diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index f67dc51..988df30 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -55,10 +55,17 @@ jobs:
         python -mpip install wheel
         python -mpip install -r requirements-dev.txt
 
-    - name: Check stubs
+    - name: Check stubs with mypy
       if: (! startsWith(matrix.python-version, 'pypy-'))
       run: make mypy PYTHON=python
 
+    - name: Check stubs with pyrefly
+      if: (! startsWith(matrix.python-version, 'pypy-'))
+      run: make pyrefly PYTHON=python
+
+    - name: Check stubs with pyright
+      if: (! startsWith(matrix.python-version, 'pypy-'))
+      run: make pyright PYTHON=python
 
   test:
     strategy:
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 72b7db8..5298de0 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -24,7 +24,13 @@ repos:
   rev: v0.12.10
   hooks:
     # Run the linter.
-    - id: ruff
+    - id: ruff-check
       args: [ --fix ]
     # Run the formatter.
     - id: ruff-format
+- repo: https://github.com/asottile/pyupgrade
+  rev: v3.20.0
+  hooks:
+  - id: pyupgrade
+    args: [ --py39-plus ]
+    exclude: src/uwwvb.py # CircuitPython prevaling standard!
diff --git a/Makefile b/Makefile
index 6e73c52..4a4a44f 100644
--- a/Makefile
+++ b/Makefile
@@ -24,7 +24,7 @@ ENVPYTHON ?= _env/bin/python3
 endif
 
 .PHONY: default
-default: coverage mypy
+default: coverage mypy pyright pyrefly
 
 COVERAGE_INCLUDE=--include "src/**/*.py"
 .PHONY: coverage
diff --git a/requirements-dev.txt b/requirements-dev.txt
index e9d451c..21f32eb 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -7,6 +7,8 @@ build
 click
 coverage >= 7.10.3
 mypy; implementation_name=="cpython"
+pyright; implementation_name=="cpython"
+pyrefly; implementation_name=="cpython"
 click>=8.1.5; implementation_name=="cpython"
 leapseconddata
 platformdirs
diff --git a/src/wwvb/__init__.py b/src/wwvb/__init__.py
index e3627b8..22b773d 100644
--- a/src/wwvb/__init__.py
+++ b/src/wwvb/__init__.py
@@ -20,15 +20,30 @@ import enum
 import json
 import warnings
 from dataclasses import dataclass
-from typing import ClassVar
+from typing import ClassVar, Literal
 
 from . import iersdata
 from .tz import Mountain
 
+WWVBChannel = Literal["amplitude", "phase", "both"]
+
 TYPE_CHECKING = False
 if TYPE_CHECKING:
     from collections.abc import Generator
-    from typing import Any, Self, TextIO, TypeVar
+    from typing import NotRequired, Self, TextIO, TypedDict, TypeVar
+
+    class JsonMinute(TypedDict):
+        """Implementation detail
+
+        This is the Python object type that is serialized by `print_timecodes_json`
+        """
+
+        year: int
+        days: int
+        hour: int
+        minute: int
+        amplitude: NotRequired[str]
+        phase: NotRequired[str]
 
     T = TypeVar("T")
 
@@ -927,7 +942,7 @@ styles = {
 def print_timecodes(
     w: WWVBMinute,
     minutes: int,
-    channel: str,
+    channel: WWVBChannel,
     style: str,
     file: TextIO,
     *,
@@ -964,7 +979,7 @@ def print_timecodes(
 def print_timecodes_json(
     w: WWVBMinute,
     minutes: int,
-    channel: str,
+    channel: WWVBChannel,
     file: TextIO,
 ) -> None:
     """Print a range of timecodes in JSON format.
@@ -984,7 +999,7 @@ def print_timecodes_json(
     """
     result = []
     for _ in range(minutes):
-        data: dict[str, Any] = {
+        data: JsonMinute = {
             "year": w.year,
             "days": w.days,
             "hour": w.hour,
diff --git a/src/wwvb/decode.py b/src/wwvb/decode.py
index d4e68e9..b6ac871 100644
--- a/src/wwvb/decode.py
+++ b/src/wwvb/decode.py
@@ -6,10 +6,10 @@
 from __future__ import annotations
 
 import sys
-from typing import TYPE_CHECKING
 
 import wwvb
 
+TYPE_CHECKING = False
 if TYPE_CHECKING:
     from collections.abc import Generator
 
diff --git a/src/wwvb/gen.py b/src/wwvb/gen.py
index 4081a40..6565f61 100755
--- a/src/wwvb/gen.py
+++ b/src/wwvb/gen.py
@@ -9,15 +9,18 @@ from __future__ import annotations
 
 import datetime
 import sys
-from typing import Any
 
 import click
 import dateutil.parser
 
 from . import WWVBMinute, WWVBMinuteIERS, print_timecodes, print_timecodes_json, styles
 
