diff --git a/swh/loader/package/npm.py b/swh/loader/package/npm.py
new file mode 100644
index 0000000..252f9a3
--- /dev/null
+++ b/swh/loader/package/npm.py
@@ -0,0 +1,362 @@
+# Copyright (C) 2019  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
+import re
+
+from codecs import BOM_UTF8
+from typing import Generator, Dict, Tuple, Sequence, List
+
+import chardet
+import iso8601
+import requests
+import tempfile
+
+from swh.model.identifiers import normalize_timestamp
+from swh.loader.package.loader import PackageLoader
+from swh.loader.package.utils import download
+
+
+logger = logging.getLogger(__name__)
+
+
+class NpmClient:
+    """
+    Helper class internally used by the npm loader to fetch
+    metadata for a specific package hosted on the npm registry.
+
+    Args:
+        temp_dir (str): Path to the temporary disk location used
+            to uncompress the package tarballs
+
+    """
+    def __init__(self, log=None):
+        self.root_temp_dir = tempfile.mkdtemp()
+        self.session = requests.session()
+        self.params = {
+            'headers': {
+                'User-Agent': 'Software Heritage npm loader'
+            }
+        }
+        self.log = log or logging
+
+    def fetch_package_metadata(self, package_metadata_url) -> None:
+        """
+        Fetch metadata for a given package and make it the focused one.
+        This must be called prior any other operations performed
+        by the other methods below.
+
+        Args:
+            package_metadata_url: the package metadata url provided
+                by the npm loader
+        """
+        self.package_metadata_url = package_metadata_url
+        self.package_metadata = self.session.get(
+            self.package_metadata_url).json()
+        self.package = self.package_metadata['name']
+        self.temp_dir = os.path.join(self.root_temp_dir, self.package)
+        return self.package_metadata
+
+    def package_versions(self, known_versions=None) -> List[Dict]:
+        """
+        Return the available versions for the focused package.
+
+        Args:
+            known_versions (dict): may be provided by the loader, it enables
+                to filter out versions already ingested in the archive.
+
+        Returns:
+            dict: A dict whose keys are Tuple[version, tarball_sha1] and
+            values dicts with the following entries:
+
+                    * **name**: the package name
+                    * **version**: the package version
+                    * **filename**: the package source tarball filename
+                    * **sha1**: the package source tarball sha1 checksum
+                    * **date**: the package release date
+                    * **url**: the package source tarball download url
+        """
+        versions = {}
+        if 'versions' in self.package_metadata:
+            for version, data in self.package_metadata['versions'].items():
+                sha1 = data['dist']['shasum']
+                key = (version, sha1)
+                if known_versions and key in known_versions:
+                    continue
+                tarball_url = data['dist']['tarball']
+                filename = os.path.basename(tarball_url)
+                date = self.package_metadata['time'][version]
+                versions[key] = {
+                    'name': self.package,
+                    'version': version,
+                    'filename': filename,
+                    'sha1': sha1,
+                    'date': date,
+                    'url': tarball_url
+                }
+        return versions
+
+
+_EMPTY_AUTHOR = {'fullname': b'', 'name': None, 'email': None}
+
+# https://github.com/jonschlinkert/author-regex
+_author_regexp = r'([^<(]+?)?[ \t]*(?:<([^>(]+?)>)?[ \t]*(?:\(([^)]+?)\)|$)'
+
+
+def parse_npm_package_author(author_str):
+    """
+    Parse npm package author string.
+
+    It works with a flexible range of formats, as detailed below::
+
+        name
+        name <email> (url)
+        name <email>(url)
+        name<email> (url)
+        name<email>(url)
+        name (url) <email>
+        name (url)<email>
+        name(url) <email>
+        name(url)<email>
+        name (url)
+        name(url)
+        name <email>
+        name<email>
+        <email> (url)
+        <email>(url)
+        (url) <email>
+        (url)<email>
+        <email>
+        (url)
+
+    Args:
+        author_str (str): input author string
+
+    Returns:
+        dict: A dict that may contain the following keys:
+            * name
+            * email
+            * url
+
+    """
+    author = {}
+    matches = re.findall(_author_regexp,
+                         author_str.replace('<>', '').replace('()', ''),
+                         re.M)
+    for match in matches:
+        if match[0].strip():
+            author['name'] = match[0].strip()
+        if match[1].strip():
+            author['email'] = match[1].strip()
+        if match[2].strip():
+            author['url'] = match[2].strip()
+    return author
+
+
+def extract_npm_package_author(package_json):
+    """
+    Extract package author from a ``package.json`` file content and
+    return it in swh format.
+
+    Args:
+        package_json (dict): Dict holding the content of parsed
+            ``package.json`` file
+
+    Returns:
+        dict: A dict with the following keys:
+            * fullname
+            * name
+            * email
+
+    """
+
+    def _author_str(author_data):
+        if type(author_data) is dict:
+            author_str = ''
+            if 'name' in author_data:
+                author_str += author_data['name']
+            if 'email' in author_data:
+                author_str += ' <%s>' % author_data['email']
+            return author_str
+        elif type(author_data) is list:
+            return _author_str(author_data[0]) if len(author_data) > 0 else ''
+        else:
+            return author_data
+
+    author_data = {}
+    for author_key in ('author', 'authors'):
+        if author_key in package_json:
+            author_str = _author_str(package_json[author_key])
+            author_data = parse_npm_package_author(author_str)
+
+    name = author_data.get('name')
+    email = author_data.get('email')
+
+    fullname = None
+
+    if name and email:
+        fullname = '%s <%s>' % (name, email)
+    elif name:
+        fullname = name
+
+    if not fullname:
+        return _EMPTY_AUTHOR
+
+    if fullname:
+        fullname = fullname.encode('utf-8')
+
+    if name:
+        name = name.encode('utf-8')
+
+    if email:
+        email = email.encode('utf-8')
+
+    return {'fullname': fullname, 'name': name, 'email': email}
+
+
+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 pypi.
+
+    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)
+
+
+class NpmLoader(PackageLoader):
+    visit_type = 'npm'
+
+    def __init__(self, package_name, package_url, package_metadata_url):
+        super().__init__(url=package_url)
+        self.package_metadata_url = package_metadata_url
+
+        self._info = None
+        self._versions = None
+        self.client = NpmClient()
+
+        # if package_url is None:
+        #     package_url = 'https://www.npmjs.com/package/%s' % package_name
+        # if package_metadata_url is None:
+        #     package_metadata_url = 'https://replicate.npmjs.com/%s/' %\
+        #                             quote(package_name, safe='')
+
+    @property
+    def info(self) -> Dict:
+        """Return the project metadata information (fetched from pypi registry)
+
+        """
+        if not self._info:
+            # This initializes the metadata retrieval on npm api
+            self._info = self.client.fetch_package_metadata(
+                self.package_metadata_url)
+        return self._info
+
+    # def get_versions(self) -> Sequence[Tuple(str, str)]:
+    def get_versions(self) -> Sequence[str]:
+        return sorted(self.info['versions'].keys())
+
+    def get_default_release(self) -> str:
+        return self.info['dist-tags'].get('latest', '')
+
+    def get_artifacts(self, version: str) -> Generator[
+            Tuple[str, str, Dict], None, None]:
+        meta = self.info['versions'][version]
+        url = meta['dist']['tarball']
+        filename = os.path.basename(url)
+        yield filename, url, meta
+
+    def fetch_artifact_archive(
+            self, artifact_uri: str, dest: str) -> Tuple[str, Dict]:
+        return download(artifact_uri, dest=dest)
+
+    def build_revision(
+            self, a_metadata: Dict, a_uncompressed_path: str) -> Dict:
+        # Parse metadata (project, artifact metadata)
+        i_metadata = extract_intrinsic_metadata(a_uncompressed_path)
+
+        # from intrinsic metadata
+        author = extract_npm_package_author(i_metadata)
+        # extrinsic metadata
+        version = i_metadata['version']
+        date = self.info['time'][version]
+        date = iso8601.parse_date(date)
+        date = normalize_timestamp(int(date.timestamp()))
+        message = version.encode('ascii')
+
+        return {
+            'author': author,
+            'date': date,
+            'committer': author,
+            'committer_date': date,
+            'message': message,
+            'metadata': {
+                'intrinsic_metadata': i_metadata,
+            },
+            'parents': [],
+        }
diff --git a/swh/loader/package/tests/common.py b/swh/loader/package/tests/common.py
index ee334dd..e8e2292 100644
--- a/swh/loader/package/tests/common.py
+++ b/swh/loader/package/tests/common.py
@@ -1,80 +1,83 @@
 # Copyright (C) 2019  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
 
