Software Alternatives, Accelerators & Startups

FastAPI VS Svelte

Compare FastAPI VS Svelte and see what are their differences

FastAPI logo FastAPI

FastAPI is an Open Source, modern, fast (high-performance), web framework for building APIs with Python 3.6+ based on standard Python type hints.

Svelte logo Svelte

Cybernetically enhanced web apps
  • FastAPI Landing page
    Landing page //
    2023-05-14
  • Svelte Landing page
    Landing page //
    2023-07-27

We recommend LibHunt Svelte for discovery and comparisons of trending Svelte projects.

FastAPI features and specs

  • High Performance
    Built on Starlette and Pydantic, FastAPI is one of the fastest frameworks for Python, providing high performance due to its asynchronous request handling.
  • Automatic Interactive API Documentation
    FastAPI automatically generates interactive API documentation via Swagger UI and ReDoc, which are very helpful for development and testing.
  • Type Checking and Validation
    With Pydantic models and Python type hints, FastAPI provides automatic data validation and type checking, reducing the chance of runtime errors.
  • Ease of Use
    Its syntax and design make it easy to learn for Python developers, offering a smooth development experience while reducing boilerplate code.
  • Asynchronous Support
    FastAPI supports asynchronous programming, allowing for better performance for I/O-bound operations, making it optimal for handling many simultaneous connections.
  • Extensive Documentation
    It has comprehensive and well-structured documentation, which is very useful for both beginners and advanced users.
  • Community and Ecosystem
    FastAPI has a growing community and ecosystem, with many plugins and integrations available to extend its functionality.

Possible disadvantages of FastAPI

  • Learning Curve for Asynchronous Programming
    Although FastAPI itself is easy to learn, grasping the concepts of asynchronous programming in Python can be challenging for beginners.
  • Complex Dependencies
    Using Pydantic for advanced validation can make the request models complex, requiring a deeper understanding of Pydantic and its functionalities.
  • Early Stage Libraries
    Some third-party libraries and extensions specifically tailored for FastAPI might still be in early stages of development and lack long-term stability.
  • Limited Real-World Examples
    Although the documentation is extensive, there might be limited real-world examples and case studies readily available compared to more mature frameworks.
  • Deployment Complexity
    Deploying FastAPI applications might be more complex in comparison to traditional synchronous frameworks, mainly due to the need for asynchronous server setups.

Svelte features and specs

  • Performance
    Svelte shifts much of the work from runtime to compile time, resulting in faster and more efficient web applications. By compiling components to highly optimized vanilla JavaScript, it reduces the overhead and boosts performance.
  • File Size
    Due to its compile-time nature, Svelte produces smaller bundle sizes compared to other frontend frameworks like React or Angular, which can significantly improve load times and performance.
  • Simplicity
    The framework is designed to be more accessible and easier to understand. Svelte’s syntax is clean and straightforward, allowing developers to get up and running quickly with minimal boilerplate.
  • Reactivity
    Svelte provides a simple and intuitive way to handle reactivity by using built-in language constructs like assignments. This means no complicated state management libraries are necessary for many use cases.
  • Less Boilerplate
    Svelte reduces the boilerplate code typically required in other frameworks, resulting in a cleaner and more maintainable codebase. This can help accelerate development and reduce bugs.
  • Reactive Programming
    SvelteKit leverages Svelte's reactive programming model, allowing developers to write less code while achieving better functionality through automatic reactivity.
  • Integrated Router
    SvelteKit includes a built-in router, which simplifies the creation of multi-page applications and enables easy setup of dynamic routes.
  • SSR and SSG
    SvelteKit supports Server-Side Rendering (SSR) and Static Site Generation (SSG) out of the box, giving developers flexibility in how they build and deploy their applications.
  • Opinionated but Flexible
    While SvelteKit provides an opinionated setup to streamline the development process, it also allows for customization to fit a developer’s specific needs.

