When comparing Flask vs Meteor, the Slant community recommends Flask for most people. In the question“What are the best backend web frameworks?” Flask is ranked 7th while Meteor is ranked 34th. The most important reason people chose Flask is:
Flask is very easy to get up and going, with vanilla HTML or with bootstrap pieces. It doesn't take much lines of Python to load Flask to get headers working, etc, and since it's all modular you don't have to have something you don't want in your application.
Specs
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Pros
Pro Minimalist without losing power
Flask is very easy to get up and going, with vanilla HTML or with bootstrap pieces. It doesn't take much lines of Python to load Flask to get headers working, etc, and since it's all modular you don't have to have something you don't want in your application.
Pro Lots of resources available online
Flask is one of the most popular Python web frameworks, if not the most popular one. As such, there's plenty of guides, tutorials, and libraries available for it. A large number of important Python libraries, such as SQLAlchemy have libraries for Flask, which add valuable bindings to make the development process and the integration between these libraries and Flask as easy as possible.
Pro Extremely easy to build a quick prototype
Even though it's pretty minimalistic out of the box, Flask still provides the necessary tools to build a quick prototype for a web app right after a fresh install. With all the main components pretty much packed in the flask
package, building a simple web app in a single Python file is as easy as it gets.
Pro Very flexible
Flask gives developers a lot of flexibility in how they develop their web applications.
For example, the choice of not having an ORM, but instead choosing one suited to the task, or another area where Flask gives a lot of options to developers is the templating. They can use Jinja2, Flask's default templating language or choose from a number of different templating languages they desire.
Pro Great documentation
The official documentation is very thorough and complete. Everything is explained in-depth and followed by extremely well-explained tutorials that tackle real-world problems.
Pro Able to use ORM or "true SQL"
Pro Easy to learn
Meteor was developed with simplicity in mind, even for beginners who have just started using JavaScript frameworks. One of the reasons that beginners should start with Meteor is that Meteor is a full-stack framework, this way they can get the complete learning experience when it comes to web development (back-end and front-end development), all by using a single platform and a single language.
Furthermore, Meteor does not have complex and esoteric concepts that may be hard to grasp by a beginner, it has a clear documentation and well-established coding conventions.
There's also a very useful resource for learning Meteor in the form of a book: Discover Meteor, by the authors of many Meteor packages.
Pro Full-stack reactivity
Changes in the database will be propagated to all subscribed clients in real time, without you having to write any code.
Pro Isomorphic package system
A Meteor package can supply code for both the client and the server, and for mobile (Cordova) apps. For example, an autocomplete package supplies both server code to search a collection, and client code to display the results. The mdg:camera package supports the native camera if the app is built for mobile, or the HTML getUserMedia API to take pictures from the browser.
Pro Built-in security
Meteor takes care of many concerns with it's out-of-the-box security measures.
Pro Seamless communication between client and server
Meteor is built on top of Node.js and jQuery on the client.
Meteor enables the client and server to communicate data seamlessly, in real-time. You don't have to write any REST API or pub/sub code - Meteor takes care of it all automatically for you.
Pro Integrated front-end library
Meteor uses both your existing front-end library and it's own library called Blaze, which is integrated beautifully in the framework and fulfills the purpose of a true MV* front-end framework.
Pro Auto reload/refresh (hot code push)
Every time a change in the source file is saved, all connected clients will refresh automatically - browser tabs, mobile apps running in the simulator or on the physical device.
Or, deploy a Meteor app (meteor deploy myapp
) and all clients, plus all mobile apps with the server set to myapp.meteor.com
will automatically reload to use the code changes.
This drastically reduces the development cycle for apps in the App Store, where a regular update can wait for one to two weeks before being approved.
Pro Popular
Meteor is the 10th most starred project on GitHub and has overtaken even Rails.
Pro Support for MySQL, PostgreSQL and Redis
While Meteor only supports MongoDB and Redis natively, MySQL support is on the roadmap, and there are 3rd-party packages that integrate MySQL reactively with Meteor to some extent, such as numtel:mysql. For reactive PostgreSQL support, there is numtel:pg.
Pro Real-time testing framework
Meteor also has an official testing framework called Velocity. Velocity enables real-time unit testing and integration with Jasmine or Mocha syntax. Tests are automatically run when code is saved and the testing result is indicated by a green or red dot in the upper right corner of the app.
Pro Includes latency compensation
The client will mimic instant server-side response, and updates automatically if it was different once the information is available.
Pro Mobile apps from the same code base
Meteor can generate mobile (iOS and Android) apps from the same codebase as the web app, using the Cordova (PhoneGap) library (which brings native device functionality to JavaScript applications).
Meteor-generated mobile apps are JavaScript, HTML and CSS bundles that run in a UIWebView (on iOS) or WebView (on Android). Apps can be run locally in the iOS/Android emulator, or on physical devices. You can also publish them to Google Play Store or Apple's App Store.
Moreover, these hybrid mobile apps benefit from hot code push, which dramatically accelerates the development cycle.
Pro Eliminates the need to look for a database to use
Meteor uses MongoDB, eliminating the choice among NoSQL databases. MongoDB is highly scalable - used to store petabytes of data and perform billions of operations daily at eBay, FIFA, Adobe, Craigslist, McAffee, Foursquare and others.
Pro Gets rid of Node's callbacks
Although Meteor's server side runs on top of Node.js, it manages to avoid callbacks by making use of Fibers.
Pro Extensive ecosystem
Meteor's package repository called Atmosphere has more than 5000 packages available. What's more is that Meteor can also use into the packages available for the Node ecosystem.
Pro Powerful performance monitoring tools
Meteor uses Kadira which is an excellent performance monitoring tool for Meteor apps. It profiles CPU and RAM consumption, subscription latency and throughput etc.
Pro VC-funded open-source
Bright future for Meteor - funded by venture capital and open-source.
Pro In-app debugging
The community behind Meteor has created a useful application for debugging Meteor apps that will automatically delete collections and display client-side documents, allow you to control subscriptions and lets you modify the documents.
Meteor also has great support for server-side debugging, and WebStorm has also released full support for Meteor, including debugging capabilities.
Cons
Con Not async-friendly
Flask is explicitly not designed to handle async programming.
Con Setting up a large project requires some previous knowledge of the framework
Setting up a large project with Flask is not that easy considering how there's no "official" way of doing it. Blueprints are a useful tool in this regard but require some additional reading and are a bit tricky to get right for a beginner.
The lack of some defaults can also be problematic. Having to choose between different libraries for a certain task is never easy, especially if you have never worked with Flask before.
Con Threadlocals and globals used everywhere
The default way of creating applications in flask makes it hard to use reusable and clean code.
Con HTML-oriented, not API-oriented
Not necessarily designed for making APIs, though that is possible
Con No native SEO support (no server-side rendering)
Meteor does not have support for server-side rendering of views, which is extremely helpful when it comes to SEO. However, there's a third-party server-side rendering package available for download. The Meteor team has also said that server-side rendering is on the roadmap.
Though lately Google has announced that the search engine can render JS and CSS files just like modern web browsers
Con Officially supports only MongoDB, which is well-known to have issues with data integrity
MongoDB advertises scalability but only if you don't care about data-integrity. There are other backend options but none of them are officially supported.
Con Requires reliable network connection
It's common for the front-end and back-end to lose sync if an internet connection is flaky. Even though the connection should be in real-time, if the connection is weak, you may lose that real-time sync. For example, in chat applications you may have to refresh the page to get the latest updated data from the server.