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:
Good for:
Not good for:
Java 8 or higher is required.
Import dependency. If you are using Apache Maven, add the following dependency to your pom.xml's dependencies:
<dependency>
<groupId>org.sqids</groupId>
<artifactId>sqids</artifactId>
<version>0.1.0</version>
</dependency>
Alternatively, if you use Gradle or are on Android, add the following to your app's build.gradle
file under dependencies:
implementation 'org.sqids:sqids:0.1.0'
Import Sqids via:
import org.sqids.Sqids;
Simple encode & decode:
Sqids sqids=Sqids.builder().build();
String id=sqids.encode(Arrays.asList(1L,2L,3L)); // "86Rf07"
List<Long> 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:
Sqids sqids=Sqids.builder()
.minLength(10)
.build();
String id=sqids.encode(Arrays.asList(1L,2L,3L)); // "86Rf07xd4z"
List<Long> numbers=sqids.decode(id); // [1, 2, 3]
Randomize IDs by providing a custom alphabet:
Sqids sqids=Sqids.builder()
.alphabet("FxnXM1kBN6cuhsAvjW3Co7l2RePyY8DwaU04Tzt9fHQrqSVKdpimLGIJOgb5ZE")
.build();
String id=sqids.encode(Arrays.asList(1L,2L,3L)); // "B4aajs"
List<Long> numbers=sqids.decode(id); // [1, 2, 3]
Prevent specific words from appearing anywhere in the auto-generated IDs:
Sqids sqids=Sqids.builder()
.blockList(new HashSet<>(Arrays.asList("86Rf07")))
.build();
String id=sqids.encode(Arrays.asList(1L,2L,3L)); // "se8ojk"
List<Long> numbers=sqids.decode(id); // [1, 2, 3]