Possible disadvantages of Svelte

  • Ecosystem Maturity
    Svelte’s ecosystem is not as mature or extensive as React’s or Angular’s. There are fewer third-party libraries, tools, and resources available, which might make it more challenging to find solutions for less common problems.
  • Learning Curve
    While Svelte itself is simpler, its approach is quite different from traditional frameworks like React and Angular. This can require a mental shift and time to learn new paradigms, especially for developers coming from those backgrounds.
  • Community Support
    Given that Svelte has a smaller user base and community compared to more established frameworks, finding community support, tutorials, and best practices can sometimes be more difficult.
  • Tooling
    While Svelte has good official tooling and support, it may lack some of the advanced tools and integrations available for other frameworks, which can slow down development for more complex applications.
  • SEO and SSR
    Although Svelte has options for server-side rendering (SSR) and improving SEO, handling these aspects is not as out-of-the-box or mature compared to frameworks like Next.js for React.
  • Community Size
    SvelteKit has a smaller community compared to other frameworks, which can affect the availability of online resources, tutorials, and community-driven support.
  • Tooling and Integration
    Some commonly used development tools and integrations may not be fully compatible with SvelteKit, necessitating workarounds or additional configuration.
  • Frequent Updates
    As a newer framework, SvelteKit undergoes frequent updates and changes, which can sometimes lead to breaking changes or require developers to frequently update their knowledge and projects.
  • Market Adoption
    SvelteKit is less adopted in the industry compared to other frameworks, which might make it a less attractive option for companies looking for widely recognized and vetted solutions.

FastAPI videos

FastAPI from the ground up

More videos:

  • Tutorial - 30 Days of Python - Day 14 - Web App with Flask, FastAPI, ngrok, and Invictify - Python TUTORIAL
  • Review - [PT] Python - API com FastAPI - Chat | twitch.tv/codeshow

Svelte videos

SvelteKit Breaking Changes 2022 - My Reactions and What You Need to Know!

More videos:

  • Review - Svelte vs React vs Angular vs Vue
  • Tutorial - SvelteKit Crash Course Tutorial #1 - What is SvelteKit?
  • Review - Why Svelte is the best JS "framework"
  • Review - Oh crap, here comes *another* JavaScript framework || SVELTE || Sveltejs

Category Popularity

0-100% (relative to FastAPI and Svelte)
Developer Tools
54 54%
46% 46
Javascript UI Libraries
0 0%
100% 100
Web Frameworks
100 100%
0% 0
JavaScript Framework
0 0%
100% 100

User comments

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Reviews

These are some of the external sources and on-site user reviews we've used to compare FastAPI and Svelte

FastAPI Reviews

The 20 Best Laravel Alternatives for Web Development
FastAPI, as the name hints, is a swift mover. Built on Starlette, it’s all about speed and performance with Python. Crafting API masterpieces at the speed of light, now that’s something.
25 Python Frameworks to Master
Since its release in 2018, it has rapidly gained popularity due to its great performance and simplicity. In fact, according to PyPi Stats, FastAPI has over 9 million monthly downloads, surpassing even full-stack frameworks like Django.
Source: kinsta.com
3 Web Frameworks to Use With Python
myapp/ is the main directory of your FastAPI application. It includes all the other files and directories needed for the application.static/ is a directory used to store static assets such as CSS, JavaScript, and image files. These assets are served directly by the web server and are typically used to add visual styling and interactivity to the application.css/, img/, js/...
Best Alternatives to FastAPI App Free for Windows (2021)
FastAPI Alternative – So many alternatives app to FastAPI that you must to know out there. And, looking for an ideal software was not easy matter. Lucky you, at this page you can find the best replacement app for FastAPI. So what you are waiting for, get the latest FastAPI alternative app for Windows 10 from this page.
Top 5 Back-End Frameworks to Consider for Web Development in 2021
FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.6+ based on standard Python type hints. It is fast when compared to other major Python frameworks like Flask and Django. FastAPI gives great flexibility to fulfill businesses’ API needs in today’s evolving world.

Svelte Reviews

Top JavaScript Frameworks in 2025
SvelteJS is a modern JavaScript framework that is useful for building static web apps that are fast, lean, and fun. You can use Svelte to build single, reusable components and large or even small-scale projects. Svelte has started gaining attention because of its ability to produce smaller code bundles that run faster in web browsers.
Source: solguruz.com
Top 10 Next.js Alternatives You Can Try
This web development framework can help you perform the easiest tasks to develop the interface components that users can interact with within their browsers, such as the comment section. Moreover, it has SvelteKit to render the components of the entire page with best practices and developments. You can utilize this platform effortlessly to add basic functionalities and...
20 Next.js Alternatives Worth Considering
Cruise into the Svelte ecosystem with Sapper, a framework that takes all the brilliance of Svelte and dials it up for app building. It’s like Svelte’s outgoing cousin, optimizing for an even smoother ride from development to go-live.
10 Best Next.js Alternatives to Consider Today
SvelteKit, the official framework for Svelte, streamlines the development of Svelte applications. With an intuitive API, SvelteKit simplifies the creation of server-side rendered (SSR) and statically generated (SSG) applications while retaining the reactive nature that makes Svelte unique. If you're seeking a framework that marries simplicity with powerful capabilities,...
The 20 Best Laravel Alternatives for Web Development
The next of these Laravel alternatives is Svelte. It cuts through the complexity, snipping off any excess, pre-compiling its magic to keep your app lightweight without shedding any muscle. The end result? Lightning strikes in web performance.

