diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..82aa411
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,37 @@
+name: CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install Poetry
+        run: pipx install poetry
+
+      - name: Install dependencies
+        run: poetry install --with dev
+
+      - name: Lint
+        run: poetry run ruff check .
+
+      - name: Check formatting
+        run: poetry run ruff format --check .
+
+      - name: Run tests
+        run: poetry run python -m pytest tests.py
diff --git a/.gitignore b/.gitignore
index 0d7594b..df6a37f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -80,6 +80,8 @@ htmlcov/
 .coverage
 .coverage.*
 .cache
+.pytest_cache/
+.ruff_cache/
 nosetests.xml
 coverage.xml
 *,cover
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index d30c0c9..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,12 +0,0 @@
-language: python
-python:
-  - 3.9
-cache:
-  pip: true
-before_install:
-  - pip install poetry
-install:
-  - poetry install
-script:
-  - poetry run python tests.py
-
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..bc10635
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,27 @@
+# Changelog
+
+## 2.1.0
+
+- Add a configurable `timeout` (default 60 seconds) to all network requests so
+  `get_bytes()`, `get_short_url()`, and `to_file()` no longer hang indefinitely.
+- Drop support for end-of-life Python 3.7; the minimum supported version is now
+  Python 3.8. Tested against Python 3.8 through 3.13.
+- Ship inline type hints and a `py.typed` marker (PEP 561).
+- Derive the client `User-Agent` version from the installed package metadata so
+  it stays in sync with the release.
+- Modernize packaging: PEP 621 `[project]` metadata, the `poetry.core.masonry.api`
+  build backend, and PEP 735 dependency groups.
+- Replace Travis CI with GitHub Actions and `autopep8` with `ruff` for linting
+  and formatting.
+- Remove leftover Python 2 compatibility code.
+
+## 2.0.0
+
+- Drop support for Python versions earlier than 3.7.
+- Set a `User-Agent` header on requests.
+- Show a detailed error message when chart creation fails.
+- Add support for the `version` parameter.
+
+## 1.0.1
+
+- Last release supporting Python 2 and Python < 3.7.
diff --git a/README.md b/README.md
index 465d9eb..cd43ace 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 # quickchart-python
-[![Build Status](https://travis-ci.com/typpo/quickchart-python.svg?branch=master)](https://travis-ci.com/typpo/quickchart-python)
+[![CI](https://github.com/typpo/quickchart-python/actions/workflows/ci.yml/badge.svg)](https://github.com/typpo/quickchart-python/actions/workflows/ci.yml)
 [![PyPI](https://img.shields.io/pypi/v/quickchart.io)](https://pypi.org/project/quickchart-io/)
 [![PyPI - License](https://img.shields.io/pypi/l/quickchart.io)](https://pypi.org/project/quickchart-io/)
 
@@ -13,7 +13,7 @@ Use the `quickchart` library in this project, or install through [pip](https://p
 pip install quickchart.io
 ```
 
-As of release 2.0, this package requires >= Python 3.7.  If you need support for earlier versions of Python, use [version 1.0.1](https://pypi.org/project/quickchart-io/1.0.1/).
+This package requires Python 3.8 or later.  If you need support for Python 3.7, use [version 2.0.0](https://pypi.org/project/quickchart-io/2.0.0/); for earlier versions of Python, use [version 1.0.1](https://pypi.org/project/quickchart-io/1.0.1/).
 
 # Usage
 
@@ -132,6 +132,9 @@ Override the host of the chart render server. Defaults to quickchart.io.
 ### key: str
 Set an API key that will be included with the request.
 
+### timeout: float
+Timeout in seconds for the network requests made by `get_bytes()`, `get_short_url()`, and `to_file()`.  Defaults to 60.0.  Set to `None` to disable the timeout.
+
 ## Getting URLs
 
 There are two ways to get a URL for your chart object.
@@ -159,3 +162,25 @@ Writes the chart image to a file path.
 ## More examples
 
 Checkout the `examples` directory to see other usage.
+
+# Development
+
+This project uses [Poetry](https://python-poetry.org/) for packaging and dependency management.
+
+```
+# Install dependencies (including dev tools)
+poetry install --with dev
+
+# Run the test suite
+poetry run python -m pytest tests.py
+
+# Lint and format
+poetry run ruff check .
+poetry run ruff format .
