diff --git a/server.js b/server.js
index c71f2f7..68886a9 100644
--- a/server.js
+++ b/server.js
@@ -3,20 +3,26 @@ import sharp from "sharp";
 
 const app = express();
 
+// Raw binary uploads (HEIC/JPEG/etc)
 app.use(express.raw({ type: "*/*", limit: "30mb" }));
 
+// Friendly "is it up" endpoints
+app.get("/", (_req, res) => res.status(200).send("postconvert: ok"));
 app.get("/health", (_req, res) => res.status(200).send("ok"));
 
 app.post("/convert", async (req, res) => {
   try {
     const token = process.env.CONVERTER_TOKEN;
     const auth = req.headers.authorization || "";
+
     if (!token || auth !== `Bearer ${token}`) {
       return res.status(401).send("Unauthorized");
     }
 
     const input = req.body; // Buffer
-    if (!input || input.length === 0) return res.status(400).send("Empty body");
+    if (!input || input.length === 0) {
+      return res.status(400).send("Empty body");
+    }
 
     const jpeg = await sharp(input, { failOnError: false })
       .rotate() // respect EXIF orientation
@@ -24,11 +30,23 @@ app.post("/convert", async (req, res) => {
       .toBuffer();
 
     res.setHeader("Content-Type", "image/jpeg");
-    res.status(200).send(jpeg);
+    return res.status(200).send(jpeg);
   } catch (e) {
-    res.status(500).send(String(e?.stack || e));
+    return res.status(500).send(String(e?.stack || e));
   }
 });
 
-const port = process.env.PORT || 8080;
-app.listen(port, () => console.log(`converter listening on ${port}`));
+// Express will throw for oversized bodies; return a clean 413
+app.use((err, _req, res, next) => {
+  if (err?.type === "entity.too.large") {
+    return res.status(413).send("Payload too large (max 30mb)");
+  }
+  return next(err);
+});
+
+const port = Number(process.env.PORT) || 8080;
+
+// IMPORTANT for Fly.io: bind to 0.0.0.0 (not localhost)
+app.listen(port, "0.0.0.0", () => {
+  console.log(`converter listening on ${port}`);
+});