 from os import path
 from urllib.parse import urlparse
 
 from swh.model.hashutil import hash_to_bytes, hash_to_hex
 
 
 DATADIR = path.join(path.abspath(path.dirname(__file__)), 'resources')
 
 
 def get_response_cb(request, context):
     """Mount point callback to fetch on disk the content of a request
 
     Args:
         request (requests.Request): Object requests
         context (requests.Context): Object holding requests metadata
                                     information (headers, etc...)
 
     Returns:
         File descriptor on the on disk file to read from the test context
 
     """
     url = urlparse(request.url)
     dirname = url.hostname  # pypi.org | files.pythonhosted.org
     # url.path: pypi/<project>/json -> local file: pypi_<project>_json
-    filename = url.path[1:].replace('/', '_')
+    filename = url.path[1:]
+    if filename.endswith('/'):
+        filename = filename[:-1]
+    filename = filename.replace('/', '_')
     filepath = path.join(DATADIR, dirname, filename)
     fd = open(filepath, 'rb')
     context.headers['content-length'] = str(path.getsize(filepath))
     return fd
 
 
 def decode_target(target):
     if not target:
         return target
     target_type = target['target_type']
 
     if target_type == 'alias':
         decoded_target = target['target'].decode('utf-8')
     else:
         decoded_target = hash_to_hex(target['target'])
 
     return {
         'target': decoded_target,
         'target_type': target_type
     }
 
 
 def check_snapshot(expected_snapshot, expected_branches, storage):
     """Check for snapshot match.
 
     Provide the hashes as hexadecimal, the conversion is done
     within the method.
 
     Args:
         expected_snapshot (Union[str, dict]): Either the snapshot
                                       identifier or the full
                                       snapshot
         expected_branches ([dict]): expected branches or nothing is
                                   the full snapshot is provided
 
