diff --git a/application/api/ApiUtils.php b/application/api/ApiUtils.php
index b8155a3..f154bb5 100644
--- a/application/api/ApiUtils.php
+++ b/application/api/ApiUtils.php
@@ -108,4 +108,30 @@ class ApiUtils
         ];
         return $link;
     }
+
+    /**
+     * Update link fields using an updated link object.
+     *
+     * @param array $oldLink data
+     * @param array $newLink data
+     *
+     * @return array $oldLink updated with $newLink values
+     */
+    public static function updateLink($oldLink, $newLink)
+    {
+        foreach (['title', 'url', 'description', 'tags', 'private'] as $field) {
+            $oldLink[$field] = $newLink[$field];
+        }
+        $oldLink['updated'] = new \DateTime();
+
+        if (empty($oldLink['url'])) {
+            $oldLink['url'] = '?' . $oldLink['shorturl'];
+        }
+
+        if (empty($oldLink['title'])) {
+            $oldLink['title'] = $oldLink['url'];
+        }
+
+        return $oldLink;
+    }
 }
diff --git a/application/api/controllers/Links.php b/application/api/controllers/Links.php
index 0db10fd..1c68b06 100644
--- a/application/api/controllers/Links.php
+++ b/application/api/controllers/Links.php
@@ -146,4 +146,46 @@ class Links extends ApiController
         return $response->withAddedHeader('Location', $redirect)
                         ->withJson($out, 201, $this->jsonStyle);
     }
+
+    /**
+     * Updates an existing link from posted request body.
+     *
+     * @param Request  $request  Slim request.
+     * @param Response $response Slim response.
+     * @param array    $args     Path parameters. including the ID.
+     *
+     * @return Response response.
+     *
+     * @throws ApiLinkNotFoundException generating a 404 error.
+     */
+    public function putLink($request, $response, $args)
+    {
+        if (! isset($this->linkDb[$args['id']])) {
+            throw new ApiLinkNotFoundException();
+        }
+
+        $index = index_url($this->ci['environment']);
+        $data = $request->getParsedBody();
+
+        $requestLink = ApiUtils::buildLinkFromRequest($data, $this->conf->get('privacy.default_private_links'));
+        // duplicate URL on a different link, return 409 Conflict
+        if (! empty($requestLink['url'])
+            && ! empty($dup = $this->linkDb->getLinkFromUrl($requestLink['url']))
+            && $dup['id'] != $args['id']
+        ) {
+            return $response->withJson(
+                ApiUtils::formatLink($dup, $index),
+                409,
+                $this->jsonStyle
+            );
+        }
+
+        $responseLink = $this->linkDb[$args['id']];
+        $responseLink = ApiUtils::updateLink($responseLink, $requestLink);
+        $this->linkDb[$responseLink['id']] = $responseLink;
+        $this->linkDb->save($this->conf->get('resource.page_cache'));
+
+        $out = ApiUtils::formatLink($responseLink, $index);
+        return $response->withJson($out, 200, $this->jsonStyle);
+    }
 }
diff --git a/index.php b/index.php
index 76aa1ae..b8d2005 100644
--- a/index.php
+++ b/index.php
@@ -2251,6 +2251,7 @@ $app->group('/api/v1', function() {
     $this->get('/links', '\Shaarli\Api\Controllers\Links:getLinks')->setName('getLinks');
     $this->get('/links/{id:[\d]+}', '\Shaarli\Api\Controllers\Links:getLink')->setName('getLink');
     $this->post('/links', '\Shaarli\Api\Controllers\Links:postLink')->setName('postLink');
+    $this->put('/links/{id:[\d]+}', '\Shaarli\Api\Controllers\Links:putLink')->setName('putLink');
 })->add('\Shaarli\Api\ApiMiddleware');
 
 $response = $app->run(true);
diff --git a/tests/api/ApiUtilsTest.php b/tests/api/ApiUtilsTest.php
index b4431d1..62baf4c 100644
--- a/tests/api/ApiUtilsTest.php
+++ b/tests/api/ApiUtilsTest.php
@@ -271,4 +271,82 @@ class ApiUtilsTest extends \PHPUnit_Framework_TestCase
 
         $this->assertEquals($expected, ApiUtils::formatLink($link, $indexUrl));
     }
+
+    /**
+     * Test updateLink with valid data, and also unnecessary fields.
