RailsHow-ToBeginner · 3 min read

How to Run Rails Server in Ruby on Rails: Simple Steps

To run the Rails server, open your terminal, navigate to your Rails project folder, and type rails server or simply rails s. This command starts a local web server where you can view your app in a browser at http://localhost:3000.

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Syntax

The basic command to start the Rails server is rails server. You can shorten it to rails s for convenience. This command launches a local web server using default settings.

rails: The command-line tool for Ruby on Rails.
server or s: Tells Rails to start the web server.

You can add options like -p to specify a port or -b to bind to a specific IP address.

bash

rails server
# or
rails s

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Example

This example shows how to start the Rails server and access your app in a browser.

bash

$ cd my_rails_app
$ rails server
=> Booting Puma
=> Rails 7.0.4 application starting in development
=> Run `bin/rails server --help` for more startup options
Puma starting in single mode...
* Version 5.6.4 (ruby 3.1.2-p20), codename: Birdie's Version
* Min threads: 5, max threads: 5
* Environment: development
* Listening on tcp://127.0.0.1:3000
Use Ctrl-C to stop

Output

=> Booting Puma => Rails 7.0.4 application starting in development => Run `bin/rails server --help` for more startup options Puma starting in single mode... * Version 5.6.4 (ruby 3.1.2-p20), codename: Birdie's Version * Min threads: 5, max threads: 5 * Environment: development * Listening on tcp://127.0.0.1:3000 Use Ctrl-C to stop

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Common Pitfalls

Some common mistakes when running the Rails server include:

Running the command outside the Rails project folder, causing errors because Rails cannot find the app files.
Port 3000 already in use, which prevents the server from starting.
Not having required gems installed, leading to startup failures.

To fix these, always navigate to your project folder first, check for running servers on port 3000, or specify a different port with rails s -p 4000. Also, run bundle install to ensure all gems are installed.

bash

$ rails server
# Error: Could not find Rails application

# Correct way:
$ cd my_rails_app
$ rails server

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Quick Reference

Command	Description
rails server	Starts the Rails web server on default port 3000
rails s	Short form of rails server
rails s -p 4000	Starts server on port 4000 instead of 3000
rails s -b 0.0.0.0	Binds server to all IP addresses (useful for external access)
Ctrl-C	Stops the running Rails server

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Key Takeaways

Run rails server inside your Rails project folder to start the local web server.

Access your app at http://localhost:3000 by default after starting the server.

Use rails s -p [port] to change the port if 3000 is busy.

Always ensure you are in the correct directory and have installed gems with bundle install.

Stop the server anytime with Ctrl-C in the terminal.