diff --git a/.gitignore b/.gitignore
index 705125d..e2333e6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,6 +17,8 @@ build/
 
 # test files
 .coverage*
+coverage.json
+coverage.xml
 
 # Generated files
 doc/whl2conda-cli.md
diff --git a/Makefile b/Makefile
index f0d9f26..a086e41 100644
--- a/Makefile
+++ b/Makefile
@@ -105,13 +105,15 @@ pytest:
 test: pytest
 
 coverage:
-	$(CONDA_RUN) pytest -s --cov=src --cov-report=html --cov-report=term test
+	$(CONDA_RUN) pytest -s --cov=src --cov-report=json --cov-report=term test
 
 slow-coverage:
-	$(CONDA_RUN) pytest -s --cov=src --cov-report=html --cov-report=term test --run-slow
+	$(CONDA_RUN) pytest -s --cov=src --cov-report=json --cov-report=term test --run-slow
 
-htmlcov/index.html:
-	$(MAKE) coverage
+htmlcov/index.html: .coverage
+	$(CONDA_RUN) coverage html
+
+html-coverage: htmlcov/index.html
 
 open-coverage: htmlcov/index.html
 	$(OPEN) $<
@@ -208,7 +210,7 @@ upload: upload-sdist upload-wheel
 #
 
 clean-coverage:
-	$(RMDIR) htmlcov .coverage
+	$(RMDIR) htmlcov .coverage coverage.json coverage.xml
 
 clean-doc:
 	$(RMDIR) site doc/whl2conda-cli.md