     """
     if isinstance(expected_snapshot, dict) and not expected_branches:
         expected_snapshot_id = expected_snapshot['id']
         expected_branches = expected_snapshot['branches']
     else:
         expected_snapshot_id = expected_snapshot
 
     snap = storage.snapshot_get(hash_to_bytes(expected_snapshot_id))
     assert snap is not None
 
     branches = {
         branch.decode('utf-8'): decode_target(target)
         for branch, target in snap['branches'].items()
     }
     assert expected_branches == branches
diff --git a/swh/loader/package/tests/resources/registry.npmjs.org/org_-_org-0.0.2.tgz b/swh/loader/package/tests/resources/registry.npmjs.org/org_-_org-0.0.2.tgz
new file mode 100644
index 0000000..b726261
Binary files /dev/null and b/swh/loader/package/tests/resources/registry.npmjs.org/org_-_org-0.0.2.tgz differ
diff --git a/swh/loader/package/tests/resources/registry.npmjs.org/org_-_org-0.0.3.tgz b/swh/loader/package/tests/resources/registry.npmjs.org/org_-_org-0.0.3.tgz
new file mode 100644
index 0000000..bc20daa
Binary files /dev/null and b/swh/loader/package/tests/resources/registry.npmjs.org/org_-_org-0.0.3.tgz differ
diff --git a/swh/loader/package/tests/resources/registry.npmjs.org/org_-_org-0.0.4.tgz b/swh/loader/package/tests/resources/registry.npmjs.org/org_-_org-0.0.4.tgz
new file mode 100644
index 0000000..a431eeb
Binary files /dev/null and b/swh/loader/package/tests/resources/registry.npmjs.org/org_-_org-0.0.4.tgz differ
diff --git a/swh/loader/package/tests/resources/replicate.npmjs.com/org b/swh/loader/package/tests/resources/replicate.npmjs.com/org
new file mode 100644
index 0000000..3aba6b1
--- /dev/null
+++ b/swh/loader/package/tests/resources/replicate.npmjs.com/org
@@ -0,0 +1,191 @@
+{
+  "_id": "org",
+  "_rev": "4-22484cc537f12d3023241211ee34e39d",
+  "name": "org",
+  "description": "A parser and converter for org-mode notation",
+  "dist-tags": {
+    "latest": "0.0.4"
+  },
+  "versions": {
+    "0.0.2": {
+      "name": "org",
+      "description": "A parser and converter for org-mode notation",
+      "homepage": "http://mooz.github.com/org-js",
+      "keywords": [
+        "org-mode",
+        "emacs",
+        "parser"
+      ],
+      "author": {
+        "name": "mooz",
+        "email": "stillpedant@gmail.com"
+      },
+      "main": "./lib/org.js",
+      "version": "0.0.2",
+      "directories": {
+        "test": "./tests"
+      },
+      "repository": {
+        "type": "git",
+        "url": "git://github.com/mooz/org-js.git"
+      },
+      "bugs": {
+        "url": "https://github.com/mooz/org-js/issues"
+      },
+      "_id": "org@0.0.2",
+      "dist": {
+        "shasum": "12c58092e7de94456a43ef7823eef45e4d1d12fe",
+        "tarball": "https://registry.npmjs.org/org/-/org-0.0.2.tgz"
+      },
+      "_from": ".",
+      "_npmVersion": "1.2.25",
+      "_npmUser": {
+        "name": "mooz",
+        "email": "stillpedant@gmail.com"
+      },
+      "maintainers": [
+        {
+          "name": "mooz",
+          "email": "stillpedant@gmail.com"
+        }
+      ]
+    },
+    "0.0.3": {
+      "name": "org",
+      "description": "A parser and converter for org-mode notation",
+      "homepage": "http://mooz.github.com/org-js",
+      "bugs": {
+        "url": "http://github.com/mooz/org-s/issues"
+      },
+      "keywords": [
+        "org-mode",
+        "emacs",
+        "parser"
+      ],
+      "author": {
+        "name": "Masafumi Oyamada",
+        "email": "stillpedant@gmail.com",
+        "url": "http://mooz.github.io/"
+      },
+      "licenses": [
+        {
+          "type": "MIT"
+        }
+      ],
+      "main": "./lib/org.js",
+      "version": "0.0.3",
+      "directories": {
+        "test": "./tests"
+      },
+      "repository": {
+        "type": "git",
+        "url": "git://github.com/mooz/org-js.git"
+      },
+      "_id": "org@0.0.3",
+      "dist": {
+        "shasum": "6a44220f88903a6dfc3b47d010238058f9faf3a0",
+        "tarball": "https://registry.npmjs.org/org/-/org-0.0.3.tgz"
+      },
+      "_from": ".",
+      "_npmVersion": "1.2.25",
+      "_npmUser": {
+        "name": "mooz",
+        "email": "stillpedant@gmail.com"
+      },
+      "maintainers": [
+        {
+          "name": "mooz",
+          "email": "stillpedant@gmail.com"
+        }
+      ]
+    },
+    "0.0.4": {
+      "name": "org",
+      "description": "A parser and converter for org-mode notation",
+      "homepage": "http://mooz.github.com/org-js",
+      "bugs": {
+        "url": "http://github.com/mooz/org-s/issues"
+      },
+      "keywords": [
+        "org-mode",
+        "emacs",
+        "parser"
+      ],
+      "author": {
+        "name": "Masafumi Oyamada",
+        "email": "stillpedant@gmail.com",
+        "url": "http://mooz.github.io/"
+      },
+      "licenses": [
+        {
+          "type": "MIT"
+        }
+      ],
+      "main": "./lib/org.js",
+      "version": "0.0.4",
+      "directories": {
+        "test": "./tests"
+      },
+      "repository": {
+        "type": "git",
+        "url": "git://github.com/mooz/org-js.git"
+      },
+      "_id": "org@0.0.4",
+      "dist": {
+        "shasum": "788b3be1a50f7c94c1500ae4d922ec76c04e06ea",
