diff --git a/.github/workflows/staging-check.yml b/.github/workflows/staging-check.yml
new file mode 100644
index 0000000..5f248a4
--- /dev/null
+++ b/.github/workflows/staging-check.yml
@@ -0,0 +1,31 @@
+name: Validate output against staging
+
+on: [pull_request]
+
+jobs:
+  validate_against_stating:
+    permissions:
+      pull-requests: write
+
+    runs-on: ubuntu-latest
+
+    env:
+      PYTHONDEVMODE: 1
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Run deployment script
+        run: |
+          pip install lxml
+          mkdir tmp/
+          python tools/convert.py -a -d tmp ispdb/*
+
+      - name: Compare output against staging
+        run: |
+          pip install requests
+          python tools/compare_out_files.py -b https://autoconfig-stage.thunderbird.net/v1.1/ tmp/
+
+      - name: Calculate generated_files.json diff with prod
+        run: |
+          python tools/calculate_generated_files_diff.py -b https://autoconfig.thunderbird.net/v1.1 -t ${{ secrets.GITHUB_TOKEN }} -r ${{ github.repository }} -n ${{ github.event.pull_request.number }}
diff --git a/tools/calculate_generated_files_diff.py b/tools/calculate_generated_files_diff.py
new file mode 100644
index 0000000..fa1561e
--- /dev/null
+++ b/tools/calculate_generated_files_diff.py
@@ -0,0 +1,84 @@
+import argparse
+import difflib
+import os.path
+import requests
+
+GENERATED_FILES_NAME = "generated_files.json"
+
+GITHUB_COMMENT_TEMPLATE_WITH_DIFF = """This PR will cause the following changes to the production `generated_files.json` file:
+
+<details>
+<summary>
+Expand to view diff
+</summary>
+
+```diff
+{deltas}
+```
+
+</details>
+"""
+
+GITHUB_COMMENT_TEMPLATE_NO_DIFF = (
+    "This PR will not cause any change to the production `generated_files.json` file."
+)
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-b", metavar="base_url", help="base URL serving ISPDB files")
+    parser.add_argument("-t", metavar="api_token", help="Github API token")
+    parser.add_argument("-r", metavar="repo", help="Github repository")
+    parser.add_argument("-n", metavar="number", help="The Github or issue number")
+    parser.add_argument(
+        "folder", help="the folder containing the local ISPDB files to compare"
+    )
+
+    args = parser.parse_args()
+
+    # Strip out any trailing slash in the base URL so we don't accidentally end
+    # up doubling it.
+    base_url: str = args.b.strip("/")
+
+    resp = requests.get(f"{base_url}/{GENERATED_FILES_NAME}")
+
+    # At the time of writing, all of the domains in ISPDB are made up of ASCII
+    # characters, but that might not stay true forever.
+    resp.encoding = "utf-8"
+
+    with open(os.path.join(args.folder, GENERATED_FILES_NAME), "r") as fp:
+        local_list = fp.readlines()
+
+        # We call the local version "staging" as a shortcut, because by this
+        # time we expect to have already validated that the
+        deltas = list(
+            difflib.unified_diff(
+                local_list,
+                resp.text.splitlines(keepends=True),
+                fromfile="staging",
+                tofile="production",
+            )
+        )
+
+        comment = (
+            GITHUB_COMMENT_TEMPLATE_WITH_DIFF.format(deltas="".join(deltas))
+            if len(deltas) > 0
+            else GITHUB_COMMENT_TEMPLATE_NO_DIFF
+        )
+
+        # Create the comment via the Github API.
+        # See <https://docs.github.com/en/rest/issues/comments?apiVersion=2022-11-28#create-an-issue-comment>
+        resp = requests.post(
+            f"https://api.github.com/repos/{args.r}/issues/{args.n}/comments",
+            headers={
+                "Accept": "application/vnd.github+json",
+                "Authorization": f"Bearer {args.t}",
+            },
+            json={"body": comment},
+        )
+
+        print(f"Posted comment {resp.json()["html_url"]}")
+
+
+if __name__ == "__main__":
+    main()
diff --git a/tools/compare_out_files.py b/tools/compare_out_files.py
new file mode 100644
index 0000000..4118c5e
--- /dev/null
+++ b/tools/compare_out_files.py
@@ -0,0 +1,134 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import argparse
+import difflib
+import json
+import os.path
+import sys
+import requests
+from typing import Dict, List
+
+GENERATED_FILES_NAME = "generated_files.json"
+
+
+def get_and_compare(file_name: str, base_url: str, local_folder: str) -> str:
+    """Reads a local file and compare it with its remote copy before returning
+    its content.
