diff --git a/swh/scanner/cli.py b/swh/scanner/cli.py
index 40a03cc..6dc6a65 100644
--- a/swh/scanner/cli.py
+++ b/swh/scanner/cli.py
@@ -1,49 +1,55 @@
 # Copyright (C) 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 click
 import asyncio
 from pathlib import PosixPath
 
 from .scanner import run
 from .model import Tree
 
 from swh.core.cli import CONTEXT_SETTINGS
 
 
 @click.group(name='scanner', context_settings=CONTEXT_SETTINGS)
 @click.pass_context
 def scanner(ctx):
     '''Software Heritage Scanner tools.'''
     pass
 
 
 def parse_url(url):
     if not url.startswith('https://'):
         url = 'https://' + url
     if not url.endswith('/'):
         url += '/'
     return url
 
 
 @scanner.command(name='scan')
 @click.argument('path', required=True, type=click.Path(exists=True))
-@click.option('--api-url',
+@click.option('-u', '--api-url',
               default='https://archive.softwareheritage.org/api/1',
               metavar='API_URL', show_default=True,
               help="url for the api request")
+@click.option('-f', '--format',
+              type=click.Choice(['text', 'json'], case_sensitive=False),
+              default='text',
+              help="select the output format")
 @click.pass_context
-def scan(ctx, path, api_url):
+def scan(ctx, path, api_url, format):
     """Scan a source code project to discover files and directories already
     present in the archive"""
+
     api_url = parse_url(api_url)
     source_tree = Tree(PosixPath(path))
     loop = asyncio.get_event_loop()
     loop.run_until_complete(run(path, api_url, source_tree))
-    source_tree.show()
+
+    source_tree.show(format)
 
 
 if __name__ == '__main__':
     scan()
diff --git a/swh/scanner/model.py b/swh/scanner/model.py
index c4a3d56..836fb61 100644
--- a/swh/scanner/model.py
+++ b/swh/scanner/model.py
@@ -1,84 +1,108 @@
 # Copyright (C) 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
 
 from __future__ import annotations
 import sys
 from pathlib import PosixPath
 from typing import Any, Dict
 from enum import Enum
 
 from swh.model.identifiers import (
     DIRECTORY, CONTENT
 )
 
 
 class Color(Enum):
     blue = '\033[94m'
     green = '\033[92m'
     red = '\033[91m'
     end = '\033[0m'
 
 
 def colorize(text: str, color: Color):
     return color.value + text + Color.end.value
 
 
 class Tree:
     """Representation of a file system structure
     """
     def __init__(self, path: PosixPath, father: Tree = None):
         self.father = father
         self.path = path
         self.otype = DIRECTORY if path.is_dir() else CONTENT
         self.pid = ''
         self.children: Dict[PosixPath, Tree] = {}
 
     def addNode(self, path: PosixPath, pid: str = None) -> None:
         """Recursively add a new node path
         """
         relative_path = path.relative_to(self.path)
 
         if relative_path == PosixPath('.'):
             if pid is not None:
                 self.pid = pid
             return
 
         new_path = self.path.joinpath(relative_path.parts[0])
         if new_path not in self.children:
             self.children[new_path] = Tree(new_path, self)
 
         self.children[new_path].addNode(path, pid)
 
-    def show(self) -> None:
+    def show(self, format) -> None:
         """Print all the tree"""
-        isatty = sys.stdout.isatty()
+        if format == 'json':
+            print(self.getJsonTree())
+        elif format == 'text':
+            isatty = sys.stdout.isatty()
 
-        print(colorize(str(self.path), Color.blue) if isatty
-              else str(self.path))
-        self.printChildren(isatty)
+            print(colorize(str(self.path), Color.blue) if isatty
+                  else str(self.path))
+            self.printChildren(isatty)
 
     def printChildren(self, isatty: bool, inc: int = 0) -> None:
         for path, node in self.children.items():
             self.printNode(node, isatty, inc)
             if node.children:
                 node.printChildren(isatty, inc+1)
 
     def printNode(self, node: Any, isatty: bool, inc: int) -> None:
         rel_path = str(node.path.relative_to(self.path))
         print('│   '*inc, end='')
         if node.otype == DIRECTORY:
             if node.pid:
                 print(colorize(rel_path, Color.blue) if isatty else rel_path,
                       end='')
             else:
                 print(colorize(rel_path, Color.red) if isatty else rel_path,
                       end='')
             print('/')
 
         elif node.otype == CONTENT:
             if node.pid:
                 print(colorize(rel_path, Color.green) if isatty else rel_path)
             else:
                 print(colorize(rel_path, Color.red) if isatty else rel_path)
+
+    def getJsonTree(self):
+        """Walk through the tree to discover content or directory that have
+        a persistent identifier. If a persistent identifier is found it saves
+        the path with the relative PID.
+
+        Returns:
+            child_tree: the tree with the content/directory found
+
+        """
+        child_tree = {}
+        for path, child_node in self.children.items():
+            rel_path = str(child_node.path.relative_to(self.path))
+            if child_node.pid:
+                child_tree[rel_path] = child_node.pid
+            else:
+                next_tree = child_node.getJsonChild()
+                if next_tree:
+                    child_tree[rel_path] = child_node.getJsonTree()
+
+        return child_tree