erlkafka is a kafka client written in erlang

https://github.com/milindparikh/erlkafka.git

Kafka Version: 0.7.x

Maintainer: Milind Parikh
*License: BSD, LGPL

Also:
https://github.com/wooga/kafka-erlang

.NET

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A fully featured .NET client for Apache Kafka based on librdkafka (a fork of rdkafka-dotnet).

Kafka Version: 0.8.x, 0.9.9.x, 0.10.x, 0.11.x

Maintainer: Confluent Inc. (original author Andreas Heider)

License: Apache 2.0

https://github.com/confluentinc/confluent-kafka-dotnet

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Pure C# client with full protocol support.  Includes consumer, producer,

lower level components and gzip support (no snappy)

Kafka Version: 0.8.x

Maintainer: James Roland 

License: Apache 2.0

https://github.com/Jroland/kafka-net

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This is a .NET implementation of a client for Kafka using C# for Kafka 0.8. It provides for an implementation that covers most basic functionalities to include a simple Producer and Consumer.

Kafka Version: 0.8.x

Maintainer: ExactTarget

License: Apache 2.0

https://github.com/ExactTargetDev/kafka-net

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.Net implementation of the Apache Kafka Protocol that provides basic functionality through Producer/Consumer classes. The project also offers balanced consumer implementation. The project is a fork from ExactTarget's Kafka-net Client.

Kafka Version: 0.8.x, 0.9.x

Maintainer: Microsoft

License: Apache 2.0

https://github.com/Microsoft/Kafkanet

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C# client, asynchronous, all 3 compressions supported (read and write), tracks leader partition changes transparently, long time in production.

Kafka Version: 0.8.x

Maintainer: Vadim Chekan
License: Apache-2.0
https://github.com/ntent-ad/kafka4net

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kafka-sharp - "High Performance" .NET Kafka Driver

Kafka Version: 0.8.x

Maintainer: Criteo

License: Apache 2.0

https://github.com/criteo/kafka-sharp

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kafunk - Fully-featured, native F# client which works on .NET Core

Kafka Version: 0.8.x, 0.9.x, 0.10.x

Maintainer: Jet.com

License: Apache 2.0

https://github.com/jet/kafunk

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Clojure

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Fast kafka api for JVM languages implemented in clojure.

Kafka Version: 0.8.x

Maintainer: https://github.com/gerritjvv

License: Apache 2.0

https://github.com/gerritjvv/kafka-fast

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Wrapper to the Java API for interacting with Kafka

Kafka Version: 0.8.x

Maintainer: https://github.com/pingles

License: Apache 2.0

https://github.com/pingles/clj-kafka/ 

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Kafka clojure client library

Kafka Version: 0.8.x

Maintainer: Pierre-Yves Ritschard

License: MIT

Code, Documentation

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Ruby

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ruby-kafka - A pure Ruby client library for the Kafka distributed log systemKarafka - Ruby and Rails multi-threaded efficient Kafka processing framework. Based on librdkafka.

Kafka Version: 0.9 1.x, 0.10.x, 0.11.x0+

Maintainer: Zendesk/ Daniel SchierbeckMaciej Mensfeld

License: LGPL-3Licence: Apache 2.0

https://github.com/zendeskkarafka/ruby-kafkakarafka

-------------Karafka - Framework used to simplify Apache Kafka based Ruby and Rails applications development. Karafka provides higher abstraction layers, including Capistrano, Docker and Heroku support. Based on ruby-kafka

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rdkafka - Modern low-level Kafka client library for Ruby based on librdkafka

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Racecar – A simple framework for writing Kafka consumers in Ruby Racecar – A simple framework for writing Kafka consumers in Ruby that integrates nicely with Rails. Based on ruby-kafka. 

Kafka Version: 0.9.x, 0.10.x, 0.11.x

Maintainer: Zendesk / Daniel Schierbeck

LicenceLicense: Apache 2.0

https://github.com/zendesk/racecar

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DeliveryBoy – A simple way to publish messages to Kafka from Ruby applications. Based on ruby-kafka.

Kafka Version: 0.9.x, 0.10.x, 0.11.x

Maintainer: Zendesk / Daniel Schierbeck

LicenceLicense: Apache 2.0

https://github.com/zendesk/delivery_boy

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JRuby wrapper for producers and consumers of the existing API

Kafka Version: 0.8.x

Maintainer: Joseph Lawson
License: Apache 2.0

https://github.com/joekiller/jruby-kafka

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[Unmaintained] Pure Ruby, Consumer and Producer implementations included, GZIP and Snappy compression supported. Ruby 1.9.3 and up (CI runs MRI 2.0, JRuby and Rubinius).

Kafka Version: 0.8.x

Maintainer: Bob Potter
License: MIT

https://github.com/bpot/poseidon

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https://github.com/acrosa/kafka-rb

Kafka Version: 0.7.x

Maintainer: Alejandro Crosa
License:: Apache 2.0

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Event machine client:
https://github.com/groupme/em-kafka

Kafka Version: 0.7.x

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JRuby Event stream processor
https://github.com/wooga/kafkaesque

Kafka Version: 0.7.x

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Node.js

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The node-rdkafka library is a high-performance NodeJS client for Apache Kafka that wraps the native librdkafka library. All the complexity of balancing writes across partitions and managing (possibly ever-changing) brokers should be encapsulated in the library.

https://github.com/Blizzard/node-rdkafka

Kafka Version: 0.9, 0.10

Node.js >= 4

Maintainer: Blizzard.com

License: MIT

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Kafka-Node is a NodeJS client with Zookeeper integration

Kafka Version: 0.8.x

Maintainer: sohu.com

License: MIT

https://github.com/SOHU-Co/kafka-node/

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Kafka-node is a pure JavaScript implementation for NodeJS Server with Vagrant and Docker support.

Kafka Version: 0.8.x

Maintainer: wurstmeister
License: Apache 2.0

https://github.com/wurstmeister/node-kafka-0.8-plus

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kafka-java-bridge is a Nodejs wrapper for the JAVA high level kafka 0.8. consumer API

Kafka Version: 0.8.x

Maintainer: LivePersonInc

License: MIT

https://www.npmjs.com/package/kafka-java-bridge

https://github.com/LivePersonInc/kafka-java-bridge

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Low-level protocol support in node.js.

https://github.com/cainus/Prozess
https://npmjs.org/package/prozess

Kafka Version: 0.7.x

Maintainers: 
Gregg Caines
Eric lee
License: MIT

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Alternate node client from Tagged
https://github.com/marcuswestin/node-kafka

Also:
https://github.com/dannycoates/franz-kafka

Kafka Version: 0.7.x

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