+```
+
+The tests that hit the live quickchart.io service are skipped by default.  Set `QUICKCHART_NETWORK_TESTS=1` to run them:
+
+```
+QUICKCHART_NETWORK_TESTS=1 poetry run python -m pytest tests.py
+```
diff --git a/__init__.py b/__init__.py
index ba8b5ef..10f147f 100644
--- a/__init__.py
+++ b/__init__.py
@@ -1 +1 @@
-from quickchart import *
+from quickchart import *  # noqa: F401,F403
diff --git a/examples/discord_bot.py b/examples/discord_bot.py
index 1eb4c30..45710f8 100644
--- a/examples/discord_bot.py
+++ b/examples/discord_bot.py
@@ -1,20 +1,23 @@
 from io import BytesIO
 
 import discord
-from PIL import Image
 from discord.ext import commands
+from PIL import Image
+
 from quickchart import QuickChart
 
-description = '''An example bot to showcase the use of QuickChart with discord.py module.'''
+description = (
+    """An example bot to showcase the use of QuickChart with discord.py module."""
+)
 
 intents = discord.Intents.default()
 
-bot = commands.Bot(command_prefix='!', description=description, intents=intents)
+bot = commands.Bot(command_prefix="!", description=description, intents=intents)
 
 
 @bot.event
 async def on_ready():
-    print(f'Logged in as {bot.user.name}')
+    print(f"Logged in as {bot.user.name}")
 
 
 @bot.command()
@@ -27,21 +30,25 @@ async def graph(ctx):
         "type": "bar",
         "data": {
             "labels": ["Hello world", "Test"],
-            "datasets": [{
-                "label": "Foo",
-                "data": [1, 2]
-            }]
-        }
+            "datasets": [{"label": "Foo", "data": [1, 2]}],
+        },
     }
     with Image.open(BytesIO(qc.get_bytes())) as chat_sample:
-        output_buffer = BytesIO()  # By using BytesIO we don't have to save the file in our system.
+        output_buffer = (
+            BytesIO()
+        )  # By using BytesIO we don't have to save the file in our system.
         chat_sample.save(output_buffer, "png")
         output_buffer.seek(0)
-    await ctx.send(file=discord.File(fp=output_buffer, filename="chart_sample.png"))  # Change the file name accordingly.
+    await ctx.send(
+        file=discord.File(fp=output_buffer, filename="chart_sample.png")
+    )  # Change the file name accordingly.
 
 
 @graph.before_invoke
 async def before_test_invoke(ctx):
-    await ctx.trigger_typing()  # Take time to render and send graph so triggering typing to reflect bot action.
+    await (
+        ctx.trigger_typing()
+    )  # Take time to render and send graph so triggering typing to reflect bot action.
+
 
-bot.run('token')
+bot.run("token")
diff --git a/examples/gradient_fill.py b/examples/gradient_fill.py
index 11f3713..8dad7c3 100644
--- a/examples/gradient_fill.py
+++ b/examples/gradient_fill.py
@@ -8,12 +8,16 @@
     "type": "bar",
     "data": {
         "labels": ["Hello world", "Test"],
-        "datasets": [{
-            "label": "Foo",
-            "data": [1, 2],
-            "backgroundColor": QuickChartFunction("getGradientFillHelper('vertical', ['rgba(63, 100, 249, 0.2)', 'rgba(255, 255, 255, 0.2)'])"),
-        }]
-    }
+        "datasets": [
+            {
+                "label": "Foo",
+                "data": [1, 2],
+                "backgroundColor": QuickChartFunction(
+                    "getGradientFillHelper('vertical', ['rgba(63, 100, 249, 0.2)', 'rgba(255, 255, 255, 0.2)'])"
+                ),
+            }
+        ],
+    },
 }
 
 print(qc.get_url())
diff --git a/examples/short_url_example.py b/examples/short_url_example.py
index d3b41cf..2ee6234 100644
--- a/examples/short_url_example.py
+++ b/examples/short_url_example.py
@@ -7,11 +7,13 @@
     "type": "line",
     "data": {
         "labels": list(range(0, 100)),
-        "datasets": [{
-            "label": "Foo",
-            "data": random.sample(range(0, 100), 100),
-        }]
-    }
+        "datasets": [
+            {
+                "label": "Foo",
+                "data": random.sample(range(0, 100), 100),
+            }
+        ],
+    },
 }
 
 print(qc.get_short_url())
diff --git a/examples/short_url_example_with_function.py b/examples/short_url_example_with_function.py
index 6835b49..6976f59 100644
--- a/examples/short_url_example_with_function.py
+++ b/examples/short_url_example_with_function.py
@@ -1,7 +1,7 @@
 from quickchart import QuickChart
 
 qc = QuickChart()
