diff --git a/swh/loader/package/npm/loader.py b/swh/loader/package/npm/loader.py
index 02b95d5..f00f963 100644
--- a/swh/loader/package/npm/loader.py
+++ b/swh/loader/package/npm/loader.py
@@ -1,323 +1,344 @@
 # Copyright (C) 2019-2020  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import json
 import logging
 import os
 
 from codecs import BOM_UTF8
 from typing import Any, Dict, Iterator, List, Optional, Sequence, Tuple, Union
 
 import attr
 import chardet
 
 from urllib.parse import quote
 from swh.model.model import (
+    MetadataAuthority,
+    MetadataAuthorityType,
     Person,
     RevisionType,
     Revision,
     TimestampWithTimezone,
     Sha1Git,
 )
 
-from swh.loader.package.loader import BasePackageInfo, PackageLoader
+from swh.loader.package.loader import (
+    BasePackageInfo,
+    PackageLoader,
+    RawExtrinsicMetadataCore,
+)
 from swh.loader.package.utils import api_info, release_name
 
 
 logger = logging.getLogger(__name__)
 
 
 EMPTY_PERSON = Person(fullname=b"", name=None, email=None)
 
 
 @attr.s
 class NpmPackageInfo(BasePackageInfo):
     raw_info = attr.ib(type=Dict[str, Any])
 
     date = attr.ib(type=Optional[str])
     shasum = attr.ib(type=str)
     """sha1 checksum"""
     version = attr.ib(type=str)
 
     @classmethod
     def from_metadata(
         cls, project_metadata: Dict[str, Any], version: str
     ) -> "NpmPackageInfo":
         package_metadata = project_metadata["versions"][version]
         url = package_metadata["dist"]["tarball"]
 
         # No date available in intrinsic metadata: retrieve it from the API
         # metadata, using the version number that the API claims this package
         # has.
         extrinsic_version = package_metadata["version"]
 
         if "time" in project_metadata:
             date = project_metadata["time"][extrinsic_version]
         elif "mtime" in package_metadata:
             date = package_metadata["mtime"]
         else:
             date = None
 
         return cls(
             url=url,
             filename=os.path.basename(url),
             date=date,
             shasum=package_metadata["dist"]["shasum"],
             version=extrinsic_version,
             raw_info=package_metadata,  # FIXME: loses some of the project metadata
         )
 
 
 class NpmLoader(PackageLoader[NpmPackageInfo]):
     """Load npm origin's artifact releases into swh archive.
 
     """
 
     visit_type = "npm"
 
     def __init__(self, url: str):
         """Constructor
 
         Args
             str: origin url (e.g. https://www.npmjs.com/package/<package-name>)
         """
         super().__init__(url=url)
         package_name = url.split("https://www.npmjs.com/package/")[1]
         safe_name = quote(package_name, safe="")
         self.provider_url = f"https://replicate.npmjs.com/{safe_name}/"
         self._info: Dict[str, Any] = {}
         self._versions = None
 
     @property
     def info(self) -> Dict[str, Any]:
         """Return the project metadata information (fetched from npm registry)
 
         """
         if not self._info:
-            self._info = json.loads(api_info(self.provider_url))
+            self._raw_info = api_info(self.provider_url)
+            self._info = json.loads(self._raw_info)
         return self._info
 
     def get_versions(self) -> Sequence[str]:
         return sorted(list(self.info["versions"].keys()))
 
     def get_default_version(self) -> str:
         return self.info["dist-tags"].get("latest", "")
 
+    def get_metadata_authority(self):
+        return MetadataAuthority(
+            type=MetadataAuthorityType.FORGE, url="https://npmjs.com/", metadata={},
+        )
+
+    def get_extrinsic_snapshot_metadata(self):
+        return [
+            RawExtrinsicMetadataCore(
+                format="replicate-npm-package-json",
+                metadata=self._raw_info,
+                discovery_date=None,
+            ),
+        ]
+
     def get_package_info(self, version: str) -> Iterator[Tuple[str, NpmPackageInfo]]:
         p_info = NpmPackageInfo.from_metadata(
             project_metadata=self.info, version=version
         )
         yield release_name(version), p_info
 
     def resolve_revision_from(
         self, known_artifacts: Dict, p_info: NpmPackageInfo
     ) -> Optional[bytes]:
         return artifact_to_revision_id(known_artifacts, p_info)
 
     def build_revision(
         self, p_info: NpmPackageInfo, uncompressed_path: str, directory: Sha1Git
     ) -> Optional[Revision]:
         i_metadata = extract_intrinsic_metadata(uncompressed_path)
         if not i_metadata:
             return None
         author = extract_npm_package_author(i_metadata)
         message = i_metadata["version"].encode("ascii")
 
         if p_info.date is None:
             url = p_info.url
             artifact_name = os.path.basename(url)
             raise ValueError(
                 "Origin %s: Cannot determine upload time for artifact %s."
                 % (p_info.url, artifact_name)
             )
 
         date = TimestampWithTimezone.from_iso8601(p_info.date)
 
