What is Sqids?

Sqids (pronounced "squids") is an open-source library that lets you generate short unique identifiers from numbers. These IDs are URL-safe, can encode several numbers, and do not contain common profanity words. Read more .

This is what they look like:

https://example.com/Lqj8a0

Quick encode & decode example:

sqids_t *sqids = sqids_new(SQIDS_DEFAULT_ALPHABET, 0, sqids_bl_list_all(NULL));
unsigned long long nums[] = {1, 2, 3};
char *hash = sqids_encode(sqids, 3, nums);  // => "86Rf07"
sqids_decode(sqids, hash, nums, 3);         // => 3

If IDs are too short, you can pad them to a certain length:

sqids_t *sqids = sqids_new(SQIDS_DEFAULT_ALPHABET, 10, sqids_bl_list_all(NULL));
unsigned long long nums[] = {1, 2, 3};
char *hash = sqids_encode(sqids, 3, nums);  // => "86Rf07xd4z"
sqids_decode(sqids, hash, nums, 3);         // => 3

Create unique IDs by shuffling the alphabet:

sqids_t *sqids = sqids_new("k3G7QAe51FCsPW92uEOyq4Bg6Sp8YzVTmnU0liwDdHXLajZrfxNhobJIRcMvKt", 0, sqids_bl_list_all(NULL));
unsigned long long nums[] = {1, 2, 3};
char *hash = sqids_encode(sqids, 3, nums);  // => "XRKUdQ"
sqids_decode(sqids, hash, nums, 3);         // => 3

Full documentation is at https://github.com/sqids/sqids-c

If you're looking for the original Hashids C, you can find it here: https://github.com/tzvetkoff/hashids.c

Use Cases

The main use of Sqids is purely visual. If you'd like to use IDs instead of numbers in your project, Sqids could be a good choice.

Good For

  • Encoding primary keys If you're using a relational database
  • Saving database lookups By encoding multiple objects
  • Temporary login tokens Profanity-free and URL-safe

Not Good For

  • Sensitive data This is not an encryption library
  • User IDs Can reveal user count if anyone finds out the encoding alphabet

Features

  • ๐Ÿ†” Generate short IDs from non-negative numbers
  • โœ… Easy encoding & decoding
  • ๐Ÿซฃ Auto-generated IDs do not contain common profanity
  • ๐ŸŽฒ Support for custom IDs through shuffled alphabet
  • ๐Ÿฅณ 44 integrations (70% using new design)
  • ๐Ÿ“Œ Every version produces the same IDs
  • ๐Ÿป Small library with a permissive license

Example / Playground