diff --git a/hooks.md b/hooks.md
new file mode 100644
index 0000000..257b787
--- /dev/null
+++ b/hooks.md
@@ -0,0 +1,33 @@
+# apiDoc Hooks
+
+
+## parser-find-elements
+
+Called on each found element. Returns a new list of elements (replace elements).
+Used to inject annotationes from an external schema.
+
+Parameter: `(elements, element, block, filename)`
+ * {array}  elements Found elements in a block without the current element.
+ * {array}  element  Contains the source, name (lowercase), sourceName (original), content.
+ * {string} block    Current source block.
+ * {string} filename Current filename.
+
+File: `parser.js`
+Function: `_findElements`
+
+
+
+## parser-find-element-{name}
+
+Called on each found element and returns the modified element.
+Used to modify a specific element.
+
+{name} is the found element.name (lowercase).
+
+Parameter: `(element, block, filename)`
+ * {array}  element  Contains the source, name (lowercase), sourceName (original), content.
+ * {string} block    Current source block.
+ * {string} filename Current filename.
+
+File: `parser.js`
+Function: `_findElements`
diff --git a/lib/filter.js b/lib/filter.js
index c55ff03..a861b70 100644
--- a/lib/filter.js
+++ b/lib/filter.js
@@ -21,9 +21,14 @@ function Filter(_app) {
     // load filters
     var filters = Object.keys(app.filters);
     filters.forEach(function(filter) {
-        var filename = app.filters[filter];
-        app.log.debug('load filter: ' + filter + ', ' + filename);
-        self.addFilter(filter, require(filename));
+        if (_.isObject( app.filters[filter] )) {
+            app.log.debug('inject filter: ' + parser);
+            self.addFilter(worker, app.filters[filter] );
+        } else {
+            var filename = app.filters[filter];
+            app.log.debug('load filter: ' + filter + ', ' + filename);
+            self.addFilter(filter, require(filename));
+        }
     });
 }
 
diff --git a/lib/index.js b/lib/index.js
index 16f8860..a154281 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -9,6 +9,8 @@ var Filter = require('./filter');
 var Parser = require('./parser');
 var Worker = require('./worker');
 
+var PluginLoader = require('./plugin_loader');
+
 var FileError      = require('./errors/file_error');
 var ParserError    = require('./errors/parser_error');
 var WorkerError    = require('./errors/worker_error');
@@ -90,7 +92,10 @@ var app = {
         apisuccessstructure      : './workers/api_success_structure.js',
         apisuccesstitle          : './workers/api_success_title.js',
         apiuse                   : './workers/api_use.js'
-    }
+    },
+    hooks: {},
+    addHook: addHook,
+    hook: applyHook
 };
 
 var defaultGenerator = {
@@ -159,6 +164,7 @@ function parse(options) {
     app.languages = _.defaults({}, options.languages, app.languages);
     app.parsers   = _.defaults({}, options.parsers, app.parsers);
     app.workers   = _.defaults({}, options.workers, app.workers);
+    app.hooks     = _.defaults({}, options.hooks, app.hooks);
 
     // options
     app.options = options;
@@ -181,10 +187,17 @@ function parse(options) {
         app.log.verbose('apidoc-core version: '      + packageJson.version);
         app.log.verbose('apidoc-spec version: '      + getSpecificationVersion());
 
+        new PluginLoader(app);
+
         var parser = new Parser(app);
         var worker = new Worker(app);
         var filter = new Filter(app);
 
+        // Make them available for plugins
+        app.parser = parser;
+        app.worker = worker;
+        app.filter = filter;
+
         // if input option for source is an array of folders,
         // parse each folder in the order provided.
         app.log.verbose('run parser');
@@ -345,6 +358,55 @@ function setPackageInfos(packageInfos) {
     app.packageInfos = packageInfos;
 }
 