+        "tarball": "https://registry.npmjs.org/org/-/org-0.0.4.tgz"
+      },
+      "_from": ".",
+      "_npmVersion": "1.2.25",
+      "_npmUser": {
+        "name": "mooz",
+        "email": "stillpedant@gmail.com"
+      },
+      "maintainers": [
+        {
+          "name": "mooz",
+          "email": "stillpedant@gmail.com"
+        }
+      ]
+    }
+  },
+  "readme": "org-js\n======\n\nParser and converter for org-mode (<http://orgmode.org/>) notation written in JavaScript.\n\nInteractive Editor\n------------------\n\nFor working example, see http://mooz.github.com/org-js/editor/.\n\nInstallation\n------------\n\n    npm install org\n\nSimple example of org -> HTML conversion\n----------------------------------------\n\n```javascript\nvar org = require(\"org\");\n\nvar parser = new org.Parser();\nvar orgDocument = parser.parse(orgCode);\nvar orgHTMLDocument = orgDocument.convert(org.ConverterHTML, {\n  headerOffset: 1,\n  exportFromLineNumber: false,\n  suppressSubScriptHandling: false,\n  suppressAutoLink: false\n});\n\nconsole.dir(orgHTMLDocument); // => { title, contentHTML, tocHTML, toc }\nconsole.log(orgHTMLDocument.toString()) // => Rendered HTML\n```\n\nWriting yet another converter\n-----------------------------\n\nSee `lib/org/converter/html.js`.\n",
+  "maintainers": [
+    {
+      "name": "mooz",
+      "email": "stillpedant@gmail.com"
+    }
+  ],
+  "time": {
+    "modified": "2019-01-05T01:37:44.220Z",
+    "created": "2014-01-01T15:40:31.231Z",
+    "0.0.2": "2014-01-01T15:40:33.020Z",
+    "0.0.3": "2014-01-01T15:55:45.497Z",
+    "0.0.4": "2014-01-02T06:10:26.485Z"
+  },
+  "author": {
+    "name": "Masafumi Oyamada",
+    "email": "stillpedant@gmail.com",
+    "url": "http://mooz.github.io/"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/mooz/org-js.git"
+  },
+  "users": {
+    "nak2k": true,
+    "bgschaid": true,
+    "422665vijay": true,
+    "nontau": true
+  },
+  "homepage": "http://mooz.github.com/org-js",
+  "keywords": [
+    "org-mode",
+    "emacs",
+    "parser"
+  ],
+  "bugs": {
+    "url": "http://github.com/mooz/org-s/issues"
+  },
+  "readmeFilename": "README.md"
+}
diff --git a/swh/loader/package/tests/resources/replicate.npmjs.com/org_metadata_visit1.json b/swh/loader/package/tests/resources/replicate.npmjs.com/org_metadata_visit1.json
new file mode 100644
index 0000000..3aba6b1
--- /dev/null
+++ b/swh/loader/package/tests/resources/replicate.npmjs.com/org_metadata_visit1.json
@@ -0,0 +1,191 @@
+{
+  "_id": "org",
+  "_rev": "4-22484cc537f12d3023241211ee34e39d",
+  "name": "org",
+  "description": "A parser and converter for org-mode notation",
+  "dist-tags": {
+    "latest": "0.0.4"
+  },
+  "versions": {
+    "0.0.2": {
+      "name": "org",
+      "description": "A parser and converter for org-mode notation",
+      "homepage": "http://mooz.github.com/org-js",
+      "keywords": [
+        "org-mode",
+        "emacs",
+        "parser"
+      ],
+      "author": {
+        "name": "mooz",
+        "email": "stillpedant@gmail.com"
+      },
+      "main": "./lib/org.js",
+      "version": "0.0.2",
+      "directories": {
+        "test": "./tests"
+      },
+      "repository": {
+        "type": "git",
+        "url": "git://github.com/mooz/org-js.git"
+      },
+      "bugs": {
+        "url": "https://github.com/mooz/org-js/issues"
+      },
+      "_id": "org@0.0.2",
+      "dist": {
+        "shasum": "12c58092e7de94456a43ef7823eef45e4d1d12fe",
+        "tarball": "https://registry.npmjs.org/org/-/org-0.0.2.tgz"
+      },
+      "_from": ".",
+      "_npmVersion": "1.2.25",
+      "_npmUser": {
+        "name": "mooz",
+        "email": "stillpedant@gmail.com"
+      },
+      "maintainers": [
+        {
+          "name": "mooz",
+          "email": "stillpedant@gmail.com"
+        }
+      ]
+    },
+    "0.0.3": {
+      "name": "org",
+      "description": "A parser and converter for org-mode notation",
+      "homepage": "http://mooz.github.com/org-js",
+      "bugs": {
+        "url": "http://github.com/mooz/org-s/issues"
+      },
+      "keywords": [
+        "org-mode",
+        "emacs",
+        "parser"
+      ],
+      "author": {
+        "name": "Masafumi Oyamada",
+        "email": "stillpedant@gmail.com",
+        "url": "http://mooz.github.io/"
+      },
+      "licenses": [
+        {
+          "type": "MIT"
+        }
+      ],
+      "main": "./lib/org.js",
+      "version": "0.0.3",
+      "directories": {
+        "test": "./tests"
+      },
+      "repository": {
+        "type": "git",
+        "url": "git://github.com/mooz/org-js.git"
+      },
+      "_id": "org@0.0.3",
+      "dist": {
+        "shasum": "6a44220f88903a6dfc3b47d010238058f9faf3a0",
+        "tarball": "https://registry.npmjs.org/org/-/org-0.0.3.tgz"
+      },
+      "_from": ".",
+      "_npmVersion": "1.2.25",
+      "_npmUser": {
+        "name": "mooz",
+        "email": "stillpedant@gmail.com"
+      },
+      "maintainers": [
+        {
+          "name": "mooz",
+          "email": "stillpedant@gmail.com"
+        }
+      ]
+    },
+    "0.0.4": {
+      "name": "org",
+      "description": "A parser and converter for org-mode notation",
+      "homepage": "http://mooz.github.com/org-js",
+      "bugs": {
+        "url": "http://github.com/mooz/org-s/issues"
