diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index ac07837e..6d0f4436 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -45,7 +45,7 @@ jobs:
             setup.py
 
       - name: Install uv
-        uses: astral-sh/setup-uv@v3
+        uses: astral-sh/setup-uv@v5
         with:
           version: "latest"
 
@@ -77,7 +77,7 @@ jobs:
       # https://github.com/github/codeql/issues/11427#issuecomment-1721059096
       - name: Dismiss alerts
         # if: github.ref == 'refs/heads/main'
-        uses: advanced-security/dismiss-alerts@v1
+        uses: advanced-security/dismiss-alerts@v2
         with:
           # specify a 'sarif-id' and 'sarif-file'
           sarif-id: ${{ steps.analyze.outputs.sarif-id }}
diff --git a/.github/workflows/nightly.yml b/.github/workflows/nightly.yml
index 1b9b74e2..cd5fa37f 100644
--- a/.github/workflows/nightly.yml
+++ b/.github/workflows/nightly.yml
@@ -14,7 +14,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: ['ubuntu-latest']
+        os: ['ubuntu-22.04']
         python-version: ['3.7', '3.8', '3.9', '3.10', '3.11', '3.12', '3.13']
         cratedb-version: ['nightly']
 
@@ -33,7 +33,7 @@ jobs:
           cache-dependency-path: 'setup.py'
 
       - name: Install uv
-        uses: astral-sh/setup-uv@v3
+        uses: astral-sh/setup-uv@v5
         with:
           version: "latest"
 
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index de847c46..eca585dc 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -19,7 +19,7 @@ jobs:
           cache-dependency-path: 'setup.py'
 
       - name: Install uv
-        uses: astral-sh/setup-uv@v3
+        uses: astral-sh/setup-uv@v5
         with:
           version: "latest"
 
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 6f9b0029..16ed304a 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -48,7 +48,7 @@ jobs:
           cache-dependency-path: setup.py
 
       - name: Install uv
-        uses: astral-sh/setup-uv@v3
+        uses: astral-sh/setup-uv@v5
         with:
           version: "latest"
 
@@ -75,7 +75,7 @@ jobs:
 
       # https://github.com/codecov/codecov-action
       - name: Upload coverage results to Codecov
-        uses: codecov/codecov-action@v4
+        uses: codecov/codecov-action@v5
         env:
           CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
         with:
diff --git a/CHANGES.rst b/CHANGES.rst
index 2cf9c9dd..e9e73d94 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -5,6 +5,26 @@ Changes for crate
 Unreleased
 ==========
 
+2025/01/30 2.0.0
+================
+
+- Switched JSON encoder to use the `orjson`_ library, to improve JSON
+  marshalling performance. Thanks, @widmogrod.
+
+  orjson is fast and in some spots even more correct when compared against
+  Python's stdlib ``json`` module. Contrary to the stdlib variant, orjson
+  will serialize to ``bytes`` instead of ``str``. When sending data to CrateDB,
+  ``crate-python`` uses a custom encoder to add support for additional data
+  types.
+
+  - Python's ``Decimal`` type will be serialized to ``str``.
+  - Python's ``dt.datetime`` and ``dt.date`` types will be serialized to
+    ``int`` (``LONG``) after converting to milliseconds since epoch, to
+    optimally accommodate CrateDB's `TIMESTAMP`_ representation.
+  - NumPy's data types will be handled by ``orjson`` without any ado.
+
+.. _orjson: https://github.com/ijl/orjson
+.. _TIMESTAMP: https://cratedb.com/docs/crate/reference/en/latest/general/ddl/data-types.html#type-timestamp
 
 2024/11/23 1.0.1
 ================
diff --git a/DEVELOP.rst b/DEVELOP.rst
index 85dfb6f7..2f39ede0 100644
--- a/DEVELOP.rst
+++ b/DEVELOP.rst
@@ -5,7 +5,7 @@ CrateDB Python developer guide
 Setup
 =====
 