Social recommendations and mentions

Svelte might be a bit more popular than FastAPI. We know about 389 links to it since March 2021 and only 288 links to FastAPI. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.

FastAPI mentions (288)

  • How to Set Up CI/CD for a Python Backend Application on Fly.io Using GitHub Actions
    The backend of this accountability AI application is built using FastAPI, a high-performance framework for Python. The app allows users to communicate with the AI, which helps them stay accountable by generating responses based on their input. Below is a breakdown of the key components used in the code:. - Source: dev.to / 4 days ago
  • 🚀 Building Recallr: How I Turned PDFs into Anki Flashcards with AI
    Until I realized Anki has their own API Interface, which made me realize that I can automate this task, efficiently, while also getting hand on experience using FastAPI and LLMs (but am I going to change the stack later?.. Lets see). - Source: dev.to / about 20 hours ago
  • Building Weather & History Story Cards with Python and FastAPI
    By the end of this tutorial, you’ll see how I used FastAPI and Jinja2 to turn raw JSON into a dynamic timeline of weather and history that feels informative and fun. - Source: dev.to / 16 days ago
  • Build Code-RAGent, an agent for your codebase
    The only thing left to do then was to build something that could showcase the power of code ingestion within a vector database, and it immediately clicked in my mind: "Why don't I ingest my entire codebase of solved Go exercises from Exercism?" That's how I created Code-RAGent, your friendly coding assistant based on your personal codebases and grounded in web search. It is built on top of GPT-4.1, powered by... - Source: dev.to / 17 days ago
  • Understanding the Relation Between FastAPI and Uvicorn
    FastAPI and Uvicorn are two essential building blocks when developing high-performance Python APIs. - Source: dev.to / 18 days ago
View more

Svelte mentions (389)

  • Plain Vanilla Web – Guide for de-frameworking yourself
    In theory, “de-frameworking yourself” is cool, but in practice, it’ll just lead to you building what effectively is your own ad hoc less battle-tested, probably less secure, and likely less performant de facto framework. I’m not convinced it’s worth it. If you want something à la KISS[0][0], just use Svelte/SvelteKit[1][1]. Nowadays, the primary exception I see to my point here is if your goal is to better... - Source: Hacker News / 5 days ago
  • Why I’m Learning Vue.js After Six Years in React
    When I teased this series on LinkedIn, one comment quipped that Vue’s been around since 2014—“you should’ve learned it by now!”—and they’re not wrong. The JS ecosystem churns out UI libraries like Svelte, Solid, RxJS, and more, each pushing reactivity forward. React’s ubiquity made it my go-to for stability and career momentum. Now I’m ready to revisit new patterns and sharpen my tool-belt. - Source: dev.to / 6 days ago
  • Hyper – Outperform React on every metric
    What is the advantage over Svelte (https://svelte.dev/)? Especially since Svelte is already established and has an ecosystem. - Source: Hacker News / 10 days ago
  • SVQK - A Web Application Development Platform Using Svelte + Quarkus
    At Project Au Lait, we are developing and publishing an open-source asset called SVQK, which combines Svelte (Frontend) and Quarkus (Backend) for web application development. The asset includes automated testing tools and source code generation tools. This article introduces an overview of SVQK. (For instructions on how to use SVQK, refer to the Quick Start.). - Source: dev.to / 24 days ago
  • Why Svelte Might Be the Best Framework You Haven't Tried Yet 🚀
    Embrace the Ecosystem: Explore tools like SvelteKit for full-fledged app development. - Source: dev.to / 3 months ago
View more

What are some alternatives?

When comparing FastAPI and Svelte, you can also consider the following products

Django - The Web framework for perfectionists with deadlines

React - A JavaScript library for building user interfaces

Flask - a microframework for Python based on Werkzeug, Jinja 2 and good intentions.

Vue.js - Reactive Components for Modern Web Interfaces

ExpressJS - Sinatra inspired web development framework for node.js -- insanely fast, flexible, and simple

Tailwind CSS - A utility-first CSS framework for rapidly building custom user interfaces.