+      },
+      "keywords": [
+        "org-mode",
+        "emacs",
+        "parser"
+      ],
+      "author": {
+        "name": "Masafumi Oyamada",
+        "email": "stillpedant@gmail.com",
+        "url": "http://mooz.github.io/"
+      },
+      "licenses": [
+        {
+          "type": "MIT"
+        }
+      ],
+      "main": "./lib/org.js",
+      "version": "0.0.4",
+      "directories": {
+        "test": "./tests"
+      },
+      "repository": {
+        "type": "git",
+        "url": "git://github.com/mooz/org-js.git"
+      },
+      "_id": "org@0.0.4",
+      "dist": {
+        "shasum": "788b3be1a50f7c94c1500ae4d922ec76c04e06ea",
+        "tarball": "https://registry.npmjs.org/org/-/org-0.0.4.tgz"
+      },
+      "_from": ".",
+      "_npmVersion": "1.2.25",
+      "_npmUser": {
+        "name": "mooz",
+        "email": "stillpedant@gmail.com"
+      },
+      "maintainers": [
+        {
+          "name": "mooz",
+          "email": "stillpedant@gmail.com"
+        }
+      ]
+    }
+  },
+  "readme": "org-js\n======\n\nParser and converter for org-mode (<http://orgmode.org/>) notation written in JavaScript.\n\nInteractive Editor\n------------------\n\nFor working example, see http://mooz.github.com/org-js/editor/.\n\nInstallation\n------------\n\n    npm install org\n\nSimple example of org -> HTML conversion\n----------------------------------------\n\n```javascript\nvar org = require(\"org\");\n\nvar parser = new org.Parser();\nvar orgDocument = parser.parse(orgCode);\nvar orgHTMLDocument = orgDocument.convert(org.ConverterHTML, {\n  headerOffset: 1,\n  exportFromLineNumber: false,\n  suppressSubScriptHandling: false,\n  suppressAutoLink: false\n});\n\nconsole.dir(orgHTMLDocument); // => { title, contentHTML, tocHTML, toc }\nconsole.log(orgHTMLDocument.toString()) // => Rendered HTML\n```\n\nWriting yet another converter\n-----------------------------\n\nSee `lib/org/converter/html.js`.\n",
+  "maintainers": [
+    {
+      "name": "mooz",
+      "email": "stillpedant@gmail.com"
+    }
+  ],
+  "time": {
+    "modified": "2019-01-05T01:37:44.220Z",
+    "created": "2014-01-01T15:40:31.231Z",
+    "0.0.2": "2014-01-01T15:40:33.020Z",
+    "0.0.3": "2014-01-01T15:55:45.497Z",
+    "0.0.4": "2014-01-02T06:10:26.485Z"
+  },
+  "author": {
+    "name": "Masafumi Oyamada",
+    "email": "stillpedant@gmail.com",
+    "url": "http://mooz.github.io/"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/mooz/org-js.git"
+  },
+  "users": {
+    "nak2k": true,
+    "bgschaid": true,
+    "422665vijay": true,
+    "nontau": true
+  },
+  "homepage": "http://mooz.github.com/org-js",
+  "keywords": [
+    "org-mode",
+    "emacs",
+    "parser"
+  ],
+  "bugs": {
+    "url": "http://github.com/mooz/org-s/issues"
+  },
+  "readmeFilename": "README.md"
+}
diff --git a/swh/loader/package/tests/resources/replicate.npmjs.com/org_metadata_visit2.json b/swh/loader/package/tests/resources/replicate.npmjs.com/org_metadata_visit2.json
new file mode 100644
index 0000000..d0e56b7
--- /dev/null
+++ b/swh/loader/package/tests/resources/replicate.npmjs.com/org_metadata_visit2.json
@@ -0,0 +1,347 @@
+{
+  "_id": "org",
+  "_rev": "4-22484cc537f12d3023241211ee34e39d",
+  "name": "org",
+  "description": "A parser and converter for org-mode notation",
+  "dist-tags": {
+    "latest": "0.2.0"
+  },
+  "versions": {
+    "0.0.2": {
+      "name": "org",
+      "description": "A parser and converter for org-mode notation",
+      "homepage": "http://mooz.github.com/org-js",
+      "keywords": [
+        "org-mode",
+        "emacs",
+        "parser"
+      ],
+      "author": {
+        "name": "mooz",
+        "email": "stillpedant@gmail.com"
+      },
+      "main": "./lib/org.js",
+      "version": "0.0.2",
+      "directories": {
+        "test": "./tests"
+      },
+      "repository": {
+        "type": "git",
+        "url": "git://github.com/mooz/org-js.git"
+      },
+      "bugs": {
+        "url": "https://github.com/mooz/org-js/issues"
+      },
+      "_id": "org@0.0.2",
+      "dist": {
+        "shasum": "12c58092e7de94456a43ef7823eef45e4d1d12fe",
+        "tarball": "https://registry.npmjs.org/org/-/org-0.0.2.tgz"
+      },
+      "_from": ".",
+      "_npmVersion": "1.2.25",
+      "_npmUser": {
+        "name": "mooz",
+        "email": "stillpedant@gmail.com"
+      },
+      "maintainers": [
+        {
+          "name": "mooz",
+          "email": "stillpedant@gmail.com"
+        }
+      ]
+    },
+    "0.0.3": {
+      "name": "org",
+      "description": "A parser and converter for org-mode notation",
+      "homepage": "http://mooz.github.com/org-js",
+      "bugs": {
+        "url": "http://github.com/mooz/org-s/issues"
+      },
+      "keywords": [
+        "org-mode",
+        "emacs",
+        "parser"
+      ],
+      "author": {
+        "name": "Masafumi Oyamada",
+        "email": "stillpedant@gmail.com",
+        "url": "http://mooz.github.io/"
+      },
+      "licenses": [
+        {
+          "type": "MIT"
+        }
+      ],
+      "main": "./lib/org.js",
+      "version": "0.0.3",
+      "directories": {
+        "test": "./tests"
+      },
+      "repository": {
+        "type": "git",
+        "url": "git://github.com/mooz/org-js.git"