+     */
+    public function testUpdateLink()
+    {
+        $created = \DateTime::createFromFormat('Ymd_His', '20170107_160102');
+        $old = [
+            'id' => 12,
+            'url' => '?abc',
+            'shorturl' => 'abc',
+            'title' => 'Note',
+            'description' => '',
+            'tags' => '',
+            'private' => '',
+            'created' => $created,
+        ];
+
+        $new = [
+            'id' => 13,
+            'shorturl' => 'nope',
+            'url' => 'http://somewhere.else',
+            'title' => 'Le Cid',
+            'description' => 'Percé jusques au fond du cœur [...]',
+            'tags' => 'corneille rodrigue',
+            'private' => true,
+            'created' => 'creation',
+            'updated' => 'updation',
+        ];
+
+        $result = ApiUtils::updateLink($old, $new);
+        $this->assertEquals(12, $result['id']);
+        $this->assertEquals('http://somewhere.else', $result['url']);
+        $this->assertEquals('abc', $result['shorturl']);
+        $this->assertEquals('Le Cid', $result['title']);
+        $this->assertEquals('Percé jusques au fond du cœur [...]', $result['description']);
+        $this->assertEquals('corneille rodrigue', $result['tags']);
+        $this->assertEquals(true, $result['private']);
+        $this->assertEquals($created, $result['created']);
+        $this->assertTrue(new \DateTime('5 seconds ago') < $result['updated']);
+    }
+
+    /**
+     * Test updateLink with minimal data.
+     */
+    public function testUpdateLinkMinimal()
+    {
+        $created = \DateTime::createFromFormat('Ymd_His', '20170107_160102');
+        $old = [
+            'id' => 12,
+            'url' => '?abc',
+            'shorturl' => 'abc',
+            'title' => 'Note',
+            'description' => 'Interesting description!',
+            'tags' => 'doggo',
+            'private' => true,
+            'created' => $created,
+        ];
+
+        $new = [
+            'url' => '',
+            'title' => '',
+            'description' => '',
+            'tags' => '',
+            'private' => false,
+        ];
+
+        $result = ApiUtils::updateLink($old, $new);
+        $this->assertEquals(12, $result['id']);
+        $this->assertEquals('?abc', $result['url']);
+        $this->assertEquals('abc', $result['shorturl']);
+        $this->assertEquals('?abc', $result['title']);
+        $this->assertEquals('', $result['description']);
+        $this->assertEquals('', $result['tags']);
+        $this->assertEquals(false, $result['private']);
+        $this->assertEquals($created, $result['created']);
+        $this->assertTrue(new \DateTime('5 seconds ago') < $result['updated']);
+    }
 }
diff --git a/tests/api/controllers/PutLinkTest.php b/tests/api/controllers/PutLinkTest.php
new file mode 100644
index 0000000..4096c1a
--- /dev/null
+++ b/tests/api/controllers/PutLinkTest.php
@@ -0,0 +1,199 @@
+<?php
+
+
+namespace Shaarli\Api\Controllers;
+
+
+use Shaarli\Config\ConfigManager;
+use Slim\Container;
+use Slim\Http\Environment;
+use Slim\Http\Request;
+use Slim\Http\Response;
+
+class PutLinkTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @var string datastore to test write operations
+     */
+    protected static $testDatastore = 'sandbox/datastore.php';
+
+    /**
+     * @var ConfigManager instance
+     */
+    protected $conf;
+
+    /**
+     * @var \ReferenceLinkDB instance.
+     */
+    protected $refDB = null;
+
+    /**
+     * @var Container instance.
+     */
+    protected $container;
+
+    /**
+     * @var Links controller instance.
+     */
+    protected $controller;
+
+    /**
+     * Number of JSON field per link.
+     */
+    const NB_FIELDS_LINK = 9;
+
+    /**
+     * Before every test, instantiate a new Api with its config, plugins and links.
+     */
+    public function setUp()
+    {
+        $this->conf = new ConfigManager('tests/utils/config/configJson.json.php');
+        $this->refDB = new \ReferenceLinkDB();
+        $this->refDB->write(self::$testDatastore);
+
+        $this->container = new Container();
+        $this->container['conf'] = $this->conf;
+        $this->container['db'] = new \LinkDB(self::$testDatastore, true, false);
+
+        $this->controller = new Links($this->container);
+
+        // Used by index_url().
+        $this->controller->getCi()['environment'] = [
+            'SERVER_NAME' => 'domain.tld',
+            'SERVER_PORT' => 80,
+            'SCRIPT_NAME' => '/',
+        ];
+    }
+
+    /**
+     * After every test, remove the test datastore.
