Builds & Workflows

Once you added an app to Bitrise, your first build will be kicked off automatically.

A build is the process specified by the app’s workflow, which is a collection of steps. The app’s build configuration is specified in the [bitrise.yml](/bitrise-cli/basics-of-bitrise-yml) configuration file which you can modify in’s graphical Workflow Editor UI, or in a yaml editor directly.

On the graphical UI of the Workflow editor, you are able to add, remove, and reorder the build steps. Steps represent a block of script execution with predefined input and output variables. Steps can be written in various languages, like bash, Go, Ruby, Swift, and more.

When a build is running, these scripts will be downloaded and executed in the order you’ve defined in your workflow, with the input parameters you set. They will produce the predefined outputs set as environment variables.

Read more about how the CLI, workflows and steps work “under the hood” in the Bitrise CLI and bitrise.yml section.

The build process

  1. Trigger builds by:
  2. Environment preparation: A virtual machine will be provisioned and prepared to run the build. Build specific environment variables are preset so you can use these in your steps. You can find more information about the available stacks in the Workflow Editor, on the Stack tab.
  3. Workflow execution: Steps in Workflows are executed in the same order as defined in the Workflow editor of your application, from top to bottom. You can reorder the steps by dragging. The log each step generates will be displayed on the build’s details page.
  4. Cleanup: After the execution of the build, a build log is created and stored on the Bitrise server and the virtual machine gets destroyed, so your code/files will not fall into the wrong hands.

Build concurrency

Build concurrency determines how many builds you can run simultaneously. Builds over your subscription plan’s concurrency count will be marked as on hold. They will start whenever your ongoing builds are finished and you have a free build slot. You can always purchase additional concurrencies with the Developer or Organization (Org Standard or Org Elite) plans to increase the concurrent builds you can run at the same time.