+      },
+      "_id": "org@0.0.3",
+      "dist": {
+        "shasum": "6a44220f88903a6dfc3b47d010238058f9faf3a0",
+        "tarball": "https://registry.npmjs.org/org/-/org-0.0.3.tgz"
+      },
+      "_from": ".",
+      "_npmVersion": "1.2.25",
+      "_npmUser": {
+        "name": "mooz",
+        "email": "stillpedant@gmail.com"
+      },
+      "maintainers": [
+        {
+          "name": "mooz",
+          "email": "stillpedant@gmail.com"
+        }
+      ]
+    },
+    "0.0.4": {
+      "name": "org",
+      "description": "A parser and converter for org-mode notation",
+      "homepage": "http://mooz.github.com/org-js",
+      "bugs": {
+        "url": "http://github.com/mooz/org-s/issues"
+      },
+      "keywords": [
+        "org-mode",
+        "emacs",
+        "parser"
+      ],
+      "author": {
+        "name": "Masafumi Oyamada",
+        "email": "stillpedant@gmail.com",
+        "url": "http://mooz.github.io/"
+      },
+      "licenses": [
+        {
+          "type": "MIT"
+        }
+      ],
+      "main": "./lib/org.js",
+      "version": "0.0.4",
+      "directories": {
+        "test": "./tests"
+      },
+      "repository": {
+        "type": "git",
+        "url": "git://github.com/mooz/org-js.git"
+      },
+      "_id": "org@0.0.4",
+      "dist": {
+        "shasum": "788b3be1a50f7c94c1500ae4d922ec76c04e06ea",
+        "tarball": "https://registry.npmjs.org/org/-/org-0.0.4.tgz"
+      },
+      "_from": ".",
+      "_npmVersion": "1.2.25",
+      "_npmUser": {
+        "name": "mooz",
+        "email": "stillpedant@gmail.com"
+      },
+      "maintainers": [
+        {
+          "name": "mooz",
+          "email": "stillpedant@gmail.com"
+        }
+      ]
+    },
+    "0.0.5": {
+      "name": "org",
+      "description": "A parser and converter for org-mode notation",
+      "homepage": "http://mooz.github.com/org-js",
+      "bugs": {
+        "url": "http://github.com/mooz/org-s/issues"
+      },
+      "keywords": [
+        "org-mode",
+        "emacs",
+        "parser"
+      ],
+      "author": {
+        "name": "Masafumi Oyamada",
+        "email": "stillpedant@gmail.com",
+        "url": "http://mooz.github.io/"
+      },
+      "licenses": [
+        {
+          "type": "MIT"
+        }
+      ],
+      "main": "./lib/org.js",
+      "version": "0.0.5",
+      "directories": {
+        "test": "./tests"
+      },
+      "repository": {
+        "type": "git",
+        "url": "git://github.com/mooz/org-js.git"
+      },
+      "_id": "org@0.0.5",
+      "dist": {
+        "shasum": "66e8c316cb37e1c176f604aa53fcb07b6f51b908",
+        "tarball": "https://registry.npmjs.org/org/-/org-0.0.5.tgz"
+      },
+      "_from": ".",
+      "_npmVersion": "1.2.25",
+      "_npmUser": {
+        "name": "mooz",
+        "email": "stillpedant@gmail.com"
+      },
+      "maintainers": [
+        {
+          "name": "mooz",
+          "email": "stillpedant@gmail.com"
+        }
+      ]
+    },
+    "0.1.0": {
+      "name": "org",
+      "description": "A parser and converter for org-mode notation",
+      "homepage": "http://mooz.github.com/org-js",
+      "bugs": {
+        "url": "http://github.com/mooz/org-s/issues"
+      },
+      "keywords": [
+        "org-mode",
+        "emacs",
+        "parser"
+      ],
+      "author": {
+        "name": "Masafumi Oyamada",
+        "email": "stillpedant@gmail.com",
+        "url": "http://mooz.github.io/"
+      },
+      "licenses": [
+        {
+          "type": "MIT"
+        }
+      ],
+      "main": "./lib/org.js",
+      "version": "0.1.0",
+      "directories": {
+        "test": "./tests"
+      },
+      "repository": {
+        "type": "git",
+        "url": "git://github.com/mooz/org-js.git"
+      },
+      "gitHead": "82ed089de208e82a3bf3463f52fa77006382674c",
+      "_id": "org@0.1.0",
+      "scripts": {},
+      "_shasum": "bfaab735973c1a88fd62a21faf527ce360a412e9",
+      "_from": ".",
+      "_npmVersion": "1.4.28",
+      "_npmUser": {
+        "name": "mooz",
+        "email": "stillpedant@gmail.com"
+      },
+      "maintainers": [
+        {
+          "name": "mooz",
+          "email": "stillpedant@gmail.com"
+        }
+      ],
+      "dist": {
+        "shasum": "bfaab735973c1a88fd62a21faf527ce360a412e9",
+        "tarball": "https://registry.npmjs.org/org/-/org-0.1.0.tgz"
+      }
+    },
+    "0.2.0": {
+      "name": "org",
+      "description": "A parser and converter for org-mode notation",
+      "homepage": "http://mooz.github.com/org-js",
+      "bugs": {
+        "url": "http://github.com/mooz/org-s/issues"
+      },
+      "keywords": [
+        "org-mode",
+        "emacs",
+        "parser"
+      ],
+      "author": {
+        "name": "Masafumi Oyamada",
+        "email": "stillpedant@gmail.com",
+        "url": "http://mooz.github.io/"
+      },
+      "licenses": [
+        {
+          "type": "MIT"
+        }
+      ],
+      "main": "./lib/org.js",
+      "version": "0.2.0",
+      "directories": {
+        "test": "./tests"
+      },
+      "repository": {
+        "type": "git",
+        "url": "git://github.com/mooz/org-js.git"
+      },
+      "gitHead": "57b4480747e6e0c26baa43f267218a34b59224a5",
+      "_id": "org@0.2.0",