-qc.config = '''{
+qc.config = """{
   type: 'bar',
   data: {
     labels: ['Q1', 'Q2', 'Q3', 'Q4'],
@@ -24,7 +24,7 @@
       }]
     }
   }
-}'''
+}"""
 
 print(qc.get_short_url())
 #
diff --git a/examples/simple_example.py b/examples/simple_example.py
index 5246766..6c3a41b 100644
--- a/examples/simple_example.py
+++ b/examples/simple_example.py
@@ -8,11 +8,8 @@
     "type": "bar",
     "data": {
         "labels": ["Hello world", "Test"],
-        "datasets": [{
-            "label": "Foo",
-            "data": [1, 2]
-        }]
-    }
+        "datasets": [{"label": "Foo", "data": [1, 2]}],
+    },
 }
 
 print(qc.get_url())
diff --git a/examples/simple_example_with_function.py b/examples/simple_example_with_function.py
index 3f341d4..6cfb773 100644
--- a/examples/simple_example_with_function.py
+++ b/examples/simple_example_with_function.py
@@ -4,7 +4,7 @@
 qc.width = 600
 qc.height = 300
 qc.device_pixel_ratio = 2.0
-qc.config = '''{
+qc.config = """{
   type: 'bar',
   data: {
     labels: ['Q1', 'Q2', 'Q3', 'Q4'],
@@ -27,6 +27,6 @@
       }]
     }
   }
-}'''
+}"""
 
 print(qc.get_url())
diff --git a/examples/using_quickchartfunction.py b/examples/using_quickchartfunction.py
index 0e3364c..0664ef0 100644
--- a/examples/using_quickchartfunction.py
+++ b/examples/using_quickchartfunction.py
@@ -10,31 +10,25 @@
     "type": "bar",
     "data": {
         "labels": [datetime(2020, 1, 15), datetime(2021, 1, 15)],
-        "datasets": [{
-            "label": "Foo",
-            "data": [1, 2]
-        }]
+        "datasets": [{"label": "Foo", "data": [1, 2]}],
     },
     "options": {
         "scales": {
-            "yAxes": [{
-                "ticks": {
-                    "callback": QuickChartFunction('(val) => val + "k"')
-                }
-            }, {
-                "ticks": {
-                    "callback": QuickChartFunction('''function(val) {
+            "yAxes": [
+                {"ticks": {"callback": QuickChartFunction('(val) => val + "k"')}},
+                {
+                    "ticks": {
+                        "callback": QuickChartFunction("""function(val) {
                       return val + '???';
-                    }''')
-                }
-            }],
-            "xAxes": [{
-                "ticks": {
-                    "callback": QuickChartFunction('(val) => "$" + val')
-                }
-            }]
+                    }""")
+                    }
+                },
+            ],
+            "xAxes": [
+                {"ticks": {"callback": QuickChartFunction('(val) => "$" + val')}}
+            ],
         }
-    }
+    },
 }
 
 print(qc.get_url())
diff --git a/examples/write_file.py b/examples/write_file.py
index 7aa849b..0b4d72f 100644
--- a/examples/write_file.py
+++ b/examples/write_file.py
@@ -8,13 +8,10 @@
     "type": "bar",
     "data": {
         "labels": ["Hello world", "Test"],
-        "datasets": [{
-            "label": "Foo",
-            "data": [1, 2]
-        }]
-    }
+        "datasets": [{"label": "Foo", "data": [1, 2]}],
+    },
 }
 
-qc.to_file('/tmp/mychart.png')
+qc.to_file("/tmp/mychart.png")
 
-print('Done.')
+print("Done.")
diff --git a/poetry.lock b/poetry.lock
index ce82696..c754ec8 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -1,124 +1,279 @@
-[[package]]
-name = "autopep8"
-version = "1.7.0"
-description = "A tool that automatically formats Python code to conform to the PEP 8 style guide"
-category = "dev"
-optional = false
-python-versions = "*"
-
-[package.dependencies]
-pycodestyle = ">=2.9.1"
-toml = "*"
+# This file is automatically @generated by Poetry 2.3.3 and should not be changed by hand.
 
 [[package]]
 name = "certifi"
 version = "2022.9.24"
 description = "Python package for providing Mozilla's CA Bundle."
-category = "main"
 optional = false
 python-versions = ">=3.6"
+groups = ["main"]
+files = [
+    {file = "certifi-2022.9.24-py3-none-any.whl", hash = "sha256:90c1a32f1d68f940488354e36370f6cca89f0f106db09518524c88d6ed83f382"},
+    {file = "certifi-2022.9.24.tar.gz", hash = "sha256:0d9c601124e5a6ba9712dbc60d9c53c21e34f5f641fe83002317394311bdce14"},
+]
 
 [[package]]
 name = "charset-normalizer"
 version = "2.1.1"
 description = "The Real First Universal Charset Detector. Open, modern and actively maintained alternative to Chardet."
