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Environment configuration

When developing a Probot App, you will need to have several different fields in a .env file which specify environment variables. Here are some common use cases:

Variable Description
APP_ID The App ID assigned to your GitHub App. Required

(Example: 1234)

Private key options One of the following is Required if there is no .pem file in your project's root directory
PRIVATE_KEY_PATH The path to the .pem file for your GitHub App.

(Example: path/to/key.pem)

PRIVATE_KEY The contents of the private key for your GitHub App. If you're unable to use multiline environment variables, use base64 encoding to convert the key to a single line string. See the Deployment docs for provider specific usage.
Webhook options
WEBHOOK_PROXY_URL Allows your local development environment to receive GitHub webhook events. Go to to get started.


WEBHOOK_SECRET The webhook secret used when creating a GitHub App. 'development' is used as a default, but the value in .env needs to match the value configured in your App settings on GitHub. Note: GitHub marks this value as optional, but for optimal security it's required for Probot apps. Required

(Example: development)

For more on the set up of these items, check out Configuring a GitHub App.

Some less common environment variables are:

Variable Description
GHE_HOST The hostname of your GitHub Enterprise instance.


GHE_PROTOCOL The protocol of your GitHub Enterprise instance. Defaults to HTTPS. Do not change unless you are certain.

(Example: https)

LOG_FORMAT By default, logs are formatted for readability in development. You can set this to json in order to disable the formatting
LOG_LEVEL The verbosity of logs to show when running your app, which can be fatal, error, warn, info, debug, trace or silent. Default: info
LOG_LEVEL_IN_STRING By default, when using the json format, the level printed in the log records is an int (10, 20, ..). This option tells the logger to print level as a string: {"level": "info"}. Default false
SENTRY_DSN Set to a Sentry DSN to report all errors thrown by your app.


PORT The port to start the local server on. Default: 3000
HOST The host to start the local server on.
WEBHOOK_PATH The URL path which will receive webhooks. Default: /
REDIS_URL Set to a redis:// url as connection option for ioredis in order to enable cluster support for request throttling.

(Example: redis://

For more information on the formatting conventions and rules of .env files, check out the npm dotenv module's documentation.

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