+
+    Returns:
+        The file's content as served by the remote server, decoded as UTF-8
+        text.
+
+    Raises:
+        RuntimeError if the local file's content doesn't match the remote copy.
+    """
+    resp = requests.get(f"{base_url}/{file_name}")
+
+    # The response might not include an content-type header, and there are some
+    # non-ASCII characters in our XML files (e.g. in display names), so we need
+    # to explicitly tell `resp` what its encoding is.
+    resp.encoding = "utf-8"
+
+    with open(os.path.join(local_folder, file_name), "r") as fp:
+        local_list = fp.readlines()
+
+        deltas = list(
+            difflib.unified_diff(
+                local_list,
+                resp.text.splitlines(keepends=True),
+                fromfile="local",
+                tofile="remote",
+            )
+        )
+
+        if len(deltas) > 0:
+            print(f"Diff deltas:\n\n{"".join(deltas)}", file=sys.stderr)
+            raise RuntimeError("local file list does not match staging copy")
+
+        return resp.text
+
+
+def get_file_list(base_url: str, local_folder: str) -> List[str]:
+    """Gets the list of files to compare.
+
+    Returns:
+        The list of file names as per the `generated_files.json` file.
+
+    Raises:
+        RuntimeError if the local `generated_files.json` file does not match the
+        remote copy.
+    """
+    file_list = get_and_compare(GENERATED_FILES_NAME, base_url, local_folder)
+    return json.loads(file_list)
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-b", metavar="base_url", help="base URL serving ISPDB files")
+    parser.add_argument(
+        "folder", help="the folder containing the local ISPDB files to compare"
+    )
+
+    args = parser.parse_args()
+
+    # Strip out any trailing slash in the base URL so we don't accidentally end
+    # up doubling it.
+    base_url: str = args.b.strip("/")
+
+    print("Fetching and comparing file list")
+
+    listed_files = get_file_list(base_url, args.folder)
+
+    failed_files: Dict[str, Exception] = {}
+    for file in listed_files:
+        print(f"Fetching and comparing {file}")
+
+        try:
+            get_and_compare(file, base_url, args.folder)
+        except Exception as e:
+            print(f"Comparison failed for file {file}: {e}", file=sys.stderr)
+            failed_files[file] = e
+
+    if len(failed_files) > 0:
+        # Print the failed files, preceded by an empty line to separate them
+        # from the previous logs.
+        print("\nComparing the following file(s) has failed:", file=sys.stderr)
+
+        for file, exc in failed_files.items():
+            print(f"{file}: {exc}", file=sys.stderr)
+
+    # Check if we can find files that exist in the local directory but isn't
+    # listed in `generated_files.json`. We could also do this check in the other
+    # direction (i.e. check if a file in `generated_files.json` is missing from
+    # the local directory), but if a file from the list is missing then trying
+    # to open it earlier will have raised an exception and will already cause
+    # the script to fail.
+    local_files = os.listdir(args.folder)
+
+    # Make sure we don't try to find the JSON list file in itself.
+    local_files.remove(GENERATED_FILES_NAME)
+
+    unknown_files = []
+    for local_file in local_files:
+        if local_file not in listed_files:
+            unknown_files.append(local_file)
+
+    if len(unknown_files) > 0:
+        print("\nUnknown file(s) in local directory:", file=sys.stderr)
+
+        for file in unknown_files:
+            print(file, file=sys.stderr)
+    else:
+        print("No unknown files found")
+
+    # Fail the script if either a comparison has failed or we found an unknown
+    # file. We could fail earlier, but it's more helpful for troubleshooting if
+    # we have the script point out as many issues in one run as possible.
+    if len(failed_files) > 0 or len(unknown_files) > 0:
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()