Java API

Open-source Java projects categorized as API | Edit details

Top 23 Java API Projects

  • openapi-generator

    OpenAPI Generator allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec (v2, v3)

    Project mention: Requesting opinion to evaluate frameworks vs stdlib for my use case | | 2022-05-03
  • JDA

    Java wrapper for the popular chat & VOIP service: Discord

    Project mention: What is the recommended programing language for building discord bots? | | 2022-05-15

    JDA (Java Discord API) For Java, used by Lawliet for example

  • Mergify

    Automate your Pull Request with Mergify. Mergify is the most powerful merge queue tool that offers speculative checks, batch merges, and multiple queueing options. Coordinated with any CI and fully integrated to GitHub. Get started or request a demo!

  • Apache Log4j 2

    Apache Log4j 2 is an upgrade to Log4j that provides significant improvements over its predecessor, Log4j 1.x, and provides many of the improvements available in Logback while fixing some inherent problems in Logback's architecture.

    Project mention: Reduce Security Risks by Keeping Dependencies Up-To-Date with GitHub Actions and Dependabot | | 2022-03-10

    Almost nothing is more ubiquitous in applications than logging libraries. No matter which type of application - hastily thrown-together prototypes, decades-old enterprise monoliths, newly built event-driven serverless apps - there is always the need to log. Even in non-production-grade applications where standard observability patterns such as monitoring and alerting might not be applied - logging is usually always used. Log4j has been without a doubt one of the pioneers in the logging framework sphere and continues to be widely used today making the recent discovery of a zero day exploit in Log4j a good time to highlight how important it is to keep all dependencies of your applications up-to-date at all times.

  • swagger2markup

    A Swagger to AsciiDoc or Markdown converter to simplify the generation of an up-to-date RESTful API documentation by combining documentation that’s been hand-written with auto-generated API documentation.

    Project mention: API documentation platforms/authoring stacks | | 2021-09-07

    I'm already up to my elbows in AsciiDoc/Antora building a new online help platform, and I noticed that Swagger2Markup exists. No idea if it's any good, but I might be able to integrate it into my existing workflow and spit out some usable static content at the other end...

  • docker-java

    Java Docker API Client

    Project mention: Java DockerSandbox Library | | 2022-05-16

    I would like to introduce an open source library I worked on under the Apache 2.0 license called DockerSandbox. It provides a wrapper API to the Docker Java Client at that allows code to be executed in sandbox containerized environments. It provides similar functionality for Java that StepikOrg provides for Python with epicbox at

  • Discord4J

    Discord4J is a fast, powerful, unopinionated, reactive library to enable quick and easy development of Discord bots for Java, Kotlin, and other JVM languages using the official Discord Bot API.

    Project mention: Been making a Discord bot with Discord4J, where do I start learning the nitty gritty? | | 2021-09-05
  • aws-serverless-java-container

    A Java wrapper to run Spring, Jersey, Spark, and other apps inside AWS Lambda.

    Project mention: Controlling access to Lambda Function URLs | | 2022-04-14

    Alice and Bob are two cloud developers working for Example Corp., which has its whole infrastructure run on AWS serverless technologies.

  • SonarQube

    Static code analysis for 29 languages.. Your projects are multi-language. So is SonarQube analysis. Find Bugs, Vulnerabilities, Security Hotspots, and Code Smells so you can release quality code every time. Get started analyzing your projects today for free.

  • Elide

    Elide is a Java library that lets you stand up a GraphQL/JSON-API web service with minimal effort.

    Project mention: Elide VS graphql-spqr - a user suggested alternative | | 2022-04-27
  • zerocode

    A community-developed, free, open source, microservices API automation and load testing framework built using JUnit core runners for Http REST, SOAP, Security, Database, Kafka and much more. Zerocode Open Source enables you to create, change, orchestrate and maintain your automated test cases declaratively with absolute ease.

    Project mention: 20+ Trending and Popular Java Open Source Project | | 2022-05-10


  • cats

    CATS is a REST API Fuzzer and negative testing tool for OpenAPI endpoints. CATS automatically generates, runs and reports tests with minimum configuration and no coding effort. Tests are self-healing and do not require maintenance. (by Endava)

    Project mention: Show HN: Mitmproxy2swagger – Automagically reverse-engineer REST APIs | | 2022-05-12

    This is great :) You can then fuzz your APIs for issues using

  • Javacord

    An easy to use multithreaded library for creating Discord bots in Java.

