diff --git a/openstack_releases/cmds/list_unreleased_changes.py b/openstack_releases/cmds/list_unreleased_changes.py
new file mode 100644
index 0000000000..f222c8c6ed
--- /dev/null
+++ b/openstack_releases/cmds/list_unreleased_changes.py
@@ -0,0 +1,305 @@
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+"""Show the changes that will be included in the release.
+"""
+
+import argparse
+import atexit
+import json
+import logging
+import os
+import os.path
+import shutil
+import subprocess
+import sys
+import tempfile
+
+import requests
+
+from openstack_releases import gitutils
+from openstack_releases import yamlutils
+
+LOG = logging.getLogger(__name__)
+
+
+def git_log(workdir, repo, git_range, extra_args=[]):
+    results = {
+        'range': git_range,
+        'logs': []
+    }
+    cmd = ['git', 'log', '--no-color']
+    cmd.extend(extra_args)
+    if isinstance(git_range, str):
+        cmd.append(git_range)
+    elif isinstance(git_range, tuple):
+        cmd.append('{start}..{end}'.format(
+            start=git_range[0], end=git_range[1]))
+    else:
+        cmd.extend(git_range)
+    LOG.debug('\n' + ' '.join(cmd) + '\n')
+    output = subprocess.check_output(cmd, cwd=os.path.join(workdir, repo))
+    results['logs'] = [el for el in output.decode('utf-8').split("\n") if el]
+    LOG.debug(results)
+    return results
+
+
+def filter_results(content,
+                   ignore_no_results=False,
+                   ignore_errors=False,
+                   ignore_not_yet_released=False,
+                   ignore_all=False):
+    filtered = []
+    for repo in content:
+        removed = False
+        if ignore_all and \
+            (repo['error'] or
+             repo['not_yet_released'] or
+             not repo['commits'] or
+             not repo['commits'].get('logs', None)):
+            removed = True
+            LOG.debug("ignoring all")
+        elif ignore_errors and repo['error']:
+            removed = True
+            LOG.debug("ignoring errors")
+        elif ignore_not_yet_released and repo['not_yet_released']:
+            removed = True
+            LOG.debug("ignoring not yet released")
+        elif ignore_no_results and (not repo.get('commits', None) or
+                                    not repo.get('commits', None).get(
+                                        'logs', None)):
+            LOG.debug("ignoring no results")
+            removed = True
+        if not removed:
+            filtered.append(repo)
+        else:
+            LOG.debug('repo {} will be ignored'.format(repo['repo']))
+            LOG.debug(repo)
+    return filtered
+
+
+def generate_output(content, output_format='std',
+                    ignore_no_results=False,
+                    ignore_errors=False,
+                    ignore_not_yet_released=False,
+                    ignore_all=False):
+    filtered = filter_results(content, ignore_no_results, ignore_errors,
+                              ignore_not_yet_released, ignore_all)
+    if output_format == 'json':
+        return json.dumps(filtered, indent=4)
+    if output_format == 'yaml':
+        return yamlutils.dumps(filtered)
+    if output_format == 'std':
+        out = []
+        for repo in filtered:
+            out.append('[ Unreleased changes in {rep} ({br}) ]'.format(
+                rep=repo['repo'], br=repo['branch']))
+
+            if repo['commits'].get('logs', None):
+                range_msg = 'Changes between {start} and {end}'.format(
+                    start=repo['commits']['range'][0],
+                    end=repo['commits']['range'][1])
+                out.append(range_msg)
+                out.append("\n".join(repo['commits']['logs']))
+        return '\n'.join(out)
+
+
+def main():
+    if not sys.stdout.encoding:
+        # Wrap sys.stdout with a writer that knows how to handle
+        # encoding Unicode data.
+        import codecs
+        wrapped_stdout = codecs.getwriter('UTF-8')(sys.stdout)
+        sys.stdout = wrapped_stdout
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        '--no-cleanup',
+        dest='cleanup',
+        default=True,
+        action='store_false',
+        help='do not remove temporary files',
+    )
+    parser.add_argument(
+        "-v",
+        "--verbosity",
+        action="count",
+        help="increase output verbosity",
+        default=0)
+    parser.add_argument(
+        "--ignore-no-results",
+        action='store_true',
+        default=False,
+        help="Ignore projects without difference between the HEAD and"
+             "the retrieved previous tag."
+             "They will be ignored in the command output.")
+    parser.add_argument(
+        "--ignore-errors",
+        action='store_true',
+        default=False,
+        help="Ignore projects in error (repos not found).")
