[Bug]: Reverse proxy error when upgrade shopify/cli from 3.69.1 to 3.84.1 for Expressjs app (Invalid path /?embedded=.....)

[NguyenQuangHuy-Harry]

Please confirm that you have:

• Searched existing issues to see if your issue is a duplicate. (If you’ve found a duplicate issue, feel free to add additional information in a comment on it.)
• Reproduced the issue in the latest CLI version.

In which of these areas are you experiencing a problem?

App

Expected behavior

It should proxy from tunnel url to localhost:8080.

Actual behavior

Verbose output

Verbose output

13:37:43 │               web-backend │ [1] PageFly Backend-0  | 2025-09-08T06:37:43.603Z socket.io-admin emit stats
13:37:43 │               web-backend │ [1] PageFly Backend-0  | 2025-09-08T06:37:43.603Z socket.io-redis publishing message
of type 3 to socket.io#/admin#
13:37:43 │               web-backend │ [1] PageFly Backend-0  | 2025-09-08T06:37:43.605Z socket.io-parser encoding packet
{"type":2,"data":["server_stats",{"serverId":"Harry.local","hostname":"Harry.local","pid":5310,"uptime":27.77813425,"client
sCount":0,"pollingClientsCount":0,"aggregatedEvents":[],"namespaces":[{"name":"/","socketsCount":0},{"name":"/admin","socke
tsCount":0}]}],"nsp":"/admin"}
13:37:43 │               web-backend │ [1] PageFly Backend-0  | 2025-09-08T06:37:43.605Z socket.io-parser encoded
{"type":2,"data":["server_stats",{"serverId":"Harry.local","hostname":"Harry.local","pid":5310,"uptime":27.77813425,"client
sCount":0,"pollingClientsCount":0,"aggregatedEvents":[],"namespaces":[{"name":"/","socketsCount":0},{"name":"/admin","socke
tsCount":0}]}],"nsp":"/admin"} as 2/admin,["server_stats",{"serverId":"Harry.local","hostname":"Harry.local","pid":5310,"up
time":27.77813425,"clientsCount":0,"pollingClientsCount":0,"aggregatedEvents":[],"namespaces":[{"name":"/","socketsCount":0
},{"name":"/admin","socketsCount":0}]}]
13:37:43 │               web-backend │ [1] PageFly Backend-0  | 2025-09-08T06:37:43.605Z socket.io-adapter
[0218b39434a7e6ab] ignore message from self

──────────────────────────────────────────────────────────────────────────────────────────────────────────────
│ (d) Dev status │ (a) App info │ (s) Store info │                                                    (q) Quit

