Frontend Frameworks

UglifyJS2

JavaScript minifier for reducing file size and improving load times.

Status
UnmaintainedNo commits in 642 days.
Last checked
Aging · Sep 5, 2026
License
Open source
Pricing
Free tier · from $0
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What it is

UglifyJS2 is a JavaScript parser/minifier/beautifier that reduces the size of your code, making it faster to download and parse. It's crucial for optimizing web applications by minimizing JavaScript files without losing functionality.

UglifyJS2 stands out with its support for modern JavaScript features and ease of integration into build systems, making it a reliable choice for developers focused on performance optimization.

When it fits — and when it doesn’t

A good fit for

  • Developers looking to optimize their JavaScript code for faster loading and parsing.

  • Projects that require efficient, automated minification as part of the build process.

Look elsewhere if

  • Scenarios where human-readable code is more important than file size reduction.

  • Real-time applications requiring unminified code for debugging purposes.

Known weaknesses

Each one links to the public issue, changelog or docs page it came from, where we have one.

  1. 01

    Limited support for modern JavaScript features

    While UglifyJS2 supports ES6 and beyond, it may still have issues with the latest ECMAScript features, leading to potential errors or suboptimal minification.

  2. 02

    Performance degradation on large codebases

    UglifyJS2 can become slow when processing very large JavaScript files or extensive codebases, which may delay build processes and development cycles.

  3. 03

    Configuration complexity for advanced use cases

    Advanced minification options require a deep understanding of UglifyJS2's configuration settings, making it challenging to optimize without thorough documentation or experience.

  4. 04

    Lack of active development and updates

    The project has seen reduced activity in recent years, which can lead to outdated features and a higher risk of encountering unresolved issues with newer JavaScript standards.

What it does well

  • Minifies JavaScript code to reduce file size.

  • Supports ES6 and beyond, including arrow functions and classes.

  • Can be used as a command-line tool or integrated into build processes.

Pricing

Free tier
YesOpen source — free to use
Paid from
$0
Model
Flat rate
Enterprise plan
No

Pricing not independently confirmed — check the vendor’s page.

Performance benchmarks

How Fast Is It?

Set up UglifyJS2

Setup steps, common gotchas and what to check after 30 days.

Open the setup guide →