-""".format(
-            keyword["default"]
-        )
+        doc += f"""
+  **Default** ``{keyword['default']}``
+"""
 
     if "predicates" in keyword.keys():
-        preds = "\n    ".join(("- ``{}``".format(x) for x in keyword["predicates"]))
-        doc += """
+        preds = "\n    ".join((f"- ``{x}``" for x in keyword["predicates"]))
+        doc += f"""
   **Predicates**
-    {}
-""".format(
-            preds
-        )
+    {preds}
+"""
 
     return doc
 
@@ -132,11 +122,9 @@ def _rec_documentation_generator(template, *, level: int = 0) -> str:
     sections = template["sections"] if "sections" in template.keys() else []
     if sections:
         docs.append(_indent("\n:red:`Sections`", level))
-        fmt = r"""
- :{0:s}: {1:s}
-"""
         for s in sections:
-            doc = fmt.format(s["name"], s["docstring"].replace("\n", " "))
+            docstring = s["docstring"].replace("\n", " ")
+            doc = f"\n :{s['name']:s}: {docstring:s}\n"
             doc += _rec_documentation_generator(s, level=level + 1)
             docs.extend(_indent(doc, level))
 
diff --git a/parselglossy/exceptions.py b/parselglossy/exceptions.py
index 5d881ca..cec3e81 100644
--- a/parselglossy/exceptions.py
+++ b/parselglossy/exceptions.py
@@ -66,9 +66,9 @@ def __eq__(self, other):
         return self.address == other.address and self.message == other.message
 
     def __repr__(self):
-        msg = "{:s}".format(self.message)
+        msg = f"{self.message:s}"
         if self.address != ():
-            msg = "At {:s}:\n  {:s}".format(location_in_dict(address=self.address), msg)
+            msg = f"At {location_in_dict(address=self.address):s}:\n  {msg:s}"
         return "- " + msg
 
 
@@ -93,9 +93,8 @@ def collate_errors(*, when: str, errors: List[Error]) -> str:
                 KeyError 'min_num_iterations' in closure
                 'user['scf']['min_num_iterations'] / 2'
     """
-    preamble = "\nError{more:s} occurred when {when:s}:".format(
-        more="s" if len(errors) > 1 else "", when=when
-    )
-    msgs = [preamble] + ["{}".format(e) for e in errors]
+    plural = "s" if len(errors) > 1 else ""
+    preamble = f"\nError{plural:s} occurred when {when:s}:"
+    msgs = [preamble] + [f"{e}" for e in errors]
 
     return "\n".join(msgs)
diff --git a/parselglossy/grammars/lexer.py b/parselglossy/grammars/lexer.py
index 3b810b9..59a7f8f 100644
--- a/parselglossy/grammars/lexer.py
+++ b/parselglossy/grammars/lexer.py
@@ -74,7 +74,7 @@ def lex_from_str(
     *,
     in_str: Union[str, Path],
     grammar: str = "standard",
-    ir_file: Optional[Union[str, Path]] = None
+    ir_file: Optional[Union[str, Path]] = None,
 ) -> JSONDict:
     """Run grammar of choice on input string.
 
@@ -100,7 +100,7 @@ def lex_from_str(
     try:
         lexer = dispatch_grammar(grammar)
     except KeyError:
-        raise ParselglossyError("Grammar {} not available.".format(grammar))
+        raise ParselglossyError(f"Grammar {grammar} not available.")
 
     ir = parse_string_to_dict(lexer, in_str)
 
diff --git a/parselglossy/types.py b/parselglossy/types.py
index 9ec1feb..a346eec 100644
--- a/parselglossy/types.py
+++ b/parselglossy/types.py
@@ -41,7 +41,7 @@
 
 ListTypes = Union[List[bool], List[str], List[int], List[float], List[complex]]
 
-allowed_list_types = ["List[{}]".format(t) for t in allowed_scalar_types]
+allowed_list_types = [f"List[{t}]" for t in allowed_scalar_types]
 
 AllowedTypes = Union[ScalarTypes, ListTypes]
 
@@ -85,7 +85,7 @@ def type_matches(value: AllowedTypes, expected_type: str) -> Optional[bool]:
 
