react-native-quick-base64

A blazing fast, native Base64 implementation for React Native using C++ and JSI.

This library is ~16x faster than base64-js on an iPhone 15 Pro Max simulator. Try the benchmarks in the example app.

| iPhone | Android | | ------------------------------------------------- | --------------------------------------------------- | | | |

Features

• ⚡ Native C++/JSI implementation for maximum performance
• 🧠 Automatically installs its JSI bindings at runtime
• 🧩 Drop-in replacement for base64-js with matching API
• 🔒 No additional native setup or linking required

ℹ️ Heads-up: Starting with recent versions of Hermes, btoa and atob are natively available in the JS runtime. You likely don't need to use the versions provided by this library anymore unless you're running on an older engine or want consistent behavior across platforms. These methods will remain in the package for compatibility but are considered deprecated.

Installation

npm install react-native-quick-base64

This module installs its native bindings automatically. Simply importing the library is enough to activate the native backend. Add it to your root entry point file or your first _layout.tsx.

import 'react-native-quick-base64' // triggers native JSI install to global namespace

You can also import individual helpers:

import { fromByteArray, toByteArray } from 'react-native-quick-base64'

Usage

import { btoa, atob } from 'react-native-quick-base64'

const base64 = btoa('foo')
const decoded = atob(base64)

API

Compatible with base64-js.

byteLength(b64: string): number

Returns the length of the byte array that corresponds to the base64 string.

toByteArray(b64: string, removeLinebreaks: boolean = false): Uint8Array

Converts a base64 string into a Uint8Array. If removeLinebreaks is true, all \n characters are removed first.

fromByteArray(uint8: Uint8Array, urlSafe: boolean = false): string

Converts a byte array into a base64 string. If urlSafe is true, the output uses a URL-safe base64 charset.

btoa(data: string): string ⚠️ Deprecated

Encodes a string into base64 format.

Avoid using this unless you're on an older JS engine. Use fromByteArray(new TextEncoder().encode(...)) instead for better encoding control.

atob(b64: string): string ⚠️ Deprecated

Decodes a base64 string into a UTF-8 string.

Avoid using this unless you're on an older JS engine. Use TextDecoder + toByteArray() for more robust decoding.

shim()

Adds global btoa and atob functions

import { shim } from 'react-native-quick-base64'

shim()

btoa('foo') // available globally

trimBase64Padding(str: string): string

Removes trailing = or . padding from base64 or base64url-encoded strings.

Contributing

See the contributing guide to learn how to contribute to the repository and the development workflow.

License

MIT © Takuya Matsuyama