+    parser.add_argument(
+        "--ignore-not-yet-released",
+        action='store_true',
+        default=False,
+        help="Ignore projects not yet released (previous tag not found).")
+    parser.add_argument(
+        "-I",
+        "--ignore-all",
+        action='store_true',
+        default=False,
+        help="Ignore projects without difference between the HEAD and"
+             "previous tag, projects not yet released, projects in error."
+             "Similar to call command with "
+             "`--ignore-no-results --ignore-errors --ignore-not-yet-released`"
+             "They will be ignored in the command output.")
+    parser.add_argument(
+        "-f",
+        "--format",
+        choices=['std', 'json', 'yaml'],
+        default='standard',
+        help="Output format")
+    parser.add_argument(
+        'branch',
+        help=('Branch to analyze'),
+    )
+    parser.add_argument(
+        'repos',
+        nargs='*',
+        help=('Repos to analyze, '
+              'repo should be e.g. openstack/glance'),
+    )
+    args = parser.parse_args()
+
+    log_level = logging.ERROR
+    if args.verbosity >= 3:
+        log_level = logging.DEBUG
+    elif args.verbosity >= 2:
+        log_level = logging.INFO
+    elif args.verbosity >= 1:
+        log_level = logging.WARNING
+
+    # Set up logging, including making some loggers quiet.
+    logging.basicConfig(
+        format='%(levelname)7s: %(message)s',
+        stream=sys.stdout,
+        level=log_level,
+    )
+    logging.getLogger('urllib3.connectionpool').setLevel(logging.WARNING)
+
+    workdir = tempfile.mkdtemp(prefix='releases-')
+    LOG.debug('creating temporary files in %s' % workdir)
+
+    def cleanup_workdir():
+        if args.cleanup:
+            shutil.rmtree(workdir, True)
+        else:
+            LOG.info('not cleaning up %s' % workdir)
+    atexit.register(cleanup_workdir)
+
+    # Remove any inherited PAGER environment variable to avoid
+    # blocking the output waiting for input.
+    os.environ['PAGER'] = ''
+    output = []
+
+    for repo in args.repos:
+        current = {
+            'repo': repo,
+            'branch': args.branch,
+            'commits': None,
+            'error': False,
+            'not_yet_released': False,
+            'msg': ''
+        }
+        url = 'https://opendev.org/{}'.format(repo)
+        res = requests.get(url)
+        if res.status_code == 404:
+            current.update({'error': True})
+            current.update(
+                {'msg': "fatal: repository '{}' not found".format(url)})
+            output.append(current)
+            continue
+
+        # Start by checking out master, always. We need the repo
+        # checked out before we can tell if the stable branch
+        # really exists.
+        gitutils.clone_repo(
+            workdir,
+            repo,
+            branch='master',
+        )
+
+        # Set some git configuration values to allow us to perform
+        # local operations like tagging.
+        gitutils.ensure_basic_git_config(
+            workdir, repo,
+            {'user.email': 'openstack-infra@lists.openstack.org',
+             'user.name': 'OpenStack Proposal Bot'},
+        )
+
+        # Determine which branch we should actually be looking
+        # at. Assume any series for which there is no stable
+        # branch will be on 'master'.
+        if gitutils.stable_branch_exists(workdir, repo, args.branch):
+            branch = 'stable/' + args.branch
+        else:
+            branch = 'master'
+
+        if branch != 'master':
+            # Check out the repo again to the right branch if we
+            # didn't get it the first time.
