README.md

Sqids JavaScript

Sqids (pronounced "squids") is a small library that lets you generate unique IDs from numbers. It's good for link shortening, fast & URL-safe ID generation and decoding back into numbers for quicker database lookups.

Features:

• Encode multiple numbers - generate short IDs from one or several non-negative numbers
• Quick decoding - easily decode IDs back into numbers
• Unique IDs - generate unique IDs by shuffling the alphabet once
• ID padding - provide minimum length to make IDs more uniform
• URL safe - auto-generated IDs do not contain common profanity
• Randomized output - Sequential input provides nonconsecutive IDs
• Many implementations - Support for 40+ programming languages

🧰 Use-cases

Good for:

• Generating IDs for public URLs (eg: link shortening)
• Generating IDs for internal systems (eg: event tracking)
• Decoding for quicker database lookups (eg: by primary keys)

Not good for:

• Sensitive data (this is not an encryption library)
• User IDs (can be decoded revealing user count)

🚀 Getting started

Install via yarn:

yarn add sqids

Or npm:

npm install sqids

Or use jsDelivr:

<script src="https://cdn.jsdelivr.net/npm/sqids/dist/sqids.min.js"></script>

👩‍💻 Examples

Simple encode & decode:

const sqids = new Sqids()
const id = sqids.encode([1, 2, 3]) // "86Rf07"
const numbers = sqids.decode(id) // [1, 2, 3]

Note 🚧 Because of the algorithm's design, multiple IDs can decode back into the same sequence of numbers. If it's important to your design that IDs are canonical, you have to manually re-encode decoded numbers and check that the generated ID matches.

Enforce a minimum length for IDs:

const sqids = new Sqids({
  minLength: 10,
})
const id = sqids.encode([1, 2, 3]) // "86Rf07xd4z"
const numbers = sqids.decode(id) // [1, 2, 3]

Randomize IDs by providing a custom alphabet:

const sqids = new Sqids({
  alphabet: 'FxnXM1kBN6cuhsAvjW3Co7l2RePyY8DwaU04Tzt9fHQrqSVKdpimLGIJOgb5ZE',
})
const id = sqids.encode([1, 2, 3]) // "B4aajs"
const numbers = sqids.decode(id) // [1, 2, 3]

Prevent specific words from appearing anywhere in the auto-generated IDs:

const sqids = new Sqids({
  blocklist: new Set(['86Rf07']),
})
const id = sqids.encode([1, 2, 3]) // "se8ojk"
const numbers = sqids.decode(id) // [1, 2, 3]

📝 License

MIT