diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 0a8342e..c4efc2a 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -19,7 +19,7 @@ repos:
     rev: 5.10.1
     hooks:
     - id: isort
-      exclude: ".*(.fits|.fts|.fit|.txt|.csv)$"
+      exclude: ".*(.fits|.fts|.fit|.txt|.csv|__init__.py)$"
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v4.3.0
     hooks:
@@ -34,7 +34,7 @@ repos:
     - id: check-yaml
     - id: debug-statements
   - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: 'v0.961'
+    rev: 'v0.971'
     hooks:
     - id: mypy
       additional_dependencies: [types-requests==2.28.0]
diff --git a/hvpy/__init__.py b/hvpy/__init__.py
index 1e28c0c..ef3dc1e 100644
--- a/hvpy/__init__.py
+++ b/hvpy/__init__.py
@@ -1,3 +1,3 @@
-from .facade import *  # NOQA
-from .io import set_api_url
+from .facade import *
+from .config import set_api_url
 from .version import __version__
diff --git a/hvpy/api_groups/jpeg2000/tests/test_get_jp2_header.py b/hvpy/api_groups/jpeg2000/tests/test_get_jp2_header.py
index 38381e7..5c0d289 100644
--- a/hvpy/api_groups/jpeg2000/tests/test_get_jp2_header.py
+++ b/hvpy/api_groups/jpeg2000/tests/test_get_jp2_header.py
@@ -1,8 +1,5 @@
-import os
-
 import pytest
 
-import hvpy
 from hvpy import getJP2Header
 from hvpy.api_groups.jpeg2000.get_jp2_header import getJP2HeaderInputParameters
 
@@ -26,17 +23,3 @@ def test_error_handling():
 def test_url_property():
     params = getJP2HeaderInputParameters(id=9838343)
     assert params.url == "https://api.helioviewer.org/v2/getJP2Header/"
-
-
-def test_set_api_url():
-    params = getJP2HeaderInputParameters(id=9838343)
-    assert params.url == "https://api.helioviewer.org/v2/getJP2Header/"
-
-    os.environ["HELIOVIEWER_API_URL"] = "https://localhost:3000/"
-    params = getJP2HeaderInputParameters(id=9838343)
-    assert params.url == "https://localhost:3000/getJP2Header/"
-
-    hvpy.set_api_url("https://api.beta.helioviewer.org/")
-    params = getJP2HeaderInputParameters(id=9838343)
-    assert params.url == "https://api.beta.helioviewer.org/getJP2Header/"
-    hvpy.set_api_url("https://api.helioviewer.org/v2/")
diff --git a/hvpy/config.py b/hvpy/config.py
new file mode 100644
index 0000000..492d436
--- /dev/null
+++ b/hvpy/config.py
@@ -0,0 +1,33 @@
+from pydantic import BaseSettings, Field
+
+__all__ = ["LiveSettings", "set_api_url", "get_api_url"]
+
+
+class Settings(BaseSettings):
+    api_url: str = Field("https://api.helioviewer.org/v2/", env="HELIOVIEWER_API_URL")
+
+
+def get_api_url() -> str:
+    """
+    Returns the API URL.
+    """
+    from hvpy.config import LiveSettings
+
+    return LiveSettings.api_url
+
+
+def set_api_url(url: str) -> None:
+    """
+    Sets the API URL.
+
+    Parameters
+    ----------
+    url : str
+        Base API URL.
+    """
+    from hvpy.config import LiveSettings
+
+    LiveSettings.api_url = url
+
+
+LiveSettings = Settings()
diff --git a/hvpy/conftest.py b/hvpy/conftest.py
new file mode 100644
index 0000000..8070f3f
--- /dev/null
+++ b/hvpy/conftest.py
@@ -0,0 +1,23 @@
+import os
+
+import pytest
+
+
+class SetEnv:
+    def __init__(self):
+        self.envars = set()
+
+    def set(self, name, value):
+        self.envars.add(name)
+        os.environ[name] = value
+
+    def clear(self):
+        for n in self.envars:
+            os.environ.pop(n)
+
+
+@pytest.fixture
+def env():
+    setenv = SetEnv()
+    yield setenv
+    setenv.clear()
diff --git a/hvpy/io.py b/hvpy/io.py
index 3da2665..4b48767 100644
--- a/hvpy/io.py
+++ b/hvpy/io.py
@@ -1,13 +1,11 @@
-import os
 from enum import Enum, auto
 from typing import Any, Dict
 
 from pydantic import BaseModel
 
-__all__ = ["HvpyParameters", "OutputType", "set_api_url"]
+from hvpy.config import get_api_url
 
