diff --git a/.gitignore b/.gitignore
index 8cd32a3368f..a57723961dd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,4 @@
-project
+/project
 smarty/templates_c
 .gitmodules
 project-*
diff --git a/modules/api/php/endpoints/candidates.class.inc b/modules/api/php/endpoints/candidates.class.inc
index a1dedbc78ae..6550fb34422 100644
--- a/modules/api/php/endpoints/candidates.class.inc
+++ b/modules/api/php/endpoints/candidates.class.inc
@@ -211,12 +211,12 @@ class Candidates extends Endpoint implements \LORIS\Middleware\ETagCalculator
             $candid = \Candidate::createNew(
                 new \CenterID("$centerid"),
                 $data['Candidate']['DoB'],
-                $data['Candidate']['EDC'],
+                $data['Candidate']['EDC'] ?? null,
                 $sex,
                 $pscid,
                 $project->getId()
             );
-        } catch (\LorisException $e) {
+        } catch (\LorisException | \InvalidArgumentException | \Exception $e) {
             return new \LORIS\Http\Response\JSON\BadRequest($e->getMessage());
         }
 
diff --git a/modules/api/php/endpoints/project/project.class.inc b/modules/api/php/endpoints/project/project.class.inc
index effc0247ceb..f11c9830194 100644
--- a/modules/api/php/endpoints/project/project.class.inc
+++ b/modules/api/php/endpoints/project/project.class.inc
@@ -110,6 +110,9 @@ class Project extends Endpoint implements \LORIS\Middleware\ETagCalculator
         case 'instruments':
             $handler = new Instruments($this->_project);
             break;
+        case 'subprojects':
+            $handler = new Subprojects($this->_project);
+            break;
         case 'visits':
             $handler = new Visits($this->_project);
             break;
diff --git a/modules/api/php/endpoints/project/subproject/subproject.class.inc b/modules/api/php/endpoints/project/subproject/subproject.class.inc
new file mode 100644
index 00000000000..83eeee56561
--- /dev/null
+++ b/modules/api/php/endpoints/project/subproject/subproject.class.inc
@@ -0,0 +1,145 @@
+<?php declare(strict_types=1);
+/**
+ * This implements the Subproject page class under Project
+ *
+ * PHP Version 7
+ *
+ * @category API
+ * @package  Loris
+ * @author   Xavier Lecours Boucher <xavier.lecours@mcin.ca>
+ * @license  http://www.gnu.org/licenses/gpl-3.0.txt GPLv3
+ * @link     https://github.com/aces/Loris
+ */
+namespace LORIS\api\Endpoints\Project\Subproject;
+
+use \Psr\Http\Message\ServerRequestInterface;
+use \Psr\Http\Message\ResponseInterface;
+use \LORIS\api\Endpoint;
+
+/**
+ * A class for handling the /projects/$projectname/subprojects/$subproject
+ * endpoint.
+ *
+ * @category API
+ * @package  Loris
+ * @author   Xavier Lecours Boucher <xavier.lecours@mcin.ca>
+ * @license  http://www.gnu.org/licenses/gpl-3.0.txt GPLv3
+ * @link     https://github.com/aces/Loris
+ */
+class Subproject extends Endpoint implements \LORIS\Middleware\ETagCalculator
+{
+    /**
+     * A cache of the results of the endpoint, so that
+     * it doesn't need to be recalculated for the ETag and handler
+     */
+    private $_cache;
+
+    /**
+     * The requested instrument
+     */
+    private $_subproject;
+
+    /**
+     * Contructor for the subproject endpoint
+     *
+     * @param \Subproject $subproject The subproject
+     */
+    public function __construct(\Subproject $subproject)
+    {
+        $this->_subproject = $subproject;
+    }
+
+    /**
+     * Return which methods are supported by this endpoint.
+     *
+     * @return array supported HTTP methods
+     */
+    protected function allowedMethods() : array
+    {
+        return ['GET'];
+    }
+
+    /**
+     * Versions of the LORIS API which are supported by this
+     * endpoint.
+     *
+     * @return array a list of supported API versions.
