pako

High-speed zlib port to pure JavaScript for deflate, inflate, and gzip operations.

DecliningOpen SourceLow lock-in

Pricing

Free tier

Flat rate

Adoption

Cooling

License

Open Source

Data freshness

Aging · Jun 8, 2026

Overview

What is pako?

Pako is a high-performance JavaScript library that provides zlib functionality in the browser or Node.js environment. It supports compression and decompression tasks such as deflate, inflate, and gzip, making it essential for developers needing efficient data handling capabilities without relying on native zlib bindings.

Key differentiator

Pako stands out as a lightweight, high-performance JavaScript library for zlib operations, offering cross-platform support without the need for native bindings.

Capability profile

Capability Radar

Ease of StartEcosystemValueMaturityFlexibilityScale Ready

Honest assessment

Strengths & Weaknesses

↑ Strengths

High-speed zlib functionality in pure JavaScriptmedium

Support for deflate, inflate, and gzip operationsmedium

Cross-platform compatibility (browser and Node.js)medium

MIT licensed open-source projectmedium

↓ Weaknesses

Limited error handling and diagnosticshigh

Pako's API does not provide detailed error messages or extensive logging, making debugging difficult.

Lack of advanced compression optionsmedium

While Pako supports basic zlib functionalities like deflate and gzip, it lacks more advanced features such as Brotli compression which are available in other libraries.

Performance may degrade with large datasetshigh

In certain scenarios, especially when handling very large data sets, Pako's performance can drop significantly compared to native zlib implementations or more optimized alternatives.

Fit analysis

Who is it for?

✓ Best for

Developers needing cross-platform zlib functionality without native bindings

Projects requiring lightweight and fast compression/decompression capabilities in JavaScript environments

✕ Not a fit for

Applications that require complex data transformations beyond basic compression/decompression tasks

Scenarios where native zlib performance is critical and cannot be achieved with pure JavaScript implementations

Cost structure

Pricing

Free Tier

Available

Open source — free to use

Starts at

$0

Model

Flat rate

Enterprise

None

Performance benchmarks

How Fast Is It?

Ecosystem

Relationships

Next step

Get Started with pako

Step-by-step setup guide with code examples and common gotchas.

View Setup Guide →