diff --git a/.vscode/launch.json b/.vscode/launch.json
index 48b3df00747..b55be648371 100644
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@@ -94,7 +94,7 @@
         },
         {
             "name": "Launch admin server",
-            "program": "${workspaceFolder}/adminSiteServer/app.tsx",
+            "program": "${workspaceFolder}/adminSiteServer/app.ts",
             "request": "launch",
             "type": "node",
             "runtimeExecutable": "yarn",
@@ -113,7 +113,7 @@
         },
         {
             "name": "Launch admin server (via fnm)",
-            "program": "${workspaceFolder}/adminSiteServer/app.tsx",
+            "program": "${workspaceFolder}/adminSiteServer/app.ts",
             "request": "launch",
             "type": "node",
             "runtimeExecutable": "fnm",
diff --git a/adminSiteServer/app.test.tsx b/adminSiteServer/app.test.ts
similarity index 100%
rename from adminSiteServer/app.test.tsx
rename to adminSiteServer/app.test.ts
diff --git a/adminSiteServer/app.tsx b/adminSiteServer/app.ts
similarity index 100%
rename from adminSiteServer/app.tsx
rename to adminSiteServer/app.ts
diff --git a/adminSiteServer/authentication.tsx b/adminSiteServer/authentication.ts
similarity index 100%
rename from adminSiteServer/authentication.tsx
rename to adminSiteServer/authentication.ts
diff --git a/adminSiteServer/functionalRouterHelpers.tsx b/adminSiteServer/functionalRouterHelpers.ts
similarity index 100%
rename from adminSiteServer/functionalRouterHelpers.tsx
rename to adminSiteServer/functionalRouterHelpers.ts
diff --git a/adminSiteServer/mockSiteRouter.tsx b/adminSiteServer/mockSiteRouter.ts
similarity index 100%
rename from adminSiteServer/mockSiteRouter.tsx
rename to adminSiteServer/mockSiteRouter.ts
diff --git a/adminSiteServer/plainRouterHelpers.tsx b/adminSiteServer/plainRouterHelpers.ts
similarity index 100%
rename from adminSiteServer/plainRouterHelpers.tsx
rename to adminSiteServer/plainRouterHelpers.ts
diff --git a/package.json b/package.json
index 0424314c722..bb5b5f03cd4 100644
--- a/package.json
+++ b/package.json
@@ -26,7 +26,7 @@
         "refreshPageviews": "tsx --tsconfig tsconfig.tsx.json db/refreshPageviewsFromDatasette.ts",
         "revertLastDbMigration": "tsx --tsconfig tsconfig.tsx.json node_modules/typeorm/cli.js migration:revert -d db/dataSource.ts",
         "startAdminServer": "node --enable-source-maps ./itsJustJavascript/adminSiteServer/app.js",
-        "startAdminDevServer": "tsx watch --ignore '**.mjs' --tsconfig tsconfig.tsx.json adminSiteServer/app.tsx",
+        "startAdminDevServer": "tsx watch --ignore '**.mjs' --tsconfig tsconfig.tsx.json adminSiteServer/app.ts",
         "startLocalCloudflareFunctions": "wrangler pages dev",
         "startDeployQueueServer": "node --enable-source-maps ./itsJustJavascript/baker/startDeployQueueServer.js",
         "startLernaWatcher": "lerna watch --scope '@ourworldindata/*' -- lerna run build --scope=\\$LERNA_PACKAGE_NAME --include-dependents",