Alternatives to FastAPI
Compare FastAPI alternatives for your business or organization using the curated list below. SourceForge ranks the best alternatives to FastAPI in 2026. Compare features, ratings, user reviews, pricing, and more from FastAPI competitors and alternatives in order to make an informed decision for your business.
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1
Gunicorn
Gunicorn
Gunicorn 'Green Unicorn' is a Python WSGI HTTP Server for UNIX. It's a pre-fork worker model. The Gunicorn server is broadly compatible with various web frameworks, simply implemented, light on server resources, and fairly speedy. -
2
Litestar
Litestar
Everything that's needed to build modern APIs, from data serialization and validation to websockets, ORM integration, session management, authentication and more. Litestar puts great emphasis on developer experience and performance: It's one of the fastest ASGI frameworks and developing with it is just as fast. Asynchronous at heart, but with synchronous execution not as a second class citizen: Synchronous applications run without performance penalties. Interfaces for various key/value stores that seamlessly integrate with your application and third party extensions. Response caching with minimal configuration and overhead to speed up response times. Response caching with minimal configuration and overhead to speed up response times. Session and JWT based authentication and utilities at your disposal to start building your authentication layer with ease. -
3
Gradio
Gradio
Build & Share Delightful Machine Learning Apps. Gradio is the fastest way to demo your machine learning model with a friendly web interface so that anyone can use it, anywhere! Gradio can be installed with pip. Creating a Gradio interface only requires adding a couple lines of code to your project. You can choose from a variety of interface types to interface your function. Gradio can be embedded in Python notebooks or presented as a webpage. A Gradio interface can automatically generate a public link you can share with colleagues that lets them interact with the model on your computer remotely from their own devices. Once you've created an interface, you can permanently host it on Hugging Face. Hugging Face Spaces will host the interface on its servers and provide you with a link you can share. -
4
Sanic
Sanic
Intuitive API with smart defaults and no bloat allows you to get straight to work building your app. Build the way you want to build without letting your tooling constrain you. Built from the ground up with speed and scalability as a main concern. It is ready to power web applications big and small. Out of the box, it comes bundled with a web server ready to power your web applications. Sanic is one of the overall most popular frameworks on PyPI, and the top async enabled framework. The project is maintained and run by the community for the community. -
5
Starlette
Starlette
Starlette includes an application class Starlette that nicely ties together all of its other functionality. A list of middleware to run for every request. A starlette application will always automatically include two middleware classes. ServerErrorMiddleware is added as the very outermost middleware, to handle any uncaught errors occurring anywhere in the entire stack. ExceptionMiddleware is added as the very innermost middleware, to deal with handled exception cases occurring in the routing or endpoints. Startup handler callables do not take any arguments and may be either standard functions or async functions. Shutdown handler callables do not take any arguments and may be either standard functions or async functions. -
6
AIOHTTP
AIOHTTP
Supports both client and server side of HTTP protocol, both client and server web-sockets out-of-the-box, and avoids callback hell and web-server with middlewares and pluggable routing. -
7
CherryPy
CherryPy
CherryPy allows developers to build web applications in much the same way they would build any other object-oriented Python program. This results in smaller source code developed in less time. CherryPy is now more than ten years old, and it has proven to be fast and reliable. It is being used in production by many sites, from the simplest to the most demanding. In order to make the most of CherryPy, you should start with the tutorials that will lead you through the most common aspects of the framework. Once done, you will probably want to browse through the basics and advanced sections that will demonstrate how to implement certain operations. Finally, you will want to carefully read the configuration and extend sections that go in-depth regarding the powerful features provided by the framework. -
8
Bottle
Bottle