+     */
+    protected function supportedVersions() : array
+    {
+        return [
+            'v0.0.4-dev',
+        ];
+    }
+
+    /**
+     * Handles a HTTP request
+     *
+     * @param ServerRequestInterface $request The incoming PSR7 request
+     *
+     * @return ResponseInterface The outgoing PSR7 response
+     */
+    public function handle(ServerRequestInterface $request) : ResponseInterface
+    {
+        $pathparts = $request->getAttribute('pathparts');
+        if (count($pathparts) !== 0) {
+            return new \LORIS\Http\Response\JSON\NotFound();
+        }
+
+        switch ($request->getMethod()) {
+        case 'GET':
+            return $this->_handleGET($request);
+
+        case 'OPTIONS':
+            return (new \LORIS\Http\Response())
+                ->withHeader('Allow', $this->allowedMethods());
+        default:
+            return new \LORIS\Http\Response\JSON\MethodNotAllowed(
+                $this->allowedMethods()
+            );
+        }
+    }
+
+    /**
+     * Create an array representation of this endpoint's reponse body
+     *
+     * @return ResponseInterface The outgoing PSR7 response
+     */
+    private function _handleGET(): ResponseInterface
+    {
+        if (isset($this->_cache)) {
+            return $this->_cache;
+        }
+
+        $data   = json_decode(json_encode($this->_subproject), true);
+        $visits = array_reduce(
+            $this->_subproject->getVisits(),
+            function ($carry, $item) {
+                // This is just changing the keys from visit_label to VisitLabel
+                // It should probably be delegated to a view object.
+                array_push($carry, ['VisitLabel' => $item['visit_label']]);
+                return $carry;
+            },
+            []
+        );
+
+        $data['Visits'] = $visits;
+
+        $this->_cache = new \LORIS\Http\Response\JsonResponse($data);
+
+        return $this->_cache;
+    }
+
+    /**
+     * Implements the ETagCalculator interface
+     *
+     * @param ServerRequestInterface $request The PSR7 incoming request.
+     *
+     * @return string etag summarizing value of this request.
+     */
+    public function ETag(ServerRequestInterface $request) : string
+    {
+        return md5(json_encode($this->_handleGET($request)->getBody()));
+    }
+}
+
diff --git a/modules/api/php/endpoints/project/subprojects.class.inc b/modules/api/php/endpoints/project/subprojects.class.inc
new file mode 100644
index 00000000000..43fb695826a
--- /dev/null
+++ b/modules/api/php/endpoints/project/subprojects.class.inc
@@ -0,0 +1,160 @@
+<?php declare(strict_types=1);
+/**
+ * This implements the Subprojects endpoint class
+ *
+ * PHP Version 7
+ *
+ * @category API
+ * @package  Loris
+ * @license  http://www.gnu.org/licenses/gpl-3.0.txt GPLv3
+ * @link     https://github.com/aces/Loris
+ */
+
+namespace LORIS\api\Endpoints\Project;
+
+use \Psr\Http\Message\ServerRequestInterface;
+use \Psr\Http\Message\ResponseInterface;
+use \LORIS\api\Endpoint;
+
+/**
+ * A class for handling the /projects/{project}/subprojects endpoint.
+ *
+ * @category API
+ * @package  Loris
+ * @license  http://www.gnu.org/licenses/gpl-3.0.txt GPLv3
+ * @link     https://github.com/aces/Loris
+ */
+class Subprojects extends Endpoint implements \LORIS\Middleware\ETagCalculator
+{
+    /**
+     * A cache of the results of the projects/ endpoint, so that it doesn't
+     * need to be recalculated for the ETag and handler
+     */
+    private $_cache;
+
+    /**
+     * The requested project
+     */
+    private $_project;
+
+    /**
+     * Contructor
+     *
+     * @param \Project $project the requested project
+     */
+    public function __construct(\Project $project)
+    {
+        $this->_project = $project;
+    }
+
+    /**
+     * Return which methods are supported by this endpoint.
+     *
+     * @return array supported HTTP methods
+     */
+    protected function allowedMethods() : array
+    {
+        return ['GET'];
+    }
+
+    /**
+     * Versions of the LORIS API which are supported by this
+     * endpoint.
+     *
+     * @return array a list of supported API versions.
