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Cover image for Distributed Uniqueness: Implementing Twitter Snowflake IDs in Rails 8
Zil Norvilis
Zil Norvilis

Posted on • Edited on • Originally published at norvilis.com

Distributed Uniqueness: Implementing Twitter Snowflake IDs in Rails 8

#architecture #database #rails #ruby

When you run rails generate model, Rails defaults to using a standard auto-incrementing integer for your primary keys. Your first user is ID: 1, your second is ID: 2, and so on.

For a long time, this was fine. But as you grow, auto-incrementing IDs become a problem for two reasons:

  1. Security: A competitor can see you only have 500 orders by looking at the URL /orders/500. They can even "scrape" your entire database by just incrementing the ID in the URL.
  2. Distributed Systems: If you ever need to scale to multiple databases or allow offline creation (like in a mobile app), two different databases might try to assign ID: 501 to different things at the same time.

Many developers switch to UUIDs to fix this. But UUIDs are huge, they are slow to index in Postgres, and they look ugly in URLs (/users/550e8400-e29b-41d4-a716-446655440000).

In 2026, the "Goldilocks" solution for the solo developer is the Snowflake ID.

What is a Snowflake ID?

Originally created by Twitter, a Snowflake ID is a 64-bit integer that is guaranteed to be unique without needing a central "counter" in the database.

The magic is in how the 64 bits are broken down:

  • 41 bits for a timestamp (gives you ~69 years of IDs).
  • 10 bits for a "Worker ID" (identifies which server generated the ID).
  • 12 bits for a sequence number (allows 4,096 IDs per millisecond, per server).

Because the first part of the ID is time, Snowflake IDs are roughly time-ordered. This makes them much faster for databases to index than random UUIDs.

The Ruby Implementation

You don't need to write the bit-shifting logic yourself. There is a great gem called snowflaked.

Add it to your Gemfile:

gem 'snowflaked'
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You can now generate an ID anywhere in Ruby:

Snowflaked.id
# => 1782345678912345678 (A clean, big integer)
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The Primary Key in Rails

Now all the models automatically generate a Snowflake ID for the :id attribute.

User.create!
# => #<User id: 7193489234823847936>
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You can also define additional Snowflake columns in migrations:

class CreateUsers < ActiveRecord::Migration[8.1]
  def change
    create_table :users do |t|
      t.snowflake :external_id
      t.bigint    :uid
    end
  end
end
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Columns created with t.snowflake are automatically detected and will have Snowflake IDs generated for them.

SQLite Warning

SQLite does not support column comments, which Snowflaked uses to auto-detect snowflake columns other than :id. When using SQLite, you must explicitly declare snowflake columns using the snowflake_id helper in your model.

If you want to generate Snowflake IDs for additional columns, you can do so by using the snowflake_id method, without having to migrate the table:

class User < ApplicationRecord
  snowflake_id :uid
end
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It is also possible to disable automatic :id generation by passing id: false to the snowflake_id method:

class Post < ApplicationRecord
  snowflake_id id: false
end
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Or generate Snowflake IDs for other columns but not 🆔

class Post < ApplicationRecord
  snowflake_id :external_id, id: false
end
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Then, in your model:

class Post < ApplicationRecord
  include HasSnowflakeId
end
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Why this is a Win for Solo Devs

1. Cleaner URLs

Your URLs go from /posts/123 (insecure) or /posts/550e8400... (ugly) to /posts/4829104928172349. It looks professional and hides your business volume from prying eyes.

2. Native Performance

Because it's just a bigint (a 64-bit integer), PostgreSQL handles it natively and extremely fast. It takes up half the space of a UUID, which keeps your database smaller and your backups faster.

3. Frontend Friendly

Since it’s just a number, JavaScript handles it easily (though be careful with very large numbers in JS - always return them as strings in your JSON API to avoid precision loss!).

Summary

Snowflake IDs give you the best of both worlds: the distributed uniqueness of a UUID and the performance of an integer.

If you are building a new Rails 8 app today, consider ditching auto-increment on day one. It’s one of those architectural choices that makes your app feel like a "real" enterprise product from the very first commit.

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