Using SSL in local development

29 Jul 2020

The first step to using SSL on local development is to generate a self-signed certificate on our development machine. If you are familiar with openssl, you can use it to generate the certificate. But it’s kinda tricky to get valid certificates. The easiest way is to use mkcert to generate self-signed certificates

Install & setup mkcert

On the mac, we can use Homebrew to install it.

brew install mkcert
brew install nss # for firefox

nss is only required if you are using Firefox

If you are on Ubuntu, first install the certutil

sudo apt install libnss3-tools

Then using Linuxbrew, install mkcert

brew install mkcert

Once the installation is successful, we need to install the rootCA by running

mkcert -install

Next, we can generate certificates for our projects

mkdir ssl/
mkcert -key-file ssl/key.pem -cert-file ssl/cert.pem "myapp.local"


Now we have the certificate and the key generated in the ssl/ folder. Also make sure to add the domain into /etc/hosts, in our case myapp.local

# /etc/hosts  myapp.local

In the following sections, we will look into how we can use the generate certificate with our different applications.

Create React App (CRA)

For CRA, we can specify the certificate and key in the .env file. Add following into .env.local or .env.development


and restart your server.


For Jekyll, we can specify the certificates using --ssl-key & --ssl-cert options

jekyll serve -D --future --ssl-key ssl/key.pem --ssl-cert ssl/cert.pem


For rails, we have to do some config changes

In webpacker.yml, toggle https to true under development -> dev_server.

# config/webpacker.yml

  <<: *default
  # ...
  # ...

  # Reference:
    https: true

If you are using a custom local domain like, myapp.local make sure to add that into config.hosts in config/environments/development.rb

# config/enviroments/development.rb

Rails.application.configure do

  config.hosts << "myapp.local"

The local domain might be different for teammates, it’s better to accept the custom domain using ENV. Add HOST to .env.local

# .env.local


and use the HOST env in the config like below

# config/environments/development.rb

Rails.application.configure do

  config.hosts << ENV.fetch("HOST")

Next, we can start the rails server using the -b option.

rails s -b "ssl://"


Hope that helped.

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