email and password login, with unique username

Hey, is it possible to enforce unique usernames with email and password login? I want it to error if the username they chose is already taken, similar to how it works with emial.

    const response = await authClient.signUp.email({
      email: data.email,
      password: data.password,
      name: data.username,
    });

    const response = await authClient.signUp.email({
      email: data.email,
      password: data.password,
      name: data.username,
    });

    const response = await authClient.signUp.email({
      email: data.email,
      password: data.password,
      name: data.username,
    });

    const response = await authClient.signUp.email({
      email: data.email,
      password: data.password,
      name: data.username,
    });

  emailAndPassword: {
    enabled: true,
  },

  emailAndPassword: {
    enabled: true,
  },

  emailAndPassword: {
    enabled: true,
  },

  emailAndPassword: {
    enabled: true,
  },

LightTab2•10/14/25, 9:24 AM

Isn't there usernameusername field and

name

name

is only for displayed name?

LightTab2•10/14/25, 9:24 AM

Let me check the docs...

LightTab2•10/14/25, 9:28 AM

name

name

is supposed to be a user real name, if you need to process such data, there is a displayUsernamedisplayUsername for display and usernameusername which I am pretty sure is unique in DB, but docs don't state that

LightTab2•10/14/25, 9:29 AM

And the login in api by username() plugin needs usernameusername not

name

name

LightTab2•10/14/25, 9:30 AM

@Better Auth Is usernameusername in username plugin unique?

Better Auth•10/14/25, 9:30 AM

The username plugin is designed so that the username field is marked as unique in the schema (it has the unique flag set) [6]. However, there has been a reported issue where this uniqueness isn’t enforced at the application level during sign-up—resulting in duplicate usernames being stored if no additional checking is implemented [1].

In short, while the intent is for usernames to be unique, you might need to add an extra layer of validation or check for updates if uniqueness is a critical requirement for your application.

Sources:
[1] Username plugin doesn't ensure username uniqueness
[6] Username | Better Auth

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GitHub

better-auth/better-auth

The most comprehensive authentication framework for TypeScript - better-auth/better-auth

GitHub

Username plugin doesn't ensure username uniqueness · Issue #866 ·...

Describe the bug Adding the username plugin doesn't ensure the username uniqueness at application level, although it should. To Reproduce Steps to reproduce the behavior: Setup a register form ...

Username | Better Auth

Username plugin

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LightTab2•10/14/25, 9:31 AM

@Better Auth The issue was closed, is there any open issue regarding this?

Better Auth•10/14/25, 9:32 AM

Hi there! Based on our current records, it looks like the issue you mentioned has been resolved and closed. There aren’t any open issues tracking that exact problem at the moment [e.g., Document 1 and others show that similar issues have been addressed]. Could you let me know if you meant a specific aspect or have additional details? That way, I can help verify if anything related is still under discussion.

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LLightTab2 And the login in api by username() plugin needs `username` not `name`

v28OP•10/14/25, 7:50 PM

cool! thank you

email and password login, with unique username

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