Cannot GET /api/users express api deployed in azure

[Dsniels]

Hey, I am new learning about devops and deployment, I ran into a problem when deploying my api in Azure, Cannot GET /api/users, I tested my application in a local environment and everything works perfectly, however I don't know what is happening, i I already specified the port as process.env.PORT and established the connection strings in azure. I would really appreciate the help, if you want to know more about my project you can visit my ExpressApi repository its a simple ecommerce api, in the same way I would appreciate opinions on my code and ideas, I'm just learning about in express

[lucianookdp]

Yeah this is almost always one of two things when it's fine locally but breaks after deploying to Azure.

If you're on Azure Static Web Apps, the routing in front of your app expects API stuff to live in a specific /api folder and get deployed as an Azure Function, not run as a regular Express server — so your Express app just never gets hit for those paths, that's why you get "Cannot GET". If that's your setup, check the staticwebapp.config.json routing rules.

If it's a regular Azure App Service instead, the usual culprits are the Startup Command not being set (or pointing at the wrong file — should be something like node index.js or npm start, whatever your actual entry point is), or the app only listening on localhost instead of all interfaces, which works fine on your machine but Azure's proxy can't reach it (app.listen(process.env.PORT) with no host arg is the safe way to write that). Also worth checking under Kudu's debug console that your routes file actually made it up in the deploy at all.

Honestly the fastest way to figure out what's actually going on instead of guessing is to turn on Log stream in the portal (or az webapp log tail) and hit the URL while watching it — usually makes it obvious real quick.

Let me know which Azure service you're on (App Service, Static Web Apps, or Functions) and I can point you more specifically.

[reysilvaa]

I have been through this exact issue, so let me save you some time.

The most important clue is the error message itself. "Cannot GET /api/users" is Express's own 404 response, which means your app is running on Azure and is receiving the request. It just cannot find a route for that path. So this is almost never a "server did not start" problem. It is either a route that does not match, or the request never reaches Express at all.

First, confirm Express is the one answering:

curl -i https://yourapp.azurewebsites.net/api/users

If the response contains "X-Powered-By: Express", your app handled the request and we move to the next step. If it does not, something in front of your app is eating the request, usually Azure Static Web Apps routing, an IIS web.config rewrite on Windows App Service, or a load balancer.

If Express is answering, make it tell you what it actually receives. Add this at the very end of your route setup, after all routers:

app.use((req, res) => {
  console.log("404 for:", req.method, req.originalUrl, req.baseUrl);
  res.status(404).json({ error: "No route matched", path: req.originalUrl });
});

Then hit the endpoint and read the Azure log stream (App Service, your app, then Log stream). You will see the exact URL that arrived.

The three causes I see most often:

1. Stale deployment. The code you tested locally is not the code that is live. This happens a lot when deploying from a different branch, or when the build finished before your last commit. Redeploy from the exact branch you tested and make sure the deploy completed.

2. Doubled mount path. If you mounted the router with app.use("/api", usersRouter) and inside usersRouter you also wrote router.get("/api/users", ...), the real path becomes /api/api/users. The router should define its paths without the /api prefix:

   app.use("/api", usersRouter);   // app.js
   router.get("/users", ...);      // usersRouter -> matches /api/users
   

3. Route registered after a catch-all. If you have app.get("*", ...) or an SPA fallback, your API routes must be registered before it.

A few more quick checks:

• Use app.listen(process.env.PORT || 3000) and never a hardcoded port. Azure injects PORT.
• Open the deployed file itself in the Kudu console (https://yourapp.scm.azurewebsites.net/DebugConsole) and confirm the routes are actually in the file that is running.
• Test with curl in a terminal, not just the browser, so you can see the status code and headers.

If you tell me which Azure service you used (App Service on Windows, App Service on Linux, Static Web Apps, or Container Apps) and the output of the curl above, I can point at the exact line. Once this clicks you will never struggle with it again.