     # first verify whether expected_type is allowed
     if expected_type not in allowed_types:
-        raise ValueError("could not recognize expected_type: {}".format(expected_type))
+        raise ValueError(f"could not recognize expected_type: {expected_type}")
 
     expected_complex = expected_type == "complex" or expected_type == "List[complex]"
 
diff --git a/parselglossy/validation_plumbing.py b/parselglossy/validation_plumbing.py
index 38b6eee..3b91def 100644
--- a/parselglossy/validation_plumbing.py
+++ b/parselglossy/validation_plumbing.py
@@ -492,16 +492,16 @@ def run_callable(f: str, d: JSONDict, *, t: str) -> Tuple[str, Optional[Any]]:
         result = eval(f"lambda user: {f}")(d)
         result = type_fixers[t](result)
     except KeyError as e:
-        msg = f"KeyError {e} in closure '{f}'"
+        msg = f"KeyError {e} in closure '{f}'."
         result = None
     except SyntaxError as e:
-        msg = f"SyntaxError {e}  in closure '{f}'"
+        msg = f"SyntaxError {e} in closure '{f}'."
         result = None
     except TypeError as e:
-        msg = f"TypeError {e}  in closure '{f}'"
+        msg = f"TypeError {e} in closure '{f}'."
         result = None
     except NameError as e:
-        msg = f"NameError {e} in closure '{f}'"
+        msg = f"NameError {e} in closure '{f}'."
         result = None
 
     return msg, result
diff --git a/parselglossy/views.py b/parselglossy/views.py
index 3e8c5f9..f85f805 100644
--- a/parselglossy/views.py
+++ b/parselglossy/views.py
@@ -131,7 +131,7 @@ def view_by(
     *,
     predicate: Callable[[Any, str], bool] = lambda x, y: True,
     missing: Optional[Type[Exception]] = None,
-    transformer: Callable[[Any], Any] = lambda x: x
+    transformer: Callable[[Any], Any] = lambda x: x,
 ) -> JSONDict:
     """Recursive decimation of a template into an input.
 
@@ -159,7 +159,7 @@ def view_by(
     allowed = ["type", "default", "docstring", "predicates"]
     if what not in allowed:
         raise ValueError(
-            "Requested view {:s} not among possible views ({})".format(what, allowed)
+            f"Requested view {what:s} not among possible views ({allowed})"
         )
 
     # Determine whether we have only sections and only keywords
diff --git a/tests/test_atoms.py b/tests/test_atoms.py
index a765b6d..720dada 100644
--- a/tests/test_atoms.py
+++ b/tests/test_atoms.py
@@ -58,13 +58,13 @@
 
 @given(a=st.sampled_from(atoms.TRUTHY + atoms.FALSEY))
 def test_atom_bool(a):
-    tokens = atoms.bool_t.parseString("{:s}".format(a)).asList()
+    tokens = atoms.bool_t.parseString(f"{a:s}").asList()
     assert tokens[0] == atoms.to_bool(a)
 
 
 @given(a=st.integers())
 def test_atoms_int(a):
-    tokens = atoms.int_t.parseString("{:d}".format(a)).asList()
+    tokens = atoms.int_t.parseString(f"{a:d}").asList()
     assert tokens[0] == a
 
 
@@ -118,12 +118,12 @@ def test_atoms_data(a):
 @pytest.mark.parametrize("a", ["[]", "[       ]", "[\n]"])
 def test_list_empty(a):
     with pytest.raises(ParseBaseException, match=r"^Empty lists not allowed"):
-        tokens = atoms.list_t.parseString("{}".format(a)).asList()
+        _ = atoms.list_t.parseString(f"{a}").asList()
 
 
 @given(a=st.lists(st.integers(), min_size=1))
 def test_list_int(a):
-    tokens = atoms.list_t.parseString("{}".format(a)).asList()
+    tokens = atoms.list_t.parseString(f"{a}").asList()
     assert tokens == a
 
 
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 89a1235..b1e77c3 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -48,7 +48,7 @@
     "switch,expected",
     [
         ([], "Console script for parselglossy"),
-        (["--version"], "parselglossy, version {}".format(__version__)),
+        (["--version"], f"parselglossy, version {__version__}"),
         (["--help"], r"--help\s+Show this message and exit"),
     ],
     ids=["plain", "version", "help"],