+     */
+    protected function supportedVersions() : array
+    {
+        return [
+            'v0.0.4-dev',
+        ];
+    }
+
+    /**
+     * Handles a HTTP request
+     *
+     * @param ServerRequestInterface $request The incoming PSR7 request
+     *
+     * @return ResponseInterface The outgoing PSR7 response
+     */
+    public function handle(ServerRequestInterface $request) : ResponseInterface
+    {
+        $pathparts = $request->getAttribute('pathparts');
+        if (count($pathparts) === 0) {
+            switch ($request->getMethod()) {
+            case 'GET':
+                return $this->_handleGET();
+
+            case 'OPTIONS':
+                return (new \LORIS\Http\Response())
+                    ->withHeader('Allow', $this->allowedMethods());
+            default:
+                return new \LORIS\Http\Response\JSON\MethodNotAllowed(
+                    $this->allowedMethods()
+                );
+            }
+        }
+
+        // Delegate to subproject specific endpoint.
+        $subproject_name =  urldecode($pathparts[0] ?? '');
+
+        try {
+            $subproject = $this->_project->getSubproject($subproject_name);
+        } catch (\NotFound $e) {
+            return new \LORIS\Http\Response\JSON\NotFound();
+        }
+
+        $endpoint = new Subproject\Subproject($subproject);
+
+        // Removing `/subprojects/<subproject_name>` from pathparts.
+        $pathparts = array_slice($pathparts, 2);
+        $request   = $request->withAttribute('pathparts', $pathparts);
+
+        return $endpoint->process($request, $endpoint);
+    }
+
+    /**
+     * Generates a JSON representation of this projecti subprojects following the API
+     * specification.
+     *
+     * @return ResponseInterface
+     */
+    private function _handleGET(): ResponseInterface
+    {
+        if (isset($this->_cache)) {
+            return $this->_cache;
+        }
+
+        $subprojects = array_map(
+            function ($subproject) {
+                return [
+                    'SubprojectID'      => $subproject['subprojectId'],
+                    'Title'             => $subproject['title'],
+                    'UseEDC'            => $subproject['useEDC'],
+                    'WindowDifference'  => $subproject['windowDifference'],
+                    'RecruitmentTarget' => $subproject['recruitmentTarget']
+                ];
+            },
+            $this->_project->getSubprojects()
+        );
+
+        $array = [
+            'Subprojects' => $subprojects
+        ];
+
+        $this->_cache = new \LORIS\Http\Response\JsonResponse($array);
+
+        return $this->_cache;
+    }
+    /**
+     * Implements the ETagCalculator interface
+     *
+     * @param ServerRequestInterface $request The PSR7 incoming request.
+     *
+     * @return string etag summarizing value of this request.
+     */
+    public function ETag(ServerRequestInterface $request) : string
+    {
+        return md5(json_encode($this->_handleGet($request)->getBody()));
+    }
+}
diff --git a/modules/api/php/endpoints/projects.class.inc b/modules/api/php/endpoints/projects.class.inc
index 584cc7ab432..670882a2c0c 100644
--- a/modules/api/php/endpoints/projects.class.inc
+++ b/modules/api/php/endpoints/projects.class.inc
@@ -108,6 +108,10 @@ class Projects extends Endpoint implements \LORIS\Middleware\ETagCalculator
             return new \LORIS\Http\Response\JSON\NotFound();
         }
 
+        if (!$project->isAccessibleBy($user)) {
+            return new \LORIS\Http\Response\JSON\Forbidden();
+        }
+
         $endpoint = new Project\Project($project);
 
         // Removing `/projects/<project_name>` from pathparts.
diff --git a/modules/api/php/endpoints/subproject/subproject.class.inc b/modules/api/php/endpoints/subproject/subproject.class.inc
new file mode 100644
index 00000000000..3fc351ffd59
--- /dev/null
+++ b/modules/api/php/endpoints/subproject/subproject.class.inc
@@ -0,0 +1,133 @@
+<?php declare(strict_types=1);
+/**
+ * This implements the Subproject page class under Subprojects
+ *
+ * PHP Version 7
+ *
+ * @category API
+ * @package  Loris
+ * @license  http://www.gnu.org/licenses/gpl-3.0.txt GPLv3
+ * @link     https://github.com/aces/Loris
+ */
+namespace LORIS\api\Endpoints\Subproject;
+
+use \Psr\Http\Message\ServerRequestInterface;
+use \Psr\Http\Message\ResponseInterface;
+use \LORIS\api\Endpoint;
+
+/**
+ * A class for handling the /subprojects/$subprojectname endpoint.
