Skip to content


Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?


Failed to load latest commit information.
Latest commit message
Commit time
November 8, 2018 12:49
November 8, 2018 12:49
December 8, 2017 11:22
July 14, 2017 11:41
August 21, 2017 14:00
November 12, 2014 11:16
September 25, 2017 11:05
November 8, 2018 12:49
August 9, 2017 17:06
November 8, 2018 12:52
August 14, 2017 17:07
September 25, 2017 10:55
July 14, 2017 11:41
November 8, 2018 12:52


Build Status

Maven Central

Colossus is a lightweight I/O framework for building Scala services.


Full documentation can be found here:

For general discussion and Q&A, check out the Google Group.

Colossus takes part in the TechEmpower web framework benchmarks under the JSON serialization and Plaintext tests.

Here's an overview of what you can find in this repo:

  • colossus : The framework
  • colossus-metrics : high-performance metrics library (does not depend on colossus)
  • colossus-examples : A few simple examples that can be run
  • colossus-testkit : Small library containing a few useful tools for testing
  • colossus-tests : The unit and integration tests for colossus
  • colossus-docs : Markdown documentation


Copyright 2016 Tumblr Inc.

Licensed 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.