A set of libraries and other tools to aid development of blockchain and other decentralized software in Java and other JVM languages

blockchain, crypto, decentralized, ethereum, securescuttlebutt, tuweni


Tuweni: Apache Core Libraries for Java (& Kotlin)

Discord Slack Github build License Maven Central Sonatype Nexus (Snapshots) codecov


See our web site for details on the project.

Tuweni is a set of libraries and other tools to aid development of blockchain and other decentralized software in Java and other JVM languages.

It includes a low-level bytes library, serialization and deserialization codecs (e.g. RLP), various cryptography functions and primatives, and lots of other helpful utilities.

Tuweni is developed for JDK 11 or higher.

Build Instructions

Install Docker.

Clone along with submodules

git clone tuweni
cd tuweni
git submodule update --init --recursive

Build the project

One step build

Requires Docker: ./

With Gradle and Java

Install Gradle >6 and JDK 11.


$>gradle setup

It will install the Gradle wrapper with the correct version.

Then build:

$>./gradlew build

After a successful build, libraries will be available in build/libs.


Your contributions are very welcome! Here are a few links to help you:

Mailing lists

More information


Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Crypto Notice

This distribution includes cryptographic software. The country in which you currently reside may have restrictions on the import, possession, use, and/or re-export to another country, of encryption software. BEFORE using any encryption software, please check your country's laws, regulations and policies concerning the import, possession, or use, and re-export of encryption software, to see if this is permitted. See [] for more information.

The Apache Software Foundation has classified this software as Export Commodity Control Number (ECCN) 5D002, which includes information security software using or performing cryptographic functions with asymmetric algorithms. The form and manner of this Apache Software Foundation distribution makes it eligible for export under the "publicly available" Section 742.15(b) exemption (see the BIS Export Administration Regulations, Section 742.15(b)) for both object code and source code. The following provides more details on the included cryptographic software: