Creating Base64 UUID in Java
Alphanumeric unique id using base64 charset


In the era of APIs, each resource is identified by unique id. UUID can be used to generate unique id in distributed systems. This article explains how to create base64 unique id based on random UUID.

Generating base64 unique id.

  1. First generate UUID using java.util.UUID.randomUUID()
  2. Internally uuid is represented as two long integers (2 long = 128 bits) which can be accessed by uuid.getMostSignificantBits()(MSB) and uuid.getLeastSignificantBits() (LSB).
  3. Using ByteBuffer create byte[] from MSB and LSB.
  4. Using UrlEncoder of Base64 convert byte[] to base64 String.
  5. Using substring remove the trailing padding ==.
  6. Now, we have base64 string which represents the UUID generated in Step 1.


Following Java code written as spring component. It should be straight forward to use it in other places as well. java.util.Base64 requires Java 8.

package com.sakthipriyan.example;

import java.nio.ByteBuffer;
import java.util.Base64;
import java.util.Base64.Encoder;
import java.util.UUID;

import org.springframework.stereotype.Component;

public class Uuid {

    private final Encoder encoder;

    public Uuid() {
        this.encoder = Base64.getUrlEncoder();

    public String randomId() {

        // Create random UUID
        UUID uuid = UUID.randomUUID();

        // Create byte[] for base64 from uuid
        byte[] src = ByteBuffer.wrap(new byte[16])

        // Encode to Base64 and remove trailing ==
        return encoder.encodeToString(src).substring(0, 22);



package com.sakthipriyan.example;

public class ExampleService {

    private Uuid uuid;

    public void doSomething(){
        String uniqueId = uuid.randomId();
        // Do whatever you want to do.

Generated IDs

Base64 IDs generating using uuid.randomId()


40% size reduced.

  • Hexadecimal uuid f487fbcf-3606-4f35-a23d-5ac3af6de754 generated using UUID.randomUUID().toString() has 36 bytes including the -.
  • Base64 uuid 9If7zzYGTzWiPVrDr23nVA generated using uuid.randomId() has only 22 bytes.
  • By using this we can save around 40% of network bytes and storage bytes for unique id.
uuid java code base64

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