Software Alternatives, Accelerators & Startups

QuickJS VS PyPy

Compare QuickJS VS PyPy and see what are their differences

Note: These products don't have any matching categories. If you think this is a mistake, please edit the details of one of the products and suggest appropriate categories.

QuickJS logo QuickJS

Application and Data, Build, Test, Deploy, and JavaScript Compilers

PyPy logo PyPy

PyPy is a fast, compliant alternative implementation of the Python language (2.7.1).
  • QuickJS Landing page
    Landing page //
    2021-08-20
  • PyPy Landing page
    Landing page //
    2023-10-15

QuickJS features and specs

  • Lightweight
    QuickJS is designed to be lightweight with a small footprint, making it easy to embed in applications and suitable for resource-constrained environments.
  • Fast Startup Time
    QuickJS offers very fast startup times, which can be beneficial for applications that require quick script execution without a long initialization period.
  • Full ES2020 Support
    QuickJS supports the full ES2020 specification, providing modern JavaScript features and syntax, which is advantageous for developers who want to use the latest JavaScript features.
  • Embeddability
    Being easy to integrate into other applications or systems, QuickJS provides a simple C API, which facilitates embedding it in various software and platforms.
  • Single File Distribution
    QuickJS can be distributed as a single file, simplifying packaging and distribution without needing external dependencies.
  • Memory Efficiency
    Its memory efficient design allows QuickJS to run scripts in environments with limited memory resources, making it suitable for IoT devices and embedded systems.

Possible disadvantages of QuickJS

  • Limited Ecosystem
    QuickJS, being a relatively new and niche project, has a smaller ecosystem compared to more established JavaScript engines like V8, which means fewer libraries and community resources are available.
  • Performance
    While QuickJS is efficient, it may not deliver the same high-performance execution as more mature engines like V8, especially in applications requiring intensive computational processing.
  • Lack of Long-term Support
    QuickJS may not have the same level of long-term support and ongoing development as larger projects maintained by large companies or communities.
  • Single-threaded
    QuickJS runs in a single thread, which can be a limitation for applications that require multithreading support for parallel processing.
  • Limited Debugging Tools
    Compared to more popular JavaScript engines, QuickJS has fewer debugging tools and integrations, which might make development and troubleshooting more challenging.

PyPy features and specs

  • Performance
    PyPy is known for its superior execution speed and performance, often outperforming the standard CPython interpreter for many workloads thanks to its Just-in-Time (JIT) compilation strategy.
  • Compatibility
    PyPy aims to be compatible with standard Python, so many programs and libraries that run on CPython should work on PyPy without or with minimal changes.
  • Memory Efficiency
    Due to its garbage collection mechanism, PyPy often results in lower memory usage as compared to CPython, which can be beneficial for memory-intensive applications.
  • Concurrency
    PyPy provides better support for concurrency, including potentially avoiding some of the Global Interpreter Lock (GIL) performance issues present in CPython.

Possible disadvantages of PyPy

  • Compatibility Limitations
    Although PyPy aims to be compatible with Python, not all extensions and libraries available for CPython work flawlessly with PyPy, particularly those relying on C extensions.
  • Startup Time
    PyPy has a slower startup time than CPython due to the JIT compilation overhead, which could be a downside for scripts primarily dealing with short-lived processes.
  • Larger Memory Footprint
    While PyPy can be more memory efficient in the long term, the JIT compilation process can result in a larger initial memory footprint which could affect applications with limited memory resources.
  • Platform Support
    PyPy might not support all platforms or the latest Python features immediately, potentially causing issues for users relying on cutting-edge Python developments or specific system architectures.

QuickJS videos

QuickJS - IO, axios, redaxios, fetch

PyPy videos

PyPy - the hero we all deserve. - Amit Ripshtos - PyCon Israel 2019

More videos:

  • Review - Using the PyPy runtime for Python
  • Review - How PyPy runs your program

Category Popularity

0-100% (relative to QuickJS and PyPy)
Application And Data
100 100%
0% 0
Website Builder
0 0%
100% 100
Development Tools
100 100%
0% 0
Development
0 0%
100% 100

User comments

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Social recommendations and mentions

Based on our record, QuickJS should be more popular than PyPy. It has been mentiond 46 times since March 2021. 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.

