diff --git a/README.md b/README.md
index 2b3d985..89cd120 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,23 @@
 # Unshorten
-Firefox Extension and API server for revealing links behind shortened URLs.
\ No newline at end of file
+Firefox Extension and API server for revealing links behind shortened URLs.
+
+## Usage
+In order to deal with CORS, Unshorten must send links to a resolver API. 
+
+```shell
+cd server
+make build
+docker -d --name unshortener -p 8000:8000 unshortener-api
+```
+
+Build the extension and import into Firefox. Right click on a link and choose 
+"Unshorten Link". The result will be copied to the clipboard.
+
+```shell
+cd extension
+make zip
+```
+
+## Supported Sites
+- t.co
+- tinyurl.com
diff --git a/server/src/main.py b/server/src/main.py
index 632de62..cc51db6 100644
--- a/server/src/main.py
+++ b/server/src/main.py
@@ -40,4 +40,4 @@ async def receive_url(url: Optional[str] = None):
         CACHE[url] = result
         return result
 
-    return {"error": f"server error"}
+    return {"error": "server error"}
diff --git a/server/src/unshorteners.py b/server/src/unshorteners.py
index c2a8c41..23d810b 100644
--- a/server/src/unshorteners.py
+++ b/server/src/unshorteners.py
@@ -1,7 +1,7 @@
 """Unshortening functions"""
 import re
-import requests
 from typing import Optional
+import requests
 
 
 def unshorten_tinyurl(url: str) -> Optional[str]: