SuperTokens is an open source authentication solution offering features like: Different types of login: Email / password, Passwordless (OTP or Magic link based).

SuperTokens.com

Hi, 
why isn't user_id unique, only user_id CHAR(36) NOT NULL ?

The unique constraint is added by the all_auth users table

But yea. We could make them unique in the db

Do you mean: CREATE TABLE IF NOT EXISTS all_auth_recipe_users(
    user_id CHAR(36) NOT NULL,
    recipe_id VARCHAR(128) NOT NULL,
    time_joined BIGINT NOT NULL,
    CONSTRAINT all_auth_recipe_users_pkey PRIMARY KEY (user_id)
);
CREATE INDEX all_auth_recipe_users_pagination_index ON all_auth_recipe_users (time_joined DESC, user_id DESC);
?

And if I add to user_id in tables UNIQUE, there can ba a problems?

I see. 
And first question is 'Yes' or 'No'?

`CONSTRAINT all_auth_recipe_users_pkey PRIMARY KEY (user_id)` is adding unique