diff --git a/.gitea/workflows/ci.yml b/.gitea/workflows/ci.yml
new file mode 100644
index 0000000000..8cda398654
--- /dev/null
+++ b/.gitea/workflows/ci.yml
@@ -0,0 +1,70 @@
+name: Validate Tryton customizations
+
+on:
+  push:
+    branches:
+      - '8.0'
+      - 'integration/8.0'
+      - 'feature/**'
+      - 'translation/**'
+  pull_request:
+    branches:
+      - '8.0'
+      - 'integration/8.0'
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  validate:
+    runs-on: ubuntu-24.04
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.13'
+          cache: pip
+
+      - name: Install validation dependencies
+        run: python -m pip install --upgrade build polib
+
+      - name: Validate Python syntax
+        run: python -m compileall -q trytond/trytond modules/translation_do
+
+      - name: Validate PO files
+        run: python ci/validate_po.py
+
+      - name: Build customized packages
+        run: |
+          python -m build trytond
+          python -m build modules/translation_do
+
+      - name: Install Tryton server and translation module
+        run: |
+          python -m pip install './trytond[test]'
+          python -m pip install modules/translation_do/dist/*.whl
+
+      - name: Run relevant Tryton tests
+        env:
+          TRYTOND_DATABASE_URI: sqlite://
+          DB_NAME: ':memory:'
+        run: |
+          python -m unittest discover -s ci/tests -p 'test_*.py'
+          python -m unittest discover -s trytond/trytond/tests -p 'test_i18n.py'
+          python -m unittest trytond.modules.translation_do.tests.test_module
+
+      - name: Upload Python distributions
+        uses: actions/upload-artifact@v4
+        with:
+          name: tryton-custom-python-${{ gitea.sha }}
+          path: |
+            trytond/dist/*
+            modules/translation_do/dist/*
+          if-no-files-found: error
+          retention-days: 14
diff --git a/ci/tests/test_upstream_pr.py b/ci/tests/test_upstream_pr.py
new file mode 100644
index 0000000000..847bac1863
--- /dev/null
+++ b/ci/tests/test_upstream_pr.py
@@ -0,0 +1,60 @@
+import importlib.util
+import os
+import pathlib
+import unittest
+from unittest.mock import ANY, patch
+
+
+SCRIPT = pathlib.Path(__file__).parents[1] / 'upstream_pr.py'
+
+
+class UpstreamPullRequestTestCase(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        environment = {
+            'GITEA_URL': 'https://gitea.example.test',
+            'CUSTOM_REPOSITORY': 'tryton-do/tryton',
+            'GITEA_TOKEN': 'test-token',
+            'INTEGRATION_BRANCH': 'integration/8.0',
+            'UPDATE_BRANCH': 'automation/upstream-8.0',
+        }
+        with patch.dict(os.environ, environment, clear=False):
+            spec = importlib.util.spec_from_file_location('upstream_pr', SCRIPT)
+            cls.module = importlib.util.module_from_spec(spec)
+            spec.loader.exec_module(cls.module)
+
+    def test_reuses_existing_pull_request(self):
+        existing = [{
+            'head': {'ref': self.module.HEAD},
+            'base': {'ref': self.module.TARGET},
+            'html_url': 'https://gitea.example.test/pulls/1',
+        }]
+        with patch.object(self.module, 'open_pulls', return_value=existing), \
+                patch.object(self.module, 'request') as request:
+            self.module.ensure_pull_request('a' * 40)
+        request.assert_not_called()
+
+    def test_creates_pull_request_with_review_target(self):
+        created = {'html_url': 'https://gitea.example.test/pulls/2'}
+        with patch.object(self.module, 'open_pulls', return_value=[]), \
+                patch.object(self.module, 'request', return_value=created) as request:
+            self.module.ensure_pull_request('b' * 40)
+        request.assert_called_once_with(
+            'POST', '/repos/tryton-do/tryton/pulls', ANY)
+        payload = request.call_args.args[2]
+        self.assertEqual(payload['head'], 'automation/upstream-8.0')
+        self.assertEqual(payload['base'], 'integration/8.0')
+
+    def test_reuses_existing_conflict_issue(self):
+        existing = [{
+            'title': 'Upstream Tryton 8.0 synchronization conflict',
+            'html_url': 'https://gitea.example.test/issues/1',
+        }]
+        with patch.object(self.module, 'request', return_value=existing) as request:
+            self.module.ensure_conflict_issue('trytond/file.py')
+        request.assert_called_once()
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/ci/validate_po.py b/ci/validate_po.py
new file mode 100755
index 0000000000..e0d3f294f2
--- /dev/null
+++ b/ci/validate_po.py
@@ -0,0 +1,35 @@
+#!/usr/bin/env python3
+"""Validate every Gettext catalog changed or maintained in this repository."""
+
+from __future__ import annotations
+
+import sys
+from pathlib import Path
+
+import polib
+
+
+def main() -> int:
+    failures: list[str] = []
+    catalogs = sorted(Path('.').glob('**/*.po'))
+    if not catalogs:
+        failures.append('no PO catalogs were found')
+
+    for path in catalogs:
+        try:
+            catalog = polib.pofile(path, check_for_duplicates=True)
+        except (OSError, UnicodeError, ValueError) as exc:
+            failures.append(f'{path}: {exc}')
+            continue
+        if not catalog.metadata.get('Content-Type', '').startswith('text/plain'):
+            failures.append(f'{path}: missing or invalid Content-Type metadata')
+
+    if failures:
+        print('\n'.join(failures), file=sys.stderr)
+        return 1
+    print(f'Validated {len(catalogs)} PO catalogs')
+    return 0
+
+
+if __name__ == '__main__':
+    raise SystemExit(main())