+TYPE_CHECKING = False
+if TYPE_CHECKING:
+    from . import WWVBChannel
 
-def parse_timespec(ctx: Any, param: Any, value: list[str]) -> datetime.datetime:  # noqa: ARG001
+
+def parse_timespec(ctx: click.Context, param: click.Parameter, value: list[str]) -> datetime.datetime:  # noqa: ARG001
     """Parse a time specifier from the commandline"""
     try:
         if len(value) == 5:
@@ -95,7 +98,7 @@ def main(
     dut1: int,
     minutes: int,
     style: str,
-    channel: str,
+    channel: WWVBChannel,
     all_timecodes: bool,
     timespec: datetime.datetime,
 ) -> None:
diff --git a/src/wwvb/wwvbtk.py b/src/wwvb/wwvbtk.py
index ef96892..fb6e5ce 100755
--- a/src/wwvb/wwvbtk.py
+++ b/src/wwvb/wwvbtk.py
@@ -8,13 +8,13 @@ from __future__ import annotations
 
 import datetime
 import functools
-from tkinter import Canvas, TclError, Tk
-from typing import TYPE_CHECKING, Any
+from tkinter import Canvas, Event, TclError, Tk
 
 import click
 
 import wwvb
 
+TYPE_CHECKING = False
 if TYPE_CHECKING:
     from collections.abc import Generator
 
@@ -25,7 +25,7 @@ def _app() -> Tk:
     return Tk()
 
 
-def validate_colors(ctx: Any, param: Any, value: str) -> list[str]:  # noqa: ARG001
+def validate_colors(ctx: click.Context, param: click.Parameter, value: str) -> list[str]:  # noqa: ARG001
     """Check that all colors in a string are valid, splitting it to a list"""
     app = _app()
     colors = value.split()
@@ -106,7 +106,7 @@ def main(colors: list[str], size: int, min_size: int | None) -> None:  # noqa: P
     canvas.pack(fill="both", expand=True)
     app.wm_deiconify()
 
-    def resize_canvas(event: Any) -> None:
+    def resize_canvas(event: Event) -> None:
         """Keep the circle filling the window when it is resized"""
         sz = min(event.width, event.height) - 8
         if sz < 0:
@@ -141,10 +141,12 @@ def main(colors: list[str], size: int, min_size: int | None) -> None:  # noqa: P
 
     controller = controller_func().__next__
 
+    # pyrefly: ignore  # bad-assignment
     def after_func() -> None:
         """Repeatedly run the controller after the desired interval"""
         app.after(controller(), after_func)
 
+    # pyrefly: ignore  # bad-argument-type
     app.after_idle(after_func)
     app.mainloop()
 
diff --git a/test/testcli.py b/test/testcli.py
index e4e8c9a..eb761e7 100644
--- a/test/testcli.py
+++ b/test/testcli.py
@@ -1,4 +1,5 @@
 #!/usr/bin/python3
+
 """Test most wwvblib commandline programs"""
 
 # ruff: noqa: N802 D102
@@ -6,13 +7,13 @@
 #
 # SPDX-License-Identifier: GPL-3.0-only
 
+from __future__ import annotations
+
 import json
 import os
 import subprocess
 import sys
 import unittest
-from collections.abc import Sequence
-from typing import Any
 
 # These imports must remain, even though the module contents are not used directly!
 import wwvb.dut1table
@@ -22,6 +23,12 @@ import wwvb.gen
 assert wwvb.dut1table.__name__ == "wwvb.dut1table"
 assert wwvb.gen.__name__ == "wwvb.gen"
 
