# UUIDv7
[](https://github.com/ryanwinchester/uuidv7/actions/workflows/ci.yml)
[](https://hex.pm/packages/uuid_v7)
[](https://hex.pm/packages/uuid_v7)
[](https://github.com/ryanwinchester/uuidv7/blob/main/LICENSE)
UUIDv7 for Elixir and (optionally) Ecto, using an 18-bit randomly-seeded counter.
Uses suggestions described in **[Section 6.2](https://www.ietf.org/archive/id/draft-ietf-uuidrev-rfc4122bis-14.html#name-monotonicity-and-counters)** from [this IETF Draft](https://www.ietf.org/archive/id/draft-ietf-uuidrev-rfc4122bis-14.html)
to add additional sort precision to a version 7 UUID.
## When should I use this package?
- You want sequential, time-based, ordered IDs (per-node).
- You are willing to trade a small amount of raw performance for these
guarantees. You are taking a hit for backwards time-leap protection and the
counter with rollover protection.
## When should I not use this package?
- You don't care about sort/order precision beyond milliseconds.
There are other UUID packages, that only have millisecond precision, for example:
- [martinthenth/uuidv7](https://github.com/martinthenth/uuidv7)
- [bitwalker/uniq](https://github.com/bitwalker/uniq)
## Installation
The package can be installed by adding `uuid_v7` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:uuid_v7, "~> 0.4.3"}
]
end
```
## Usage
```elixir
iex> UUIDv7.generate()
"018e90d8-06e8-7f9f-bfd7-6730ba98a51b"
iex> UUIDv7.bingenerate()
<<1, 142, 144, 216, 124, 16, 127, 196, 158, 92, 92, 74, 83, 46, 116, 173>>
```
## Usage with Ecto
Use this the same way you would use `Ecto.UUID`. For example:
```elixir
defmodule MyApp.Blog.Post do
use Ecto.Schema
@primary_key {:id, UUIDv7, autogenerate: true}
@foreign_key_type UUIDv7
schema "blog_posts" do
field :text, :string
# etc.
end
end
```