         # FIXME: this is to remain bug-compatible with earlier versions:
         date = attr.evolve(date, timestamp=attr.evolve(date.timestamp, microseconds=0))
 
         r = Revision(
             type=RevisionType.TAR,
             message=message,
             author=author,
             date=date,
             committer=author,
             committer_date=date,
             parents=(),
             directory=directory,
             synthetic=True,
             metadata={
                 "intrinsic": {"tool": "package.json", "raw": i_metadata,},
                 "extrinsic": {
                     "provider": self.provider_url,
                     "when": self.visit_date.isoformat(),
                     "raw": p_info.raw_info,
                 },
             },
         )
         return r
 
 
 def artifact_to_revision_id(
     known_artifacts: Dict, p_info: NpmPackageInfo
 ) -> Optional[bytes]:
     """Given metadata artifact, solves the associated revision id.
 
     The following code allows to deal with 2 metadata formats:
 
     - old format sample::
 
         {
             'package_source': {
                 'sha1': '05181c12cd8c22035dd31155656826b85745da37',
             }
         }
 
     - new format sample::
 
         {
             'original_artifact': [{
                 'checksums': {
                     'sha256': '6975816f2c5ad4046acc676ba112f2fff945b01522d63948531f11f11e0892ec', # noqa
                     ...
                 },
             }],
             ...
         }
 
     """
     shasum = p_info.shasum
     for rev_id, known_artifact in known_artifacts.items():
         known_original_artifact = known_artifact.get("original_artifact")
         if not known_original_artifact:
             # previous loader-npm version kept original artifact elsewhere
             known_original_artifact = known_artifact.get("package_source")
             if not known_original_artifact:
                 continue
             original_hash = known_original_artifact["sha1"]
         else:
             assert isinstance(known_original_artifact, list)
             original_hash = known_original_artifact[0]["checksums"]["sha1"]
         if shasum == original_hash:
             return rev_id
     return None
 
 
 def _author_str(author_data: Union[Dict, List, str]) -> str:
     """Parse author from package.json author fields
 
     """
     if isinstance(author_data, dict):
         author_str = ""
         name = author_data.get("name")
         if name is not None:
             if isinstance(name, str):
                 author_str += name
             elif isinstance(name, list):
                 author_str += _author_str(name[0]) if len(name) > 0 else ""
         email = author_data.get("email")
         if email is not None:
             author_str += f" <{email}>"
         result = author_str
     elif isinstance(author_data, list):
         result = _author_str(author_data[0]) if len(author_data) > 0 else ""
     else:
         result = author_data
     return result
 
 
 def extract_npm_package_author(package_json: Dict[str, Any]) -> Person:
     """
     Extract package author from a ``package.json`` file content and
     return it in swh format.
 
     Args:
         package_json: Dict holding the content of parsed
             ``package.json`` file
 
     Returns:
         Person
 
     """
     for author_key in ("author", "authors"):
         if author_key in package_json:
             author_data = package_json[author_key]
             if author_data is None:
                 return EMPTY_PERSON
             author_str = _author_str(author_data)
             return Person.from_fullname(author_str.encode())
 
     return EMPTY_PERSON
 
 
 def _lstrip_bom(s, bom=BOM_UTF8):
     if s.startswith(bom):
         return s[len(bom) :]
     else:
         return s
 
 
 def load_json(json_bytes):
     """
     Try to load JSON from bytes and return a dictionary.
 
     First try to decode from utf-8. If the decoding failed,
     try to detect the encoding and decode again with replace
     error handling.
 
     If JSON is malformed, an empty dictionary will be returned.
 