Bottle is a fast, simple and lightweight WSGI micro web-framework for Python. It is distributed as a single file module and has no dependencies other than the Python Standard Library. Requests to function-call mapping with support for clean and dynamic URLs. Fast and pythonic built-in template engine and support for mako, jinja2 and cheetah templates. Convenient access to form data, file uploads, cookies, headers and other HTTP-related metadata. Built-in HTTP development server and support for paste, bjoern, gae, cherrypy or any other WSGI capable HTTP server. -
9
Giotto
Giotto
It is based on the concept of Model, View and Controllers. The framework is designed to enforce a clean style that results in code that is maintainable over a long period. Other popular web frameworks are built with a mindset of launching fast. This results in code that will deploy quickly, but falls under it’s own complexity after many iterations. An example of a controller process is Apache, or gunicorn. A manifest is given to the controller process when it is started. All incoming requests to the controller process will be routed to a program contained within the manifest. A manifest is just a collection of programs. A user makes a request to the controller process. This can be a web request, or a command line invocation, or any other action that is handled by a controller process. -
10
hug
hug
Drastically simplify API development over multiple interfaces. With hug, design and develop your API once, then expose it however your clients need to consume it. Be it locally, over HTTP, or through the command line - hug is the fastest and most modern way to create APIs on Python3. hug has been built from the ground up with performance in mind. It is built to consume resources only when necessary and is then compiled with Cython to achieve amazing performance. As a result, hug consistently benchmarks as one of the fastest Python frameworks and without question takes the crown as the fastest high-level framework for Python 3. hug makes it easy to expose multiple versions of your API. With hug you can simply specify what version or range of versions an endpoint supports and then automatically have that enforced and communicated to your API's users. -
11
Falcon
Falcon
Falcon is a blazing fast, minimalist Python web API framework for building robust app backends and microservices. The framework works great with both asyncio (ASGI) and gevent/meinheld (WSGI). The Falcon web framework encourages the REST architectural style. Resource classes implement HTTP method handlers that resolve requests and perform state transitions. Falcon complements more general Python web frameworks by providing extra reliability, flexibility, and performance wherever you need it. A number of Falcon add-ons, templates, and complementary packages are available for use in your projects. We've listed several of these on the Falcon wiki as a starting point, but you may also wish to search PyPI for additional resources. -
12
LoopBack
LoopBack
A highly extensible Node.js and TypeScript framework for building APIs and microservices. A brand new LoopBack core to deliver great extensibility and flexibility written in TypeScript/ES2017. Create powerful APIs easily with a new creative experience for defining REST APIs and handling API requests/responses. A new, improved programming model with dependency injection and new concepts such as components, mixins, repositories, etc. make this the most extensible version yet. The LoopBack 4 CLI is a command-line interface that can scaffold a project or extension. The CLI provides the fastest way to get started with a LoopBack 4 project that adheres to best practices. LoopBack is a highly-extensible, open-source Node.js framework that enables you to create dynamic end-to-end REST APIs with little or no coding. Access data from major relational databases, MongoDB, SOAP, and REST APIs. Incorporate model relationships and access controls for complex APIs. -
13
restify
restify
A Node.js web service framework optimized for building semantically correct RESTful web services ready for production use at scale. restify optimizes for introspection and performance and is used in some of the largest Node.js deployments on Earth. Running at scale requires tracing problems back to their origin by separating noise from the signal. restify is built from the ground up with post-mortem debugging in mind. Staying true to the spec is one of the foremost goals of the project. You will see references to RFCs littered throughout GitHub issues and the codebase. restify is used by some of the industry's most respected companies to power some of the largest deployments of Node.js on planet Earth—the future of Node.js REST development. Setting up a server is quick and easy. Like many other Node. js-based REST frameworks, restify leverages a Sinatra-style syntax for defining routes and the function handlers that service those routes.Starting Price: Free -
14
Rio
Rio