-Optionally install Python package and project manager ``uv``,
+Optionally install Python package and project manager `uv`_,
 in order to significantly speed up the package installation::
 
     {apt,brew,pip,zypper} install uv
@@ -67,16 +67,11 @@ To inspect the whole list of test cases, run::
 
     bin/test --list-tests
 
-You can run the tests against multiple Python interpreters with `tox`_::
-
-    tox
-
-To do this, you will need the respective Python interpreter versions available
-on your ``$PATH``.
-
-To run against a single interpreter, you can also invoke::
-
-    tox -e py37
+The CI setup on GitHub Actions (GHA) provides a full test matrix covering
+relevant Python versions. You can invoke the software tests against a specific
+Python interpreter or multiple `Python versions`_ on your workstation using
+`uv`_, by supplying the ``--python`` command-line option, or by defining the
+`UV_PYTHON`_ environment variable prior to invoking ``source bootstrap.sh``.
 
 *Note*: Before running the tests, make sure to stop all CrateDB instances which
 are listening on the default CrateDB transport port to avoid side effects with
@@ -168,12 +163,14 @@ nothing special you need to do to get the live docs to update.
 .. _@crate/docs: https://github.com/orgs/crate/teams/docs
 .. _buildout: https://pypi.python.org/pypi/zc.buildout
 .. _PyPI: https://pypi.python.org/pypi
+.. _Python versions: https://docs.astral.sh/uv/concepts/python-versions/
 .. _Read the Docs: http://readthedocs.org
 .. _ReStructuredText: http://docutils.sourceforge.net/rst.html
 .. _Sphinx: http://sphinx-doc.org/
 .. _tests/assets/pki/*.pem: https://github.com/crate/crate-python/tree/main/tests/assets/pki
-.. _tox: http://testrun.org/tox/latest/
 .. _twine: https://pypi.python.org/pypi/twine
 .. _useful command-line options for zope-testrunner: https://pypi.org/project/zope.testrunner/#some-useful-command-line-options-to-get-you-started
+.. _uv: https://docs.astral.sh/uv/
+.. _UV_PYTHON: https://docs.astral.sh/uv/configuration/environment/#uv_python
 .. _versions hosted on ReadTheDocs: https://readthedocs.org/projects/crate-python/versions/
 .. _zope.testrunner: https://pypi.org/project/zope.testrunner/
diff --git a/docs/by-example/http.rst b/docs/by-example/http.rst
index aacf3481..5afd3dee 100644
--- a/docs/by-example/http.rst
+++ b/docs/by-example/http.rst
@@ -228,7 +228,7 @@ When connecting to non-CrateDB servers, the HttpClient will raise a ConnectionEr
     >>> http_client.server_infos(http_client._get_server())
     Traceback (most recent call last):
     ...
-    crate.client.exceptions.ProgrammingError: Invalid server response of content-type 'text/html; charset=UTF-8':
+    crate.client.exceptions.ProgrammingError: Invalid server response of content-type 'text/html':
     ...
     >>> http_client.close()
 
diff --git a/pyproject.toml b/pyproject.toml
index 31717680..08b0d321 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -71,6 +71,13 @@ lint.per-file-ignores."tests/*" = [
   "S106",  # Possible hardcoded password assigned to argument: "password"
   "S311",  # Standard pseudo-random generators are not suitable for cryptographic purposes
 ]
+lint.per-file-ignores."src/crate/client/{connection.py,http.py}" = [
+  "A004",  # Import `ConnectionError` is shadowing a Python builtin
+  "A005",  # Import `ConnectionError` is shadowing a Python builtin
+]
+lint.per-file-ignores."tests/client/test_http.py" = [
+  "A004",  # Import `ConnectionError` is shadowing a Python builtin
+]
 