     Args:
         json_bytes (bytes): binary content of a JSON file
 
     Returns:
         dict: JSON data loaded in a dictionary
     """
     json_data = {}
     try:
         json_str = _lstrip_bom(json_bytes).decode("utf-8")
     except UnicodeDecodeError:
         encoding = chardet.detect(json_bytes)["encoding"]
         if encoding:
             json_str = json_bytes.decode(encoding, "replace")
     try:
         json_data = json.loads(json_str)
     except json.decoder.JSONDecodeError:
         pass
     return json_data
 
 
 def extract_intrinsic_metadata(dir_path: str) -> Dict:
     """Given an uncompressed path holding the pkginfo file, returns a
        pkginfo parsed structure as a dict.
 
        The release artifact contains at their root one folder. For example:
        $ tar tvf zprint-0.0.6.tar.gz
        drwxr-xr-x root/root         0 2018-08-22 11:01 zprint-0.0.6/
        ...
 
     Args:
 
         dir_path (str): Path to the uncompressed directory
                         representing a release artifact from npm.
 
     Returns:
         the pkginfo parsed structure as a dict if any or None if
         none was present.
 
     """
     # Retrieve the root folder of the archive
     if not os.path.exists(dir_path):
         return {}
     lst = os.listdir(dir_path)
     if len(lst) == 0:
         return {}
     project_dirname = lst[0]
     package_json_path = os.path.join(dir_path, project_dirname, "package.json")
     if not os.path.exists(package_json_path):
         return {}
     with open(package_json_path, "rb") as package_json_file:
         package_json_bytes = package_json_file.read()
         return load_json(package_json_bytes)
diff --git a/swh/loader/package/npm/tests/test_npm.py b/swh/loader/package/npm/tests/test_npm.py
index 1607bee..8d8a02a 100644
--- a/swh/loader/package/npm/tests/test_npm.py
+++ b/swh/loader/package/npm/tests/test_npm.py
@@ -1,659 +1,705 @@
 # Copyright (C) 2019-2020  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import json
 import os
 import pytest
 
-from swh.model.hashutil import hash_to_bytes
-from swh.model.model import Person, Snapshot, SnapshotBranch, TargetType
+from swh.model.hashutil import hash_to_bytes, hash_to_hex
+from swh.model.identifiers import SWHID
+from swh.model.model import (
+    MetadataAuthority,
+    MetadataAuthorityType,
+    MetadataFetcher,
+    MetadataTargetType,
+    Person,
+    RawExtrinsicMetadata,
+    Snapshot,
+    SnapshotBranch,
+    TargetType,
+)
+
+from swh.storage.interface import PagedResult
 
+from swh.loader.package import __version__
 from swh.loader.package.npm.loader import (
     _author_str,
     NpmLoader,
     extract_npm_package_author,
     artifact_to_revision_id,
 )
 from swh.loader.package.tests.common import check_metadata_paths
 from swh.loader.tests import (
     assert_last_visit_matches,
     check_snapshot,
     get_stats,
 )
 
 
+@pytest.fixture
+def org_api_info(datadir) -> bytes:
+    with open(os.path.join(datadir, "https_replicate.npmjs.com", "org"), "rb",) as f:
+        return f.read()
+
+
 def test_npm_author_str():
     for author, expected_author in [
         ("author", "author"),
         (
             ["Al from quantum leap", "hal from 2001 space odyssey"],
             "Al from quantum leap",
         ),
         ([], ""),
         ({"name": "groot", "email": "groot@galaxy.org",}, "groot <groot@galaxy.org>"),
         ({"name": "somebody",}, "somebody"),
         ({"email": "no@one.org"}, " <no@one.org>"),  # note first elt is an extra blank
         ({"name": "no one", "email": None,}, "no one"),
         ({"email": None,}, ""),
         ({"name": None}, ""),
         ({"name": None, "email": None,}, ""),
         ({}, ""),
         (None, None),
         ({"name": []}, "",),
         (
             {"name": ["Susan McSween", "William H. Bonney", "Doc Scurlock",]},
             "Susan McSween",
         ),
         (None, None),
     ]:
         assert _author_str(author) == expected_author
 
 
 def test_extract_npm_package_author(datadir):
     package_metadata_filepath = os.path.join(
         datadir, "https_replicate.npmjs.com", "org_visit1"
     )
 
     with open(package_metadata_filepath) as json_file:
         package_metadata = json.load(json_file)
 
     extract_npm_package_author(package_metadata["versions"]["0.0.2"]) == Person(
         fullname=b"mooz <stillpedant@gmail.com>",
         name=b"mooz",
         email=b"stillpedant@gmail.com",
     )
 