+      "scripts": {},
+      "_shasum": "d76378387dc506fb8e3ccff73a0ad04e3afc6391",
+      "_from": ".",
+      "_npmVersion": "1.4.28",
+      "_npmUser": {
+        "name": "mooz",
+        "email": "stillpedant@gmail.com"
+      },
+      "maintainers": [
+        {
+          "name": "mooz",
+          "email": "stillpedant@gmail.com"
+        }
+      ],
+      "dist": {
+        "shasum": "d76378387dc506fb8e3ccff73a0ad04e3afc6391",
+        "tarball": "https://registry.npmjs.org/org/-/org-0.2.0.tgz"
+      }
+    }
+  },
+  "readme": "org-js\n======\n\nParser and converter for org-mode (<http://orgmode.org/>) notation written in JavaScript.\n\nInteractive Editor\n------------------\n\nFor working example, see http://mooz.github.com/org-js/editor/.\n\nInstallation\n------------\n\n    npm install org\n\nSimple example of org -> HTML conversion\n----------------------------------------\n\n```javascript\nvar org = require(\"org\");\n\nvar parser = new org.Parser();\nvar orgDocument = parser.parse(orgCode);\nvar orgHTMLDocument = orgDocument.convert(org.ConverterHTML, {\n  headerOffset: 1,\n  exportFromLineNumber: false,\n  suppressSubScriptHandling: false,\n  suppressAutoLink: false\n});\n\nconsole.dir(orgHTMLDocument); // => { title, contentHTML, tocHTML, toc }\nconsole.log(orgHTMLDocument.toString()) // => Rendered HTML\n```\n\nWriting yet another converter\n-----------------------------\n\nSee `lib/org/converter/html.js`.\n",
+  "maintainers": [
+    {
+      "name": "mooz",
+      "email": "stillpedant@gmail.com"
+    }
+  ],
+  "time": {
+    "modified": "2019-01-05T01:37:44.220Z",
+    "created": "2014-01-01T15:40:31.231Z",
+    "0.0.2": "2014-01-01T15:40:33.020Z",
+    "0.0.3": "2014-01-01T15:55:45.497Z",
+    "0.0.4": "2014-01-02T06:10:26.485Z",
+    "0.0.5": "2014-01-03T13:58:20.540Z",
+    "0.1.0": "2014-11-23T03:47:12.464Z",
+    "0.2.0": "2015-02-21T07:14:47.785Z"
+  },
+  "author": {
+    "name": "Masafumi Oyamada",
+    "email": "stillpedant@gmail.com",
+    "url": "http://mooz.github.io/"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/mooz/org-js.git"
+  },
+  "users": {
+    "nak2k": true,
+    "bgschaid": true,
+    "422665vijay": true,
+    "nontau": true
+  },
+  "homepage": "http://mooz.github.com/org-js",
+  "keywords": [
+    "org-mode",
+    "emacs",
+    "parser"
+  ],
+  "bugs": {
+    "url": "http://github.com/mooz/org-s/issues"
+  },
+  "readmeFilename": "README.md"
+}
diff --git a/swh/loader/package/tests/test_npm.py b/swh/loader/package/tests/test_npm.py
new file mode 100644
index 0000000..81cdfa1
--- /dev/null
+++ b/swh/loader/package/tests/test_npm.py
@@ -0,0 +1,474 @@
+# Copyright (C) 2019  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 re
+import unittest
+
+from swh.model.hashutil import hash_to_bytes
+
+from swh.loader.package.npm import (
+    parse_npm_package_author, extract_npm_package_author
+)
+from swh.loader.package.tests.common import (
+    DATADIR, get_response_cb, check_snapshot
+)
+from swh.loader.package.npm import NpmLoader
+
+
+def package_metadata_file(package, visit=''):
+    json_filename = '%s_metadata' % package
+    if visit:
+        json_filename += '_visit%s' % visit
+    json_filename += '.json'
+    return json_filename
+
+
+class TestNpmClient(unittest.TestCase):
+
+    def _parse_author_string_test(self, author_str, expected_result):
+        self.assertEqual(
+            parse_npm_package_author(author_str),
+            expected_result
+        )
+        self.assertEqual(
+            parse_npm_package_author(' %s' % author_str),
+            expected_result
+        )
+        self.assertEqual(
+            parse_npm_package_author('%s ' % author_str),
+            expected_result
+        )
+
+    def test_parse_npm_package_author(self):
+
+        self._parse_author_string_test(
+            'John Doe',
+            {
+                'name': 'John Doe'
+            }
+        )
+
+        self._parse_author_string_test(
+            '<john.doe@foo.bar>',
+            {
+                'email': 'john.doe@foo.bar'
+            }
+        )
+
+        self._parse_author_string_test(
+            '(https://john.doe)',
+            {
+                'url': 'https://john.doe'
+            }
+        )
+
+        self._parse_author_string_test(
+            'John Doe <john.doe@foo.bar>',
+            {
+                'name': 'John Doe',
+                'email': 'john.doe@foo.bar'
+            }
+        )
+
+        self._parse_author_string_test(
+            'John Doe<john.doe@foo.bar>',
+            {
+                'name': 'John Doe',
+                'email': 'john.doe@foo.bar'
+            }
+        )
+
+        self._parse_author_string_test(
+            'John Doe (https://john.doe)',
+            {
+                'name': 'John Doe',
+                'url': 'https://john.doe'
+            }
+        )
+
+        self._parse_author_string_test(
+            'John Doe(https://john.doe)',
+            {
+                'name': 'John Doe',
+                'url': 'https://john.doe'
+            }
+        )
+
+        self._parse_author_string_test(
+            '<john.doe@foo.bar> (https://john.doe)',
+            {
+                'email': 'john.doe@foo.bar',