+ *
+ * @category API
+ * @package  Loris
+ * @author   Xavier Lecours Boucher <xavier.lecours@mcin.ca>
+ * @license  http://www.gnu.org/licenses/gpl-3.0.txt GPLv3
+ * @link     https://github.com/aces/Loris
+ */
+class Subproject extends Endpoint implements \LORIS\Middleware\ETagCalculator
+{
+    /**
+     * A cache of the results of the subprojects/$subprojectname endpoint, so that
+     * it doesn't need to be recalculated for the ETag and handler
+     */
+    private $_cache;
+
+    /**
+     * The requested subproject
+     */
+    private $_subproject;
+
+    /**
+     * Contructor
+     *
+     * @param string $subproject The requested subproject
+     */
+    public function __construct(string $subproject)
+    {
+        $this->_subproject = $subproject;
+    }
+
+    /**
+     * Return which methods are supported by this endpoint.
+     *
+     * @return array supported HTTP methods
+     */
+    protected function allowedMethods() : array
+    {
+        return ['GET'];
+    }
+
+    /**
+     * Versions of the LORIS API which are supported by this
+     * endpoint.
+     *
+     * @return array a list of supported API versions.
+     */
+    protected function supportedVersions() : array
+    {
+        return [
+            'v0.0.4-dev',
+        ];
+    }
+
+    /**
+     * Handles a request that starts with /subprojects/$subprojectname
+     *
+     * @param ServerRequestInterface $request The incoming PSR7 request
+     *
+     * @return ResponseInterface The outgoing PSR7 response
+     */
+    public function handle(ServerRequestInterface $request) : ResponseInterface
+    {
+        $pathparts = $request->getAttribute('pathparts');
+        if (count($pathparts) === 0) {
+            switch ($request->getMethod()) {
+            case 'GET':
+                return $this->_handleGET($request);
+
+            case 'OPTIONS':
+                return (new \LORIS\Http\Response())
+                    ->withHeader('Allow', $this->allowedMethods());
+
+            default:
+                return new \LORIS\Http\Response\JSON\MethodNotAllowed(
+                    $this->allowedMethods()
+                );
+            }
+        }
+        return new \LORIS\Http\Response\JSON\NotFound();
+    }
+
+    /**
+     * Generates a JSON representation of this subproject following the API
+     * specification.
+     *
+     * @param ServerRequestInterface $request The incoming PSR7 request @unused-param
+     *
+     * @return ResponseInterface
+     */
+    private function _handleGET($request): ResponseInterface
+    {
+        if (isset($this->_cache)) {
+            return $this->_cache;
+        }
+
+        $view         = (new \LORIS\api\Views\SubProject($this->_subproject))
+                          ->toArray();
+        $this->_cache = new \LORIS\Http\Response\JsonResponse($view);
+
+        return $this->_cache;
+    }
+
+    /**
+     * Implements the ETagCalculator interface
+     *
+     * @param ServerRequestInterface $request The incoming PSR7 request
+     *
+     * @return string etag summarizing value of this request.