     assert extract_npm_package_author(package_metadata["versions"]["0.0.3"]) == Person(
         fullname=b"Masafumi Oyamada <stillpedant@gmail.com>",
         name=b"Masafumi Oyamada",
         email=b"stillpedant@gmail.com",
     )
 
     package_json = json.loads(
         """
     {
         "name": "highlightjs-line-numbers.js",
         "version": "2.7.0",
         "description": "Highlight.js line numbers plugin.",
         "main": "src/highlightjs-line-numbers.js",
         "dependencies": {},
         "devDependencies": {
             "gulp": "^4.0.0",
             "gulp-rename": "^1.4.0",
             "gulp-replace": "^0.6.1",
             "gulp-uglify": "^1.2.0"
         },
         "repository": {
             "type": "git",
             "url": "https://github.com/wcoder/highlightjs-line-numbers.js.git"
         },
         "author": "Yauheni Pakala <evgeniy.pakalo@gmail.com>",
         "license": "MIT",
         "bugs": {
             "url": "https://github.com/wcoder/highlightjs-line-numbers.js/issues"
         },
         "homepage": "http://wcoder.github.io/highlightjs-line-numbers.js/"
     }"""
     )
 
     assert extract_npm_package_author(package_json) == Person(
         fullname=b"Yauheni Pakala <evgeniy.pakalo@gmail.com>",
         name=b"Yauheni Pakala",
         email=b"evgeniy.pakalo@gmail.com",
     )
 
     package_json = json.loads(
         """
     {
         "name": "3-way-diff",
         "version": "0.0.1",
         "description": "3-way diffing of JavaScript objects",
         "main": "index.js",
         "authors": [
             {
                 "name": "Shawn Walsh",
                 "url": "https://github.com/shawnpwalsh"
             },
             {
                 "name": "Markham F Rollins IV",
                 "url": "https://github.com/mrollinsiv"
             }
         ],
         "keywords": [
             "3-way diff",
             "3 way diff",
             "three-way diff",
             "three way diff"
         ],
         "devDependencies": {
             "babel-core": "^6.20.0",
             "babel-preset-es2015": "^6.18.0",
             "mocha": "^3.0.2"
         },
         "dependencies": {
             "lodash": "^4.15.0"
         }
     }"""
     )
 
     assert extract_npm_package_author(package_json) == Person(
         fullname=b"Shawn Walsh", name=b"Shawn Walsh", email=None
     )
 
     package_json = json.loads(
         """
     {
         "name": "yfe-ynpm",
         "version": "1.0.0",
         "homepage": "http://gitlab.ywwl.com/yfe/yfe-ynpm",
         "repository": {
             "type": "git",
             "url": "git@gitlab.ywwl.com:yfe/yfe-ynpm.git"
         },
         "author": [
             "fengmk2 <fengmk2@gmail.com> (https://fengmk2.com)",
             "xufuzi <xufuzi@ywwl.com> (https://7993.org)"
         ],
         "license": "MIT"
     }"""
     )
 
     assert extract_npm_package_author(package_json) == Person(
         fullname=b"fengmk2 <fengmk2@gmail.com> (https://fengmk2.com)",
         name=b"fengmk2",
         email=b"fengmk2@gmail.com",
     )
 
     package_json = json.loads(
         """
     {
         "name": "umi-plugin-whale",
         "version": "0.0.8",
         "description": "Internal contract component",
         "authors": {
             "name": "xiaohuoni",
             "email": "448627663@qq.com"
         },
         "repository": "alitajs/whale",
         "devDependencies": {
             "np": "^3.0.4",
             "umi-tools": "*"
         },
         "license": "MIT"
     }"""
     )
 
     assert extract_npm_package_author(package_json) == Person(
         fullname=b"xiaohuoni <448627663@qq.com>",
         name=b"xiaohuoni",
         email=b"448627663@qq.com",
     )
 
     package_json_no_authors = json.loads(
         """{
         "authors": null,
         "license": "MIT"
     }"""
     )
 
     assert extract_npm_package_author(package_json_no_authors) == Person(
         fullname=b"", name=None, email=None
     )
 
 
 def normalize_hashes(hashes):
     if isinstance(hashes, str):
         return hash_to_bytes(hashes)
     if isinstance(hashes, list):
         return [hash_to_bytes(x) for x in hashes]
     return {hash_to_bytes(k): hash_to_bytes(v) for k, v in hashes.items()}
 