 
 # ===================
diff --git a/setup.py b/setup.py
index b5c87934..15591f88 100644
--- a/setup.py
+++ b/setup.py
@@ -54,6 +54,7 @@ def read(path):
     packages=find_namespace_packages("src"),
     package_dir={"": "src"},
     install_requires=[
+        "orjson<4",
         "urllib3",
         "verlib2",
     ],
@@ -66,11 +67,10 @@ def read(path):
             'backports.zoneinfo<1; python_version<"3.9"',
             "certifi",
             "createcoverage>=1,<2",
-            "mypy<1.14",
-            "poethepoet<0.31",
-            "ruff<0.8",
+            "mypy<1.15",
+            "poethepoet<0.33",
+            "ruff<0.10",
             "stopit>=1.1.2,<2",
-            "tox>=3,<5",
             "pytz",
             "zc.customdoctests>=1.0.1,<2",
             "zope.testing>=4,<6",
diff --git a/src/crate/client/__init__.py b/src/crate/client/__init__.py
index 2fec7abd..ac58fb77 100644
--- a/src/crate/client/__init__.py
+++ b/src/crate/client/__init__.py
@@ -29,7 +29,7 @@
 
 # version string read from setup.py using a regex. Take care not to break the
 # regex!
-__version__ = "1.0.1"
+__version__ = "2.0.0"
 
 # codeql[py/unused-global-variable]
 apilevel = "2.0"
diff --git a/src/crate/client/http.py b/src/crate/client/http.py
index d9a0598f..a1251d34 100644
--- a/src/crate/client/http.py
+++ b/src/crate/client/http.py
@@ -21,22 +21,22 @@
 
 
 import calendar
+import datetime as dt
 import heapq
 import io
-import json
 import logging
 import os
 import re
 import socket
 import ssl
 import threading
+import typing as t
 from base64 import b64encode
-from datetime import date, datetime, timezone
 from decimal import Decimal
 from time import time
 from urllib.parse import urlparse
-from uuid import UUID
 
+import orjson
 import urllib3
 from urllib3 import connection_from_url
 from urllib3.connection import HTTPConnection
@@ -86,25 +86,53 @@ def super_len(o):
     return None
 
 
-class CrateJsonEncoder(json.JSONEncoder):
-    epoch_aware = datetime(1970, 1, 1, tzinfo=timezone.utc)
-    epoch_naive = datetime(1970, 1, 1)
-
-    def default(self, o):
-        if isinstance(o, (Decimal, UUID)):
-            return str(o)
-        if isinstance(o, datetime):
-            if o.tzinfo is not None:
-                delta = o - self.epoch_aware
-            else:
-                delta = o - self.epoch_naive
-            return int(
-                delta.microseconds / 1000.0
-                + (delta.seconds + delta.days * 24 * 3600) * 1000.0
-            )
-        if isinstance(o, date):
-            return calendar.timegm(o.timetuple()) * 1000
-        return json.JSONEncoder.default(self, o)
+epoch_aware = dt.datetime(1970, 1, 1, tzinfo=dt.timezone.utc)
+epoch_naive = dt.datetime(1970, 1, 1)
+
+
+def json_encoder(obj: t.Any) -> t.Union[int, str]:
+    """
+    Encoder function for orjson, with additional type support.
+
+    - Python's `Decimal` type will be serialized to `str`.
+    - Python's `dt.datetime` and `dt.date` types will be
+      serialized to `int` after converting to milliseconds
+      since epoch.
+
+    https://github.com/ijl/orjson#default
+    https://cratedb.com/docs/crate/reference/en/latest/general/ddl/data-types.html#type-timestamp
+    """
+    if isinstance(obj, Decimal):
+        return str(obj)
+    if isinstance(obj, dt.datetime):
+        if obj.tzinfo is not None:
+            delta = obj - epoch_aware
+        else:
+            delta = obj - epoch_naive
+        return int(
+            delta.microseconds / 1000.0
+            + (delta.seconds + delta.days * 24 * 3600) * 1000.0
+        )
+    if isinstance(obj, dt.date):
+        return calendar.timegm(obj.timetuple()) * 1000
+    raise TypeError
+
+
+def json_dumps(obj: t.Any) -> bytes:
+    """
+    Serialize to JSON format, using `orjson`, with additional type support.
+
+    https://github.com/ijl/orjson
+    """
+    return orjson.dumps(
+        obj,
+        default=json_encoder,
+        option=(
+            orjson.OPT_PASSTHROUGH_DATETIME
+            | orjson.OPT_NON_STR_KEYS
+            | orjson.OPT_SERIALIZE_NUMPY
+        ),
+    )
 