    Project mention: Is there a Java version for the Discord api? | | 2022-03-09

    Catnip, Discord4J, Javacord and JDA

  • PublicAPI

    Official Java implementation of the Hypixel Public API.

    Project mention: Who lives devs | | 2022-03-15
  • Para

    Multitenant backend server for building web and mobile apps rapidly. The backend for busy developers. (self-hosted or hosted) (by Erudika)

  • DeepfakeHTTP

    DeepfakeHTTP is a web server that uses HTTP dumps as a source for responses.

    Project mention: DeepfakeHTTP v6.3.1 | | 2021-10-25

    A new version of DeepfakeHTTP is out! I decided to add a new --dir option, allowing to host static content as static servers do. However, unlike regular static servers, DeepfakeHTTP can also host executable stuff, such as shell scripts or JavaScript. In order to have JavaScript executed on the server side you need to specify 'use server' at the beginning of the code (similar to the well-known 'use strict').

  • Membrane Service Proxy

    API gateway for REST and SOAP written in Java.

  • opentest

    Open source test automation tool for web applications, mobile apps and APIs

    Project mention: Constructing Custom Locators in OpenTest | | 2021-10-23

    On a previous project, I got to use a nifty tool called OpenTest to orchestrate test automation on an Android app. It's not a widely popular framework yet, but I hope it grows because it solves one particular problem quite well. OpenTest enables a QA team to write tests once that can run across multiple environments and platforms. It's a solid tool if you're looking to do something like automate an iOS and Android app that have identical UIs, or just want a shared language for your web and mobile app testing frameworks. OpenTest is also written in YAML, so it's approachable for even quite junior SDET teams.

  • twitch4j

    Modular Async/Sync/Reactive Twitch API Client / IRC Client

  • XSeries

    Library for cross-version Minecraft Bukkit support and various efficient API methods.

    Project mention: saberfactions problem with id | | 2021-05-24

    even according to XSeries it should be that...

  • JMapper Framework

    Elegance, high performance and robustness all in one java bean mapper

  • CustomStage

    A JavaFX UI framework to create fully customized undecorated windows

    Project mention: Beautiful menubar, like intellij | | 2022-03-18

    You'd probably want to look into forking and modifying it to suite your needs.

  • gemini

    Cloud Native and Low Code Platform to create FullStack web Admin applications in minutes (by gemini-projects)

    Project mention: Cloud Native and Low Code Platform to create FullStack web Admin applications in minutes | | 2022-02-09
  • LibGui

    Buttons & Co

    Project mention: Adding a new menu | | 2021-10-28

    I recommend you try the library LibGui. It has a decent wiki, easy to use, and is great for widgets. Link:

  • revapi

    Revapi is an API analysis and change tracking tool written in Java. Its focus is mainly on Java language itself but it has been specifically designed to not be limited to just Java. API is much more than just java classes - also various configuration files, schemas, etc. can contribute to it and users can become reliant on them.

    Project mention: JavaDoc Specification (JDK 8 etc) | | 2022-05-17
NOTE: The open source projects on this list are ordered by number of github stars. The number of mentions indicates repo mentiontions in the last 12 Months or since we started tracking (Dec 2020). The latest post mention was on 2022-05-17.

Java API related posts


What are some of the best open-source API projects in Java? This list will help you:

Project Stars
1 openapi-generator 12,141
2 JDA 2,985
3 Apache Log4j 2 2,800
4 swagger2markup 2,365
5 docker-java 2,285
6 Discord4J 1,409
7 aws-serverless-java-container 1,191
8 Elide 874
9 zerocode 604
10 cats 599
11 Javacord 549
12 PublicAPI 436
13 Para 434
14 DeepfakeHTTP 393
15 Membrane Service Proxy 375
16 opentest 297
17 twitch4j 281
18 XSeries 229
19 JMapper Framework 190
20 CustomStage 173
21 gemini 169
22 LibGui 166
23 revapi 154
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