diff --git a/swh/loader/package/cran/loader.py b/swh/loader/package/cran/loader.py
--- a/swh/loader/package/cran/loader.py
+++ b/swh/loader/package/cran/loader.py
@@ -38,6 +38,7 @@
     raw_info = attr.ib(type=Dict[str, Any])
     version = attr.ib(type=str)
 
+    EXTID_TYPE = "cran-sha256"
     MANIFEST_FORMAT = string.Template("$version $url")
 
     @classmethod
diff --git a/swh/loader/package/npm/loader.py b/swh/loader/package/npm/loader.py
--- a/swh/loader/package/npm/loader.py
+++ b/swh/loader/package/npm/loader.py
@@ -38,7 +38,7 @@
 EMPTY_PERSON = Person(fullname=b"", name=None, email=None)
 
 
-EXTID_TYPE = "archive-sha1"
+EXTID_TYPE = "npm-archive-sha1"
 
 
 @attr.s
diff --git a/swh/loader/package/npm/tests/test_npm.py b/swh/loader/package/npm/tests/test_npm.py
--- a/swh/loader/package/npm/tests/test_npm.py
+++ b/swh/loader/package/npm/tests/test_npm.py
@@ -557,7 +557,7 @@
 
     sha1 = "05181c12cd8c22035dd31155656826b85745da37"
     assert NpmLoader.known_artifact_to_extid({"package_source": {"sha1": sha1,}}) == (
-        "archive-sha1",
+        "npm-archive-sha1",
         hash_to_bytes(sha1),
     )
 
@@ -569,7 +569,7 @@
     sha1 = "05181c12cd8c22035dd31155656826b85745da37"
     assert NpmLoader.known_artifact_to_extid(
         {"original_artifact": [{"checksums": {"sha1": sha1},}],}
-    ) == ("archive-sha1", hash_to_bytes(sha1))
+    ) == ("npm-archive-sha1", hash_to_bytes(sha1))
 
     assert (
         NpmLoader.known_artifact_to_extid(
diff --git a/swh/loader/package/pypi/loader.py b/swh/loader/package/pypi/loader.py
--- a/swh/loader/package/pypi/loader.py
+++ b/swh/loader/package/pypi/loader.py
@@ -34,7 +34,7 @@
 logger = logging.getLogger(__name__)
 
 
-EXTID_TYPE = "archive-sha256"
+EXTID_TYPE = "pypi-archive-sha256"
 
 
 @attr.s
diff --git a/swh/loader/package/pypi/tests/test_pypi.py b/swh/loader/package/pypi/tests/test_pypi.py
--- a/swh/loader/package/pypi/tests/test_pypi.py
+++ b/swh/loader/package/pypi/tests/test_pypi.py
@@ -810,7 +810,7 @@
     sha256 = "6975816f2c5ad4046acc676ba112f2fff945b01522d63948531f11f11e0892ec"
     assert PyPILoader.known_artifact_to_extid(
         {"original_artifact": {"sha256": sha256}}
-    ) == ("archive-sha256", hash_to_bytes(sha256))
+    ) == ("pypi-archive-sha256", hash_to_bytes(sha256))
 
 
 def test_pypi__known_artifact_to_extid__current_loader_version():
@@ -821,7 +821,7 @@
 
     assert PyPILoader.known_artifact_to_extid(
         {"original_artifact": [{"checksums": {"sha256": sha256,},}],}
-    ) == ("archive-sha256", hash_to_bytes(sha256))
+    ) == ("pypi-archive-sha256", hash_to_bytes(sha256))
 
     assert (
         PyPILoader.known_artifact_to_extid(