 
 class Server:
@@ -180,7 +208,7 @@ def close(self):
 
 def _json_from_response(response):
     try:
-        return json.loads(response.data.decode("utf-8"))
+        return orjson.loads(response.data)
     except ValueError as ex:
         raise ProgrammingError(
             "Invalid server response of content-type '{}':\n{}".format(
@@ -223,7 +251,7 @@ def _raise_for_status_real(response):
     if response.status == 503:
         raise ConnectionError(message)
     if response.headers.get("content-type", "").startswith("application/json"):
-        data = json.loads(response.data.decode("utf-8"))
+        data = orjson.loads(response.data)
         error = data.get("error", {})
         error_trace = data.get("error_trace", None)
         if "results" in data:
@@ -323,7 +351,7 @@ def _update_pool_kwargs_for_ssl_minimum_version(server, kwargs):
             kwargs["ssl_minimum_version"] = ssl.TLSVersion.MINIMUM_SUPPORTED
 
 
-def _create_sql_payload(stmt, args, bulk_args):
+def _create_sql_payload(stmt, args, bulk_args) -> bytes:
     if not isinstance(stmt, str):
         raise ValueError("stmt is not a string")
     if args and bulk_args:
@@ -334,7 +362,7 @@ def _create_sql_payload(stmt, args, bulk_args):
         data["args"] = args
     if bulk_args:
         data["bulk_args"] = bulk_args
-    return json.dumps(data, cls=CrateJsonEncoder)
+    return json_dumps(data)
 
 
 def _get_socket_opts(
@@ -670,7 +698,7 @@ def _drop_server(self, server, message):
         # if this is the last server raise exception, otherwise try next
         if not self._active_servers:
             raise ConnectionError(
-                ("No more Servers available, " "exception from last server: %s")
+                ("No more Servers available, exception from last server: %s")
                 % message
             )
 
diff --git a/tests/client/test_http.py b/tests/client/test_http.py
index 610197a8..c4c0609e 100644
--- a/tests/client/test_http.py
+++ b/tests/client/test_http.py
@@ -49,9 +49,9 @@
 )
 from crate.client.http import (
     Client,
-    CrateJsonEncoder,
     _get_socket_opts,
     _remove_certs_for_non_https,
+    json_dumps,
 )
 
 REQUEST = "crate.client.http.Server.request"
@@ -724,10 +724,10 @@ def test_username(self):
 class TestCrateJsonEncoder(TestCase):
     def test_naive_datetime(self):
         data = dt.datetime.fromisoformat("2023-06-26T09:24:00.123")
-        result = json.dumps(data, cls=CrateJsonEncoder)
-        self.assertEqual(result, "1687771440123")
+        result = json_dumps(data)
+        self.assertEqual(result, b"1687771440123")
 
     def test_aware_datetime(self):
         data = dt.datetime.fromisoformat("2023-06-26T09:24:00.123+02:00")
-        result = json.dumps(data, cls=CrateJsonEncoder)
-        self.assertEqual(result, "1687764240123")
+        result = json_dumps(data)
+        self.assertEqual(result, b"1687764240123")
diff --git a/tox.ini b/tox.ini
deleted file mode 100644
index 1ea931fa..00000000
--- a/tox.ini
+++ /dev/null
@@ -1,14 +0,0 @@
-[tox]
-envlist = py{py3,35,36,37,38,39}-sa_{1_0,1_1,1_2,1_3,1_4}
-
-[testenv]
-usedevelop = True
-passenv = JAVA_HOME
-deps =
-    zope.testrunner
-    zope.testing
-    zc.customdoctests
-    mock
-    urllib3
-commands =
-    zope-testrunner -c --path=tests