-category = "main"
 optional = false
 python-versions = ">=3.6.0"
+groups = ["main"]
+files = [
+    {file = "charset-normalizer-2.1.1.tar.gz", hash = "sha256:5a3d016c7c547f69d6f81fb0db9449ce888b418b5b9952cc5e6e66843e9dd845"},
+    {file = "charset_normalizer-2.1.1-py3-none-any.whl", hash = "sha256:83e9a75d1911279afd89352c68b45348559d1fc0506b054b346651b5e7fee29f"},
+]
 
 [package.extras]
-unicode_backport = ["unicodedata2"]
+unicode-backport = ["unicodedata2"]
+
+[[package]]
+name = "colorama"
+version = "0.4.6"
+description = "Cross-platform colored terminal text."
+optional = false
+python-versions = "!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,!=3.5.*,!=3.6.*,>=2.7"
+groups = ["dev"]
+markers = "sys_platform == \"win32\""
+files = [
+    {file = "colorama-0.4.6-py2.py3-none-any.whl", hash = "sha256:4f1d9991f5acc0ca119f9d443620b77f9d6b33703e51011c16baf57afb285fc6"},
+    {file = "colorama-0.4.6.tar.gz", hash = "sha256:08695f5cb7ed6e0531a20572697297273c47b8cae5a63ffc6d6ed5c201be6e44"},
+]
+
+[[package]]
+name = "exceptiongroup"
+version = "1.3.1"
+description = "Backport of PEP 654 (exception groups)"
+optional = false
+python-versions = ">=3.7"
+groups = ["dev"]
+markers = "python_version < \"3.11\""
+files = [
+    {file = "exceptiongroup-1.3.1-py3-none-any.whl", hash = "sha256:a7a39a3bd276781e98394987d3a5701d0c4edffb633bb7a5144577f82c773598"},
+    {file = "exceptiongroup-1.3.1.tar.gz", hash = "sha256:8b412432c6055b0b7d14c310000ae93352ed6754f70fa8f7c34141f91c4e3219"},
+]
+
+[package.dependencies]
+typing-extensions = {version = ">=4.6.0", markers = "python_version < \"3.13\""}
+
+[package.extras]
+test = ["pytest (>=6)"]
 
 [[package]]
 name = "idna"
 version = "3.4"
 description = "Internationalized Domain Names in Applications (IDNA)"
-category = "main"
 optional = false
 python-versions = ">=3.5"
+groups = ["main"]
+files = [
+    {file = "idna-3.4-py3-none-any.whl", hash = "sha256:90b77e79eaa3eba6de819a0c442c0b4ceefc341a7a2ab77d7562bf49f425c5c2"},
+    {file = "idna-3.4.tar.gz", hash = "sha256:814f528e8dead7d329833b91c5faa87d60bf71824cd12a7530b5526063d02cb4"},
+]
 
 [[package]]
-name = "pycodestyle"
-version = "2.9.1"
-description = "Python style guide checker"
-category = "dev"
+name = "iniconfig"
+version = "2.1.0"
+description = "brain-dead simple config-ini parsing"
 optional = false
-python-versions = ">=3.6"
+python-versions = ">=3.8"
+groups = ["dev"]
+files = [
+    {file = "iniconfig-2.1.0-py3-none-any.whl", hash = "sha256:9deba5723312380e77435581c6bf4935c94cbfab9b1ed33ef8d238ea168eb760"},
+    {file = "iniconfig-2.1.0.tar.gz", hash = "sha256:3abbd2e30b36733fee78f9c7f7308f2d0050e88f0087fd25c2645f63c773e1c7"},
+]
+
+[[package]]
+name = "packaging"
+version = "26.2"
+description = "Core utilities for Python packages"
+optional = false
+python-versions = ">=3.8"
+groups = ["dev"]
+files = [
+    {file = "packaging-26.2-py3-none-any.whl", hash = "sha256:5fc45236b9446107ff2415ce77c807cee2862cb6fac22b8a73826d0693b0980e"},
+    {file = "packaging-26.2.tar.gz", hash = "sha256:ff452ff5a3e828ce110190feff1178bb1f2ea2281fa2075aadb987c2fb221661"},
+]
+
+[[package]]
+name = "pluggy"
+version = "1.5.0"
+description = "plugin and hook calling mechanisms for python"
+optional = false
+python-versions = ">=3.8"
+groups = ["dev"]
+files = [
+    {file = "pluggy-1.5.0-py3-none-any.whl", hash = "sha256:44e1ad92c8ca002de6377e165f3e0f1be63266ab4d554740532335b9d75ea669"},
+    {file = "pluggy-1.5.0.tar.gz", hash = "sha256:2cffa88e94fdc978c4c574f15f9e59b7f4201d439195c3715ca9e2486f1d0cf1"},
+]
+
+[package.extras]
+dev = ["pre-commit", "tox"]
+testing = ["pytest", "pytest-benchmark"]
+
+[[package]]
+name = "pytest"
+version = "8.3.5"
+description = "pytest: simple powerful testing with Python"
+optional = false
+python-versions = ">=3.8"
+groups = ["dev"]
+files = [
