FastAPI vs Express: Which One for Side Projects?
FastAPI has amassed 96,460 GitHub stars while Express sits at 60,678 stars. It’s clear developers have their preferences, but here’s the kicker: stars don’t ship features. FastAPI has gained traction in recent years due to its asynchronous capabilities and type hints, but does that make it better than Express for side projects? Let’s put these two under the microscope.
| Framework | Stars | Forks | Open Issues | License | Last Release Date | Pricing |
|---|---|---|---|---|---|---|
| FastAPI | 96,460 | 8,897 | 163 | MIT | 2026-03-20 | Free |
| Express | 60,678 | 39,036 | 1,006 | MIT | 2026-02-15 | Free |
FastAPI Deep Dive
FastAPI is a modern web framework for building APIs with Python 3.6+ based on standard Python type hints. It’s built on Starlette for the web parts and Pydantic for the data parts. What does this mean? You can create APIs with automatic interactive documentation (thanks to Swagger UI and ReDoc) just by using Python type declarations. This isn’t just a slight convenience; it enhances development speed significantly. Here’s a simple example:
from fastapi import FastAPI
app = FastAPI()
@app.get("/")
def read_root():
return {"Hello": "World"}
@app.get("/items/{item_id}")
def read_item(item_id: int, q: str = None):
return {"item_id": item_id, "q": q}
What’s Good About FastAPI
For starters, FastAPI is incredibly fast—like, really fast. According to the benchmarks, it’s one of the fastest web frameworks available for Python. This speed is primarily due to its asynchronous capabilities, which can handle a higher number of concurrent requests compared to standard synchronous frameworks. APIs developed with FastAPI can automatically validate and serialize data, catching bugs at development time rather than runtime. The automatic generation of Swagger docs is a fantastic feature. It saves a ton of time when you’re building APIs, providing live documentation you can interact with. Also, type hints not only help document the code but also enable editors to provide better autocomplete suggestions.
What Sucks About FastAPI
But not everything is peachy. If you’re coming from a more traditional Python framework like Flask, the steep learning curve might throw you. The specific way FastAPI uses Python type hints and the dependency injection can seem overwhelming at first. Also, while FastAPI is fast, you might not always need that scalability for smaller side projects. If you’re building something simple, this could be like bringing a bazooka to a knife fight. There are still a few bugs and quirks with the framework, especially concerning asynchronous integration and error handling, which can lead to frustrating debugging sessions.
Express Deep Dive
Express.js is a minimal and flexible Node.js web application framework providing a solid set of features to develop web and mobile applications. It’s the de facto standard for building server-side applications in Node.js land. Express provides a thin layer of fundamental web application features, without obscuring Node.js features. Here’s a basic example of what an Express app looks like:
const express = require('express');
const app = express();
app.get('/', (req, res) => {
res.send('Hello World!');
});
app.get('/items/:id', (req, res) => {
const itemId = req.params.id;
res.send({ item_id: itemId });
});
app.listen(3000, () => {
console.log('Server is running on http://localhost:3000');
});
What’s Good About Express
Express is superb for quick prototypes or small applications. If you need to whip up a server—boop, you’re done. The simplicity of setting it up is unmatched. You have flexibility with middleware and routing, which allows for pretty complex applications without much hassle. Furthermore, the Node ecosystem is massive. Need a library for just about anything? npm’s got your back. The community is solid, and there’s a wealth of resources available. Official documentation is generally straightforward, which makes onboarding easy.
What Sucks About Express
But honestly, if you’re working on larger applications, you might find Express’s “minimalist” architecture limiting. The lack of built-in structure can lead to spaghetti code if you’re not careful. Error handling is a pain; there’s just not as much made for you as in other frameworks, like FastAPI does. If you’re not mindful, you could end up sinking time into figuring out a suitable folder structure or implementing functionality that comes out of the box with FastAPI. Aspects like asynchronous programming can get clunky with Express, especially when you start mixing callbacks and Promises without clear organization.
Head-to-Head Comparison
1. Speed and Performance
FastAPI clobbers Express in terms of performance, especially for APIs where rapid response times are paramount. Benchmarks show FastAPI can outperform Express by a significant margin during concurrent loads.
2. Documentation and Standards
FastAPI also takes the cake here. The interactive documentation makes API development and debugging smoother. Express requires you to build your documentation or rely on third-party libraries, which could add additional overhead.
3. Learning Curve
Learning Express is way easier for developers coming from any JavaScript background. However, FastAPI’s type hinting might make it less of a hassle once you get over the initial curve. For developers cozy with Python, FastAPI could be more intuitive despite the initial bumps.
4. Community and Ecosystem
While FastAPI is gaining traction rapidly, the extensive npm ecosystem vouches for Express. However, fast adoption rates for FastAPI suggest its community is maturing quickly. Regardless, Express allows for more out-of-the-box middleware options.
The Money Question: Pricing Comparison
Both FastAPI and Express are free, which is a huge plus. However, it can be important to factor in hidden costs. If you go with FastAPI, you may end up spending more on infrastructure due to its speed and resource consumption during heavy loads. Express, on the other hand, is quite lean. If you’re running this on a server with limited resources, Express would consume less, thereby saving you costs in server provisioning. Depending on the project, a highly scaled FastAPI service could lead to a higher bill on platforms like AWS or Azure compared to an Express app.
My Take: Who Should Choose What?
If you’re a developer just getting started or if your side project is relatively small, I’d recommend Express. Its simplicity allows for rapid development without much fuss. Finish that MVP quickly and focus on actual features rather than wrestling with the framework.
Now, if you’re a seasoned developer or doing something that demands high performance and scalability, you should consider FastAPI. It’s an excellent choice if you need a solid API that’s fast and can handle a lot of traffic efficiently.
For enterprise developers or teams building apps that need solid documentation and automation, FastAPI is again the right bet. The time savings on documentation and auto-validation can’t be understated—they’re both significant factors that can influence project timelines.
FAQ
Can I use FastAPI for asyncio-based applications?
Absolutely! FastAPI is built to work with asynchronous programming in Python, so if you’re in an asyncio-based environment, it plays very nicely.
Is Express good for large-scale applications?
Yes, but you’ll need to be careful. Many large applications are running on Express, but they require a solid architectural approach to avoid messy code. Using frameworks like NestJS (built on Express) could offer better structure.
How do FastAPI and Express handle WebSocket connections?
FastAPI has native support for WebSockets through Starlette. Express has third-party libraries, but they don’t have the same first-class support out of the box.
Can you mix FastAPI and Express in the same project?
While it’s generally not advised to mix the two, you technically could. For instance, you could have a FastAPI service handling your API and use Express to handle some microservices if that’s your architecture decision.
Data Sources
- FastAPI GitHub – Accessed March 20, 2026
- Express Documentation – Accessed March 20, 2026
- Reddit Discussion – Accessed March 20, 2026
- Medium Article on Scaling – Accessed March 20, 2026
- DhiWise Comparison – Accessed March 20, 2026
Data as of March 22, 2026. Sources: [list URLs]
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🕒 Last updated: · Originally published: March 22, 2026