+            gitutils.clone_repo(
+                workdir,
+                repo,
+                branch=branch,
+            )
+
+        # look at the previous tag for the parent of the commit
+        # getting the new release
+        previous_tag = gitutils.get_latest_tag(workdir, repo, always=False)
+
+        if not previous_tag:
+            current.update({'not_yet_released': True})
+            current.update(
+                {'msg': '{} has not yet been released'.format(repo)})
+            output.append(current)
+            continue
+
+        start_range = previous_tag
+        head_sha = gitutils.get_head(workdir, repo)
+
+        if not start_range:
+            current.update({'not_yet_released': True})
+            current.update(
+                {'msg': '{} has not yet been released'.format(repo)})
+            output.append(current)
+            continue
+
+        commits = git_log(workdir, repo, (start_range, head_sha),
+                          extra_args=[
+                              '--no-color',
+                              '--no-merges',
+                              '--graph',
+                              '--format=%h %ci %s'])
+
+        current.update({'commits': commits})
+        output.append(current)
+
+    out = generate_output(output, output_format=args.format,
+                          ignore_no_results=args.ignore_no_results,
+                          ignore_errors=args.ignore_errors,
+                          ignore_not_yet_released=args.ignore_not_yet_released,
+                          ignore_all=args.ignore_all)
+    print("".join(out))
+    return 0
diff --git a/openstack_releases/gitutils.py b/openstack_releases/gitutils.py
index db395896c4..875f76cd29 100644
--- a/openstack_releases/gitutils.py
+++ b/openstack_releases/gitutils.py
@@ -307,6 +307,20 @@ def check_ancestry(workdir, repo, old_version, sha):
         return False
 
 
+def get_head(workdir, repo):
+    cmd = ['git', 'log', '-n', '1', '--pretty=tformat:%h']
+    try:
+        return processutils.check_output(
+            cmd,
+            cwd=os.path.join(workdir, repo),
+            stderr=subprocess.STDOUT,
+        ).decode('utf-8').strip()
+    except processutils.CalledProcessError as e:
+        LOG.warning('failed to retrieve HEAD: %s [%s]',
+                    e, e.output.strip())
+        return None
+
+
 def get_latest_tag(workdir, repo, sha=None, always=True):
     cmd = ['git', 'describe', '--abbrev=0']
     if always:
diff --git a/openstack_releases/tests/units/cmd/__init__.py b/openstack_releases/tests/units/cmd/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/openstack_releases/tests/units/cmd/test_list_unreleased_changes.py b/openstack_releases/tests/units/cmd/test_list_unreleased_changes.py
new file mode 100644
index 0000000000..a4003e3a84
--- /dev/null
+++ b/openstack_releases/tests/units/cmd/test_list_unreleased_changes.py
@@ -0,0 +1,156 @@
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import json
+import textwrap
+
+from oslotest import base
+
+from openstack_releases.cmds import list_unreleased_changes as luc
+
+
+class TestStableStatus(base.BaseTestCase):
+
+    _data = json.loads(textwrap.dedent('''
+        [
+            {
+                "repo": "openstack/castellan",
+                "branch": "victoria",
+                "commits": {
+                    "range": [
+                        "3.2.0",
+                        "3a3a738"
+                    ],
+                    "logs": [
+                        "* 3a3a738 2020-06-26 13:51:12 +0200 Bump vault version"
+                    ]
+                },
+                "error": false,
+                "not_yet_released": false,
+                "msg": ""
+            },
+            {
+                "repo": "openstack/devstack-plugin-amqp1",
+                "branch": "victoria",
+                "commits": null,
+                "error": false,
+                "not_yet_released": true,
+                "msg": "openstack/devstack-plugin-amqp1 has not yet been released"
+            },
+            {
+                "repo": "openstack/oslo.cache",
+                "branch": "victoria",
+                "commits": {
+                    "range": [
+                        "2.5.0",
+                        "f3f006c"
+                    ],
+                    "logs": [
+                        "* a5ff884 2020-05-04 18:18:10 +0200 Align contributing doc with oslo's policy"
+                    ]
+                },
+                "error": false,
+                "not_yet_released": false,
+                "msg": ""
+            },
+            {
+                "repo": "openstack/oslo.service",
+                "branch": "victoria",
+                "commits": {
+                    "range": [
+                        "2.3.1",
+                        "585768b"
+                    ],
+                    "logs": []
+                },
+                "error": false,
+                "not_yet_released": false,
+                "msg": ""
+            },
+            {
+                "repo": "openstack/devstack-plugin-kafka",
+                "branch": "victoria",
+                "commits": null,
+                "error": false,
+                "not_yet_released": true,
+                "msg": "openstack/devstack-plugin-kafka has not yet been released"
