Web Development · head to head
Flask vs Ruby on Rails
Ruby on Rails
Web Development
A full-stack framework for building web applications
- From
- Free
- Rated
- -
The short version
- Each has a real cost: Flask requires manual configuration of many common features like authentication, ORM, and admin panels; Ruby on Rails licensed under the MIT License per rubyonrails.org; as open source software it has no paid tier or vendor price to compare
Where they differ
Only the attributes on which Flask and Ruby on Rails actually diverge.
| Attribute | Flask | Ruby on Rails |
|---|---|---|
| Pricing model | free | open-source |
| Platforms | Linux, macOS, Windows, Cloud (any platform supporting Python) | Web |
| Founded | 2010 | Unknown |
Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Web Development).
What each one covers
Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.
Only in Flask
- Lightweight framework
- Jinja2 templating
- Werkzeug WSGI toolkit
- URL routing
- Request handling
- Session management
- Cookie handling
- Blueprint organization
Only in Ruby on Rails
Nothing recorded that Flask does not also cover.
What people use each for
The jobs each tool is most often brought in to do.
Flask
- REST APIs and backend servicesnot Ruby on Rails
- Small-to-medium web applications and prototypesnot Ruby on Rails
- Microservicesnot Ruby on Rails
- Server-rendered apps using Jinja templatingnot Ruby on Rails
- Teaching and learning web developmentnot Ruby on Rails
Ruby on Rails
No use cases recorded yet. See the Ruby on Rails review.
Where each one falls short
Documented limitations, not opinions. Every one is a constraint you would hit in normal use.
Flask
- Requires manual configuration of many common features like authentication, ORM, and admin panels
- No built-in admin interface or scaffolding tools
- Minimal built-in security features compared to full frameworks
Ruby on Rails
- Licensed under the MIT License per rubyonrails.org; as open source software it has no paid tier or vendor price to compare
- The framework is Ruby-only by design, per rubyonrails.org's own description of its convention over configuration approach, requiring the Ruby runtime rather than supporting alternate languages
Pricing, plan by plan
Flask
Free- Open SourceFree
- Micro web framework
- Flexible architecture
- Jinja2 templating
Ruby on Rails
FreeNo published plan breakdown. See the Ruby on Rails review.
Which should you pick?
Choose Flask if
- You need lightweight framework.
- You want to start without paying.
- You work on Linux, macOS, Windows, Cloud (any platform supporting Python).
- You also want jinja2 templating.
Questions people ask
- Is Flask or Ruby on Rails better?
- Neither clearly leads. Flask starts at Free and Ruby on Rails at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
- Which is cheaper, Flask or Ruby on Rails?
- Flask starts at Free and Ruby on Rails at Free.
- Does Flask or Ruby on Rails run on more platforms?
- Flask runs on Linux, macOS, Windows, Cloud (any platform supporting Python). Ruby on Rails runs on Web.
- Can I use Flask for free?
- Both have a free tier, so you can try either at no cost before committing.
- What is Flask best used for?
- Flask is most often used for rest apis and backend services, small-to-medium web applications and prototypes, microservices, server-rendered apps using jinja templating. Of those, rest apis and backend services and small-to-medium web applications and prototypes are not what Ruby on Rails is typically brought in for.
- What can Flask do that Ruby on Rails cannot?
- Flask covers Lightweight framework, Jinja2 templating, Werkzeug WSGI toolkit, URL routing.
Answered from the vendors’ own pages
Flask: Is Flask free to use?
Yes. Flask is open-source software released under the BSD-3-Clause License, available free for any use including commercial applications.
SourceFlask: What are Flask's core dependencies?
Flask depends on three main libraries: Werkzeug (WSGI toolkit), Jinja (template engine), and Click (CLI toolkit).
SourceFlask: Does Flask provide built-in database support?
No. Flask is a microframework that does not include built-in database support. Developers must choose and integrate their own database libraries, though Flask-SQLAlchemy is a popular community extension.
SourceFlask: What platforms does Flask support?
Flask is a microframework for Python that runs on any platform that supports Python, including Linux, macOS, Windows, and cloud platforms.
SourceFlask: Can Flask scale to large applications?
Yes. While designed to be lightweight and simple, Flask is designed with the ability to scale up to complex applications through blueprints, extensions, and modular architecture.
SourceFlask: Does Flask require a build step to run?
No. Flask does not require a build step. Applications can run directly with the Flask development server using 'flask run' from the command line.
Source