BIG FAT LIST OF NETLIFY ENV VARS - now documented at https://docs.netlify.com/configure-builds/environment-variables/#declare-variables

NETLIFY_ENV_VARS.js

// please check https://docs.netlify.com/configure-builds/environment-variables/#declare-variables for most up to date info
// this was created before those docs existed

process.env = {
  /**
   * 
   * AUTOMATICALLY SET BY NETLIFY. IMMUTABLE!
   * docs: https://www.netlify.com/docs/continuous-deployment/#environment-variables
   * 
   */
  NETLIFY: 'true',

  // // URLs 
  DEPLOY_URL: 'https://5d4aeac2ccabf517d2f219b7--plsdelete-potato2323.netlify.com',
  DEPLOY_PRIME_URL: 'https://5d4aeac2ccabf517d2f219b7--plsdelete-potato2323.netlify.com',
  NETLIFY_IMAGES_CDN_DOMAIN: 'd33wubrfki0l68.cloudfront.net',
  REPOSITORY_URL: 'https://x-access-token:[email protected]/sw-yx/plsdelete-potato123232', //  URL to the Git repository the build pulls changes from.
  URL: 'https://plsdelete-potato2323.netlify.com',
  // // git
  BRANCH: 'master', // Reference to check out after fetching changes from the Git repository. useful in split testing https://www.netlify.com/docs/split-testing/#exposing-split-test-information-in-your-site
  COMMIT_REF: '1652d2fa7fe231835e4971ca8ba367f6fd629e8a', // Reference of the commit we’re building.
  HEAD: 'master', // Name of the head branch received from a Git provider.
  // netlify metadata you can use
  BUILD_ID: '5d4aeac2ccabf517d2f219b8',
  CONTEXT: 'production', // Name of the context a deploy is built around, it can be `production`, `deploy-preview` or `branch-deploy`.
  DEPLOY_ID: '5d4aeac2ccabf517d2f219b7',

  // // PR DEPLOY PREVIEW Related
  PULL_REQUEST: 'false', // Whether the build is from a pull/merge request or not.
  REVIEW_ID: 'deploy-preview-1211', // the ID of a Deploy Preview and the pull/merge request that generated it (e.g. 1211). These two numbers will always match (deploy-preview-12 is for PR # 12 in your repository).

  // // WEBHOOK TRIGGERED Related
  INCOMING_HOOK_TITLE: 'foo', // todo: document
  INCOMING_HOOK_URL: 'foo', // todo: document
  INCOMING_HOOK_BODY: 'foo', // todo: document https://www.netlify.com/docs/webhooks/#build-hook-payload
  // note build hooks accept metadata as well https://www.netlify.com/docs/webhooks/#build-hook-metadata

  /**
   *  THINGS YOU CAN SET TO CHANGE THE BUILD ENVIRONMENT
   * https://www.netlify.com/docs/build-settings/#build-environment-variables
   */

  // // settings
  GIT_LFS_ENABLED: undefined, // If you set a GIT_LFS_ENABLED variable, we’ll use git lfs clone to check out your repository — otherwise we just use git clone. https://www.netlify.com/docs/build-settings/#additional-variables-that-can-affect-the-build
  // https://www.netlify.com/docs/build-settings/#node-npm-and-yarn
  NODE_ENV: 'development',
  YARN_VERSION: '1.17',  // only if yarn.lock exists
  YARN_FLAGS: '--ignore-optional', // only if yarn.lock exists
  NPM_VERSION: '?', // if package.json exists but yarn.lock does not exist. same npm version that ships with NODE_VERSION
  NPM_FLAGS: '',  // if package.json exists but yarn.lock does not exist.
  NPM_TOKEN: '?', //  If you use NPM, then you can set an NPM_TOKEN environment variable which can be configured to use to fetch dependencies from npmjs.org.  TODO: document.  https://gist.github.com/biilmann/0b2250095eedc188d0c9
  // if bower.json exists we also run bower install --config.interactive=false https://www.netlify.com/docs/build-settings/#bower
  // grunt: https://www.netlify.com/docs/build-settings/#grunt
  // build image (Xenial vs Legacy): set in UI https://www.netlify.com/docs/build-settings/#build-image-selection