+    {file = "pytest-8.3.5-py3-none-any.whl", hash = "sha256:c69214aa47deac29fad6c2a4f590b9c4a9fdb16a403176fe154b79c0b4d4d820"},
+    {file = "pytest-8.3.5.tar.gz", hash = "sha256:f4efe70cc14e511565ac476b57c279e12a855b11f48f212af1080ef2263d3845"},
+]
+
+[package.dependencies]
+colorama = {version = "*", markers = "sys_platform == \"win32\""}
+exceptiongroup = {version = ">=1.0.0rc8", markers = "python_version < \"3.11\""}
+iniconfig = "*"
+packaging = "*"
+pluggy = ">=1.5,<2"
+tomli = {version = ">=1", markers = "python_version < \"3.11\""}
+
+[package.extras]
+dev = ["argcomplete", "attrs (>=19.2)", "hypothesis (>=3.56)", "mock", "pygments (>=2.7.2)", "requests", "setuptools", "xmlschema"]
 
 [[package]]
 name = "requests"
-version = "2.28.1"
+version = "2.32.4"
 description = "Python HTTP for Humans."
-category = "main"
 optional = false
-python-versions = ">=3.7, <4"
+python-versions = ">=3.8"
+groups = ["main"]
+files = [
+    {file = "requests-2.32.4-py3-none-any.whl", hash = "sha256:27babd3cda2a6d50b30443204ee89830707d396671944c998b5975b031ac2b2c"},
+    {file = "requests-2.32.4.tar.gz", hash = "sha256:27d0316682c8a29834d3264820024b62a36942083d52caf2f14c0591336d3422"},
+]
 
 [package.dependencies]
 certifi = ">=2017.4.17"
-charset-normalizer = ">=2,<3"
+charset_normalizer = ">=2,<4"
 idna = ">=2.5,<4"
-urllib3 = ">=1.21.1,<1.27"
+urllib3 = ">=1.21.1,<3"
 
 [package.extras]
 socks = ["PySocks (>=1.5.6,!=1.5.7)"]
-use_chardet_on_py3 = ["chardet (>=3.0.2,<6)"]
+use-chardet-on-py3 = ["chardet (>=3.0.2,<6)"]
 
 [[package]]
-name = "toml"
-version = "0.10.2"
-description = "Python Library for Tom's Obvious, Minimal Language"
-category = "dev"
+name = "ruff"
+version = "0.15.20"
+description = "An extremely fast Python linter and code formatter, written in Rust."
 optional = false
-python-versions = ">=2.6, !=3.0.*, !=3.1.*, !=3.2.*"
+python-versions = ">=3.7"
+groups = ["dev"]
+files = [
+    {file = "ruff-0.15.20-py3-none-linux_armv6l.whl", hash = "sha256:00e188c53e499c3c1637f73c91dcf2fb56d576cab76ce1be50a27c4e80e37078"},
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diff --git a/pyproject.toml b/pyproject.toml
index fd3c977..3f680ef 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,25 +1,57 @@
-[tool.poetry]
+[project]
 name = "quickchart.io"
-version = "2.0.0"
+version = "2.1.0"
 description = "A client for quickchart.io, a service that generates static chart images"
 keywords = ["chart api", "chart image", "charts"]
-authors = ["Ian Webster <ianw_pypi@ianww.com>"]
-maintainers = ["Ian Webster <ianw_pypi@ianww.com>"]
-homepage = "https://quickchart.io/"
+authors = [{ name = "Ian Webster", email = "ianw_pypi@ianww.com" }]
+maintainers = [{ name = "Ian Webster", email = "ianw_pypi@ianww.com" }]
 readme = "README.md"
-repository = "https://github.com/typpo/quickchart-python"
-license = "MIT"
-packages = [
-    { include = "quickchart" },
+license = { text = "MIT" }
+requires-python = ">=3.8"
+dependencies = ["requests>=2.28.1"]
+classifiers = [
+    "Development Status :: 5 - Production/Stable",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: MIT License",
+    "Operating System :: OS Independent",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: Python :: 3 :: Only",
+    "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
+    "Topic :: Multimedia :: Graphics",
+    "Typing :: Typed",
 ]
 
-[tool.poetry.dependencies]
-python = ">=3.7, <4"
-requests = "^2.28.1"
+[project.urls]
+Homepage = "https://quickchart.io/"
+Repository = "https://github.com/typpo/quickchart-python"
+
+[dependency-groups]
+dev = ["pytest>=8.0", "ruff>=0.6"]
+
+[tool.poetry]
+packages = [{ include = "quickchart" }]
+
+[tool.ruff]
+line-length = 88
+target-version = "py38"
+
+[tool.ruff.lint]
+select = ["E", "F", "I", "UP", "B"]
+# We still support Python 3.8, where `X | Y` union syntax is not natively
+# available at runtime, so keep the typing.Optional / typing.Union spellings.
