Describe the bug

When calling supabase.auth.signUp() method, the returned response contains:

{
  "data": {
    "user": null,
    "session": null
  },
  "error": null
}

However:

• the user is successfully created in Supabase Auth
• the network response from the /signup request contains valid user data
• no error is returned by the SDK

This creates a mismatch between the raw API response and the SDK return value.

I am doing:

const result = await supabase.auth.signUp({
  email,
  password,
  options: {
    emailRedirectTo: `${siteUrl}/login`,
  },
});

What I expect is:

• data.user to contain the created user object
• data.session to either contain a session OR explicitly be null when email confirmation is enabled

What is actually happening:

• both data.user and data.session are null
• error is also null
• the user still gets created successfully

Additionally, inspecting the network tab shows the API response includes valid user data, which suggests the SDK may be transforming or discarding the response incorrectly.

Library affected

supabase-js

Reproduction

No response

Steps to reproduce

1. Enable email confirmation in Supabase Auth settings
   Call:

const result = await supabase.auth.signUp({
  email,
  password,
  options: {
    emailRedirectTo: `${siteUrl}/login`,
  },
});
console.log(result);

2. Observe:
   Auth user is successfully created
   network response contains user payload
   SDK returns:

{
  "data": {
    "user": null,
    "session": null
  },
  "error": null
}

System Info

System:
    OS: macOS 15.7.4
    CPU: (8) x64 Intel(R) Core(TM) i5-8279U CPU @ 2.40GHz
    Memory: 1.37 GB / 8.00 GB
    Shell: 3.2.57 - /bin/bash
  Binaries:
    Node: 24.4.1 - /usr/local/bin/node
    Yarn: 1.22.10 - /Users/oyelekeafolarin/.npm-global/bin/yarn
    npm: 10.1.0 - /Users/oyelekeafolarin/.npm-global/bin/npm
    pnpm: 10.3.0 - /usr/local/bin/pnpm
    Watchman: 2025.04.28.00 - /usr/local/bin/watchman
  Browsers:
    Firefox: 149.0.2
    Safari: 26.2
  npmPackages:
    @supabase/supabase-js: ^2.106.1 => 2.106.1

Used Package Manager

yarn

Logs

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Make sure this is a Supabase JS Library issue and not an issue with the Supabase platform. If it's a Supabase platform related bug, it should likely be reported to supabase/supabase instead.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.