  // env version numbers
  CUSTOM_RUBY: '0',
  GIMME_GO_VERSION: '1.12',
  GO_VERSION: '1.12',
  JAVA_VERSION: 'default_sdk',
  NODE_VERSION: 'v10.16.2', // can also set a /.nvmrc https://www.netlify.com/docs/continuous-deployment/#node
  PIPENV_DEFAULT_PYTHON_VERSION: '2.7',
  PIPENV_RUNTIME: '2.7', // can also set runtime.txt https://www.netlify.com/docs/continuous-deployment/#python
  // or requirements.txt https://www.netlify.com/docs/build-settings/#python
  PIPENV_VENV_IN_PROJECT: '1',
  PS1: '(python2.7) ',
  RUBY_VERSION: '2.6.2', // can also set .ruby-version https://www.netlify.com/docs/continuous-deployment/#ruby and https://www.netlify.com/docs/build-settings/#ruby
  SHLVL: '1',
  YARN_VERSION: '1.17.0',
  _system_arch: 'x86_64',
  _system_version: '16.04',
  rvm_ruby_string: 'ruby-2.6.2',
  rvm_version: '1.29.7 (latest)',
  HUGO_VERSION: 'foo', // todo: document https://www.netlify.com/docs/continuous-deployment/#common-build-tools
  // or https://www.netlify.com/docs/build-settings/#hugo

  // settings for functions
  GO_IMPORT_PATH: 'foo', // todo: document https://www.netlify.com/docs/functions/#building-go-functions-with-netlify-s-continuous-deployment
  AWS_LAMBDA_JS_RUNTIME: '8.10' // you can set to 'nodejs10.x'. todo: document https://www.netlify.com/docs/functions/#javascript-runtime-settings

  /**
   * 
   * MISC VARS
   * 
   */

  // settings & flags
  GIMME_CGO_ENABLED: 'true',
  NVM_CD_FLAGS: '',


  // directories
  GEM_HOME: '/opt/buildhome/.rvm/gems/ruby-2.6.2',
  GEM_PATH: '/opt/buildhome/.rvm/gems/ruby-2.6.2:/opt/buildhome/.rvm/gems/ruby-2.6.2@global',
  GIMME_ENV_PREFIX: '/opt/buildhome/.gimme/env',
  GOCACHE: '/opt/buildhome/.gimme_cache/gocache',
  GOPATH: '/opt/buildhome/.gimme_cache/gopath',
  GOROOT: '/opt/buildhome/.gimme/versions/go1.12.linux.amd64',
  HOME: '/opt/buildhome',
  IRBRC: '/opt/buildhome/.rvm/rubies/ruby-2.6.2/.irbrc',
  MY_RUBY_HOME: '/opt/buildhome/.rvm/rubies/ruby-2.6.2',
  NETLIFY_BUILD_BASE: '/opt/build',
  NVM_BIN: '/opt/buildhome/.nvm/versions/node/v10.16.2/bin',
  NVM_DIR: '/opt/buildhome/.nvm',
  OLDPWD: '/opt/build/repo',
  PATH: '/opt/buildhome/.wasmer/bin:/opt/buildhome/.wasmer/globals/wapm_packages/.bin:/opt/buildhome/.gimme/versions/go1.12.linux.amd64/bin:/opt/buildhome/.rvm/gems/ruby-2.6.2/bin:/opt/buildhome/.rvm/gems/ruby-2.6.2@global/bin:/opt/buildhome/.rvm/rubies/ruby-2.6.2/bin:/opt/buildhome/.rvm/bin:/opt/buildhome/.nvm/versions/node/v10.16.2/bin:/opt/buildhome/python2.7/bin:/opt/buildhome/.php:/opt/buildhome/.binrc/bin:/usr/local/rvm/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/opt/buildhome/.cask/bin:/opt/buildhome/.gimme/bin:/opt/buildhome/.dotnet/tools:/opt/buildhome/.dotnet',
  PWD: '/opt/build/repo',
  RVM_DIR: '/opt/buildhome/.rvm',
  VIRTUAL_ENV: '/opt/buildhome/python2.7',
  WASMER_CACHE_DIR: '/opt/buildhome/.wasmer/cache',
  WASMER_DIR: '/opt/buildhome/.wasmer',
  _: '/opt/buildhome/.nvm/versions/node/v10.16.2/bin/node',
  rvm_bin_path: '/opt/buildhome/.rvm/bin',
  rvm_path: '/opt/buildhome/.rvm',
  rvm_prefix: '/opt/buildhome',


  // misc 🤷🏼‍
  GIMME_NO_ENV_ALIAS: 'true',
  GIMME_TYPE: 'binary',
  LANG: 'en_US.UTF-8',
  LANGUAGE: 'en_US:en',
  LC_ALL: 'en_US.UTF-8',
  _system_name: 'Ubuntu',
  _system_type: 'Linux',
  rvm_delete_flag: '0',
}

more build stuff: https://github.com/netlify/build-image/blob/xenial/run-build-functions.sh

• NETLIFY_BUILD_BASE: '/opt/buildhome'
• NELTIFY_CACHE_DIR: '/opt/buildhome/cache'
• NELTIFY_REPO_DIR: '/opt/buildhome/repo'
• BUNDLER_FLAGS: ""
• SHA1: # something
• SHA2: # something