diff --git a/backend/app.py b/backend/app.py
index 951a1f9..1ffda7a 100644
--- a/backend/app.py
+++ b/backend/app.py
@@ -4,24 +4,36 @@
 import requests
 from flask import Flask, jsonify, request, abort
 from flask_cors import CORS
+from flasgger import Swagger, swag_from
 from datetime import datetime, UTC
 from embedding_description import main as classify_description
 from embedding_url import main as classify_url
 from aurora_api import main as aurora_classify
+from swagger_docs import (
+    SWAGGER_TEMPLATE,
+    HELLO_DOC,
+    CLASSIFY_AURORA_DOC,
+    CLASSIFY_ST_DESCRIPTION_DOC,
+    CLASSIFY_ST_URL_DOC,
+    OSDG_API_DOC,
+)
 
 
 app = Flask(__name__)
 CORS(app)
+swagger = Swagger(app, template=SWAGGER_TEMPLATE)
 
 
 
 @app.route('/api/hello', methods=['GET'])
+@swag_from(HELLO_DOC)
 def hello():
     return jsonify({'message': 'Hello, World!'})
 
 
 
 @app.route('/api/classify_aurora', methods=['POST'])
+@swag_from(CLASSIFY_AURORA_DOC)
 def classify_aurora():
     data = request.json
     projectName = data.get('projectName')
@@ -70,6 +82,7 @@ def classify_aurora():
 
 
 @app.route('/api/classify_st_description', methods=['POST'])
+@swag_from(CLASSIFY_ST_DESCRIPTION_DOC)
 def classify_st_description():
     data = request.json
     projectName = data.get('projectName')
@@ -113,6 +126,7 @@ def classify_st_description():
 
 
 @app.route('/api/classify_st_url', methods=['POST'])
+@swag_from(CLASSIFY_ST_URL_DOC)
 def classify_st_url():
     data = request.json
     projectName = data.get('projectName')
@@ -163,6 +177,7 @@ def classify_st_url():
         }), 200
 
 @app.route("/api/osdg_api", methods=["POST"])
+@swag_from(OSDG_API_DOC)
 def osdg_external_api():
     data = request.json
     projectName = data.get('projectName')
diff --git a/backend/requirements.txt b/backend/requirements.txt
index 4c8586c..e5c55b0 100644
--- a/backend/requirements.txt
+++ b/backend/requirements.txt
@@ -6,4 +6,5 @@ numpy
 accelerate
 flask
 flask-cors
-Flask-UUID
\ No newline at end of file
+Flask-UUID
+flasgger
\ No newline at end of file
diff --git a/backend/swagger_docs.py b/backend/swagger_docs.py
new file mode 100644
index 0000000..6ca802c
--- /dev/null
+++ b/backend/swagger_docs.py
@@ -0,0 +1,154 @@
+"""
+Swagger/OpenAPI docs definitions for Flask routes.
+Keeping specs here keeps app.py focused on request handling.
+"""
+
+SWAGGER_TEMPLATE = {
+    "swagger": "2.0",
+    "info": {
+        "title": "UNSDG Classifier API",
+        "description": "API docs for SDG classification routes.",
+        "version": "1.0.0",
+    },
+    "basePath": "/",
+    "schemes": ["http", "https"],
+}
+
+HELLO_DOC = {
+    "tags": ["Health"],
+    "responses": {
+        200: {
+            "description": "API is alive",
+            "schema": {
+                "type": "object",
+                "properties": {
+                    "message": {"type": "string", "example": "Hello, World!"}
+                },
+            },
+        }
+    },
+}
+
+CLASSIFY_AURORA_DOC = {
+    "tags": ["Classification"],
+    "parameters": [
+        {
+            "in": "body",
+            "name": "body",
+            "required": True,
+            "schema": {
+                "type": "object",
+                "required": ["projectDescription"],
+                "properties": {
+                    "projectName": {"type": "string", "example": "My Project"},
+                    "projectUrl": {
+                        "type": "string",
+                        "example": "https://github.com/org/repo",
+                    },
+                    "projectDescription": {
+                        "type": "string",
+                        "example": "AI tool for clean energy monitoring.",
+                    },
+                },
+            },
+        }
+    ],
+    "responses": {
+        200: {"description": "SDG predictions"},
+        400: {"description": "Missing projectDescription"},
+        500: {"description": "Classification failed"},
+    },
+}
+
+CLASSIFY_ST_DESCRIPTION_DOC = {
+    "tags": ["Classification"],
+    "parameters": [
+        {
+            "in": "body",
+            "name": "body",
+            "required": True,
+            "schema": {
+                "type": "object",
+                "required": ["projectDescription"],
+                "properties": {
+                    "projectName": {"type": "string", "example": "My Project"},
+                    "projectUrl": {
+                        "type": "string",
+                        "example": "https://github.com/org/repo",
+                    },
+                    "projectDescription": {
+                        "type": "string",
+                        "example": "Open source project for digital education.",
+                    },
+                },
+            },
+        }
+    ],
+    "responses": {
+        200: {"description": "SDG predictions"},
+        400: {"description": "Missing projectDescription"},
+        500: {"description": "Classification failed"},
+    },
+}
+
+CLASSIFY_ST_URL_DOC = {
+    "tags": ["Classification"],
+    "parameters": [
+        {
+            "in": "body",
+            "name": "body",
+            "required": True,
+            "schema": {
+                "type": "object",
+                "required": ["projectDescription", "projectUrl"],
+                "properties": {
+                    "projectName": {"type": "string", "example": "My Project"},
+                    "projectUrl": {
+                        "type": "string",
+                        "example": "https://github.com/org/repo",
+                    },
+                    "projectDescription": {
+                        "type": "string",
+                        "example": "Required by current route validation.",
+                    },
+                },
+            },
+        }
+    ],
+    "responses": {
+        200: {"description": "SDG predictions"},
+        400: {"description": "Invalid request or repository URL"},
+        500: {"description": "Classification failed"},
+    },
+}
+
+OSDG_API_DOC = {
+    "tags": ["External"],
+    "parameters": [
+        {
+            "in": "body",
+            "name": "body",
+            "required": True,
+            "schema": {
+                "type": "object",
+                "required": ["projectDescription"],
+                "properties": {
+                    "projectName": {"type": "string", "example": "My Project"},
+                    "projectUrl": {
+                        "type": "string",
+                        "example": "https://github.com/org/repo",
+                    },
+                    "projectDescription": {
+                        "type": "string",
+                        "example": "Project summary text.",
+                    },
+                },
+            },
+        }
+    ],
+    "responses": {
+        200: {"description": "External API predictions"},
+        400: {"description": "Missing projectDescription"},
+        500: {"description": "External API request failed"},
+    },
+}