bug: iOS simulator cannot sign in on Discord

[zxt-tzx]

Provide environment information

  System:
    OS: macOS 15.4.1
    CPU: (10) arm64 Apple M1 Pro
    Memory: 155.23 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.14.0 - ~/.nvm/versions/node/v22.14.0/bin/node
    Yarn: 1.22.22 - ~/.yarn/bin/yarn
    npm: 10.9.2 - ~/.nvm/versions/node/v22.14.0/bin/npm
    pnpm: 10.6.3 - ~/Library/pnpm/pnpm
    bun: 1.2.5 - ~/.bun/bin/bun
    Watchman: 2025.04.28.00 - /opt/homebrew/bin/watchman

Describe the bug

On iOS Simulator on macOS, unable to sign in on Discord.

The strange thing is:

• Login flow works fine via Expo Go on my iPhone
• Login flow works fine via browser
• iOS Simulator could connect to all websites via Safari with no issue (including Discord)
• I vaguely remember getting to the Discord sign in page on iOS Simulator previously, but can't seem to do that now, even after reverting the changes and starting from a clean repo

Link to reproduction

n/a

To reproduce

How to reproduce the bug:

• follow instructions to setup (add env vars, deploy auth-proxy server to Vercel, create dev client on Discord)
• on iOS Simulator: tap Sign In With Discord > Continue > Sign in With Discord > Error

Screenshot:

On the NextJS logs:

GET /api/auth/signin?expo-redirect=exp%3A%2F%2F192.168.0.239%3A8081%2F--%2Flogin 200 in 33ms
POST /api/auth/signin/discord 302 in 39ms

Additional information

No response

[Skayfa]

Could you clarify a bit more about the flow you implemented?
It could potentially be a domain issue.
I see that in the URL received by Discord, it’s 192... (as shown in the image), and maybe your project launch URL is different. So, it’s possible that the login works but happens under the wrong domain.

[ritmillio]

This is a know "issue?" on iOS simulator as far as I know. iOS restricts the IP Address/localhost. Best if you would use some app for creating tunnel like ngrok/expose for local testing.