diff --git a/README.md b/README.md
index e520e7e..433a4b9 100644
--- a/README.md
+++ b/README.md
@@ -21,7 +21,9 @@ TODO: architecture
 
 ## API
 
-TODO: Swagger file
+Base API contract is stored in the [doc](/doc/contract.json) folder.
+You can see the UI in http://<ENDPOINT>:<PORT>/ and the live documentation in
+http://<ENDPOINT>:<PORT>/swagger.json tho.
 
 ## Run
 
@@ -31,6 +33,12 @@ $ FLASK_APP=src/app flask run
 $ python src/app.py
 ```
 
+```bash
+$ curl -X PUT http://<ENDPOINT>:<PORT>/search \
+      -H 'content-type: application/json' \
+      -d @'base.template.json'
+```
+
 ## Deploy
 
 The deployment is automated by the CI/CD pipeline but you can always run it in
diff --git a/base.template.json b/base.template.json
new file mode 100644
index 0000000..4f9fc5b
--- /dev/null
+++ b/base.template.json
@@ -0,0 +1,7 @@
+{
+  "query": {
+    "word": "fit",
+    "strict": true
+  },
+  "source": "https://www.virtusize.jp/"
+}
diff --git a/complex.template.json b/complex.template.json
new file mode 100644
index 0000000..5366978
--- /dev/null
+++ b/complex.template.json
@@ -0,0 +1,8 @@
+{
+  "query": {
+    "word": "fit",
+    "strict": false
+  },
+  "source": "https://www.virtusize.jp/"
+}
+
diff --git a/doc/contract.json b/doc/contract.json
new file mode 100644
index 0000000..a257563
--- /dev/null
+++ b/doc/contract.json
@@ -0,0 +1,122 @@
+{
+    "swagger": "2.0",
+    "basePath": "/",
+    "paths": {
+        "/health": {
+            "get": {
+                "responses": {
+                    "200": {
+                        "description": "Success"
+                    }
+                },
+                "operationId": "get_health",
+                "tags": [
+                    ""
+                ]
+            }
+        },
+        "/search": {
+            "put": {
+                "responses": {
+                    "200": {
+                        "description": "Success",
+                        "schema": {
+                            "$ref": "#/definitions/Word"
+                        }
+                    }
+                },
+                "operationId": "put_search",
+                "parameters": [
+                    {
+                        "name": "payload",
+                        "required": true,
+                        "in": "body",
+                        "schema": {
+                            "$ref": "#/definitions/Search"
+                        }
+                    },
+                    {
+                        "name": "X-Fields",
+                        "in": "header",
+                        "type": "string",
+                        "format": "mask",
+                        "description": "An optional fields mask"
+                    }
+                ],
+                "tags": [
+                    ""
+                ]
+            }
+        }
+    },
+    "info": {
+        "title": "Word search engine",
+        "version": "1.0",
+        "description": "The service will allow a user to search an specific word in an URL"
+    },
+    "produces": [
+        "application/json"
+    ],
+    "consumes": [
+        "application/json"
+    ],
+    "tags": [
+        {
+            "name": "",
+            "description": "Simple word search engine"
+        }
+    ],
+    "definitions": {
+        "Search": {
+            "properties": {
+                "query": {
+                    "$ref": "#/definitions/Query"
+                },
+                "source": {
+                    "type": "string"
+                }
+            },
+            "type": "object"
+        },
+        "Query": {
+            "properties": {
+                "word": {
+                    "type": "string"
+                },
+                "strict": {
+                    "type": "boolean",
+                    "default": true
+                }
+            },
+            "type": "object"
+        },
+        "Word": {
+            "properties": {
+                "__this": {
+                    "type": "string"
+                },
+                "query": {
+                    "$ref": "#/definitions/Query"
+                },
+                "source": {
+                    "type": "string"
+                },
+                "found": {
+                    "type": "boolean"
+                },
+                "count": {
+                    "type": "integer"
+                }
+            },
+            "type": "object"
+        }
+    },
+    "responses": {
+        "ParseError": {
+            "description": "When a mask can't be parsed"
+        },
+        "MaskError": {
+            "description": "When any error occurs on mask"
+        }
+    }
+}
diff --git a/environment.yml b/environment.yml
index 6ca3407..d836682 100644
--- a/environment.yml
+++ b/environment.yml
@@ -4,3 +4,4 @@ dependencies:
   - flask
   - pip:
     - flask-restplus
+    - prometheus-client
diff --git a/src/api/controller.py b/src/api/controller.py
index be06edc..a2ee963 100644
--- a/src/api/controller.py
+++ b/src/api/controller.py
@@ -3,11 +3,28 @@
 from flask_restplus import abort
 from flask import request
 
+from api.schema import response_schema
+from api.schema import request_schema
+from api.schema import query_schema
+
 
 ns = Namespace('', description='Simple word search engine')
 
+ns.add_model('Word', response_schema)
+ns.add_model('Query', query_schema)
+ns.add_model('Search', request_schema)
+
 
 @ns.route("/health")
 class Health(Resource):
     def get(self, **kwargs):
         return {"alive": True}
+
+
+@ns.route("/search")
+class Search(Resource):
+    @ns.doc(body=request_schema)
+    @ns.expect(request_schema)
+    @ns.marshal_with(response_schema, skip_none=True, code=200)
+    def put(self, **kwargs):
+        return {"strict": True}
diff --git a/src/api/model.py b/src/api/model.py
new file mode 100644
index 0000000..5d83974
--- /dev/null
+++ b/src/api/model.py
@@ -0,0 +1,4 @@
+class Search:
+    def __init__(self, **kwargs):
+        for key, value in kwargs.items():
+            setattr(self, key, value)
diff --git a/src/api/schema.py b/src/api/schema.py
new file mode 100644
index 0000000..8e77262
--- /dev/null
+++ b/src/api/schema.py
@@ -0,0 +1,21 @@
+from flask_restplus import fields
+from flask_restplus import Model
+
+
+query_schema = Model('Query', {
+    'word': fields.String,
+    'strict': fields.Boolean(default=True),
+})
+
+response_schema = Model('Word', {
+    '__this': fields.Url(absolute=True),
+    'query': fields.Nested(query_schema),
+    'source': fields.String,
+    'found': fields.Boolean,
+    'count': fields.Integer,
+})
+
+request_schema = Model('Search', {
+    'query': fields.Nested(query_schema),
+    'source': fields.String,
+})
diff --git a/src/api/utils/__init__.py b/src/api/utils/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/requirements.txt b/src/requirements.txt
index 99e5f4d..901a44d 100644
--- a/src/requirements.txt
+++ b/src/requirements.txt
@@ -3,3 +3,4 @@ get==1.0.3
 httplib2==0.11.3
 pytest==4.2.0
 flask-restplus==0.12.1
+prometheus-client==0.6.0