Rio is an open source Python framework that enables developers to build modern web and desktop applications entirely in Python. Inspired by frameworks like React and Flutter, Rio introduces a declarative UI model where components are defined as Python data classes with a build() method, allowing for reactive state management and seamless UI updates. It includes over 50 built-in components adhering to Google's Material Design, facilitating the creation of professional-grade interfaces. Rio's layout system is Pythonic and intuitive, calculating each component's natural size before distributing available space, eliminating the need for traditional CSS. Developers can run applications locally or in the browser with the backend powered by FastAPI and communication handled via WebSockets.Starting Price: Free -
15
Flask
Flask
Flask is a lightweight WSGI web application framework. It is designed to make getting started quick and easy, with the ability to scale up to complex applications. It began as a simple wrapper around Werkzeug and Jinja and has become one of the most popular Python web application frameworks. Flask offers suggestions, but doesn't enforce any dependencies or project layout. It is up to the developer to choose the tools and libraries they want to use. There are many extensions provided by the community that make adding new functionality easy.Starting Price: Free -
16
Express
OpenJS Foundation
Express is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications. With a myriad of HTTP utility methods and middleware at your disposal, creating a robust API is quick and easy. Express provides a thin layer of fundamental web application features, without obscuring Node.js features that you know and love. Express has no notion of a database. This concept is left up to third-party Node modules, allowing you to interface with nearly any database. In Express, 404 responses are not the result of an error, so the error-handler middleware will not capture them. This behavior is because a 404 response simply indicates the absence of additional work to do; in other words, Express has executed all middleware functions and routes, and found that none of them responded.Starting Price: Free -
17
PydanticAI
Pydantic
PydanticAI is a Python-based agent framework designed to simplify the development of production-grade applications using generative AI. Built by the team behind Pydantic, the framework integrates seamlessly with popular AI models such as OpenAI, Anthropic, Gemini, and others. It offers type-safe design, real-time debugging, and performance monitoring through Pydantic Logfire. PydanticAI also provides structured responses by leveraging Pydantic to validate model outputs, ensuring consistency. The framework includes a dependency injection system to support iterative development and testing, as well as the ability to stream LLM outputs for rapid validation. It is ideal for AI-driven projects that require flexible and efficient agent composition using standard Python best practices. We built PydanticAI with one simple aim: to bring that FastAPI feeling to GenAI app development.Starting Price: Free -
18
hapi
hapi
Build powerful, scalable applications, with minimal overhead and full out-of-the-box functionality, your code, your way. Developed initially to handle Walmart’s Black Friday sales, hapi continues to be the proven choice for enterprise-grade backend needs. When you install hapi, every single line of code you get has been verified. You never have to worry about some deep dependency being poorly maintained (or handed over to someone sketchy). hapi is the only leading node framework without any external code dependencies. hapi requires the most secure settings to manage, control, and distribute code, including 2FA for all contributors. Every hapi component comes with the most secure defaults out of the box. Along with protecting server load with payload limits and request timeouts, hapi blocks error messages that could leak information or echo back exploits. The most comprehensive authorization and authentication API available in a Node framework.Starting Price: Free -
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Echo
Echo
High-performance, extensible, minimalist Go web framework. Highly optimized HTTP router with zero dynamic memory allocation which smartly prioritizes routes. Build robust and scalable RESTful API, easily organized into groups. Automatically install TLS certificates from Let's Encrypt. HTTP/2 support improves speed and provides a better user experience. Many built-in middleware to use, or define your own. Middleware can be set at root, group, or route level. Data binding for HTTP request payload, including JSON, XML or form data. API to send a variety of HTTP responses, including JSON, XML, HTML, file, attachment, inline, stream, or blob. Template rendering using any template engine. Customized central HTTP error handling. Easily extendable API. Optimized HTTP router which smartly prioritizes routes. Build robust and scalable RESTful APIs. Extensible middleware framework. Define middleware at root, group, or route level Data binding for JSON, XML, and form payload.Starting Price: Free -
20
Javalin
Javalin
