.. index:: single: sqids(Representation) .. _sqids/1:

.. rst-class:: right

object

sqids(Representation)

• Representation - Text representation for identifiers. Possible values are atom, chars, and codes. Encoding and decoding of short, obfuscated, URL-safe ids from lists of non-negative integers, per the Sqids specification.

  | Availability: | logtalk_load(sqids(loader))

  | Author: Paulo Moura | Version: 1:0:0 | Date: 2026-08-09

  | Compilation flags: | static, context_switching_calls

  | Imports: | public :ref:`options <options/0>` | Uses: | :ref:`list <list/0>` | :ref:`type <type/0>`

  | Remarks:

  • Specification: https://github.com/sqids/sqids-spec
  • Homepage: https://sqids.org
  • Default blocklist: https://github.com/sqids/sqids-blocklist (not bundled; see blocklist/1 option).

  | Inherited public predicates: | Â :ref:`options_protocol/0::check_option/1` Â :ref:`options_protocol/0::check_options/1` Â :ref:`options_protocol/0::default_option/1` Â :ref:`options_protocol/0::default_options/1` Â :ref:`options_protocol/0::option/2` Â :ref:`options_protocol/0::option/3` Â :ref:`options_protocol/0::valid_option/1` Â :ref:`options_protocol/0::valid_options/1` Â

  .. contents:: :local: :backlinks: top

Public predicates

.. index:: encode/2 .. _sqids/1::encode/2:

encode/2 ^^^^^^^^^^^^

Encodes a list of non-negative integers into an identifier using the default options.

| Compilation flags: | static

| Template: | encode(Numbers,Id) | Mode and number of proofs: | encode(+list(integer),-text) - one

| Exceptions: | Numbers is a variable or a partial list: | instantiation_error | Numbers is neither a variable nor a list: | type_error(list(non_negative_integer),Numbers) | An element Number of the list Numbers is not an integer: | type_error(integer,Number) | An element Number of the list Numbers of Numbers is a negative integer: | domain_error(non_negative_integer,Number) | Too many blocklist collisions occurred while generating the id: | resource_error(blocklist_retries)

---

.. index:: encode/3 .. _sqids/1::encode/3:

encode/3 ^^^^^^^^^^^^

Encodes a list of non-negative integers into an id using the given options. Recognized options are alphabet(Atom) (an atom with at least three unique characters; default is the standard 62-character alphabet), min_length(Integer) (an integer between 0 and 255; default is 0), and blocklist(list(atom)) (words that must not occur in the generated id; default is []). If Numbers is empty, Id is unified with the empty atom regardless of the other options.

| Compilation flags: | static

| Template: | encode(Numbers,Id,Options) | Mode and number of proofs: | encode(+list(integer),-text,+list(compound)) - one_or_error

| Exceptions: | Numbers is a variable or a partial list: | instantiation_error | Numbers is neither a variable nor a list: | type_error(list(non_negative_integer),Numbers) | An element Number of the list Numbers is not an integer: | type_error(integer,Number) | An element Number of the list Numbers of Numbers is a negative integer: | domain_error(non_negative_integer,Number) | Options is a variable or a partial list: | instantiation_error | Options is neither a variable nor a list: | type_error(list,Options) | An element Option of the list Options is neither a variable nor a compound term: | type_error(compound,Option) | An element Option of the list Options is a compound term but not a valid option: | domain_error(option,Option) | Too many blocklist collisions occurred while generating the id: | resource_error(blocklist_retries)

---

.. index:: decode/2 .. _sqids/1::decode/2:

decode/2 ^^^^^^^^^^^^

Decodes an identifier back into a list of non-negative integers using the default options. Equivalent to decode/3 with an empty options list. Numbers is [] if Id is the empty atom or contains a character that is not in the alphabet. Decoding does not check that Id is a canonical (minimal) encoding: ids rejected by encode/2-3 due to the blocklist still decode successfully, as do ids with extraneous minimum-length padding.

| Compilation flags: | static

| Template: | decode(Id,Numbers) | Mode and number of proofs: | decode(+text,-list(integer)) - one_or_error

| Exceptions: | Id is a variable: | instantiation_error | Id is neither a variable nor an atom: | type_error(atom,Id)

---

.. index:: decode/3 .. _sqids/1::decode/3:

decode/3 ^^^^^^^^^^^^

Decodes an identifier back into a list of non-negative integers using the given options. The only recognized option is alphabet(Atom); it must be the same alphabet that was used to encode Id. Numbers is [] if Id is the empty atom or contains a character that is not in the alphabet.

| Compilation flags: | static

| Template: | decode(Id,Numbers,Options) | Mode and number of proofs: | decode(+text,-list(integer),+list(compound)) - one_or_error

| Exceptions: | Id is a variable: | instantiation_error | Id is neither a variable nor an atom: | type_error(atom,Id) | Options is a variable or a partial list: | instantiation_error | Options is neither a variable nor a list: | type_error(list,Options) | An element Option of the list Options is neither a variable nor a compound term: | type_error(compound,Option) | An element Option of the list Options is a compound term but not a valid option: | domain_error(option,Option)

---

Protected predicates

(no local declarations; see entity ancestors if any)

Private predicates

(no local declarations; see entity ancestors if any)

Operators

(none)

.. seealso::

:ref:`sqids <sqids/0>`, :ref:`ids(Representation,Bytes) <ids/2>`, :ref:`cuid2(Representation,Size,Alphabet) <cuid2/3>`, :ref:`ksuid(Representation,Alphabet) <ksuid/2>`, :ref:`nanoid(Representation,Size,Alphabet) <nanoid/3>`, :ref:`snowflakeid(Representation,EpochMilliseconds,TimeUnitMilliseconds,TimestampBits,NodeBits,SequenceBits,Node) <snowflakeid/7>`, :ref:`typeid(Representation) <typeid/1>`, :ref:`ulid(Representation) <ulid/1>`, :ref:`uuid(Representation) <uuid/1>`