diff --git a/packages/bbob-core/README.md b/packages/bbob-core/README.md
index 1272302..276b6d0 100644
--- a/packages/bbob-core/README.md
+++ b/packages/bbob-core/README.md
@@ -1,4 +1,4 @@
-# bbob
+# @bbob/core
 
 ## Usage
 
@@ -7,5 +7,7 @@ const bbob = require('@bbob/core');
 const presetHTML5 = require('@bbob/preset-html5');
 const code = `[i]Text[/i]`;
 
-const processor = bbob([presetHTML5]).process(code, {sync: true}).html
+const html = bbob([presetHTML5()]).process(code).html;
+
+console.log(html); // <span style="font-style: italic;">Text</span>
 ```
diff --git a/packages/bbob-core/lib/index.js b/packages/bbob-core/lib/index.js
index cb71e68..d870286 100644
--- a/packages/bbob-core/lib/index.js
+++ b/packages/bbob-core/lib/index.js
@@ -1,21 +1,44 @@
-class BBob {
-  constructor(plugins) {
-    this.plugins = plugins;
-  }
+const parser = require('@bbob/parser');
+const render = require('@bbob/html');
 
-  // parse() {
-  //
-  // }
-  //
-  // stringify() {
-  //
-  // }
-  //
-  // process(input) {
-  //
-  // }
+const { iterate, match } = require('./utils');
+
+function walk(cb) {
+  return iterate(this, cb);
 }
 
-module.exports = function bbob(...plugins) {
-  return new BBob(plugins);
+module.exports = function bbob(plugs) {
+  const plugins = typeof plugs === 'function' ? [plugs] : plugs || [];
+
+  let options = {
+    skipParse: false,
+  };
+
+  return {
+    process(input, opts) {
+      options = opts || {};
+
+      const parseFn = options.parser || parser;
+      const renderFn = options.render || render;
+
+      let tree = options.skipParse
+        ? input || []
+        : parseFn(input, options);
+
+      tree.walk = walk;
+      tree.match = match;
+
+      plugins.forEach((plugin) => {
+        tree = plugin(tree) || tree;
+      });
+
+      return {
+        get html() {
+          return renderFn(tree, tree.options);
+        },
+        tree,
+        messages: tree.messages,
+      };
+    },
+  };
 };
diff --git a/packages/bbob-core/lib/utils.js b/packages/bbob-core/lib/utils.js
new file mode 100644
index 0000000..89fac36
--- /dev/null
+++ b/packages/bbob-core/lib/utils.js
@@ -0,0 +1,65 @@
+/* eslint-disable no-plusplus */
+const isObj = value => (typeof value === 'object');
+const isBool = value => (typeof value === 'boolean');
+
+function iterate(t, cb) {
+  const tree = t;
+
+  if (Array.isArray(tree)) {
+    for (let idx = 0; idx < tree.length; idx++) {
+      tree[idx] = iterate(cb(tree[idx]), cb);
+    }
+  } else if (tree && isObj(tree) && tree.content) {
+    iterate(tree.content, cb);
+  }
+
+  return tree;
+}
+
+function same(expected, actual) {
+  if (typeof expected !== typeof actual) {
+    return false;
+  }
+
+  if (!isObj(expected) || expected === null) {
+    return expected === actual;
+  }
+
+  if (Array.isArray(expected)) {
+    return expected.every(exp => [].some.call(actual, act => same(exp, act)));
+  }
+
+  return Object.keys(expected).every((key) => {
+    const ao = actual[key];
+    const eo = expected[key];
+
+    if (isObj(eo) && eo !== null && ao !== null) {
+      return same(eo, ao);
+    }
+
+    if (isBool(eo)) {
+      return eo !== (ao === null);
+    }
+
+    return ao === eo;
+  });
+}
+
+function match(expression, cb) {
+  return Array.isArray(expression)
+    ? iterate(this, (node) => {
+      for (let idx = 0; idx < expression.length; idx++) {
+        if (same(expression[idx], node)) {
+          return cb(node);
+        }
+      }
+
+      return node;
+    })