You never extend classes and you rarely implement interfaces. Javalin is just a few thousand lines of code on top of Jetty, and its performance is equivalent to raw Jetty code. Due to its size, it's very easy to reason about the source code. Other Java and Kotlin web frameworks usually offer one version for each language. Javalin is being made with inter-operability in mind, apps are built the same way in both Java and Kotlin. Javalin runs on top of Jetty, one of the most used and stable web servers on the JVM. You can configure the Jetty server fully, including SSL and HTTP3 and everything else that Jetty offers. Many lightweight Java and Kotlin web frameworks don't support OpenAPI, but Javalin does. -
21
NiceGUI
NiceGUI
NiceGUI is an open source Python library that enables developers to create web-based graphical user interfaces (GUIs) using only Python code. It provides a gentle learning curve while still offering the option for advanced customizations. NiceGUI follows a backend-first philosophy: it handles all the web development details, allowing developers to focus on writing Python code. This makes it ideal for a wide range of projects, including short scripts, dashboards, robotics projects, IoT solutions, smart home automation, and machine learning. The framework is built on FastAPI for backend operations, Vue.js for frontend interaction, and Tailwind CSS for styling. Developers can create buttons, dialogs, Markdown, 3D scenes, plots, and more, all within a Python environment. NiceGUI supports real-time interactivity through WebSocket connections, enabling instant updates in the browser without page reloads. It offers a variety of components and layout options, such as rows, columns, etc.Starting Price: Free -
22
Koa
Koa
Koa is a new web framework designed by the team behind Express, which aims to be a smaller, more expressive, and more robust foundation for web applications and APIs. By leveraging async functions, Koa allows you to ditch callbacks and greatly increase error handling. Koa does not bundle any middleware within its core, and it provides an elegant suite of methods that make writing servers fast and enjoyable. A Koa application is an object containing an array of middleware functions that are composed and executed in a stack-like manner upon request. Koa is similar to many other middleware systems that you may have encountered such as Ruby's Rack, Connect, and so on - however, a key design decision was made to provide high-level "sugar" at the otherwise low-level middleware layer. This improves interoperability, and robustness, and makes writing middleware much more enjoyable.Starting Price: Free -
23
Jersey
Eclipse Foundation
Developing RESTful web services that seamlessly support exposing your data in a variety of representation media types and abstracting away the low-level details of client-server communication is not an easy task without a good toolkit. In order to simplify the development of RESTful web services and their clients in Java, a standard and portable JAX-RS API has been designed. Jersey RESTful web services 3. x framework is an open-source, production-quality, framework that provides support for Jakarta RESTful web services 3.0. Jersey framework is more than the JAX-RS reference implementation. Jersey provides its own API that extends the JAX-RS toolkit with additional features. Track the JAX-RS API and provide regular releases of production quality reference implementations that ship with GlassFish. Provides APIs to extend Jersey & build a community of users and developers. Makes it easy to build RESTful Web services utilizing Java and the Java Virtual Machine.Starting Price: Free -
24
Slim Framework
Slim Framework
Slim is an ideal tool to create APIs that consume, repurpose, or publish data. Slim is also a great tool for rapid prototyping. Heck, you can even build full-featured web applications with user interfaces. More importantly, Slim is super fast and has very little code. You don’t always need a kitchen-sink solution like Symfony or Laravel. These are great tools, for sure. But they are often overkill. Instead, Slim provides only a minimal set of tools that do what you need and nothing else. First, you need a web server like Nginx or Apache. A Slim app contains routes that respond to specific HTTP requests. Each route invokes a callback and returns an HTTP response. To get started, you first instantiate and configure the Slim application. Next, you define your application routes. -
25
Nancy
Nancy
Welcome to Nancy, our main inspiration is the Sinatra framework for Ruby and, hence, Nancy was named after the daughter of Frank Sinatra. NancyFx is the name of the umbrella project that contains all the components. Nancy is a lightweight, low-ceremony, framework for building HTTP-based services on .NET and Mono. The goal of the framework is to stay out of the way as much as possible and provide a super-duper-happy path to all interactions. This means that everything in Nancy is setup to have sensible defaults and conventions, instead of making you jump through hoops and go through configuration hell just to get up and running. With Nancy you can go from zero to website in a matter of minutes. Nancy is built to run anywhere and we mean it. Right from the start, Nancy was designed to not have any dependencies on existing frameworks. Built with the .NET framework client profile, Nancy can be used pretty much wherever you want to.Starting Price: Free -
