Case Study: Par8o achieves 8x faster Rails CI builds with Semaphore Boosters

How par8o Sped up Rails CI Builds 8x with Semaphore Boosters

Par8o, a Rails team, was struggling with test runs that took more than 2 hours on development laptops and even with Semaphore’s parallel jobs still took around 50 minutes, making it hard to get fast feedback and avoid context switching. As the test suite grew, manually organizing files and maintaining parallel test setup became tedious and error-prone.

Semaphore solved this with Semaphore Boosters, a Ruby gem that records test timings and automatically splits RSpec tests into balanced jobs. With Semaphore Boosters, Par8o reduced its full test suite time to about 13 minutes, cutting run time from over 2 hours to 13 minutes while also saving developer time spent managing test folders.

Par8o

Kendal Miller

Senior Engineer