+     */
+    public function ETag($request) : string
+    {
+        return md5(json_encode($this->_handleGET($request)->getBody()));
+    }
+}
diff --git a/modules/api/php/views/project.class.inc b/modules/api/php/views/project.class.inc
index 387b53cb7db..27aaa3e4290 100644
--- a/modules/api/php/views/project.class.inc
+++ b/modules/api/php/views/project.class.inc
@@ -29,7 +29,7 @@ class Project
      *
      * @var \Project
      */
-    protected $_project;
+    private $_project;
 
     /**
      * Constructor
@@ -55,7 +55,7 @@ class Project
             'Meta'        => $meta,
             'Candidates'  => $this->_project->getCandidateIds(),
             'Instruments' => array_keys(\Utility::getAllInstruments()),
-            'Visits'      => $this->getVisits(),
+            'Visits'      => $this->_getVisits(),
         ];
     }
 
@@ -87,7 +87,7 @@ class Project
 
         return [
             'Meta'   => $meta,
-            'Visits' => $this->getVisits(),
+            'Visits' => $this->_getVisits(),
         ];
     }
 
@@ -96,7 +96,7 @@ class Project
      *
      * @return array
      */
-    protected function getVisits(): array
+    private function _getVisits(): array
     {
         // TODO :: This should be replaced by $this->_project->getVisitLabels();
         return array_keys(
diff --git a/modules/api/php/views/project_0_0_4_dev.class.inc b/modules/api/php/views/project_0_0_4_dev.class.inc
index b8df8bd15f5..28583688c7c 100644
--- a/modules/api/php/views/project_0_0_4_dev.class.inc
+++ b/modules/api/php/views/project_0_0_4_dev.class.inc
@@ -20,8 +20,25 @@ namespace LORIS\api\Views;
  * @link     https://www.github.com/aces/Loris/
  */
 
-class Project_0_0_4_Dev extends Project
+class Project_0_0_4_Dev
 {
+    /**
+     * The project to format
+     *
+     * @var \Project
+     */
+    protected $_project;
+
+    /**
+     * Constructor
+     *
+     * @param \Project $project The project to format
+     */
+    public function __construct(\Project $project)
+    {
+        $this->_project = $project;
+    }
+
     /**
      * Produce an array representation of this project.
      *
@@ -29,18 +46,18 @@ class Project_0_0_4_Dev extends Project
      */
     public function toArray(): array
     {
-        $meta = ['Project' => $this->_project->getName()];
+        $name = $this->_project->getName();
 
         return [
-            'Meta'        => $meta,
-            'Subprojects' => array_values(
-                \Utility::getSubprojectList(
-                    $this->_project->getId()
-                )
-            ),
-            'Candidates'  => $this->_project->getCandidateIds(),
-            'Instruments' => array_keys(\Utility::getAllInstruments()),
-            'Visits'      => $this->getVisits(),
+            'Id'                 => $this->_project->getId(),
+            'Name'               => $this->_project->getName(),
+            'Alias'              => $this->_project->getAlias(),
+            'RecruitementTarget' => $this->_project->getRecruitmentTarget(),
+            'Links'              => [
+                'Candidates'  => "/projects/$name/candidates",
+                'Instruments' => "/projects/$name/instruments",
+                'Subprojects' => "/projects/$name/subprojects"
+            ]
         ];
     }
 }
diff --git a/modules/api/php/views/subproject.class.inc b/modules/api/php/views/subproject.class.inc
new file mode 100644
index 00000000000..7ab4dae9147
--- /dev/null
+++ b/modules/api/php/views/subproject.class.inc
@@ -0,0 +1,91 @@
+<?php declare(strict_types=1);
+/**
+ * PHP Version 7
+ *
+ * @category ApiViews
+ * @package  Loris
+ * @license  http://www.gnu.org/licenses/gpl-3.0.txt GPLv3
+ * @link     https://www.github.com/aces/Loris/
+ */
+
+namespace LORIS\api\Views;
+
+/**
+ * This class formats a Subproject object into arrays following the API
+ * specifications.
+ *
+ * @category ApiViews
+ * @package  Loris
+ * @license  http://www.gnu.org/licenses/gpl-3.0.txt GPLv3
+ * @link     https://www.github.com/aces/Loris/
+ */
+
+class Subproject
+{
+    /**
+     * The project to format
+     *
+     * @var string
+     */
+    protected $_subproject;
+
+    /**
+     * Constructor
+     *
+     * @param string $subproject The subproject to format
+     */
+    public function __construct(string $subproject)
+    {
+        $this->_subproject = $subproject;
+    }
+
+    /**
+     * Produce an array representation of this project.