26
Ruby Grape
Ruby Grape
An opinionated framework for creating REST-like APIs in Ruby. -
27
asyncio
asyncio
asyncio is used as a foundation for multiple Python asynchronous frameworks that provide high-performance network and web-servers, database connection libraries, distributed task queues, etc. asyncio is often a perfect fit for IO-bound and high-level structured network code. -
28
Sinatra
Sinatra
Sinatra includes a number of built-in settings that control whether certain features are enabled. Settings are application-level variables that are modified using one of the set, enable, or disable methods and are available within the request context via the settings object. Applications are free to set custom settings as well as the default, built-in settings provided by the framework. In its simplest form, the set method takes a setting name and value and creates an attribute on the application. Extensions provide helper or class methods for Sinatra applications. These methods are customarily listed and described on extensions home pages. Using an extension is usually as simple as installing a gem or library and requiring a file. -
29
Atri Framework
Atri Labs
Atri framework is a full-stack web development framework to build Progressive Web Apps. Use our visual editor to increase your productivity. You can also add your custom React code. Currently, we support Python for backend development. We are planning to add support for NodeJS soon. Our CLI provides rich support for easy deployment at your platform of choice such as GitHub Pages, AWS, etc. Atri framework comes with a suite of productivity tools such as a visual editor, asset management tools, etc. that significantly reduce development time from months to hours. Atri framework is extending the definition of full-stack to include non-web developers in the development and maintenance of an app.Starting Price: $100 per user per month -
30
Streamlit
Streamlit
Streamlit. The fastest way to build and share data apps. Turn data scripts into sharable web apps in minutes. All in Python. All for free. No front-end experience required. Streamlit combines three simple ideas. Embrace Python scripting. Build an app in a few lines of code with our magically simple API. Then see it automatically update as you save the source file. Weave in interaction. Adding a widget is the same as declaring a variable. No need to write a backend, define routes, handle HTTP requests, etc. Deploy instantly. Use Streamlit’s sharing platform to effortlessly share, manage, and collaborate on your apps. A minimal framework for powerful apps. Face-GAN explorer. App that uses Shaobo Guan’s TL-GAN project from Insight Data Science, TensorFlow, and NVIDIA's PG-GAN to generate faces that match selected attributes. Real time object detection. An image browser for the Udacity self-driving-car dataset with real-time object detection. -
31
Ktor
JetBrains
Create asynchronous client and server applications. Anything from microservices to multiplatform HTTP client apps in a simple way. Open Source, free, and fun! Ktor is built from the ground up using Kotlin and Coroutines. You get to use a concise, multiplatform language, as well as the power of asynchronous programming with an intuitive imperative flow. Ktor allows you to use only what you need, and to structure your application the way you need it. In addition, you can also extend Ktor with your own plugin very easily. Brought to you by JetBrains, creators of IntelliJ IDEA, Kotlin, and more. Ktor is not only used by our customers but also internally at JetBrains. In addition, you have top-notch tooling support! -
32
Growler
Growler
Growler is a web framework built atop asyncio, the asynchronous library described in PEP 3156 and added to the standard library in python 3.4. It takes a cue from the Connect & Express frameworks in the nodejs ecosystem, using a single application object and series of middleware to process HTTP requests. The custom chain of middleware provides an easy way to implement complex applications. The pip utility allows packages to provide optional requirements, so features may be installed only upon request. This meshes well with the minimal nature of the Growler project: don't install anything the user doesn't need. That being said, there are (will be) community packages that are blessed by the growler developers (after ensuring they work as expected and are well tested with each version of growler) that will be available as extras directly from the growler package. -
33
Wasp
Wasp, Inc.
