Software Alternatives & Startups

bundlejs VS FastAPI

Compare bundlejs VS FastAPI and see what are their differences

bundlejs logo bundlejs

A quick and easy way to bundle, minify, and compress (gzip and brotli) your ts, js, jsx and npm projects all online, with the bundle file size.

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.
  • bundlejs Landing page
    Landing page //
    2025-09-16

bundle is a quick and easy way to bundle your projects, minify and see it's gzip size. It's an online tool similar to bundlephobia, but bundle does all the bundling locally on you browser and can treeshake and bundle multiple packages (both commonjs and esm) together, all without having to install any npm packages and with typescript support.

If there is something I missed, a mistake, or a feature you would like added please create an issue or a pull request and I'll try to get to it. You can contribute to this project at okikio/bundle.

You can join the discussion on Github discussions or Twitter.

You can now use search queries in bundle, all you need to do is add this to the url
?q={packages}&treeshake={methods to treeshake}

e.g.
You want react, react-dom, vue, and @okikio/animate, but only want the Animate and toStr methods exported from @okikio/animate.

You would add this to the url bundlejs.com/?q=react,react-dom,vue,@okikio/animate&treeshake=[*],[*],[*],[{Animate,toStr}]

  • FastAPI Landing page
    Landing page //
    2023-05-14

bundlejs

$ Details
free
Platforms
Web Google Chrome Firefox Safari JavaScript Edge
Release Date
2021 May

FastAPI

$ Details
free
Platforms
-
Release Date
-
Startup details
Country
Colombia

bundlejs features and specs

  • brotli
  • gzip
  • lz4
  • npm
  • deno
  • Configurable
  • jsx
  • TypeScript
  • Offline
  • Error and warning alerting
  • Open-source

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.

Analysis of FastAPI

Overall verdict

  • FastAPI is widely regarded as a good choice, especially for applications that require high performance, scalability, and modern Python features. It is suitable for both simple and complex projects, making it a versatile tool in the web development ecosystem.

Why this product is good

  • FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.7+ based on standard Python type hints. It is built on top of Starlette for web framework capabilities and Pydantic for data validation and settings management. FastAPI is known for its excellent performance, automatic generation of interactive API documentation (with Swagger and Redoc), and support for asynchronous programming. Developers appreciate its ease of use, detailed documentation, and helpful error messages.

Recommended for

  • Developers building RESTful APIs
  • Teams looking for a high-performance ASGI-based web framework
  • Projects that require asynchronous programming capabilities
  • Applications needing automatic generation of interactive API documentation
  • Python developers who prefer utilizing type hints for code clarity and validation

bundlejs videos

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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

Category Popularity

0-100% (relative to bundlejs and FastAPI)
Developer Tools
4 4%
96% 96
Web Application Bundler
100 100%
0% 0
API Tools
0 0%
100% 100
Compression
100 100%
0% 0

User comments

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Reviews

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

bundlejs Reviews

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FastAPI Reviews

  1. Kurslog team
    · Working at Kurslog ·

    When our backend team needs to build services for data parsing, aggregators, or high-load APIs, FastAPI is our absolute go-to choice. It completely lives up to its name-development speed is outstanding.

    The combination of Pydantic for data validation and built-in async support keeps our shared codebase clean, strictly typed, and reliable. But the biggest highlight for our cross-functional team is the automatic generation of interactive OpenAPI (Swagger) documentation. Our frontend and mobile developers no longer have to wait for backend engineers to manually update API docs; everything stays perfectly in sync automatically. It has drastically improved our team's communication and delivery speed.

    Pros:    Blazing fast performance (on par with nodejs and go)|Native asynchronous support out of the box|Automatic, interactive documentation generation (swagger/redoc)|Strict typing and data validation with pydantic
    Cons:    Smaller plug-and-play ecosystem compared to older frameworks like django|Requires our architects to design the project structure and directory layout from scratch

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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.
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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/...
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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.

Social recommendations and mentions

Based on our record, FastAPI seems to be a lot more popular than bundlejs. While we know about 312 links to FastAPI, we've tracked only 10 mentions of bundlejs. 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.

bundlejs mentions (10)

  • Show HN: Duper – The Format That's Super
    I think a neat route would be to use this as an authoring plugin in VS Code, like prettier: write Duper (or JSON5, or whatever), and then downlevel it to regular json automatically when pressing cmd-s. You wouldn't get to keep your comments (or they could be transformed to { "//": "comment text" }). Outside of that, it's tough to compete with JSON in the "human readable unschematized serialization format" market,... - Source: Hacker News / 10 months ago
  • I Built the Same App 10 Times: Evaluating Frameworks for Mobile Performance
    React's bundling system and published packages has gotten noticeably more complicated over time. First, there's the separation between the generic cross-platform `react` package, and the platform-specific reconcilers like `react-dom` and `react-native. All the actual "React" logic is built into the reconciler packages (ie, each contains a complete copy of the actual `react-reconciler` package + all the... - Source: Hacker News / 10 months ago
  • Zod 4
    These numbers don't reflect anything useful. This is the total size of the code in the package, most of which will be tree-shaken. In Zod's case, the package now contains three independent sub-libraries. I recommend plugging a script into bundlejs.com[0] to see bundle size numbers for a particular script [0] https://bundlejs.com. - Source: Hacker News / over 1 year ago
  • PackagePhobia – Find the cost of adding a new dev dependency to your project
    [bundlejs](https://bundlejs.com/) is the better alternative to check your dependency sizes with. - Source: Hacker News / over 1 year ago
  • ESM & CJS: The subtle shift in bundlejs' behaviour
    I was closing out some long lived issues over on bundlejs, when issue #50 reminded me of the ongoing debate about how bundlejs should handle the ESM and CJS packages. - Source: dev.to / about 3 years ago
View more

FastAPI mentions (312)

  • I Built My First Machine Learning API — Here's Everything I Learned
    I used FastAPI, a Python framework built specifically for creating APIs quickly, with automatic validation and interactive documentation baked in. - Source: dev.to / 25 days ago
  • Shipping Sovereign SDK: Cryptographic Forensic Receipts and the End of the AI "Prose Tax"
    The Sovereign SDK is a Python-native framework designed to minimize prose overhead while generating ironclad, cryptographic execution receipts for AI agents, complete with drop-in FastAPI/Starlette ASGI middleware. - Source: dev.to / 3 months ago
  • 5-Minute AI Jobs and Closed Tabs — Why We Built Replay-Then-Tail SSE
    We had a feature in production where a single user request could run for five-plus minutes — fetch documents, chunk them, hit an LLM per chunk, synthesize a final answer. We did the obvious thing first: a FastAPI handler that ran the pipeline and streamed progress back to the browser over Server-Sent Events. - Source: dev.to / 4 months ago
  • FastAPI With LangChain and MongoDB
    FastAPI is a Python framework for building APIs quickly, efficiently, and with very little code. - Source: dev.to / 5 months ago
  • I Built A " CrowdSense AI " : A Scalable, Context-Aware Platform for Smart Stadiums
    Backend: Python-based FastAPI for its asynchronous I/O capabilities and rapid JSON serialization. - Source: dev.to / 5 months ago
View more

What are some alternatives?

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

BundlePhobia - Find the performance impact of adding a npm package to your bundle.

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

esbuild - An extremely fast JavaScript bundler and minifier

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

Webpack - Webpack is a module bundler. Its main purpose is to bundle JavaScript files for usage in a browser, yet it is also capable of transforming, bundling, or packaging just about any resource or asset.

Django - The Web framework for perfectionists with deadlines