+            },
+            {
+                "repo": "openstack/tttt",
+                "branch": "victoria",
+                "commits": null,
+                "error": true,
+                "not_yet_released": false,
+                "msg": "fatal: repository 'https://opendev.org/openstack/tttt' not found"
+            }
+        ]
+    '''))  # noqa
+
+    def test_filter_results(self):
+        results = luc.filter_results(self._data)
+        self.assertEqual(6, len(results))
+        results = luc.filter_results(self._data, ignore_all=True)
+        self.assertEqual(2, len(results))
+        results = luc.filter_results(self._data, ignore_errors=True)
+        self.assertEqual(5, len(results))
+        results = luc.filter_results(self._data, ignore_not_yet_released=True)
+        self.assertEqual(4, len(results))
+        results = luc.filter_results(self._data,
+                                     ignore_not_yet_released=True,
+                                     ignore_errors=True)
+        self.assertEqual(3, len(results))
+        results = luc.filter_results(self._data, ignore_no_results=True)
+        self.assertEqual(2, len(results))
+
+    def test_generate_output(self):
+        results = luc.generate_output(self._data, output_format='json')
+        self.assertEqual(json.dumps(self._data, indent=4), results)
+        results = luc.generate_output(self._data, ignore_all=True)
+        expected_result = textwrap.dedent('''\
+            [ Unreleased changes in openstack/castellan (victoria) ]
+            Changes between 3.2.0 and 3a3a738
+            * 3a3a738 2020-06-26 13:51:12 +0200 Bump vault version
+            [ Unreleased changes in openstack/oslo.cache (victoria) ]
+            Changes between 2.5.0 and f3f006c
+            * a5ff884 2020-05-04 18:18:10 +0200 Align contributing doc with oslo's policy''')  # noqa
+        self.assertEqual(expected_result, "".join(results))
+        results = luc.generate_output(self._data, output_format='yaml',
+                                      ignore_all=True)
+        expected_result = textwrap.dedent("""\
+            ---
+              - repo: openstack/castellan
+                branch: victoria
+                commits:
+                  range:
+                    - 3.2.0
+                    - 3a3a738
+                  logs:
+                    - '* 3a3a738 2020-06-26 13:51:12 +0200 Bump vault version'
+                error: false
+                not_yet_released: false
+                msg: ''
+              - repo: openstack/oslo.cache
+                branch: victoria
+                commits:
+                  range:
+                    - 2.5.0
+                    - f3f006c
+                  logs:
+                    - "* a5ff884 2020-05-04 18:18:10 +0200 Align contributing doc\\
+                      \\ with oslo's policy"
+                error: false
+                not_yet_released: false
+                msg: ''
+        """)  # noqa
+        self.assertEqual(expected_result, results)
diff --git a/setup.cfg b/setup.cfg
index 7942b8e222..bc38ba3064 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -24,6 +24,7 @@ packages = openstack_releases
 console_scripts =
     validate-request = openstack_releases.cmds.validate:main
     list-changes = openstack_releases.cmds.list_changes:main
+    list-unreleased-changes = openstack_releases.cmds.list_unreleased_changes:main
     list-constraints = openstack_releases.cmds.list_constraints:main
     new-release = openstack_releases.cmds.new_release:main
     format-yaml = openstack_releases.cmds.reformat_yaml:main
diff --git a/tools/list_unreleased_changes.sh b/tools/list_unreleased_changes.sh
index 534b335826..68760459c5 100755
--- a/tools/list_unreleased_changes.sh
+++ b/tools/list_unreleased_changes.sh
@@ -17,46 +17,20 @@
 if [[ $# -lt 2 ]]; then
     echo "Usage: $(basename $0) <branch> <repo> [<repo>...]"
     echo "repo should be e.g. openstack/glance"
+    echo
+    echo "Example: $(basename $0) victoria oslo.rootwrap"
+    echo "Example: $(basename $0) independent reno bugfix"
+    echo
+    echo "For further details about how to use the command:"
+    echo "tox -e venv -- list-unreleased-changes --help"
     exit 1
 fi
 
-branch="$1"
-shift
-repos="$@"
-
-TOOLSDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
-BASEDIR=$(dirname $TOOLSDIR)
-source $TOOLSDIR/functions
-
-# Make sure no pager is configured so the output is not blocked
-export PAGER=
-
-setup_temp_space 'list-unreleased'
-
-function list_changes {
-    title "Unreleased changes in $repo ($branch)"
-    clone_repo $repo $branch
-    if [[ $? -ne 0 ]]; then
-        return 1
+if [[ -z "$VIRTUAL_ENV" ]]; then
+    if [[ ! -d .tox/venv ]]; then
+        tox -e venv --notest
     fi
-    cd $repo
-    prev_tag=$(get_last_tag)
-    if [ -z "$prev_tag" ]; then
-        echo "$repo has not yet been released"
-    else
-        echo
-        end_sha=$(git log -n 1 --pretty=tformat:%h)
-        echo "Changes between $prev_tag and $end_sha"
-        echo
-        git log --no-color --no-merges --format='%h %ci %s' \
-            --graph ${prev_tag}..${end_sha}
-        echo
-    fi
-}
+    source ./.tox/venv/bin/activate
+fi
 
-# Show the unreleased changes for each repository.
-for repo in $repos; do
-    cd $MYTMPDIR
-    echo
-    list_changes "$repo"
-done
+list-unreleased-changes $@