Wasp is a full-stack web application framework that allows developers to build apps faster with less boilerplate code. It integrates React for frontend development, Node.js for backend, and Prisma for database management, enabling developers to focus on the essential parts of their app. The framework’s declarative syntax and simplified configuration mean that developers can describe their app's high-level structure in a .wasp file, and the system automatically handles much of the repetitive work, including routing, authentication, and API management. Wasp's goal is to simplify app development without sacrificing flexibility, making it ideal for building MVPs and production-ready applications.Starting Price: Free -
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Nitric
Nitric
Nitric is an open source, cloud-agnostic backend framework that enables developers to declare infrastructure as code and automate deployments using pluggable plugins. It supports multiple languages, including JavaScript, TypeScript, Python, Go, and Dart. Key features include defining APIs (REST, HTTP), serverless functions, routing, authentication/authorization (OIDC-compatible), storage (object/file storage, signed URLs, bucket events), databases (e.g., managed Postgres with migrations), messaging (queues, topics, pub/sub), websockets, scheduled tasks, and secrets management. Nitric integrates with tools like Terraform or Pulumi, or lets you write your own plugins, and works with major cloud providers (AWS, Azure, Google Cloud). It also supports local development with simulated cloud environments so you can prototype, test, and iterate without incurring cloud cost. The framework emphasizes declarative security, resource access management, and portability.Starting Price: Free -
35
Solara
Widgetti BV
Many Python frameworks can handle basic dashboards but falter with complex ones, often leading teams to split into frontend and backend roles, causing various challenges. Solara is a new web framework that integrates ReactJS principles with Python simplicity. It offers a flexible API for various UI complexities and efficient state management. Solara supports a range of applications, from prototypes to intricate dashboards, and is compatible with platforms like Jupyter, Voilà, and various web servers. It emphasizes code quality, developer accessibility, and robust testing. -
36
Tornado Web Server
Tornado
Tornado is a Python web framework and asynchronous networking library, originally developed at FriendFeed. By using non-blocking network I/O, Tornado can scale to tens of thousands of open connections, making it ideal for long polling, WebSockets, and other applications that require a long-lived connection to each user. Tornado is different from most Python web frameworks. It is not based on WSGI, and it is typically run with only one thread per process. While some support of WSGI is available in the tornado.wsgi module, it is not a focus of development and most applications should be written to use Tornado’s own interfaces (such as tornado.web) directly instead of using WSGI. In general, Tornado code is not thread-safe. Tornado is integrated with the standard library asyncio module and shares the same event loop (by default since Tornado 5.0). In general, libraries designed for use with asyncio can be mixed freely with Tornado. -
37
Jinja
Jinja
Jinja is a fast, expressive, extensible templating engine. Special placeholders in the template allow writing code similar to Python syntax. Then the template is passed data to render the final document.Starting Price: Free -
38
Sails
Sails
Build practical, production-ready Node.js apps in a matter of weeks, not months. Sails is the most popular MVC framework for Node.js, designed to emulate the familiar MVC pattern of frameworks like Ruby on Rails, but with support for the requirements of modern apps, data-driven APIs with scalable, service-oriented architecture. Sails makes it easy to build custom, enterprise-grade Node.js apps. Building on top of Sails means your app is written entirely in JavaScript, the language you and your team are already using in the browser. Sails bundles a powerful ORM, Waterline, which provides a simple data access layer that just works, no matter what database you're using. Sails comes with blueprints that help jumpstart your app's backend without writing any code. Since Sails translates incoming socket messages for you, they're automatically compatible with every route in your Sails app. Sails offers commercial support to accelerate development and ensure best practices in your code.Starting Price: Free -
39
Horovod
Horovod
Horovod was originally developed by Uber to make distributed deep learning fast and easy to use, bringing model training time down from days and weeks to hours and minutes. With Horovod, an existing training script can be scaled up to run on hundreds of GPUs in just a few lines of Python code. Horovod can be installed on-premise or run out-of-the-box in cloud platforms, including AWS, Azure, and Databricks. Horovod can additionally run on top of Apache Spark, making it possible to unify data processing and model training into a single pipeline. Once Horovod has been configured, the same infrastructure can be used to train models with any framework, making it easy to switch between TensorFlow, PyTorch, MXNet, and future frameworks as machine learning tech stacks continue to evolve.Starting Price: Free -