+     *
+     * @return array
+     */
+    public function toArray(): array
+    {
+        $meta = ['Subproject' => $this->_subproject];
+
+        return [
+            'Meta'   => $meta,
+            'Visits' => $this->getVisits(),
+        ];
+    }
+
+    /**
+     * Generates the list of valid visit_labels for the subproject
+     * as defined in the config settings
+     *
+     * @return array
+     */
+    protected function getVisits(): array
+    {
+        $visits = [];
+
+        $subprojectID = array_search(
+            $this->_subproject,
+            \Utility::getSubprojectList()
+        );
+
+        $config =& \NDB_Config::singleton();
+        $visitLabelSettings = $config->getSetting('visitLabel');
+        foreach (\Utility::associativeToNumericArray($visitLabelSettings)
+                 as $visitLabelSetting) {
+            if ($visitLabelSetting['@']['subprojectID'] == $subprojectID) {
+
+                $items = \Utility::associativeToNumericArray(
+                    $visitLabelSetting['labelSet']['item']
+                );
+                foreach ($items as $item) {
+                    $visits[] = $item['@']['value'];
+                }
+                break;
+            }
+        }
+
+        return $visits;
+    }
+}
+
diff --git a/modules/api/php/views/subprojects.class.inc b/modules/api/php/views/subprojects.class.inc
new file mode 100644
index 00000000000..815384d6590
--- /dev/null
+++ b/modules/api/php/views/subprojects.class.inc
@@ -0,0 +1,54 @@
+<?php declare(strict_types=1);
+/**
+ * PHP Version 7
+ *
+ * @category ApiViews
+ * @package  Loris
+ * @license  http://www.gnu.org/licenses/gpl-3.0.txt GPLv3
+ * @link     https://www.github.com/aces/Loris/
+ */
+
+namespace LORIS\api\Views;
+
+/**
+ * Create a array representations of this LORIS instance subprojects
+ *  suitable to the API specifications.
+ *
+ * @category ApiViews
+ * @package  Loris
+ * @license  http://www.gnu.org/licenses/gpl-3.0.txt GPLv3
+ * @link     https://www.github.com/aces/Loris/
+ */
+
+class Subprojects
+{
+    private $_subprojects;
+
+    /**
+     * Create an api formated view of an array of subprojects
+     *
+     * @param [] $subprojects The subprojects
+     */
+    public function __construct(array $subprojects)
+    {
+        $this->_subprojects = $subprojects;
+    }
+
+    /**
+     * Gets the required data from the projects.
+     *
+     * @return array
+     */
+    public function toArray(): array
+    {
+        $subprojects = [];
+        foreach ($this->_subprojects as $subproject) {
+            $subprojects[$subproject['title']] = [
+                'useEDC'            => $subproject['useEDC'],
+                'WindowDifference'  => $subproject['WindowDifference'],
+                'RecruitmentTarget' => $subproject['RecruitmentTarget']
+            ];
+        }
+        return ['Subprojects' => $subprojects];
+    }
+}
diff --git a/modules/api/static/schema-v0.0.4-dev.yml b/modules/api/static/schema-v0.0.4-dev.yml
new file mode 100644
index 00000000000..54887f3e70e
--- /dev/null
+++ b/modules/api/static/schema-v0.0.4-dev.yml
@@ -0,0 +1,157 @@
+openapi: 3.0.1
+info:
+  title: LORIS - REST API endpoints
+  description: The LORIS API uses standard HTTP error codes and the body of any response will either be empty or contain only a JSON object for any request.