+                'url': 'https://john.doe'
+            }
+        )
+
+        self._parse_author_string_test(
+            '(https://john.doe) <john.doe@foo.bar>',
+            {
+                'email': 'john.doe@foo.bar',
+                'url': 'https://john.doe'
+            }
+        )
+
+        self._parse_author_string_test(
+            'John Doe <john.doe@foo.bar> (https://john.doe)',
+            {
+                'name': 'John Doe',
+                'email': 'john.doe@foo.bar',
+                'url': 'https://john.doe'
+            }
+        )
+
+        self._parse_author_string_test(
+            'John Doe (https://john.doe) <john.doe@foo.bar>',
+            {
+                'name': 'John Doe',
+                'email': 'john.doe@foo.bar',
+                'url': 'https://john.doe'
+            }
+        )
+
+        self._parse_author_string_test(
+            'John Doe<john.doe@foo.bar> (https://john.doe)',
+            {
+                'name': 'John Doe',
+                'email': 'john.doe@foo.bar',
+                'url': 'https://john.doe'
+            }
+        )
+
+        self._parse_author_string_test(
+            'John Doe<john.doe@foo.bar>(https://john.doe)',
+            {
+                'name': 'John Doe',
+                'email': 'john.doe@foo.bar',
+                'url': 'https://john.doe'
+            }
+        )
+
+        self._parse_author_string_test('', {})
+        self._parse_author_string_test('<>', {})
+        self._parse_author_string_test(' <>', {})
+        self._parse_author_string_test('<>()', {})
+        self._parse_author_string_test('<> ()', {})
+        self._parse_author_string_test('()', {})
+        self._parse_author_string_test(' ()', {})
+
+        self._parse_author_string_test(
+            'John Doe <> ()',
+            {
+                'name': 'John Doe'
+            }
+        )
+
+        self._parse_author_string_test(
+            'John Doe <>',
+            {
+                'name': 'John Doe'
+            }
+        )
+
+        self._parse_author_string_test(
+            'John Doe ()',
+            {
+                'name': 'John Doe'
+            }
+        )
+
+    def test_extract_npm_package_author(self):
+        package_metadata_filepath = os.path.join(
+            DATADIR, 'replicate.npmjs.com', 'org_metadata_visit2.json')
+
+        with open(package_metadata_filepath) as json_file:
+            package_metadata = json.load(json_file)
+
+        self.assertEqual(
+            extract_npm_package_author(package_metadata['versions']['0.0.2']),
+            {
+                'fullname': b'mooz <stillpedant@gmail.com>',
+                'name': b'mooz',
+                'email': b'stillpedant@gmail.com'
+            }
+        )
+
+        self.assertEqual(
+            extract_npm_package_author(package_metadata['versions']['0.0.3']),
+            {
+                '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/"
+        }''') # noqa
+
+        self.assertEqual(
+            extract_npm_package_author(package_json),
+            {
+                '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"
+            }
+        }''')
+
+        self.assertEqual(
+            extract_npm_package_author(package_json),
+            {
+                '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"
+        }''')
+
+        self.assertEqual(
+            extract_npm_package_author(package_json),
+            {
+                'fullname': b'fengmk2 <fengmk2@gmail.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"
+        }''')
+
+        self.assertEqual(
+            extract_npm_package_author(package_json),
+            {
+                'fullname': b'xiaohuoni <448627663@qq.com>',
+                'name': b'xiaohuoni',
+                'email': b'448627663@qq.com'
+            }
+        )
+
+
+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'}
+)
+
+_expected_new_snapshot_first_visit_id = normalize_hashes(
+    'd0587e1195aed5a8800411a008f2f2d627f18e2d')
+
+_expected_branches_first_visit = {
+    'HEAD': {
+        'target': 'releases/0.0.4',
+        'target_type': 'alias'
+    },
+    'releases/0.0.2': {
+        'target': 'd8a1c7474d2956ac598a19f0f27d52f7015f117e',
+        'target_type': 'revision'
+    },
+    'releases/0.0.3': {
+        'target': '5f9eb78af37ffd12949f235e86fac04898f9f72a',
+        'target_type': 'revision'
+    },
+    'releases/0.0.4': {
+        'target': 'ba019b192bdb94bd0b5bd68b3a5f92b5acc2239a',
+        'target_type': 'revision'
+    }
+}
+
+
+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_npm_loader_2_first_visit(requests_mock):
+
+    package = 'org'
+    requests_mock.get(re.compile('https://'),
+                      body=get_response_cb)
+    loader = NpmLoader(package,
+                       package_url(package),
+                       package_metadata_url(package))
+
+    actual_load_status = loader.load()
+    assert actual_load_status == {'status': 'eventful'}
+
+    stats = loader.storage.stat_counters()
+
+    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)) == []
+
+    check_snapshot(
+        _expected_new_snapshot_first_visit_id,
+        _expected_branches_first_visit,
+        storage=loader.storage)