+TYPE_CHECKING = False
+if TYPE_CHECKING:
+    from collections.abc import Sequence
+
+    from wwvb import JsonMinute
+
 
 class CLITestCase(unittest.TestCase):
     """Test various CLI commands within wwvbpy"""
@@ -55,9 +62,10 @@ class CLITestCase(unittest.TestCase):
     def assertStarts(self, expected: str, actual: str, *args: str) -> None:
         self.assertMultiLineEqual(expected, actual[: len(expected)], f"args={args}")
 
-    def assertModuleJson(self, expected: Any, *args: str) -> None:
+    def assertModuleJson(self, expected: list[JsonMinute], *args: str) -> None:
         """Check the output from invoking a `python -m modulename` program matches the expected"""
         actual = self.moduleOutput(*args)
+        # Note: in mypy, revealed type of json.loads is typing.Any!
         self.assertEqual(json.loads(actual), expected)
 
     def assertModuleOutputStarts(self, expected: str, *args: str) -> None:
diff --git a/test/testls.py b/test/testls.py
index 209651e..73ccdb7 100755
--- a/test/testls.py
+++ b/test/testls.py
@@ -56,7 +56,3 @@ class TestLeapSecond(unittest.TestCase):
                 assert not our_is_ls
             d = datetime.datetime.combine(nm, datetime.time(), tzinfo=datetime.timezone.utc)
         self.assertEqual(leap, bench)
-
-
-if __name__ == "__main__":
-    unittest.main()
diff --git a/test/testpm.py b/test/testpm.py
index 5bc5c93..54fe589 100755
--- a/test/testpm.py
+++ b/test/testpm.py
@@ -27,7 +27,3 @@ class TestPhaseModulation(unittest.TestCase):
 
         self.assertEqual(ref_am, test_am)
         self.assertEqual(ref_pm, test_pm)
-
-
-if __name__ == "__main__":
-    unittest.main()
diff --git a/test/testuwwvb.py b/test/testuwwvb.py
index f29f4b5..9b5df65 100644
--- a/test/testuwwvb.py
+++ b/test/testuwwvb.py
@@ -47,7 +47,7 @@ class WWVBRoundtrip(unittest.TestCase):
         any_leap_second = False
         for _ in range(20):
             timecode = minute.as_timecode()
-            decoded = None
+            decoded: uwwvb.WWVBMinute | None = None
             if len(timecode.am) == 61:
                 any_leap_second = True
             for code in timecode.am:
@@ -215,7 +215,3 @@ class WWVBRoundtrip(unittest.TestCase):
             datetime.datetime(2020, 12, 31, 17, 00, tzinfo=zoneinfo.ZoneInfo("America/Denver")),  # Mountain time!
             uwwvb.as_datetime_local(decoded),
         )
-
-
-if __name__ == "__main__":
-    unittest.main()
diff --git a/test/testwwvb.py b/test/testwwvb.py
index 8ba535c..e171bff 100755
--- a/test/testwwvb.py
+++ b/test/testwwvb.py
@@ -14,11 +14,12 @@ import io
 import pathlib
 import random
 import sys
+import typing
 import unittest
 
 import uwwvb
 import wwvb
-from wwvb import decode, iersdata, tz
+from wwvb import WWVBChannel, decode, iersdata, tz
 
 
 class WWVBMinute2k(wwvb.WWVBMinute):
@@ -44,11 +45,16 @@ class WWVBTestCase(unittest.TestCase):
                 header = lines[0].split()
                 timestamp = " ".join(header[:10])
                 options = header[10:]
-                channel = "amplitude"
+                channel: WWVBChannel = "amplitude"
                 style = "default"
                 for o in options:
                     if o.startswith("--channel="):
-                        channel = o[10:]
+                        value = o[10:]
+                        if value in {"both", "amplitude", "phase"}:
+                            # pyrefly: ignore  # redundant-cast
+                            channel = typing.cast("WWVBChannel", value)
+                        else:
+                            raise ValueError(f"Unknown channel {o!r}")
                     elif o.startswith("--style="):
                         style = o[8:]
                     else:
@@ -430,7 +436,3 @@ class WWVBRoundtrip(unittest.TestCase):
         minute.am[57] = wwvb.AmplitudeModulation.MARK
         decoded_minute = wwvb.WWVBMinute.from_timecode_am(minute)
         assert decoded_minute is None
-
-
-if __name__ == "__main__":
-    unittest.main()