When comparing Flask vs Spark, the Slant community recommends Flask for most people. In the question“What are the best backend web frameworks?” Flask is ranked 7th while Spark is ranked 41st. 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 Custom quick swipe features
Pro Free
Pro Robust customization options
Pro Syncs across devices
Pro Unified inbox
Pro Free snooze options
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 Horrible privacy policy
- Sends statistical data to several services known for bad privacy policies (Google, Facebook), also there's no way to opt out.
- Automatically creates an acount with the first address entered and subscribes you to their newsletter.
- Stores credentials for your email accounts on their servers.
- Stores your emails on their servers to push them to your devices.
- Server infrastructure seems to be located in the US.
Con Doesn't support many services
Many services such as Spam filters, Pocket, and other apps are not supported.
Con Doesn't show the counts of emails next to the folders
- On the Mac platform will show +999 for the folder that contains more than 1000 emails.
- On the iPhone, the platform will not show the counts next to the folder unless they are new emails.