 
 _expected_new_contents_first_visit = normalize_hashes(
     [
         "4ce3058e16ab3d7e077f65aabf855c34895bf17c",
         "858c3ceee84c8311adc808f8cdb30d233ddc9d18",
         "0fa33b4f5a4e0496da6843a38ff1af8b61541996",
         "85a410f8ef8eb8920f2c384a9555566ad4a2e21b",
         "9163ac8025923d5a45aaac482262893955c9b37b",
         "692cf623b8dd2c5df2c2998fd95ae4ec99882fb4",
         "18c03aac6d3e910efb20039c15d70ab5e0297101",
         "41265c42446aac17ca769e67d1704f99e5a1394d",
         "783ff33f5882813dca9239452c4a7cadd4dba778",
         "b029cfb85107aee4590c2434a3329bfcf36f8fa1",
         "112d1900b4c2e3e9351050d1b542c9744f9793f3",
         "5439bbc4bd9a996f1a38244e6892b71850bc98fd",
         "d83097a2f994b503185adf4e719d154123150159",
         "d0939b4898e83090ee55fd9d8a60e312cfadfbaf",
         "b3523a26f7147e4af40d9d462adaae6d49eda13e",
         "cd065fb435d6fb204a8871bcd623d0d0e673088c",
         "2854a40855ad839a54f4b08f5cff0cf52fca4399",
         "b8a53bbaac34ebb8c6169d11a4b9f13b05c583fe",
         "0f73d56e1cf480bded8a1ecf20ec6fc53c574713",
         "0d9882b2dfafdce31f4e77fe307d41a44a74cefe",
         "585fc5caab9ead178a327d3660d35851db713df1",
         "e8cd41a48d79101977e3036a87aeb1aac730686f",
         "5414efaef33cceb9f3c9eb5c4cc1682cd62d14f7",
         "9c3cc2763bf9e9e37067d3607302c4776502df98",
         "3649a68410e354c83cd4a38b66bd314de4c8f5c9",
         "e96ed0c091de1ebdf587104eaf63400d1974a1fe",
         "078ca03d2f99e4e6eab16f7b75fbb7afb699c86c",
         "38de737da99514de6559ff163c988198bc91367a",
     ]
 )
 
 _expected_new_directories_first_visit = normalize_hashes(
     [
         "3370d20d6f96dc1c9e50f083e2134881db110f4f",
         "42753c0c2ab00c4501b552ac4671c68f3cf5aece",
         "d7895533ef5edbcffdea3f057d9fef3a1ef845ce",
         "80579be563e2ef3e385226fe7a3f079b377f142c",
         "3b0ddc6a9e58b4b53c222da4e27b280b6cda591c",
         "bcad03ce58ac136f26f000990fc9064e559fe1c0",
         "5fc7e82a1bc72e074665c6078c6d3fad2f13d7ca",
         "e3cd26beba9b1e02f6762ef54bd9ac80cc5f25fd",
         "584b5b4b6cf7f038095e820b99386a9c232de931",
         "184c8d6d0d242f2b1792ef9d3bf396a5434b7f7a",
         "bb5f4ee143c970367eb409f2e4c1104898048b9d",
         "1b95491047add1103db0dfdfa84a9735dcb11e88",
         "a00c6de13471a2d66e64aca140ddb21ef5521e62",
         "5ce6c1cd5cda2d546db513aaad8c72a44c7771e2",
         "c337091e349b6ac10d38a49cdf8c2401ef9bb0f2",
         "202fafcd7c0f8230e89d5496ad7f44ab12b807bf",
         "775cc516543be86c15c1dc172f49c0d4e6e78235",
         "ff3d1ead85a14f891e8b3fa3a89de39db1b8de2e",
     ]
 )
 
 _expected_new_revisions_first_visit = normalize_hashes(
     {
         "d8a1c7474d2956ac598a19f0f27d52f7015f117e": (
             "42753c0c2ab00c4501b552ac4671c68f3cf5aece"
         ),
         "5f9eb78af37ffd12949f235e86fac04898f9f72a": (
             "3370d20d6f96dc1c9e50f083e2134881db110f4f"
         ),
         "ba019b192bdb94bd0b5bd68b3a5f92b5acc2239a": (
             "d7895533ef5edbcffdea3f057d9fef3a1ef845ce"
         ),
     }
 )
 
 
 def package_url(package):
     return "https://www.npmjs.com/package/%s" % package
 
