diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index 229f28821..08f5cc187 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -69,10 +69,6 @@ jobs:
       MKL_NUM_THREADS: 1
       PYTHONHASHSEED: 0
       NUTILS_TENSORIAL: ${{ matrix.tensorial }}
-      # Use PEP669's sys.monitoring for faster coverage analysis, if available.
-      # This also fixes a significant regression in coverage analysis on Python
-      # 3.12. Related issue: https://github.com/python/cpython/issues/107674 .
-      COVERAGE_CORE: sysmon
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -96,7 +92,7 @@ jobs:
           _numpy_version: ${{ matrix.numpy-version }}
         run: |
           python -um pip install --upgrade --upgrade-strategy eager wheel
-          python -um pip install --upgrade --upgrade-strategy eager coverage numpy$_numpy_version
+          python -um pip install --upgrade --upgrade-strategy eager numpy$_numpy_version
           # Install Nutils from `dist` dir created in job `build-python-package`.
           python -um pip install "$_wheel[import_gmsh,export_mpl]"
       - name: Install Scipy
@@ -108,11 +104,29 @@ jobs:
           python -um pip install --upgrade --upgrade-strategy eager mkl
           python -um devtools.gha.configure_mkl
       - name: Test
-        run: python -um coverage run -m unittest discover -b -q -t . -s tests
-      - name: Post-process coverage
-        run: python -um devtools.gha.coverage_report_xml
-      - name: Upload coverage
-        uses: codecov/codecov-action@v3
+        run: python -um devtools.gha.unittest
+      - name: Upload coverage artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: _coverage_${{ matrix.name }}
+          path: target/coverage/
+          if-no-files-found: error
+  process-coverage:
+    if: ${{ always() }}
+    needs: test
+    name: 'Process coverage'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Download coverage artifacts
+        uses: actions/download-artifact@v4
+        with:
+          pattern: _coverage_*
+          path: target/coverage
+          merge-multiple: true
+      - name: Generete summary
+        run: python -um devtools.gha.report_coverage
   test-examples:
     needs: build-python-package
     name: 'Test examples ${{ matrix.os }}'
diff --git a/devtools/gha/coverage_report_xml.py b/devtools/gha/coverage_report_xml.py
deleted file mode 100644
index 795bdb8c9..000000000
--- a/devtools/gha/coverage_report_xml.py
+++ /dev/null
@@ -1,55 +0,0 @@
-import sys
-import re
-import os.path
-from typing import Sequence
-from xml.etree import ElementTree
-from pathlib import Path
-from coverage import Coverage
-
-paths = []
-for path in sys.path:
-    try:
-        paths.append(str(Path(path).resolve()).lower()+os.path.sep)
-    except FileNotFoundError:
-        pass
-paths = list(sorted(paths, key=len, reverse=True))
-unix_paths = tuple(p.replace('\\', '/') for p in paths)
-packages = tuple(p.replace('/', '.') for p in unix_paths)
-
-dst = Path('coverage.xml')
-
-# Generate `coverage.xml` with absolute file and package names.
-cov = Coverage()
-cov.load()
-cov.xml_report(outfile=str(dst))
-
-# Load the report, remove the largest prefix in `packages` from attribute
-# `name` of element `package`, if any, and similarly the largest prefix in
-# `paths` from attribute `filename` of element `class` and from the content of
-# element `source`. Matching prefixes is case insensitive for case insensitive
-# file systems.