QuickJS mentions (46)

  • Vim 9.2 Released
    You don't need V8 for running JS for scripting, you have quickjs[1] or mquickjs[2] for example. You might have problems importing npm packages, but as we can see from lua plugins you don't even need support for package managers. Performance is not as good as luajit, but it is good enough [1]: https://bellard.org/quickjs/ [2]: https://github.com/bellard/mquickjs. - Source: Hacker News / 5 months ago
  • Fabrice Bellard Releases MicroQuickJS
    - QuickJS: https://bellard.org/quickjs/ Legendary. - Source: Hacker News / 7 months ago
  • Building a JavaScript Runtime from Scratch using C
    For those who would like a true "from scratch" implementation of JavaScript, Fabrice Bellard's QuickJS [1] is clean, readable and approachable. It's a full implementation of modern JavaScript in a straightforward project, not nearly as complex or difficult as V8. [1] https://bellard.org/quickjs/. - Source: Hacker News / 9 months ago
  • The many, many, many JavaScript runtimes of the last decade
    I see a few mentions of QuickJS, but they all refer to the fork of Bellard's QuickJS https://bellard.org/quickjs/, which I think deserves a mention. It seems to be still active (last release 2025-04-26, GitHub mirror at https://github.com/bellard/quickjs shows some activity). - Source: Hacker News / 12 months ago
  • SQLite JavaScript: Extend your database with JavaScript
    This is a fantastic approach. BTW, it looks like the js engine is "QuickJS" [0]. (I'm not familiar with it myself.) I like it because sqlite by itself lacks a host language. (e.g., Oracle's plsql, Postgreses pgplsql, Sqlserver's t-sql, etc). That is: code that runs on compute that is local to your storage. That's a nice flexible design -- you can choose whatever language you want. But quite typically you... - Source: Hacker News / about 1 year ago
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PyPy mentions (9)

  • CPython Internals Explained
    There are quite a few JITs: JIT-compiler for Python https://pypy.org/ Python enhancement proposal for JIT in CPython https://peps.python.org/pep-0744/ And there are several JIT-compilers for various subsets of Python, usually with focus on numerical code and often with GPU support, for example Numba https://numba.pydata.org/numba-doc/dev/user/jit.html Taichi Lang https://github.com/taichi-dev/taichi. - Source: Hacker News / 6 months ago
  • Pydrofoil: Accelerating Sail-based instruction set simulators
    Gains than using either compiler alone. This uses the PyPy JIT framework to speed up a RISC-V simulator. https://pypy.org/ https://github.com/pydrofoil/pydrofoil Pydrofoil: A fast RISC-V emulator generated from the Sail model, using PyPy's JIT. - Source: Hacker News / about 1 year ago
  • One Billion Nested Loop Iterations
    "On average, PyPy is 4.4 times faster than CPython 3.7." https://pypy.org/. - Source: Hacker News / over 1 year ago
  • Ask HN: Are my HPC professors right? Is Python worthless compared to C?
    If you're going the pure Python route, don't forget to try PyPy[1], an alternative JITed implementation of the language. A seriously underrated project, IMHO. Most time it speeds up execution by a factor of 2x-4x, but improvements of about two orders of magnitude are not unheard of. See for example [2]. Numeric, long-running code shoud suit PyPy optimizations well. [1] https://pypy.org/ [2]... - Source: Hacker News / over 1 year ago
  • Yes, Ruby is fast, butโ€ฆ
    Python: My Python-foo is limited, so I only ported the last problem (a simple while loop) and ran it with PyPy. It takes a bit less of time:. - Source: dev.to / about 2 years ago
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What are some alternatives?

When comparing QuickJS and PyPy, you can also consider the following products

Sciter - Embeddable HTML/CSS/script engine

cx_Freeze - cx_Freeze is a set of scripts and modules for freezing Python scripts into executables in much the...

nuitka - Nuitka is a Python compiler.

bbfreeze - create stand-alone executables from python scripts

DaisyUI - Free UI components plugin for Tailwind CSS

Numba - Numba gives you the power to speed up your applications with high performance functions written...