 
 def package_metadata_url(package):
     return "https://replicate.npmjs.com/%s/" % package
 
 
 def test_revision_metadata_structure(swh_config, requests_mock_datadir):
     package = "org"
     loader = NpmLoader(package_url(package))
 
     actual_load_status = loader.load()
     assert actual_load_status["status"] == "eventful"
     assert actual_load_status["snapshot_id"] is not None
 
     expected_revision_id = hash_to_bytes("d8a1c7474d2956ac598a19f0f27d52f7015f117e")
     revision = list(loader.storage.revision_get([expected_revision_id]))[0]
 
     assert revision is not None
 
     check_metadata_paths(
         revision["metadata"],
         paths=[
             ("intrinsic.tool", str),
             ("intrinsic.raw", dict),
             ("extrinsic.provider", str),
             ("extrinsic.when", str),
             ("extrinsic.raw", dict),
             ("original_artifact", list),
         ],
     )
 
     for original_artifact in revision["metadata"]["original_artifact"]:
         check_metadata_paths(
             original_artifact,
             paths=[("filename", str), ("length", int), ("checksums", dict),],
         )
 
 
-def test_npm_loader_first_visit(swh_config, requests_mock_datadir):
+def test_npm_loader_first_visit(swh_config, requests_mock_datadir, org_api_info):
     package = "org"
     url = package_url(package)
     loader = NpmLoader(url)
 
     actual_load_status = loader.load()
     expected_snapshot_id = hash_to_bytes("d0587e1195aed5a8800411a008f2f2d627f18e2d")
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id.hex(),
     }
 
     assert_last_visit_matches(
         loader.storage, url, status="full", type="npm", snapshot=expected_snapshot_id
     )
 
     stats = get_stats(loader.storage)
 
     assert {
         "content": len(_expected_new_contents_first_visit),
         "directory": len(_expected_new_directories_first_visit),
         "origin": 1,
         "origin_visit": 1,
         "person": 2,
         "release": 0,
         "revision": len(_expected_new_revisions_first_visit),
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     assert len(
         list(loader.storage.content_get(_expected_new_contents_first_visit))
     ) == len(_expected_new_contents_first_visit)
 
     assert (
         list(loader.storage.directory_missing(_expected_new_directories_first_visit))
         == []
     )
 
     assert (
         list(loader.storage.revision_missing(_expected_new_revisions_first_visit)) == []
     )
 
     expected_snapshot = Snapshot(
         id=expected_snapshot_id,
         branches={
             b"HEAD": SnapshotBranch(
                 target=b"releases/0.0.4", target_type=TargetType.ALIAS
             ),
             b"releases/0.0.2": SnapshotBranch(
                 target=hash_to_bytes("d8a1c7474d2956ac598a19f0f27d52f7015f117e"),
                 target_type=TargetType.REVISION,
             ),
             b"releases/0.0.3": SnapshotBranch(
                 target=hash_to_bytes("5f9eb78af37ffd12949f235e86fac04898f9f72a"),
                 target_type=TargetType.REVISION,
             ),
             b"releases/0.0.4": SnapshotBranch(
                 target=hash_to_bytes("ba019b192bdb94bd0b5bd68b3a5f92b5acc2239a"),
                 target_type=TargetType.REVISION,
             ),
         },
     )
     check_snapshot(expected_snapshot, loader.storage)
 
+    snapshot_swhid = SWHID(
+        object_type="snapshot", object_id=hash_to_hex(expected_snapshot_id)
+    )
+    metadata_authority = MetadataAuthority(
+        type=MetadataAuthorityType.FORGE, url="https://npmjs.com/",
+    )
+    expected_metadata = [
+        RawExtrinsicMetadata(
+            type=MetadataTargetType.SNAPSHOT,
+            id=snapshot_swhid,
+            authority=metadata_authority,
+            fetcher=MetadataFetcher(
+                name="swh.loader.package.npm.loader.NpmLoader", version=__version__,
+            ),
+            discovery_date=loader.visit_date,
+            format="replicate-npm-package-json",
+            metadata=org_api_info,
+            origin="https://www.npmjs.com/package/org",
+        )
+    ]
+    assert loader.storage.raw_extrinsic_metadata_get(
+        type=MetadataTargetType.SNAPSHOT,
+        id=snapshot_swhid,
+        authority=metadata_authority,
+    ) == PagedResult(next_page_token=None, results=expected_metadata,)
+
 