+ignore = ["UP007", "UP045"]
 
-[tool.poetry.dev-dependencies]
-autopep8 = "^1.5.5"
+[tool.ruff.lint.per-file-ignores]
+# Assertions on URL-encoded strings cannot be reasonably line-wrapped.
+"tests.py" = ["E501"]
+# Example scripts contain long chart strings and illustrative comments.
+"examples/*" = ["E501"]
 
 [build-system]
-requires = ["poetry>=0.12"]
-build-backend = "poetry.masonry.api"
+requires = ["poetry-core>=2.0.0"]
+build-backend = "poetry.core.masonry.api"
diff --git a/quickchart/__init__.py b/quickchart/__init__.py
index 22e8385..1f7bda3 100644
--- a/quickchart/__init__.py
+++ b/quickchart/__init__.py
@@ -1,122 +1,130 @@
-"""A python client for quickchart.io, a web service that generates static
+"""A Python client for quickchart.io, a web service that generates static
 charts."""
 
+from __future__ import annotations
+
 import datetime
 import json
 import re
+from importlib import metadata
+from typing import Any, Optional, Union
+from urllib.parse import urlencode
+
+import requests
+
 try:
-    from urllib import urlencode
-except:
-    # For Python 3
-    from urllib.parse import urlencode
+    __version__ = metadata.version("quickchart.io")
+except metadata.PackageNotFoundError:  # pragma: no cover
+    # Package is not installed (e.g. running from a source checkout).
+    __version__ = "0.0.0"
 
-USER_AGENT = 'quickchart-python (2.0.0)'
+USER_AGENT = f"quickchart-python ({__version__})"
 
-FUNCTION_DELIMITER_RE = re.compile('\"__BEGINFUNCTION__(.*?)__ENDFUNCTION__\"')
+FUNCTION_DELIMITER_RE = re.compile(r'"__BEGINFUNCTION__(.*?)__ENDFUNCTION__"')
 
 
 class QuickChartFunction:
-    def __init__(self, script):
+    def __init__(self, script: str):
         self.script = script
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         return self.script
 
 
-def serialize(obj):
+def serialize(obj: Any) -> Any:
     if isinstance(obj, QuickChartFunction):
-        return '__BEGINFUNCTION__' + obj.script + '__ENDFUNCTION__'
+        return "__BEGINFUNCTION__" + obj.script + "__ENDFUNCTION__"
     if isinstance(obj, (datetime.date, datetime.datetime)):
         return obj.isoformat()
     return obj.__dict__
 
 
-def dump_json(obj):
-    ret = json.dumps(obj, default=serialize, separators=(',', ':'))
+def dump_json(obj: Any) -> str:
+    ret = json.dumps(obj, default=serialize, separators=(",", ":"))
     ret = FUNCTION_DELIMITER_RE.sub(
-        lambda match: json.loads('"' + match.group(1) + '"'), ret)
+        lambda match: json.loads('"' + match.group(1) + '"'), ret
+    )
     return ret
 
 
 class QuickChart:
-    def __init__(self):
-        self.config = None
-        self.width = 500
-        self.height = 300
-        self.background_color = '#ffffff'
-        self.device_pixel_ratio = 1.0
-        self.format = 'png'
-        self.version = '2.9.4'
-        self.key = None
-        self.scheme = 'https'
-        self.host = 'quickchart.io'
-
-    def is_valid(self):
+    def __init__(self) -> None:
+        self.config: Optional[Union[dict, str]] = None
+        self.width: int = 500
+        self.height: int = 300
+        self.background_color: str = "#ffffff"
+        self.device_pixel_ratio: float = 1.0
+        self.format: str = "png"
+        self.version: str = "2.9.4"
+        self.key: Optional[str] = None
+        self.scheme: str = "https"
+        self.host: str = "quickchart.io"
+        self.timeout: Optional[float] = 60.0
+
+    def is_valid(self) -> bool:
         return self.config is not None
 
-    def get_url_base(self):
-        return '%s://%s' % (self.scheme, self.host)
+    def get_url_base(self) -> str:
+        return f"{self.scheme}://{self.host}"
+
+    def _serialized_config(self) -> str:
+        return dump_json(self.config) if isinstance(self.config, dict) else self.config
 
-    def get_url(self):
+    def get_url(self) -> str:
         if not self.is_valid():
             raise RuntimeError(
-                'You must set the `config` attribute before generating a url')
+                "You must set the `config` attribute before generating a url"
+            )
         params = {