✅ Ready, watching for changes in your app

› (g) Open GraphiQL (Admin API) in your browser
› (p) Preview in your browser

Preview URL: https://harry8888.myshopify.com/admin/oauth/redirect_from_cli?client_id=74ee652f154c461aca77d4054117b354
GraphiQL URL: http://localhost:3457/graphiql
2025-09-08T06:37:43.707Z: 
Reverse HTTP proxy error - Invalid path: /?embedded=1&hmac=820a5f7c91fccf246511eefbe2535a158c7b7714041c0393ff0a148c148fac42&host=YWRtaW4uc2hvcGlmeS5jb20vc3RvcmUvaGFycnk4ODg4&id_token=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwczpcL1wvaG
13:37:45 │               web-backend │ [1] PageFly Backend-0  | 2025-09-08T06:37:45.604Z socket.io-admin emit stats
13:37:45 │               web-backend │ [1] PageFly Backend-0  | 2025-09-08T06:37:45.604Z socket.io-redis publishing message
of type 3 to socket.io#/admin#
13:37:45 │               web-backend │ [1] PageFly Backend-0  | 2025-09-08T06:37:45.606Z socket.io-adapter
[0218b39434a7e6ab] ignore message from self
13:37:45 │               web-backend │ [1] PageFly Backend-0  | 2025-09-08T06:37:45.606Z socket.io-parser encoding packet
{"type":2,"data":["server_stats",{"serverId":"Harry.local","hostname":"Harry.local","pid":5310,"uptime":29.779204125,"clien
tsCount":0,"pollingClientsCount":0,"aggregatedEvents":[],"namespaces":[{"name":"/","socketsCount":0},{"name":"/admin","sock
etsCount":0}]}],"nsp":"/admin"}
13:37:45 │               web-backend │ PageFly Backend-0  | 2025-09-08T06:37:45.606Z socket.io-parser encoded
{"type":2,"data":["server_stats",{"serverId":"Harry.local","hostname":"Harry.local","pid":5310,"uptime":29.779204125,"clien
tsCount":0,"pollingClientsCount":0,"aggregatedEvents":[],"namespaces":[{"name":"/","socketsCount":0},{"name":"/admin","sock
etsCount":0}]}],"nsp":"/admin"} as 2/admin,["server_stats",{"serverId":"Harry.local","hostname":"Harry.local","pid":5310,"u
ptime":29.779204125,"clientsCount":0,"pollingClientsCount":0,"aggregatedEvents":[],"namespaces":[{"name":"/","socketsCount"
:0},{"name":"/admin","socketsCount":0}]}]
13:37:47 │               web-backend │ [1] PageFly Backend-0  | 2025-09-08T06:37:47.604Z socket.io-admin emit stats
13:37:47 │               web-backend │ [1] PageFly Backend-0  | 2025-09-08T06:37:47.605Z socket.io-redis publishing message
of type 3 to socket.io#/admin#
13:37:47 │               web-backend │ [1] PageFly Backend-0  | 2025-09-08T06:37:47.606Z socket.io-adapter
[0218b39434a7e6ab] ignore message from self
13:37:47 │               web-backend │ [1] PageFly Backend-0  | 2025-09-08T06:37:47.606Z socket.io-parser encoding packet
{"type":2,"data":["server_stats",{"serverId":"Harry.local","hostname":"Harry.local","pid":5310,"uptime":31.779546334,"clien
tsCount":0,"pollingClientsCount":0,"aggregatedEvents":[],"namespaces":[{"name":"/","socketsCount":0},{"name":"/admin","sock
etsCount":0}]}],"nsp":"/admin"}
13:37:47 │               web-backend │ [1] PageFly Backend-0  | 2025-09-08T06:37:47.606Z socket.io-parser encoded
{"type":2,"data":["server_stats",{"serverId":"Harry.local","hostname":"Harry.local","pid":5310,"uptime":31.779546334,"clien
tsCount":0,"pollingClientsCount":0,"aggregatedEvents":[],"namespaces":[{"name":"/","socketsCount":0},{"name":"/admin","sock
etsCount":0}]}],"nsp":"/admin"} as 2/admin,["server_stats",{"serverId":"Harry.local","hostname":"Harry.local","pid":5310,"u
ptime":31.779546334,"clientsCount":0,"pollingClientsCount":0,"aggregatedEvents":[],"namespaces":[{"name":"/","socketsCount"
:0},{"name":"/admin","socketsCount":0}]}]
13:37:49 │               web-backend │ [1] Page  ```

</details>

### Reproduction steps

1. Run shopify app dev for a express js app

### Operating System

Mac OD

### Shopify CLI version (`shopify --version`)

3.84.1

### Shell

_No response_

### Node version (run `node -v` if you're not sure)

_No response_

### What language and version are you using in your application?

_No response_

[NguyenQuangHuy-Harry]

in the verbose out put, it only allow this path: "/extensions"
Reverse HTTP proxy error - Invalid path: /?embedded=1&hmac=9f73e9061718e2a082e92c77b58fd3708fc313904002a1856fdbc070a7d8f9d3&host=YWRtaW4uc2hvcGlmeS5jb20vc3RvcmUvbmd1eWVucXVhbmdodXk4OA&id_token=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwczpcL1wvbmd1eWVucXVhbmdodXk4OC5teXNob3BpZnkuY29tXC9hZG1pbiIsImRlc3QiOiJodHRwczpcL1wvbmd1eWVucXVhbmdodXk4OC5teXNob3BpZnkuY29tIiwiYXVkIjoiMzk2N2I2ZDIyYjcxYjE5OTA0NDAyY2Q4NWU3NTk5MGUiLCJzdWIiOiI4NzYzMTEwMjA5MCIsImV4cCI6MTc1NzM5NTk5MiwibmJmIjoxNzU3Mzk1OTMyLCJpYXQiOjE3NTczOTU5MzIsImp0aSI6IjdhNTBmZDllLWI0MWUtNDE4ZC1iNzAyLTAwYmIwNGU4NmIzOSIsInNpZCI6IjFiODdiZTAxLWRkN2EtNDBiZi05ZGIwLWU0YWE1YzFiNTM5OCIsInNpZyI6IjBjNTU0NTUzZmE3YTA3ODQ4Nzg2M2I3ZjBmOWY5YTg5Y2ExNzYxZWRiMTVhZTZlMzIxMWY2N2JjZTdjMzdjNTcifQ.1se1rl5bnDYrAhGv3Wrbao7I5QJlEJrKm2fbNWsm2jw&locale=en&session=4ec5d84a0e78bb75ba509bf19165bac6aba510741b5bf57001ceb480f6386ba7&shop=nguyenquanghuy88.myshopify.com&timestamp=1757395932 These are the allowed paths: { "/extensions": "http://localhost:63286" }

