What we learnt by migrating from CircleCI to Buildkite

Hasura recently migrated from CircleCI to Buildkite as their primary CI system. The main reason for this change was to control costs, as the usage of CircleCI had doubled after creating a monorepo and the engineering team grew significantly. They aimed to reduce annual CI spend by 40-50%. Additionally, they sought to improve the overall CI experience with features not provided by their old system. After evaluating various options, Buildkite was chosen due to its alignment with cost requirements and ability to provide more control. The new CI system allowed for running CI jobs on various platforms, autoscaling build nodes, and multiple triggering strategies. It also supported the use of a programming language (Go) instead of YAML for configuration, which was considered more expressive and helpful while building and modifying pipelines. The new CI system has been running on Hasura's internal monorepo for about 45 days now, with no major outages during the entire project. While it is difficult to predict if they will achieve their cost goals, they believe that they are staying on track for it.