Warning: This is a pre-alpha software. Things are going to change drastically while we develop towards v1.

Unqid is a distributed unique ID generator library for in-application embedded use.

Components of the ID:

| timestamp (40-bits) | machine-id (16-bits) | sequence-number (7-bits)|

timestamp is calculated since the epoch of Jan. 1, 2021 machine-id is the lower 16 bits of the private ip from the machine’s os pid sequence-number is monotonically increasing number reset every millisecond

Due to the component sizes:

  • The lifetime of id generation is ~34 years (2^40 – 1 milliseconds from custom epoch)
  • concurrently used from ~65k hosts (2^16-1)
  • generate 128k ids/sec per instance

When to use (and not use)

Use this library if:

  • You will generate less than 128 ids/ms (or 128k ids/sec) per instance of unqid
  • You run only one instance of your app per machine or use containers with networking
  • You’re confident that instances of your app don’t run on subnets with overlapping lower 16-bits of the network
  • You’re ok with your application having a theoretical lifetime limit of 34 years.

Design Goals

  • No external dependencies (this might be relaxed in later versions)
  • Zero configuration, i.e., import library and start generating ids (this might be relaxed in later versions)
  • Roughly time sortable
  • Fast id generation
  • Protect against clock rollbacks
  • Protect against accidental overflow of sequence-number component


go get github.com/shivakar/unqid


import "github.com/shivakar/unqid"

func main() {
    for i := 0; i < 10; i++ {



View Github