-            'c': dump_json(self.config) if type(self.config) == dict else self.config,
-            'w': self.width,
-            'h': self.height,
-            'bkg': self.background_color,
-            'devicePixelRatio': self.device_pixel_ratio,
-            'f': self.format,
-            'v': self.version,
+            "c": self._serialized_config(),
+            "w": self.width,
+            "h": self.height,
+            "bkg": self.background_color,
+            "devicePixelRatio": self.device_pixel_ratio,
+            "f": self.format,
+            "v": self.version,
         }
         if self.key:
-            params['key'] = self.key
-        return '%s/chart?%s' % (self.get_url_base(), urlencode(params))
-
-    def _post(self, url):
-        try:
-            import requests
-        except:
-            raise RuntimeError('Could not find `requests` dependency')
+            params["key"] = self.key
+        return f"{self.get_url_base()}/chart?{urlencode(params)}"
 
+    def _post(self, url: str) -> requests.Response:
         postdata = {
-            'chart': dump_json(self.config) if type(self.config) == dict else self.config,
-            'width': self.width,
-            'height': self.height,
-            'backgroundColor': self.background_color,
-            'devicePixelRatio': self.device_pixel_ratio,
-            'format': self.format,
-            'version': self.version,
+            "chart": self._serialized_config(),
+            "width": self.width,
+            "height": self.height,
+            "backgroundColor": self.background_color,
+            "devicePixelRatio": self.device_pixel_ratio,
+            "format": self.format,
+            "version": self.version,
         }
         if self.key:
-            postdata['key'] = self.key
+            postdata["key"] = self.key
         headers = {
-            'user-agent': USER_AGENT,
+            "user-agent": USER_AGENT,
         }
-        resp = requests.post(url, json=postdata, headers=headers)
+        resp = requests.post(url, json=postdata, headers=headers, timeout=self.timeout)
         if resp.status_code != 200:
-            err_description = resp.headers.get('x-quickchart-error')
+            err_description = resp.headers.get("x-quickchart-error")
+            detail = f"\n{err_description}" if err_description else ""
             raise RuntimeError(
-                'Invalid response code from chart creation endpoint: %d%s'
-                % (resp.status_code, '\n%s' % err_description if err_description else '')
+                "Invalid response code from chart creation endpoint: "
+                f"{resp.status_code}{detail}"
             )
         return resp
 
-
-    def get_short_url(self):
-        resp = self._post('%s/chart/create' % self.get_url_base())
+    def get_short_url(self) -> str:
+        resp = self._post(f"{self.get_url_base()}/chart/create")
         parsed = json.loads(resp.text)
-        if not parsed['success']:
-            raise RuntimeError(
-                'Chart creation endpoint failed to create chart')
-        return parsed['url']
+        if not parsed["success"]:
+            raise RuntimeError("Chart creation endpoint failed to create chart")
+        return parsed["url"]
 
-    def get_bytes(self):
-        resp = self._post('%s/chart' % self.get_url_base())
+    def get_bytes(self) -> bytes:
+        resp = self._post(f"{self.get_url_base()}/chart")
         return resp.content
 
-    def to_file(self, path):
+    def to_file(self, path: str) -> None:
         content = self.get_bytes()
-        with open(path, 'wb') as f:
+        with open(path, "wb") as f:
             f.write(content)
diff --git a/quickchart/py.typed b/quickchart/py.typed
new file mode 100644
index 0000000..e69de29
diff --git a/scripts/format.sh b/scripts/format.sh
index 539db9d..59116d3 100755
--- a/scripts/format.sh
+++ b/scripts/format.sh
@@ -1,3 +1,5 @@
 #!/bin/bash -e
 
-poetry run autopep8 --in-place examples/*.py quickchart/*.py
+# Format and autofix lint issues across the package, examples, and tests.
+poetry run ruff format .