-
-
-def remove_prefix(value: str, prefixes: Sequence[str]) -> str:
-    lvalue = value.lower()
-    for prefix in prefixes:
-        if lvalue.startswith(prefix):
-            return value[len(prefix):]
-    return value
-
-
-root = ElementTree.parse(str(dst))
-for elem in root.iter('package'):
-    for package in packages:
-        name = elem.get('name')
-        if name:
-            elem.set('name', remove_prefix(name, packages))
-    for elem in root.iter('class'):
-        filename = elem.get('filename')
-        if filename:
-            elem.set('filename', remove_prefix(filename, unix_paths))
-    for elem in root.iter('source'):
-        text = elem.text
-        if text:
-            elem.text = remove_prefix(text, paths)
-root.write('coverage.xml')
diff --git a/devtools/gha/report_coverage.py b/devtools/gha/report_coverage.py
new file mode 100644
index 000000000..931c33cff
--- /dev/null
+++ b/devtools/gha/report_coverage.py
@@ -0,0 +1,29 @@
+import json
+import os
+from pathlib import Path
+
+coverage = {}
+cov_dir = Path() / 'target' / 'coverage'
+
+for part in cov_dir.glob('*.json'):
+    with part.open('r') as f:
+        part = json.load(f)
+        for file_name, part_file_coverage in part.items():
+            file_coverage = coverage.setdefault(file_name, {})
+            for line, covered in part_file_coverage.items():
+                file_coverage[line] = file_coverage.get(line, False) | covered
+
+with open(os.environ.get('GITHUB_STEP_SUMMARY', None) or cov_dir / 'summary.md', 'w') as f:
+    print('| Name | Stmts | Miss | Cover |', file=f)
+    print('| ---- | ----: | ---: | ----: |', file=f)
+    total_covered = 0
+    total_executable = 0
+    for file_name, file_coverage in sorted(coverage.items()):
+        file_covered = sum(file_coverage.values())
+        file_executable = len(file_coverage)
+        file_percentage = 100 * file_covered / file_executable if file_executable else 0
+        print(f'| {file_name} | {file_executable} | {file_covered} | {file_percentage:.1f}% |', file=f)
+        total_covered += file_covered
+        total_executable += file_executable
+    total_percentage = 100 * total_covered / total_executable if total_executable else 0
+    print(f'| TOTAL | {total_executable} | {total_covered} | {total_percentage:.1f}% |', file=f)
diff --git a/devtools/gha/unittest.py b/devtools/gha/unittest.py
new file mode 100644
index 000000000..6d5e954f0
--- /dev/null
+++ b/devtools/gha/unittest.py
@@ -0,0 +1,49 @@
+import inspect
+import json
+import os
+from pathlib import Path
+import sys
+import unittest
+
+source = str(Path().resolve() / 'nutils') + os.sep
+coverage = {}
+
+if hasattr(sys, 'monitoring'):
+
+    def start(code, _):
+        if isinstance(code.co_filename, str) and code.co_filename.startswith(source) and not sys.monitoring.get_local_events(sys.monitoring.COVERAGE_ID, code):
+            file_coverage = coverage.setdefault(code.co_filename, {})
+            for _, _, l in code.co_lines():
+                if l:
+                    file_coverage.setdefault(l, False)
+            sys.monitoring.set_local_events(sys.monitoring.COVERAGE_ID, code, sys.monitoring.events.LINE)
+            for obj in code.co_consts:
+                if inspect.iscode(obj):
+                    start(obj, None)
+        elif isinstance(code.co_filename, str) and 'nutils' in code.co_filename:
+            print(code.co_filename)
+            print(source)
+            raise ValueError
+        return sys.monitoring.DISABLE
+
+    def line(code, line_number):
+        coverage.get(code.co_filename)[line_number] = True
+        return sys.monitoring.DISABLE
+
+    sys.monitoring.register_callback(sys.monitoring.COVERAGE_ID, sys.monitoring.events.PY_START, start)
+    sys.monitoring.register_callback(sys.monitoring.COVERAGE_ID, sys.monitoring.events.LINE, line)
+    sys.monitoring.use_tool_id(sys.monitoring.COVERAGE_ID, 'test')
+    sys.monitoring.set_events(sys.monitoring.COVERAGE_ID, sys.monitoring.events.PY_START)
+
+loader = unittest.TestLoader()
+#suite = loader.discover('tests')
+suite = loader.loadTestsFromName('tests.test_unit')
+runner = unittest.TextTestRunner(buffer=True)
+runner.run(suite)
+
+coverage = {file_name[len(source) - 7:]: file_coverage for file_name, file_coverage in coverage.items()}
+cov_dir = (Path() / 'target' / 'coverage')
+cov_dir.mkdir(parents=True, exist_ok=True)
+cov_file = cov_dir / ((os.environ.get('GITHUB_JOB', '') or 'coverage') + '.json')
+with cov_file.open('w') as f:
+    json.dump(coverage, f)