+  contact:
+    name: LORIS Development Team
+    url: 'https://github.com/aces/loris'
+  license:
+    name: 'GNU Public License, Version 3'
+    url: 'https://opensource.org/licenses/GPL-3.0'
+  version: 0.0.4-dev
+servers:
+  - url: /api/v0.0.4-dev
+security:
+  - ApiKeyAuth: []
+paths:
+  '/projects/{project}':
+    get:
+      tags:
+        - Projects
+      summary: Get that project descriptor
+      parameters:
+        - name: project
+          in: path
+          description: The project name
+          required: true
+          style: simple
+          explode: false
+          schema:
+            type: string
+      responses:
+        '200':
+          description: An object containing the project descriptor
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Project'
+  '/projects/{project}/subprojects':
+    get:
+      tags:
+        - Projects
+      summary: List all subprojects of that project
+      parameters:
+        - name: project
+          in: path
+          description: The project name
+          required: true
+          style: simple
+          explode: false
+          schema:
+            type: string
+      responses:
+        '200':
+          description: An object containing the list of instrument summary descriptors
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ProjectSubprojects'
+  '/projects/{project}/subprojects/{subproject}':
+    get:
+      tags:
+        - Projects
+      summary: Get a subproject descriptor in that project
+      parameters:
+        - name: project
+          in: path
+          description: The project name
+          required: true
+          style: simple
+          explode: false
+          schema:
+            type: string
+        - name: subproject
+          in: path
+          description: The subproject title
+          required: true
+          style: simple
+          explode: false
+          schema:
+            type: string
+      responses:
+        '200':
+          description: An JSON representation of the subproject
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ProjectSubproject'
+components:
+  schemas:
+    Project:
+      type: object
+      properties:
+        Id:
+          type: string
+        Name:
+          type: string
+        Alias:
+          type: string
+        RecruitementTarget:
+          type: integer
+        Links:
+          type: object
+          properties:
+            Candidates:
+              type: string
+            Instruments:
+              type: string
+            Subprojects:
+              type: string
+    ProjectSubprojects:
+      type: object
+      properties:
+        Subprojects:
+          type: array
+          items:
+            $ref: '#/components/schemas/Subproject'
+    Subproject:
+      type: object
+      properties:
+        SubprojectID:
+          type: string
+        Title:
+          type: string
+        UseEDC:
+          type: boolean
+        WindowDifference:
+          type: string
+        RecruitmentTarget:
+          type: integer
+    ProjectSubproject:
+      type: object
+      properties:
+        SubprojectID:
+          type: string
+        Title:
+          type: string
+        UseEDC:
+          type: boolean
+        WindowDifference:
+          type: string
+          enum:
+            - 'optimal'
+            - 'battery'
+        RecruitmentTarget:
+          type: integer
+        Visits:
+          type: array
+          items:
+            type: object
+            properties:
+              VisitLabel:
+                type: string
+  securitySchemes:
+    ApiKeyAuth:
+      type: apiKey
+      name: Authorization
+      in: header
diff --git a/php/libraries/Project.class.inc b/php/libraries/Project.class.inc
index b030a18b8d9..b5365ba8c3f 100644
--- a/php/libraries/Project.class.inc
+++ b/php/libraries/Project.class.inc
@@ -12,6 +12,7 @@
  * @link     https://www.github.com/aces/Loris/
  */
 
+use \LORIS\StudyEntities\AccessibleResource;
 /**
  * The Project class encapsulates all details of a project.
  *
@@ -21,7 +22,7 @@
  * @license  http://www.gnu.org/licenses/gpl-3.0.txt GPLv3
  * @link     https://www.github.com/aces/Loris/
  */
-class Project implements \JsonSerializable
+class Project implements \JsonSerializable, AccessibleResource
 {
     private static $_instances = [];
 
@@ -383,6 +384,42 @@ class Project implements \JsonSerializable
         return $subProjectData;
     }
 
+    /**
+     * Get a specific subproject associated with this project.
+     *
+     * @param string $title The subproject title
+     *
+     * @return \Subproject
+     */
+    public function getSubproject(string $title): \Subproject
+    {
+        $filtered = array_filter(
+            $this->getSubprojects(),
+            function ($subproject) use ($title) {
+                return $subproject['title'] == $title;
+            }
+        );
+
+        if (empty($filtered)) {
+            throw new \NotFound('There is no matching subproject title');
+        }
+
+        if (count($filtered) > 1) {
+            throw new \LorisException('Multiple subprojects with the same title');
+        }
+
+        $subproject = array_shift($filtered);
+
+        return new \Subproject(
+            $subproject['subprojectId'],
+            $this->_projectId,
+            $subproject['title'],
+            $subproject['useEDC'],
+            $subproject['windowDifference'],
+            $subproject['recruitmentTarget']
+        );
+    }
+
     /**
      * Get that project's participants
      *
@@ -470,4 +507,18 @@ class Project implements \JsonSerializable
     {
         return $this->_projectName;
     }
+
+    /**
+     * Implements the AccessibleResource interface. A candidate can
+     * be accessed by a user if it shares the same registration project
+     * and site or it has access to any of the timepoints.