[NguyenQuangHuy-Harry]

async function setPortsAndAddProxyProcess(processes, proxyPort, reverseProxyCert) {
  let processesAndRules = await Promise.all(processes.map(async (process10) => {
    let rules = {};
    if (process10.type === "web" && process10.options.roles.includes(WebType.Frontend)) {
      let targetPort = process10.options.portFromConfig ?? process10.options.port;
      rules.default = `http://localhost:${targetPort}`;
      let hmrServer = process10.options.hmrServerOptions;
      hmrServer && (rules.websocket = `http://localhost:${hmrServer.port}`, hmrServer.httpPaths.forEach((path4) => rules[path4] = `http://localhost:${hmrServer.port}`)), process10.options.port = targetPort;
    } else if (process10.type === "previewable-extension") {
      let targetPort = await getAvailableTCPPort();
      rules[process10.options.pathPrefix] = `http://localhost:${targetPort}`, process10.options.port = targetPort;
    }
    return { process: process10, rules };
  })), newProcesses = processesAndRules.map(({ process: process10 }) => process10), allRules = processesAndRules.map(({ rules }) => rules).reduce((acc, rules) => ({ ...acc, ...rules }), {});

I see in the sourcecode of shopify/cli has this code: process10.options.roles.includes(WebType.Frontend).
So that in the shopify.web.toml, we should add this:

roles = ["frontend", "backend"]
port = 3000

[NguyenQuangHuy-Harry]

If i undo this work from this PR, it works.

[isaacroldan]

Hi @NguyenQuangHuy-Harry , thanks for the report. Can you add more details on how do you run the CLI? Any custom ports/tunnel?

[NguyenQuangHuy-Harry]

Hi @NguyenQuangHuy-Harry , thanks for the report. Can you add more details on how do you run the CLI? Any custom ports/tunnel?

I just run yarn shopify app dev and it will run yarn dev then it will run node server.js to run server.

Here is my configs for shopify.web.toml
roles = ["backend"] [commands] dev = "npm run dev"

[isaacroldan]

Hi @NguyenQuangHuy-Harry, not sure I follow. In your shopify.web.toml you only define a backend role, what frontend do you expect to see when running dev?

If your app has a frontend too, you should have roles = ["frontend", "backend"]

This "error" is expected if you don't have a frontend (there is nothing to show)

[NguyenQuangHuy-Harry]

Hi @NguyenQuangHuy-Harry, not sure I follow. In your shopify.web.toml you only define a backend role, what frontend do you expect to see when running dev?

If your app has a frontend too, you should have roles = ["frontend", "backend"]

This "error" is expected if you don't have a frontend (there is nothing to show)

My project is separated between backend and frontend (not in the same project like shopify node template). My frontend (React App) is just running on localhost:3000. And as expected, the tunnel URL will be proxy to this path. So that basically, the issue is it not proxy from the tunnel URL to localhost:3000 and it said it only allows paths: { "/extensions": "http://localhost:63286" }

[isaacroldan]

Is just running on localhost:3000. And as expected, the tunnel URL will be proxy to this path

Well, I don't think we can assume that expectation :)
The CLI proxy will proxy to whatever it knows to exists, in this case your backend. You need to tell it that there is also a frontend it needs to be aware of. Not sure how it worked for you before if you never told the CLI that your frontend was running on port 3000 🤔

You have two options, update your web.toml as you said to

roles = ["frontend", "backend"]
port = 3000

This should work for your case, since you are starting the frontend yourself, the CLI will automatically connect to it via port 3000.

let me know if this doesn't work

[NguyenQuangHuy-Harry]

Is just running on localhost:3000. And as expected, the tunnel URL will be proxy to this path

Well, I don't think we can assume that expectation :) The CLI proxy will proxy to whatever it knows to exists, in this case your backend. You need to tell it that there is also a frontend it needs to be aware of. Not sure how it worked for you before if you never told the CLI that your frontend was running on port 3000 🤔

You have two options, update your web.toml as you said to

roles = ["frontend", "backend"]
port = 3000

This should work for your case, since you are starting the frontend yourself, the CLI will automatically connect to it via port 3000.

let me know if this doesn't work

It works when using this

roles = ["frontend", "backend"]
port = 3000

But i dont know why it cause the app load very slow. It takes so much time to proxy from tunnel url to localhost:3000

[isaacroldan]

You can try with --use-localhost, this uses a localhost URL instead of a tunnel, it should be faster, but some features like webhooks are not supported in this mode.

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