-
-_base_url = None
+__all__ = ["HvpyParameters", "OutputType"]
 
 
 class OutputType(Enum):
@@ -56,29 +54,4 @@ def url(self) -> str:
         """
         Final API endpoint URL.
         """
-
         return get_api_url() + self.__class__.__name__[:-15] + "/"
-
-
-def get_api_url() -> str:
-    """
-    Returns the base API URL.
-    """
-    if _base_url:
-        return _base_url
-    if "HELIOVIEWER_API_URL" in os.environ:
-        return os.environ["HELIOVIEWER_API_URL"]
-    return "https://api.helioviewer.org/v2/"
-
-
-def set_api_url(url: str) -> None:
-    """
-    Sets the base API URL.
-
-    Parameters
-    ----------
-    url : str
-        Base API URL.
-    """
-    global _base_url
-    _base_url = url
diff --git a/hvpy/tests/test_io.py b/hvpy/tests/test_io.py
index deb0ec5..af6e2b7 100644
--- a/hvpy/tests/test_io.py
+++ b/hvpy/tests/test_io.py
@@ -1,3 +1,4 @@
+from hvpy import set_api_url
 from hvpy.io import HvpyParameters, OutputType
 
 
@@ -9,3 +10,35 @@ def test_default_get_output_type_is_raw():
 def test_url_property():
     params = HvpyParameters()
     assert params.url == "https://api.helioviewer.org/v2//"
+
+
+def test_set_url():
+    # This is not safe if we ever decide to parallelize the tests.
+    params_first = HvpyParameters()
+    assert params_first.url == "https://api.helioviewer.org/v2//"
+
+    set_api_url("https://api.beta.helioviewer.org/")
+    params_second = HvpyParameters()
+    assert params_second.url == "https://api.beta.helioviewer.org//"
+    assert params_first.url == params_second.url
+
+    set_api_url("https://api.helioviewer.org/v2/")
+
+
+def test_set_url_env(env):
+    env.set("HELIOVIEWER_API_URL", "https://fake_env_url/")
+
+    # We need to instantiate a new Settings since the environmental variable
+    # is only read at init. Therefore using the live one in a test is tricky.
+    from hvpy.config import LiveSettings, Settings
+
+    temp_config = Settings()
+    assert temp_config.api_url == "https://fake_env_url/"
+    assert temp_config.api_url != LiveSettings.api_url
+
+    set_api_url("https://api.beta.helioviewer.org/")
+    params = HvpyParameters()
+    assert params.url == "https://api.beta.helioviewer.org//"
+    assert LiveSettings.api_url == "https://api.beta.helioviewer.org/"
+
+    set_api_url("https://api.helioviewer.org/v2/")
diff --git a/tox.ini b/tox.ini
index 2e31e2c..5fefdaa 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 [tox]
 envlist =
-    py{38,39,310}{,-online}
+    py{38,39,310}
     build_docs
     codestyle
 requires =
@@ -12,7 +12,6 @@ isolated_build = true
 passenv = HOME WINDIR LC_ALL LC_CTYPE CC CI TRAVIS
 setenv =
     PYTEST_COMMAND = pytest -vvv -r a --pyargs hvpy --cov-report=xml --cov=hvpy --cov-config={toxinidir}/setup.cfg {toxinidir}/docs
-    HIDE_PARFIVE_PROGESS = True
 # Run the tests in a temporary directory to make sure that we don't import
 # the package from the source tree
 changedir = .tmp/{envname}
@@ -25,8 +24,7 @@ extras =
     tests
 commands =
     pip freeze --all --no-input
-    !online: {env:PYTEST_COMMAND} {posargs}
-    online: {env:PYTEST_COMMAND} --remote-data=any {posargs}
+    {env:PYTEST_COMMAND} {posargs}
 
 [testenv:build_docs]
 changedir = docs