+     *
+     * @param \User $user The user whose access should be validated.
+     *
+     * @return bool
+     */
+    public function isAccessibleBy(\User $user): bool
+    {
+        return in_array($this->_projectId, $user->getProjectIDs());
+    }
 }
diff --git a/php/libraries/Subproject.class.inc b/php/libraries/Subproject.class.inc
new file mode 100644
index 00000000000..077e8190e16
--- /dev/null
+++ b/php/libraries/Subproject.class.inc
@@ -0,0 +1,111 @@
+<?php declare(strict_types=1);
+/**
+ * This file contains a class which encapsulates the concept of a "Subproject"
+ * in LORIS.
+ *
+ * PHP Version 7
+ *
+ * @category Main
+ * @package  Loris
+ * @author   Xavier Lecours Boucher <xavier.lecours@mcin.ca>
+ * @license  http://www.gnu.org/licenses/gpl-3.0.txt GPLv3
+ * @link     https://www.github.com/aces/Loris/
+ */
+
+/**
+ * The Project class encapsulates all details of a project.
+ *
+ * @category Main
+ * @package  Loris
+ * @author   Xavier Lecours Boucher <xavier.lecours@mcin.ca>
+ * @license  http://www.gnu.org/licenses/gpl-3.0.txt GPLv3
+ * @link     https://www.github.com/aces/Loris/
+ */
+class Subproject implements \JsonSerializable
+{
+    private $_subproject_id;
+    private $_project_id;
+    private $_title;
+    private $_useEDC;
+    private $_windowDifference;
+    private $_recruitmentTarget;
+
+    /**
+     * Contructor
+     *
+     * @param string     $id                The subproject id
+     * @param \ProjectID $project_id        the associated project id
+     * @param string     $title             This title
+     * @param ?string    $useEDC            useEDC Either "0", "1" or null
+     * @param ?string    $windowDifference  Value from the database
+     * @param ?string    $recruitmentTarget A numeric string or null
+     */
+    public function __construct(
+        string $id,
+        \ProjectID $project_id,
+        string $title,
+        ?string $useEDC = null,
+        ?string $windowDifference = null,
+        ?string $recruitmentTarget = null
+    ) {
+        $this->_subproject_id = $id;
+        $this->_project_id    = $project_id;
+        $this->_title         = $title;
+        if (!is_null($useEDC)) {
+            $this->_useEDC = boolval($useEDC);
+        }
+        $this->_windowDifference = $windowDifference;
+        if (!is_null($recruitmentTarget)) {
+            $this->_recruitmentTarget = intval($recruitmentTarget);
+        }
+    }
+
+    /**
+     * Gets the visit label for that subproject
+     *
+     * @return array An array of string
+     */
+    public function getVisits(): array
+    {
+        $factory    = \NDB_Factory::singleton();
+        $visitsData = $factory->database()->pselect(
+            "
+             SELECT
+               v.VisitName visit_label
+             FROM visit v
+             LEFT JOIN visit_project_subproject_rel vpsr
+               ON (v.VisitID = vpsr.VisitID)
+             LEFT JOIN project_subproject_rel psr
+               ON (vpsr.ProjectSubprojectRelID = psr.ProjectSubprojectRelID)
+             WHERE
+               psr.SubprojectID = :v_subproject_id AND
+               psr.ProjectID = :v_project_id
+            ",
+            [
+                'v_subproject_id' => $this->_subproject_id,
+                'v_project_id'    => $this->_project_id
+            ]
+        );
+
+        return $visitsData;
+    }
+
+    /**
+     * Specify data which should be serialized to JSON.
+     * Returns data which can be serialized by json_encode(), which is a value of
+     * any type other than a resource.
+     *
+     * @see    https://www.php.net/manual/en/jsonserializable.jsonserialize.php
+     * @return mixed
+     */
+    public function jsonSerialize()
+    {
+        return [
+            "SubprojectID"       => $this->_subproject_id,
+            "Title"              => $this->_title,
+            "UseEDC"             => $this->_useEDC,
+            "WindowDifference"   => $this->_windowDifference,
+            "RecruitementTarget" => $this->_recruitmentTarget
+        ];
+    }
+}