is a service on that allows you to submit "build manifests" for us to work on. We spin up a virtual machine per your specifications and run your scripts in it. This is generally used to compile and test patches, deploy websites, build and publish packages, and so on.

Heads up: Unlike most services during the alpha period, requires users to have a paid account ahead of the larger beta payment migration. Refer to this page for details.

See also:

How jobs are submitted

Unlike some other build systems, does not let you configure builds on the website itself. Instead, you write build manifests — YAML files that tell what to do. You can then submit these manifests via the API and we'll assign a runner and execute your job.

For convenience, there are ways of submitting builds automatically throughout the ecosystem — for example by pushing to repositories on These integrations are discussed below. For details on submitting jobs via the API, see the API reference.

Build manifests

Build manifests are YAML files that contain a description of your build environment and steps to run in that environment. A very simple example could be:

image: alpine/edge
  - say-hello: |
      echo hello
  - say-world: |
      echo world

When you submit this build, we'll fire up a virtual machine running an up-to-date image of Alpine Linux. Then, we'll copy your scripts into the machine and run them one at a time. More complex build jobs will probably use more features of the build.yml — here's an example that deploys

image: archlinux
  - nodejs
  - npm
  - rsync
  - 7ebab768-e5e4-4c9d-ba57-ec41a72c5665
  - setup: |
      cd receptor
      npm install
  - build: |
      cd receptor
      npm run build:production
  - deploy: |
      cd receptor
      sshopts="ssh -o StrictHostKeyChecking=no"
      rsync --rsh="$sshopts" -rP index.html $deploy:/var/www/
      rsync --rsh="$sshopts" -rP dist $deploy:/var/www/

A full reference for build manifests is available.

Build images

View the full list of supported build images.

Secrets can keep track of secrets for you, like SSH keys or PGP keys, and include them in builds for the purpose of deployment. You can manage your secrets at the secrets dashboard.

Keeping your secrets a secret

If you need to reference a secret in a command line argument or shell variable, make sure to run set +x first to temporarily disable detailed command logging in the build shell. Run set -x again once you're done handling secret information to re-enable command logging. You also need to be careful that secrets are not printed to stdout or stderr by the commands which use them — add >/dev/null 2>&1 to the affected commands if you need to hide this output.

Whenever you submit a build via the API, you can pass the secrets parameter (a boolean) to explicitly disable secrets. In this case, they will be discarded and the build run without including them (it's up to you to deal with this gracefully in your shell scripts, by the way). It is important that you use this parameter whenever submitting a build which runs code anyone you don't trust could have tampered with. This includes not only the build manifests themselves, but any code run as a side-effect, like your Makefile.

This is done for you automatically whenever you submit builds using features. When building patches from your mailing list, will automatically disable secrets.

In any case, if your secret is leaked, you must consider it permanently compromised, revoke it from any services it provides authentication for, and generate new secrets from scratch. All build logs are public, and to encourage users to roll over secrets which are compromised, our policy is to refuse to redact secrets leaked in this manner. If you require some time to fully address the consequences of a secret leak, we may redact them for up to one week — email support if you require this.

Build environment

Each task's script is given a preamble that looks like this:

#!/usr/bin/env bash
. ~/.buildenv
set -xe

# Deprecated -- use hut instead
acurl() (
	set +x
	curl --oauth2-bearer "$OAUTH2_TOKEN" "$@"

The actual shell varies depending on your build image. ~/.buildenv contains the environment variables you specified in your manifest, but feel free to modify it to communicate state between build steps.

The following environment variables are defined for all builds:

  • JOB_ID: The ID assigned to this build job
  • JOB_URL: The URL at which the build logs and information can be viewed with a web browser

The following environment variables are commonly added by integrations:

  • BUILD_SUBMITTER: The name of the integration which submitted the job
  • BUILD_REASON: The reason the integration submitted the build

Build status badges

If you add tags to your build, or enter search terms, you can use these to create a build status badge like this (the example being the latest status of itself): status

The image URL and a markdown snippet are shown in the sidebar of the search results page or tag detail page.


Do you have something that integrates with Submit a patch for this page! will automatically submit builds for you if you store a manifest in the repository as .build.yml. Each time you push, a build with this manifest will be submitted. We'll edit the manifest's sources array to point to the ref you just pushed. You can also submit up to 4 builds on each push by providing .builds/*.yml (if more are submitted, 4 manifests will be randomly chosen). Use git push -o skip-ci if you don't want to submit builds.


  • GIT_REF: Git reference which triggered the build (e.g. refs/heads/master) will also automatically submit builds for you. The naming conventions and other details are the same as the process used by — described above. will automatically submit builds when a patch to a repo with .build.yml is sent to a mailing list (do not forget to add the project name as a prefix to the subject of the message, for example [PATCH project-name]).

Note that builds submitted by patchset triggers ignore changes to the build manifest (instead they run from the latest merged state) and do not have access to secrets. For more details, see Keeping your secrets a secret.


  • BUILD_REASON: patchset
  • PATCHSET_ID: ID of the patchset (e.g. 20273)
  • PATCHSET_URL: link to the patchset (e.g.

About this wiki

commit a290ce243e74f89fc35cd4e3467a580edbc35399
Author: Drew DeVault <>
Date:   2024-05-27T14:24:11+02:00 add link to joinup chooser
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