Last updated March 13, 2023

This article explains how to use the Heroku Local CLI plugin.

Run your app locally using the Heroku Local command line tool

Heroku Local is a command-line tool to run Procfile-backed apps. It is installed automatically as part of the Heroku CLI. Heroku Local reads configuration variables from a .env file. Heroku Local makes use of node-foreman to accomplish its tasks.

Start your app locally

To locally start all of the process types that are defined in your Procfile:

$ heroku local

To locally start a particular process type, specify the process type. For example, “web” or “worker”:

$ heroku local web

You can now test the app locally. Press Ctrl+C to shut it down when you are done.

Here are some of the command line options:

• To use a different Procfile, use the -f flag: heroku local -f Procfile.test.

• To use a different environment file, use the -e flag: heroku local -e .env.test.

• To use a different port, use the -p flag: heroku local -p 7000. If you don’t specify a port, 5000 is used.

For more information, type heroku help local at the command line.

Run a one-off command locally

Heroku Local also lets you easily run a single one-off command locally. For example: heroku local:run rails console. This is analogous to Heroku’s one-off dynos.

Set up your local environment variables

When running your app, you will typically use a set of config vars to capture the configuration of the app. For example: say your app uses S3 for image storage. You would want to store the credentials to S3 as config vars. If you’re running your app locally, you typically want to use a different S3 bucket than if you were running it in production.

The .env file lets you capture all the config vars that you need in order to run your app locally. When you start your app using any of the heroku local commands, the .env file is read, and each name/value pair is inserted into the environment, to mimic the action of config vars.

View your app’s config vars

To view all of your app’s config vars, type heroku config.

Look at the contents of your .env file

$ cat .env

Here’s an example .env file:

S3_KEY=mykey
S3_SECRET=mysecret

Add a config var to your .env file

To add a config var to your .env file, edit it and add a new name=value pair on a new line.

Copy Heroku config vars to your local .env file

Sometimes you may want to use the same config var in both local and Heroku environments. For each config var that you want to add to your .env file, use the following command:

$ heroku config:get CONFIG-VAR-NAME -s  >> .env

Do not commit the .env file to source control. It should only be used for local configuration. Update your .gitignore file to exclude the .env file.

Keep in mind that your deployed production app may be connecting to different services than your local development app. For example, your deployed production app might have a DATABASE_URL config var that references a Heroku Postgres database, but your local app might have a DATABASE_URL variable in the .env file that references your local installation of Postgres.

Run your app locally using Foreman

As an alternative to using Heroku Local, you can still use Foreman to run your app locally. It’s not officially supported but if you want to use it, you can get more information by visiting the Foreman GitHub repository.

Foreman is a command-line tool for running Procfile-backed apps. Foreman reads configuration variables from a .env file.

Start your app locally

$ foreman start
18:06:23 web.1     | started with pid 47219
18:06:23 worker.1  | started with pid 47220
18:06:25 worker.1  | (in /Users/adam/myapp)
18:06:27 web.1     | => Awesome web application server output

If you had a Procfile with both web and worker process types, Foreman will start one of each process type, with the output interleaved on your terminal. Your web process loads on port 5000 because this is what Foreman provides as a default in the $PORT env var. It’s important that your web process respect this value, since it’s used by the Heroku platform when you deploy.

You can now test the app locally. Press Ctrl+C to shut it down when you are done.

Alternatively, you can select a different environment file at launch by using the -e flag like this: foreman -e alternate_env start.

Run a one-off command locally

Foreman also lets you easily run a single one-off command locally. For example: foreman run rails console. This is analogous to Heroku’s one-off dynos.