+     */
+    public function tearDown()
+    {
+        @unlink(self::$testDatastore);
+    }
+
+    /**
+     * Test link update without value: reset the link to default values
+     */
+    public function testPutLinkMinimal()
+    {
+        $env = Environment::mock([
+            'REQUEST_METHOD' => 'PUT',
+        ]);
+        $id = '41';
+        $request = Request::createFromEnvironment($env);
+
+        $response = $this->controller->putLink($request, new Response(), ['id' => $id]);
+        $this->assertEquals(200, $response->getStatusCode());
+        $data = json_decode((string) $response->getBody(), true);
+        $this->assertEquals(self::NB_FIELDS_LINK, count($data));
+        $this->assertEquals($id, $data['id']);
+        $this->assertEquals('WDWyig', $data['shorturl']);
+        $this->assertEquals('http://domain.tld/?WDWyig', $data['url']);
+        $this->assertEquals('?WDWyig', $data['title']);
+        $this->assertEquals('', $data['description']);
+        $this->assertEquals([], $data['tags']);
+        $this->assertEquals(false, $data['private']);
+        $this->assertEquals(
+            \DateTime::createFromFormat('Ymd_His', '20150310_114651'),
+            \DateTime::createFromFormat(\DateTime::ATOM, $data['created'])
+        );
+        $this->assertTrue(new \DateTime('5 seconds ago') < \DateTime::createFromFormat(\DateTime::ATOM, $data['updated']));
+    }
+
+    /**
+     * Test link update with new values
+     */
+    public function testPutLinkWithValues()
+    {
+        $env = Environment::mock([
+            'REQUEST_METHOD' => 'PUT',
+            'CONTENT_TYPE' => 'application/json'
+        ]);
+        $id = 41;
+        $update = [
+            'url' => 'http://somewhere.else',
+            'title' => 'Le Cid',
+            'description' => 'Percé jusques au fond du cœur [...]',
+            'tags' => ['corneille', 'rodrigue'],
+            'private' => true,
+        ];
+        $request = Request::createFromEnvironment($env);
+        $request = $request->withParsedBody($update);
+
+        $response = $this->controller->putLink($request, new Response(), ['id' => $id]);
+        $this->assertEquals(200, $response->getStatusCode());
+        $data = json_decode((string) $response->getBody(), true);
+        $this->assertEquals(self::NB_FIELDS_LINK, count($data));
+        $this->assertEquals($id, $data['id']);
+        $this->assertEquals('WDWyig', $data['shorturl']);
+        $this->assertEquals('http://somewhere.else', $data['url']);
+        $this->assertEquals('Le Cid', $data['title']);
+        $this->assertEquals('Percé jusques au fond du cœur [...]', $data['description']);
+        $this->assertEquals(['corneille', 'rodrigue'], $data['tags']);
+        $this->assertEquals(true, $data['private']);
+        $this->assertEquals(
+            \DateTime::createFromFormat('Ymd_His', '20150310_114651'),
+            \DateTime::createFromFormat(\DateTime::ATOM, $data['created'])
+        );
+        $this->assertTrue(new \DateTime('5 seconds ago') < \DateTime::createFromFormat(\DateTime::ATOM, $data['updated']));
+    }
+
+    /**
+     * Test link update with an existing URL: 409 Conflict with the existing link as body
+     */
+    public function testPutLinkDuplicate()
+    {
+        $link = [
+            'url' => 'mediagoblin.org/',
+            'title' => 'new entry',
+            'description' => 'shaare description',
+            'tags' => ['one', 'two'],
+            'private' => true,
+        ];
+        $env = Environment::mock([
+            'REQUEST_METHOD' => 'PUT',
+            'CONTENT_TYPE' => 'application/json'
+        ]);
+
+        $request = Request::createFromEnvironment($env);
+        $request = $request->withParsedBody($link);
+        $response = $this->controller->putLink($request, new Response(), ['id' => 41]);
+
+        $this->assertEquals(409, $response->getStatusCode());
+        $data = json_decode((string) $response->getBody(), true);
+        $this->assertEquals(self::NB_FIELDS_LINK, count($data));
+        $this->assertEquals(7, $data['id']);
+        $this->assertEquals('IuWvgA', $data['shorturl']);
+        $this->assertEquals('http://mediagoblin.org/', $data['url']);
+        $this->assertEquals('MediaGoblin', $data['title']);
+        $this->assertEquals('A free software media publishing platform #hashtagOther', $data['description']);
+        $this->assertEquals(['gnu', 'media', 'web', '.hidden', 'hashtag'], $data['tags']);
+        $this->assertEquals(false, $data['private']);
+        $this->assertEquals(
+            \DateTime::createFromFormat(\LinkDB::LINK_DATE_FORMAT, '20130614_184135'),
+            \DateTime::createFromFormat(\DateTime::ATOM, $data['created'])
+        );
+        $this->assertEquals(
+            \DateTime::createFromFormat(\LinkDB::LINK_DATE_FORMAT, '20130615_184230'),
+            \DateTime::createFromFormat(\DateTime::ATOM, $data['updated'])
+        );
+    }
+
+    /**
+     * Test link update on non existent link => ApiLinkNotFoundException.
+     *
+     * @expectedException Shaarli\Api\Exceptions\ApiLinkNotFoundException
+     * @expectedExceptionMessage Link not found
+     */
+    public function testGetLink404()
+    {
+        $env = Environment::mock([
+            'REQUEST_METHOD' => 'PUT',
+        ]);
+        $request = Request::createFromEnvironment($env);
+
+        $this->controller->putLink($request, new Response(), ['id' => -1]);
+    }
+}