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Reflex
Pynecone
Reflex is an open source framework that empowers Python developers to build full-stack web applications entirely in pure Python, eliminating the need for JavaScript or complex frontend frameworks. With Reflex, you can write, test, and refine your app using just Python, making it fast, flexible, and scalable. It features an AI Builder that allows you to describe your app idea, and it will generate a working Python app instantly, complete with backend, frontend, and database integration. Reflex's architecture compiles the frontend down to a single-page Next.js app, while the backend is powered by FastAPI, with communication handled via WebSockets. This setup ensures that all the app logic and state management stay in Python and run on the server. The framework offers over 60 built-in components based on Radix UI and supports custom React components, enabling developers to create complex UIs without writing HTML or CSS.Starting Price: $20 per month -
41
QUnit
QUnit
The powerful, easy-to-use JavaScript testing framework. Easy, zero-configuration setup for any Node.js project and minimal configuration for browser-based projects. Tests can be run anywhere; Node, your browser, even inside a web worker. Test your code where it runs. Flexible APIs for custom assertions, runners, and reporters mean you can extend QUnit to fit your needs. Getting started with QUnit for Node.js projects is quick and easy. First, install the QUnit package using npm. You can now run the test suite through the QUnit CLI. It is recommended that you run the QUnit command via an npm script, which will find the QUnit command automatically from your local dependencies. Check out the API documentation to learn more about the QUnit APIs for organizing tests and making assertions.QUnit follows the Node.js Long-term Support (LTS) schedule and provides support for current, active LTS, and maintenance LTS releases.Starting Price: Free -
42
Instructor
Instructor
Instructor is a tool that enables developers to extract structured data from natural language using Large Language Models (LLMs). Integrating with Python's Pydantic library allows users to define desired output structures through type hints, facilitating schema validation and seamless integration with IDEs. Instructor supports various LLM providers, including OpenAI, Anthropic, Litellm, and Cohere, offering flexibility in implementation. Its customizable nature permits the definition of validators and custom error messages, enhancing data validation processes. Instructor is trusted by engineers from platforms like Langflow, underscoring its reliability and effectiveness in managing structured outputs powered by LLMs. Instructor is powered by Pydantic, which is powered by type hints. Schema validation and prompting are controlled by type annotations; less to learn, and less code to write, and it integrates with your IDE.Starting Price: Free -
43
NestJS
NestJS
Gives you true flexibility by allowing use of any other libraries thanks to modular architecture. An adaptable ecosystem that is a fully-fledged backbone for all kinds of server-side applications. Takes advantage of latest JavaScript features, bringing design patterns and mature solutions to Node.js world. A complete development kit for building scalable server-side apps. In recent years, thanks to Node.js, JavaScript has become the “lingua franca” of the web for both front and backend applications. This has given rise to awesome projects like Angular, React and Vue, which improve developer productivity and enable the creation of fast, testable, and extensible frontend applications. However, while plenty of superb libraries, helpers, and tools exist for Node (and server-side JavaScript), none of them effectively solve the main problem of - Architecture. -
44
Swoole
Swoole
Powering the next-generation microservices and applications. Build high-performance, scalable, concurrent TCP, UDP, Unix Socket, HTTP, GRPC services with PHP and easy-to-use coroutine, fibers API. Write your next scalable async application with PHP coroutines and fibers. Compared with other async programming frameworks or software such as Nginx, Tornado, and Node.js, Swoole is a complete async solution that has built-in support for async programming via fibers/coroutines, a range of multi-threaded I/O modules (HTTP server, GRPC, process pools) and support for popular PHP clients like PDO for MySQL, Redis, and CURL. You can use sync or async, coroutine, or fiber API to write the applications or create thousands of lightweight fibers within one Linux process. Swoole enhances the efficiency of your PHP applications and brings you out of the traditional stateless model, enabling you to focus on the development of innovative products at a high scale.Starting Price: Free -
45
UnionML
Union