+poetry run ruff check --fix .
diff --git a/tests.py b/tests.py
index 31b6a3f..3d3ba78 100644
--- a/tests.py
+++ b/tests.py
@@ -1,8 +1,15 @@
+import os
 import unittest
 from datetime import datetime
 
 from quickchart import QuickChart, QuickChartFunction
 
+# Network-dependent tests hit the live quickchart.io service. They are skipped
+# by default so the rest of the suite stays deterministic and offline-friendly.
+# Set QUICKCHART_NETWORK_TESTS=1 to opt in.
+RUN_NETWORK_TESTS = os.environ.get("QUICKCHART_NETWORK_TESTS") == "1"
+
+
 class TestQuickChart(unittest.TestCase):
     def test_simple(self):
         qc = QuickChart()
@@ -13,35 +20,29 @@ def test_simple(self):
             "type": "bar",
             "data": {
                 "labels": ["Hello world", "Test"],
-                "datasets": [{
-                    "label": "Foo",
-                    "data": [1, 2]
-                }]
-            }
+                "datasets": [{"label": "Foo", "data": [1, 2]}],
+            },
         }
 
         url = qc.get_url()
-        self.assertIn('w=600', url)
-        self.assertIn('h=300', url)
-        self.assertIn('devicePixelRatio=2', url)
-        self.assertIn('Hello+world', url)
+        self.assertIn("w=600", url)
+        self.assertIn("h=300", url)
+        self.assertIn("devicePixelRatio=2", url)
+        self.assertIn("Hello+world", url)
 
     def test_version(self):
         qc = QuickChart()
-        qc.version = '3.4.0'
+        qc.version = "3.4.0"
         qc.config = {
             "type": "bar",
             "data": {
                 "labels": ["Hello world", "Test"],
-                "datasets": [{
-                    "label": "Foo",
-                    "data": [1, 2]
-                }]
-            }
+                "datasets": [{"label": "Foo", "data": [1, 2]}],
+            },
         }
 
         url = qc.get_url()
-        self.assertIn('v=3.4.0', url)
+        self.assertIn("v=3.4.0", url)
 
     def test_no_chart(self):
         qc = QuickChart()
@@ -51,6 +52,7 @@ def test_no_chart(self):
 
         self.assertRaises(RuntimeError, qc.get_url)
 
+    @unittest.skipUnless(RUN_NETWORK_TESTS, "set QUICKCHART_NETWORK_TESTS=1 to run")
     def test_get_bytes(self):
         qc = QuickChart()
         qc.width = 600
@@ -59,44 +61,46 @@ def test_get_bytes(self):
             "type": "bar",
             "data": {
                 "labels": ["Hello world", "Test"],
-                "datasets": [{
-                    "label": "Foo",
-                    "data": [1, 2]
-                }]
-            }
+                "datasets": [{"label": "Foo", "data": [1, 2]}],
+            },
         }
         self.assertTrue(len(qc.get_bytes()) > 8000)
 
     def test_with_function_and_dates(self):
         qc = QuickChart()
         qc.config = {
-          "type": "bar",
-          "data": {
-            "labels": [datetime(2020, 1, 15), datetime(2021, 1, 15)],
-            "datasets": [{
-              "label": "Foo",
-              "data": [1, 2]
-            }]
-          },
-          "options": {
-            "scales": {
-              "yAxes": [{
-                "ticks": {
-                  "callback": QuickChartFunction('(val) => val + "k"')
-                }
-              }],
-              "xAxes": [{
-                "ticks": {
-                  "callback": QuickChartFunction('(val) => "$" + val')
+            "type": "bar",
+            "data": {
+                "labels": [datetime(2020, 1, 15), datetime(2021, 1, 15)],
+                "datasets": [{"label": "Foo", "data": [1, 2]}],
+            },
+            "options": {
+                "scales": {
+                    "yAxes": [
+                        {
+                            "ticks": {
+                                "callback": QuickChartFunction('(val) => val + "k"')
+                            }
+                        }
+                    ],
+                    "xAxes": [
+                        {
+                            "ticks": {
+                                "callback": QuickChartFunction('(val) => "$" + val')
+                            }
+                        }
+                    ],
                 }
-              }]
-            }
-          }
+            },
         }
 
         url = qc.get_url()
-        self.assertIn('7B%22ticks%22%3A%7B%22callback%22%3A%28val%29+%3D%3E+%22%24%22+%2B+val%7D%7D%5D%7D%7D%7D', url)
-        self.assertIn('2020-01-15T00%3A00%3A00', url)
+        self.assertIn(
+            "7B%22ticks%22%3A%7B%22callback%22%3A%28val%29+%3D%3E+%22%24%22+%2B+val%7D%7D%5D%7D%7D%7D",
+            url,
+        )
+        self.assertIn("2020-01-15T00%3A00%3A00", url)
+
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main()