diff --git a/.github/workflows/core-tests.yml b/.github/workflows/core-tests.yml
index 332a610..d548217 100644
--- a/.github/workflows/core-tests.yml
+++ b/.github/workflows/core-tests.yml
@@ -15,8 +15,6 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "pypy-3.10"]
-    env:
-      TOTAL_COVERAGE: "-"
 
     steps:
     - uses: actions/checkout@v3
@@ -40,26 +38,17 @@ jobs:
     - name: Unit tests with pytest
       run: |
         poetry run pytest
-    - name: prepare coverage data
-      continue-on-error: true
-      run: |
-        poetry run coverage json
-        export TOTAL=$(python -c "import json;print(json.load(open('coverage.json'))['totals']['percent_covered_display'])")
-        echo "TOTAL_COVERAGE=$TOTAL" >> $GITHUB_ENV
-        echo "### Total coverage: ${TOTAL}%" >> $GITHUB_STEP_SUMMARY
-    - name: create coverage badge
-      if : ${{ matrix.python-version == '3.11' }}
-      uses: schneegans/dynamic-badges-action@v1.7.0
+      env:
+        COVERAGE_FILE: .coverage.${{ matrix.python-version }}
+    - name: Upload coverage data
+      if: success() || failure()
+      uses: actions/upload-artifact@v4
       with:
-        auth: ${{ secrets.GIST_TOKEN }}
-        gistID: 1a66c9e88a9e4267f7e0b1d185be98f4
-        filename: covbadge.json
-        label: coverage
-        message: ${{ env.TOTAL_COVERAGE }}%
-        minColorRange: 50
-        maxColorRange: 90
-        valColorRange: ${{ env.TOTAL_COVERAGE }}
-        isError: ${{ env.TOTAL_COVERAGE == '-' }}
+        name: coverage-data-${{ matrix.python-version }}
+        if-no-files-found: warn
+        path: ./.coverage*
+        compression-level: 0  # no compression
+        retention-days: 1
     - name: Static typechecking with mypy
       if: ${{ !startsWith(matrix.python-version, 'pypy') }}
       run: |
@@ -68,3 +57,40 @@ jobs:
       if: ${{ matrix.python-version != '3.8' }}
       run: |
         poetry run pylint ./zammadoo
+
+  process-test-data:
+    if: success() || failure()
+    runs-on: ubuntu-latest
+    needs: test
+    env:
+      TOTAL_COVERAGE: "-"
+    steps:
+      - run: pipx install coverage
+      - name: Download coverage data
+        uses: actions/download-artifact@v4
+        with:
+          merge-multiple: true
+      - name: Merge coverage data
+        continue-on-error: true
+        run: |
+          coverage combine .coverage.*
+          coverage report
+      - name: Compute total coverage
+        continue-on-error: true
+        run: |
+          coverage json
+          export TOTAL=$(python -c "import json;print(json.load(open('coverage.json'))['totals']['percent_covered_display'])")
+          echo "TOTAL_COVERAGE=$TOTAL" >> $GITHUB_ENV
+          echo "### Total coverage: ${TOTAL}%" >> $GITHUB_STEP_SUMMARY
+      - name: create coverage badge
+        uses: schneegans/dynamic-badges-action@v1.7.0
+        with:
+          auth: ${{ secrets.GIST_TOKEN }}
+          gistID: 1a66c9e88a9e4267f7e0b1d185be98f4
+          filename: covbadge.json
+          label: coverage
+          message: ${{ env.TOTAL_COVERAGE }}%
+          minColorRange: 50
+          maxColorRange: 90
+          valColorRange: ${{ env.TOTAL_COVERAGE }}
+          isError: ${{ env.TOTAL_COVERAGE == '-' }}