 def test_npm_loader_incremental_visit(swh_config, requests_mock_datadir_visits):
     package = "org"
     url = package_url(package)
     loader = NpmLoader(url)
 
     expected_snapshot_id = hash_to_bytes("d0587e1195aed5a8800411a008f2f2d627f18e2d")
     actual_load_status = loader.load()
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id.hex(),
     }
     assert_last_visit_matches(
         loader.storage, url, status="full", type="npm", snapshot=expected_snapshot_id
     )
 
     stats = get_stats(loader.storage)
 
     assert {
         "content": len(_expected_new_contents_first_visit),
         "directory": len(_expected_new_directories_first_visit),
         "origin": 1,
         "origin_visit": 1,
         "person": 2,
         "release": 0,
         "revision": len(_expected_new_revisions_first_visit),
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     loader._info = None  # reset loader internal state
     actual_load_status2 = loader.load()
     assert actual_load_status2["status"] == "eventful"
     snap_id2 = actual_load_status2["snapshot_id"]
     assert snap_id2 is not None
     assert snap_id2 != actual_load_status["snapshot_id"]
 
     assert_last_visit_matches(loader.storage, url, status="full", type="npm")
 
     stats = get_stats(loader.storage)
 
     assert {  # 3 new releases artifacts
         "content": len(_expected_new_contents_first_visit) + 14,
         "directory": len(_expected_new_directories_first_visit) + 15,
         "origin": 1,
         "origin_visit": 2,
         "person": 2,
         "release": 0,
         "revision": len(_expected_new_revisions_first_visit) + 3,
         "skipped_content": 0,
         "snapshot": 2,
     } == stats
 
     urls = [
         m.url
         for m in requests_mock_datadir_visits.request_history
         if m.url.startswith("https://registry.npmjs.org")
     ]
     assert len(urls) == len(set(urls))  # we visited each artifact once across
 
 
 @pytest.mark.usefixtures("requests_mock_datadir")
 def test_npm_loader_version_divergence(swh_config):
     package = "@aller_shared"
     url = package_url(package)
     loader = NpmLoader(url)
 
     actual_load_status = loader.load()
     expected_snapshot_id = hash_to_bytes("b11ebac8c9d0c9e5063a2df693a18e3aba4b2f92")
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id.hex(),
     }
     assert_last_visit_matches(
         loader.storage, url, status="full", type="npm", snapshot=expected_snapshot_id
     )
 
     stats = get_stats(loader.storage)
 
     assert {  # 1 new releases artifacts
         "content": 534,
         "directory": 153,
         "origin": 1,
         "origin_visit": 1,
         "person": 1,
         "release": 0,
         "revision": 2,
         "skipped_content": 0,
         "snapshot": 1,
     } == stats
 
     expected_snapshot = Snapshot(
         id=expected_snapshot_id,
         branches={
             b"HEAD": SnapshotBranch(
                 target_type=TargetType.ALIAS, target=b"releases/0.1.0"
             ),
             b"releases/0.1.0": SnapshotBranch(
                 target_type=TargetType.REVISION,
                 target=hash_to_bytes("845673bfe8cbd31b1eaf757745a964137e6f9116"),
             ),
             b"releases/0.1.1-alpha.14": SnapshotBranch(
                 target_type=TargetType.REVISION,
                 target=hash_to_bytes("05181c12cd8c22035dd31155656826b85745da37"),
             ),
         },
     )
     check_snapshot(expected_snapshot, loader.storage)
 
 
 def test_npm_artifact_to_revision_id_none():
     """Current loader version should stop soon if nothing can be found
 
     """
 
     class artifact_metadata:
         shasum = "05181c12cd8c22035dd31155656826b85745da37"
 
     known_artifacts = {
         "b11ebac8c9d0c9e5063a2df693a18e3aba4b2f92": {},
     }
 
     assert artifact_to_revision_id(known_artifacts, artifact_metadata) is None
 
 
 def test_npm_artifact_to_revision_id_old_loader_version():
     """Current loader version should solve old metadata scheme
 
     """
 
     class artifact_metadata:
         shasum = "05181c12cd8c22035dd31155656826b85745da37"
 
     known_artifacts = {
         hash_to_bytes("b11ebac8c9d0c9e5063a2df693a18e3aba4b2f92"): {
             "package_source": {"sha1": "something-wrong"}
         },
         hash_to_bytes("845673bfe8cbd31b1eaf757745a964137e6f9116"): {
             "package_source": {"sha1": "05181c12cd8c22035dd31155656826b85745da37",}
         },
     }
 
     assert artifact_to_revision_id(known_artifacts, artifact_metadata) == hash_to_bytes(
         "845673bfe8cbd31b1eaf757745a964137e6f9116"
     )
 
 
 def test_npm_artifact_to_revision_id_current_loader_version():
     """Current loader version should be able to solve current metadata scheme
 