Creating ML apps should be simple and frictionless. UnionML is an open-source Python framework built on top of Flyte™, unifying the complex ecosystem of ML tools into a single interface. Combine the tools that you love using a simple, standardized API so you can stop writing so much boilerplate and focus on what matters: the data and the models that learn from them. Fit the rich ecosystem of tools and frameworks into a common protocol for machine learning. Using industry-standard machine learning methods, implement endpoints for fetching data, training models, serving predictions (and much more) to write a complete ML stack in one place. Data science, ML engineering, and MLOps practitioners can all gather around UnionML apps as a way of defining a single source of truth about your ML system’s behavior. -
46
Django
Django
Django is a high-level Python web framework that encourages rapid development and clean, pragmatic design. Built by experienced developers, it takes care of much of the hassle of web development, so you can focus on writing your app without needing to reinvent the wheel. Django was designed to help developers take applications from concept to completion as quickly as possible. Django takes security seriously and helps developers avoid many common security mistakes. Some of the busiest sites on the web leverage Django’s ability to quickly and flexibly scale. Django includes dozens of extras you can use to handle common web development tasks. Django takes care of user authentication, content administration, site maps, RSS feeds, and many more tasks — right out of the box.Starting Price: Free -
47
Koyeb
Koyeb
Push code to production, everywhere, in minutes with Koyeb. Accelerate backend apps at the edge with high-performance hardware. Connect your GitHub account to Koyeb, choose a repository to deploy, and leave us the infrastructure. We build, deploy, run, and scale your application with zero configuration. Simply git push, and we build and deploy your app with blazing fast built-in continuous deployment. Develop fearlessly with native versioning of all deployments. Build Docker containers, host them on any registry, and atomically deploy your new version worldwide in a single API call. Invite your team to build together and enjoy a live preview after each push with built-in CI/CD. The Koyeb platform lets you combine the languages, frameworks, and technologies you use. Deploy any application without modifications thanks to native support of popular languages and Docker containers. Koyeb detects and builds apps in Node.js, Python, Go, Ruby, Java, PHP, Scala, Clojure, and more.Starting Price: $2.7 per month -
48
Preact
Preact
Preact provides the thinnest possible Virtual DOM abstraction on top of the DOM. It builds on stable platform features, registers real event handlers and plays nicely with other libraries. Most UI frameworks are large enough to be the majority of an app's JavaScript size. Preact is different: it's small enough that your code is the largest part of your application. That means less JavaScript to download, parse and execute - leaving more time for your code, so you can build an experience you define without fighting to keep a framework under control. Preact is fast, and not just because of its size. It's one of the fastest Virtual DOM libraries out there, thanks to a simple and predictable diff implementation. We automatically batch updates and tune Preact to the extreme when it comes to performance. We work closely with browser engineers to get the maximum performance possible out of Preact.Starting Price: Free -
49
Aurelia
Aurelia
Aurelia's standards-based, unobtrusive style makes it the only framework that empowers you to build components using vanilla JavaScript or TypeScript. If you know modern JS and HTML, there's little more to learn to build even the most complex apps. At the core of Aurelia is a high-performance, reactive system, capable of batching DOM updates in a way that leaves other frameworks, and their virtual DOMs, in the dust. Experience consistent, scalable performance, no matter how complex your UI. Aurelia enables powerful reactive binding to any object. By using adaptive techniques Aurelia selects the most efficient way to observe each property in your model and automatically syncs your UI and your state with best-in-class performance. State management, internationalization and validation - all official plugins from the core team. CLI, VS Code plugin, and Chrome debugger - optional tools to enhance development.Starting Price: Free -
50
Cython
Cython
Cython is an optimizing static compiler for both the Python programming language and the extended Cython programming language (based on Pyrex). It makes writing C extensions for Python as easy as Python itself. Cython gives you the combined power of Python and C to let you write Python code that calls back and forth from and to C or C++ code natively at any point. Easily tune readable Python code into plain C performance by adding static type declarations, also in Python syntax. Use combined source code level debugging to find bugs in your Python, Cython, and C code. Interact efficiently with large data sets, e.g. using multi-dimensional NumPy arrays. Quickly build your applications within the large, mature, and widely used CPython ecosystem. The Cython language is a superset of the Python language that additionally supports calling C functions and declaring C types on variables and class attributes.Starting Price: Free