+    : iterate(this, node => (same(expression, node) ? cb(node) : node));
+}
+
+module.exports = {
+  iterate,
+  match,
+};
diff --git a/packages/bbob-core/test/index.test.js b/packages/bbob-core/test/index.test.js
index 832aa75..060a5f6 100644
--- a/packages/bbob-core/test/index.test.js
+++ b/packages/bbob-core/test/index.test.js
@@ -1,5 +1,99 @@
+const core = require('../lib');
+
+const stringify = val => JSON.stringify(val);
+
 describe('@bbob/core', () => {
-  test('1', () => {
-    expect(1).toBe(1);
+  test('parse bbcode string to ast and html', () => {
+    const res = core().process('[style size="15px"]Large Text[/style]');
+    const ast = res.tree;
+
+    expect(res.html).toBe(`<style size="15px">Large Text</style>`);
+    expect(ast).toBeInstanceOf(Array);
+    expect(stringify(ast)).toEqual(stringify([
+      {
+        tag: 'style',
+        attrs: { size: '15px' },
+        content: ["Large", " ", "Text"]
+      }
+    ]))
   });
+
+  test('plugin walk api', () => {
+    const testPlugin = () => (tree) => tree.walk(node => {
+      if (node.tag === 'mytag') {
+        node.attrs = {
+          pass: 1
+        };
+
+        node.content.push('Test');
+      }
+
+      return node
+    });
+
+    const res = core([testPlugin()]).process('[mytag size="15px"]Large Text[/mytag]');
+    const ast = res.tree;
+
+    expect(ast).toBeInstanceOf(Array);
+    expect(ast.walk).toBeInstanceOf(Function);
+    expect(stringify(ast)).toEqual(stringify([
+      {
+        tag: 'mytag',
+        attrs: {
+          pass: 1
+        },
+        content: [
+          'Large',
+          ' ',
+          'Text',
+          'Test'
+        ]
+      }
+    ]));
+  });
+
+  test('plugin match api', () => {
+    const testPlugin = () => (tree) => tree.match([{ tag: 'mytag1' }, { tag: 'mytag2' }], node => {
+      if (node.attrs) {
+        node.attrs['pass'] = 1
+      }
+
+      return node
+    });
+
+    const res = core([testPlugin()]).process(`[mytag1 size="15"]Tag1[/mytag1][mytag2 size="16"]Tag2[/mytag2][mytag3]Tag3[/mytag3]`);
+    const ast = res.tree;
+
+    expect(ast).toBeInstanceOf(Array);
+    expect(ast.walk).toBeInstanceOf(Function);
+    expect(stringify(ast)).toEqual(stringify([
+      {
+        tag: 'mytag1',
+        attrs: {
+          size: '15',
+          pass: 1
+        },
+        content: [
+          'Tag1'
+        ]
+      },
+      {
+        tag: 'mytag2',
+        attrs: {
+          size: '16',
+          pass: 1
+        },
+        content: [
+          'Tag2'
+        ]
+      },
+      {
+        tag: 'mytag3',
+        attrs: {},
+        content: [
+          'Tag3'
+        ]
+      }
+    ]));
+  })
 });
diff --git a/packages/bbob-core/test/utils.test.js b/packages/bbob-core/test/utils.test.js
new file mode 100644
index 0000000..e57c21d
--- /dev/null
+++ b/packages/bbob-core/test/utils.test.js
@@ -0,0 +1,29 @@
+const { iterate } = require('../lib/utils');
+
+describe('@bbob/core utils', () => {
+  test('iterate', () => {
+    const testArr = [{
+      one: true,
+      content: [{ oneInside: true }]
+    }, {
+      two: true,
+      content: [{ twoInside: true }]
+    }];
+
+    const resultArr = iterate(testArr, node => {
+      node.pass = 1;
+
+      return node;
+    });
+
+    expect(resultArr).toEqual([{
+      one: true,
+      pass: 1,
+      content: [{ oneInside: true, pass: 1, }]
+    }, {
+      two: true,
+      pass: 1,
+      content: [{ twoInside: true, pass: 1, }]
+    }]);
+  });
+});