diff --git a/app/__init__.py b/app/__init__.py
index 7747cd6..68c20e1 100644
--- a/app/__init__.py
+++ b/app/__init__.py
@@ -1,5 +1,58 @@
 # retoor <retoor@molodetz.nl>
 
 from flask import Flask
+from flask import jsonify
+from flask import make_response
+from flask import request
+from flask.wrappers import Response
+
+from src.calculator import add
+from src.calculator import clamp
+from src.calculator import clamp_to_byte
+from src.calculator import subtract
 
 app = Flask(__name__)
+
+
+@app.route('/add', methods=['GET'])
+def add_route() -> Response:
+    try:
+        left = int(request.args['left'])
+        right = int(request.args['right'])
+    except (KeyError, TypeError, ValueError):
+        return make_response(jsonify({'error': 'Invalid or missing parameters'}), 400)
+    return make_response(jsonify({'result': add(left, right)}), 200)
+
+
+@app.route('/subtract', methods=['GET'])
+def subtract_route() -> Response:
+    try:
+        left = int(request.args['left'])
+        right = int(request.args['right'])
+    except (KeyError, TypeError, ValueError):
+        return make_response(jsonify({'error': 'Invalid or missing parameters'}), 400)
+    return make_response(jsonify({'result': subtract(left, right)}), 200)
+
+
+@app.route('/clamp', methods=['GET'])
+def clamp_route() -> Response:
+    try:
+        value = int(request.args['value'])
+        low = int(request.args['low'])
+        high = int(request.args['high'])
+    except (KeyError, TypeError, ValueError):
+        return make_response(jsonify({'error': 'Invalid or missing parameters'}), 400)
+    try:
+        result = clamp(value, low, high)
+    except ValueError:
+        return make_response(jsonify({'error': 'Invalid or missing parameters'}), 400)
+    return make_response(jsonify({'result': result}), 200)
+
+
+@app.route('/clamp_to_byte', methods=['GET'])
+def clamp_to_byte_route() -> Response:
+    try:
+        value = int(request.args['value'])
+    except (KeyError, TypeError, ValueError):
+        return make_response(jsonify({'error': 'Invalid or missing parameters'}), 400)
+    return make_response(jsonify({'result': clamp_to_byte(value)}), 200)