     """
 
     class artifact_metadata:
         shasum = "05181c12cd8c22035dd31155656826b85745da37"
 
     known_artifacts = {
         hash_to_bytes("b11ebac8c9d0c9e5063a2df693a18e3aba4b2f92"): {
             "original_artifact": [
                 {"checksums": {"sha1": "05181c12cd8c22035dd31155656826b85745da37"},}
             ],
         },
         hash_to_bytes("845673bfe8cbd31b1eaf757745a964137e6f9116"): {
             "original_artifact": [{"checksums": {"sha1": "something-wrong"},}],
         },
     }
 
     assert artifact_to_revision_id(known_artifacts, artifact_metadata) == hash_to_bytes(
         "b11ebac8c9d0c9e5063a2df693a18e3aba4b2f92"
     )
 
 
 def test_npm_artifact_with_no_intrinsic_metadata(swh_config, requests_mock_datadir):
     """Skip artifact with no intrinsic metadata during ingestion
 
     """
     package = "nativescript-telerik-analytics"
     url = package_url(package)
     loader = NpmLoader(url)
 
     actual_load_status = loader.load()
     # no branch as one artifact without any intrinsic metadata
     expected_snapshot = Snapshot(
         id=hash_to_bytes("1a8893e6a86f444e8be8e7bda6cb34fb1735a00e"), branches={},
     )
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot.id.hex(),
     }
 
     check_snapshot(expected_snapshot, loader.storage)
 
     assert_last_visit_matches(
         loader.storage, url, status="full", type="npm", snapshot=expected_snapshot.id
     )
 
 
 def test_npm_artifact_with_no_upload_time(swh_config, requests_mock_datadir):
     """With no time upload, artifact is skipped
 
     """
     package = "jammit-no-time"
     url = package_url(package)
     loader = NpmLoader(url)
 
     actual_load_status = loader.load()
     # no branch as one artifact without any intrinsic metadata
     expected_snapshot = Snapshot(
         id=hash_to_bytes("1a8893e6a86f444e8be8e7bda6cb34fb1735a00e"), branches={},
     )
     assert actual_load_status == {
         "status": "uneventful",
         "snapshot_id": expected_snapshot.id.hex(),
     }
 
     check_snapshot(expected_snapshot, loader.storage)
 
     assert_last_visit_matches(
         loader.storage, url, status="partial", type="npm", snapshot=expected_snapshot.id
     )
 
 
 def test_npm_artifact_use_mtime_if_no_time(swh_config, requests_mock_datadir):
     """With no time upload, artifact is skipped
 
     """
     package = "jammit-express"
     url = package_url(package)
     loader = NpmLoader(url)
 
     actual_load_status = loader.load()
     expected_snapshot_id = hash_to_bytes("d6e08e19159f77983242877c373c75222d5ae9dd")
 
     assert actual_load_status == {
         "status": "eventful",
         "snapshot_id": expected_snapshot_id.hex(),
     }
 
     # artifact is used
     expected_snapshot = Snapshot(
         id=expected_snapshot_id,
         branches={
             b"HEAD": SnapshotBranch(
                 target_type=TargetType.ALIAS, target=b"releases/0.0.1"
             ),
             b"releases/0.0.1": SnapshotBranch(
                 target_type=TargetType.REVISION,
                 target=hash_to_bytes("9e4dd2b40d1b46b70917c0949aa2195c823a648e"),
             ),
         },
     )
     check_snapshot(expected_snapshot, loader.storage)
 
     assert_last_visit_matches(
         loader.storage, url, status="full", type="npm", snapshot=expected_snapshot.id
     )
 
 
 def test_npm_no_artifact(swh_config, requests_mock_datadir):
     """If no artifacts at all is found for origin, the visit fails completely
 
     """
     package = "catify"
     url = package_url(package)
     loader = NpmLoader(url)
     actual_load_status = loader.load()
     assert actual_load_status == {
         "status": "failed",
     }
 
     assert_last_visit_matches(loader.storage, url, status="partial", type="npm")