diff --git a/README.md b/README.md
index 35ae80d..3feeb18 100644
--- a/README.md
+++ b/README.md
@@ -33,12 +33,12 @@ data
 
 If you have nix available, run:
 ```bash
-$ nix run . -- --user-agent <your-email> -s chesscom
+$ nix run . -- --user-agent <your-email> -s <site>
 ```
 If not, ensure you have [poetry](https://python-poetry.org/) on your machine and
 instead run the following:
 ```bash
-$ poetry run python3 -m app -u <your-email> -s chesscom
+$ poetry run python3 -m app -u <your-email> -s <site>
 ```
 
 ## Database
@@ -83,8 +83,7 @@ necessary to scrape coach data from our chess website and dump the results into
 the database in one fell swoop. Assuming our database is open with a socket
 connection available at `@scraper`:
 ```bash
-nix run . -- --user-agent <your-email> -s chesscom
-nix run . -- --user-agent <your-email> -s lichess
+nix run . -- --user-agent <your-email> -s chesscom -s lichess
 cat data/{chesscom,lichess}/export.json > data/export.json
 psql -h @scraper -f sql/load_export.sql -v export="'$PWD/data/export.json'"
 ```
diff --git a/app/__main__.py b/app/__main__.py
index ed86bd6..7b7bdba 100644
--- a/app/__main__.py
+++ b/app/__main__.py
@@ -24,6 +24,7 @@ async def run():
         "-s",
         "--site",
         required=True,
+        action="append",
         choices=[
             Site.CHESSCOM.value,
             Site.LICHESS.value,
@@ -34,22 +35,25 @@ async def run():
     async with aiohttp.ClientSession(
         headers={"User-Agent": f"BoardWise coach-scraper ({args.user_agent})"}
     ) as session:
-        if args.site == Site.CHESSCOM.value:
-            scraper = ChesscomScraper(session)
-            exporter_cls = ChesscomExporter
-        elif args.site == Site.LICHESS.value:
-            scraper = LichessScraper(session)
-            exporter_cls = LichessExporter
+        for site in set(args.site):
+            scraper, exporter_cls = None, None
 
-        # Write out each coach data into NDJSON file.
-        dump = []
-        usernames = await scraper.scrape()
-        for username in usernames:
-            export = exporter_cls(username).export()
-            dump.append(f"{json.dumps(export)}\n")
+            if site == Site.CHESSCOM.value:
+                scraper = ChesscomScraper(session)
+                exporter_cls = ChesscomExporter
+            elif site == Site.LICHESS.value:
+                scraper = LichessScraper(session)
+                exporter_cls = LichessExporter
 
-        with open(scraper.path_site_file("export.json"), "w") as f:
-            f.writelines(dump)
+            # Write out each coach data into NDJSON file.
+            dump = []
+            usernames = await scraper.scrape()
+            for username in usernames:
+                export = exporter_cls(username).export()
+                dump.append(f"{json.dumps(export)}\n")
+
+            with open(scraper.path_site_file("export.json"), "w") as f:
+                f.writelines(dump)
 
 
 def main():