+/**
+ * Register a hook function.
+ *
+ * @param {String}   name           Name of the hook. Hook overview: https://github.com/apidoc/apidoc-core/hooks.md
+ * @param {Function} func           Callback function.
+ * @param {Integer}  [priority=100] Hook priority. Lower value will be executed first.
+ *                                  Same value overwrite a previously defined hook.
+ */
+function addHook(name, func, priority) {
+    priority = priority || 100;
+
+    if ( ! app.hooks[name])
+        app.hooks[name] = [];
+
+    app.log.debug('add hook: ' + name + ' [' + priority + ']');
+
+    // Find position and overwrite same priority
+    var replace = 0;
+    var pos = 0;
+    app.hooks[name].forEach( function(entry, index) {
+        if (priority === entry.priority) {
+            pos = index;
+            replace = 1;
+        } else if (priority > entry.priority) {
+            pos = index + 1;
+        }
+    });
+
+    app.hooks[name].splice(pos, replace, {
+        func: func,
+        priority: priority
+    });
+}
+
+/**
+ * Execute a hook.
+ */
+function applyHook(name /* , ...args */) {
+    if ( ! app.hooks[name])
+        return Array.prototype.slice.call(arguments, 1, 2)[0];
+
+    var args = Array.prototype.slice.call(arguments, 1);
+    app.hooks[name].forEach( function(hook) {
+        hook['func'].apply(this, args);
+    });
+    return args[0];
+}
+
+
 module.exports = {
     getSpecificationVersion: getSpecificationVersion,
     parse                  : parse,
diff --git a/lib/parser.js b/lib/parser.js
index 234e853..e0243b5 100644
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -27,17 +27,27 @@ function Parser(_app) {
     // load languages
     var languages = Object.keys(app.languages);
     languages.forEach(function(language) {
-        var filename = app.languages[language];
-        app.log.debug('load parser language: ' + language + ', ' + filename);
-        self.addLanguage(language, require(filename));
+        if (_.isObject( app.languages[language] )) {
+            app.log.debug('inject parser language: ' + language);
+            self.addLanguage(language, app.languages[language] );
+        } else {
+            var filename = app.languages[language];
+            app.log.debug('load parser language: ' + language + ', ' + filename);
+            self.addLanguage(language, require(filename));
+        }
     });
 
     // load parser
     var parsers = Object.keys(app.parsers);
     parsers.forEach(function(parser) {
-        var filename = app.parsers[parser];
-        app.log.debug('load parser: ' + parser + ', ' + filename);
-        self.addParser(parser, require(filename));
+        if (_.isObject( app.parsers[parser] )) {
+            app.log.debug('inject parser: ' + parser);
+            self.addParser(parser, app.parsers[parser] );
+        } else {
+            var filename = app.parsers[parser];
+            app.log.debug('load parser: ' + parser + ', ' + filename);
+            self.addParser(parser, require(filename));
+        }
     });
 }
 
@@ -127,7 +137,7 @@ Parser.prototype.parseFile = function(filename, encoding) {
 
     // determine elements in blocks
     self.elements = self.blocks.map(function(block, i) {
-        var elements = self._findElements(block);
+        var elements = self.findElements(block, filename);
         app.log.debug('count elements in block ' + i + ': ' + elements.length);
         return elements;
     });
@@ -420,7 +430,7 @@ Parser.prototype._findBlockWithApiGetIndex = function(blocks) {
 /**
  * Get Elements of Blocks
  */
-Parser.prototype._findElements = function(block) {
+Parser.prototype.findElements = function(block, filename) {
     var elements = [];
 
     // Replace Linebreak with Unicode
@@ -441,8 +451,12 @@ Parser.prototype._findElements = function(block) {
         element.content = element.content.replace(/\uffff/g, '\n');
         element.source = element.source.replace(/\uffff/g, '\n');
 
+        app.hook('parser-find-element-' + element.name, element, block, filename);
+
         elements.push(element);
 
+        app.hook('parser-find-elements', elements, element, block, filename);
+
         // next Match
         matches = elementsRegExp.exec(block);
     }
diff --git a/lib/plugin_loader.js b/lib/plugin_loader.js
new file mode 100644
index 0000000..e1bb6fb
--- /dev/null
+++ b/lib/plugin_loader.js
@@ -0,0 +1,92 @@
+var _    = require('lodash');
+var fs   = require('fs');
+var path = require('path');
+var util = require('util');
+var glob = require('glob');
+
+var app = {};
+
+function PluginLoader(_app) {
+    var self = this;
+
+    // global variables
+    app = _app;
+
+    // class variables
+    self.plugins = {};
+
+    // Try to load global apidoc-plugins (if apidoc is installed locally it tries only local)
+    this.detectPugins(__dirname);
+
+    // Try to load local apidoc-plugins
+    this.detectPugins( path.join(process.cwd(), '/node_modules') );
+
+    if (Object.keys(this.plugins).length === 0)
+        app.log.debug('No plugins found.');
+
+    this.loadPlugins();
+}
+/**
+ * Inherit
+ */
+util.inherits(PluginLoader, Object);
+
+/**
+ * Exports
+ */
+module.exports = PluginLoader;
+
+/**
+ * Detect modules start with "apidoc-plugin-".
+ * Search up to root until found a plugin.
+ */
+PluginLoader.prototype.detectPugins = function(dir) {
+    var self = this;
+
+    // Search from the given dir up to root.
+    // Every dir start with "apidoc-plugin-", because for the tests of apidoc-plugin-test.
+    var plugins = glob.sync(dir + '/apidoc-plugin-*');
+    if (plugins.length === 0) {
+        dir = path.join(dir, '..');
+        if (dir === '/')
+            return;
+        return this.detectPugins(dir);
+    }
+
+    var offset = dir.length + 1;
+    plugins.forEach( function(plugin) {
+        var name = plugin.substr(offset);
+        var filename = path.relative(__dirname, plugin);
+        app.log.debug('add plugin: ' + name + ', ' + filename);
+        self.addPlugin(name, plugin);
+    });
+};
+
+/**
+ * Add Plugin to plugin list.
+ */
+PluginLoader.prototype.addPlugin = function(name, filename) {
+    if (this.plugins[name])
+        app.log.debug('overwrite plugin: ' + name + ', ' + this.plugins[name]);
+
+    this.plugins[name] = filename;
+};
+
+/**
+ * Load and initialize Plugins.
+ */
+PluginLoader.prototype.loadPlugins = function() {
+    _.forEach(this.plugins, function(filename, name) {
+        app.log.debug('load plugin: ' + name + ', ' + filename);
+        var plugin;
+        try {
+            plugin = require(filename);
+        } catch(e) {
+        }
+        if (plugin && plugin.init) {
+            plugin.init(app);
+        } else {
+            app.log.debug('Ignored, no init function found.');
+        }
+    });
+};
diff --git a/lib/worker.js b/lib/worker.js
index f74c19e..cac372c 100644
--- a/lib/worker.js
+++ b/lib/worker.js
@@ -26,9 +26,14 @@ function Worker(_app) {
     // load worker
     var workers = Object.keys(app.workers);
     workers.forEach(function(worker) {
-        var filename = app.workers[worker];
-        app.log.debug('load worker: ' + worker + ', ' + filename);
-        self.addWorker(worker, require(filename));
+        if (_.isObject( app.workers[worker] )) {
+            app.log.debug('inject worker: ' + parser);
+            self.addWorker(worker, app.workers[worker] );
+        } else {
+            var filename = app.workers[worker];
+            app.log.debug('load worker: ' + worker + ', ' + filename);
+            self.addWorker(worker, require(filename));
+        }
     });
 }
 
diff --git a/package.json b/package.json
index 555daad..4cfecb9 100644
--- a/package.json
+++ b/package.json
@@ -33,6 +33,7 @@
     "node": ">= 0.10.0"
   },
   "dependencies": {
+    "glob": "^7.0.3",
     "iconv-lite": "^0.4.13",
     "lodash": "~4.5.0",
     "semver": "~5.1.0",