---
title: "@std/encoding"
description: "Utilities for encoding and decoding common formats like hex, base64, and varint"
jsr: jsr:@std/encoding
pkg: encoding
version: 1.0.10
generated: true
stability: stable
---
## Overview
Utilities for encoding and decoding common formats like hex, base64, and varint.
Basic Usage
```js
import { encodeBase64, decodeBase64 } from "@std/encoding";
import { assertEquals } from "@std/assert";
const foobar = new TextEncoder().encode("foobar");
assertEquals(encodeBase64(foobar), "Zm9vYmFy");
assertEquals(decodeBase64("Zm9vYmFy"), foobar);
```
Various Encoding Formats
```js
import {
encodeHex,
encodeBase32,
encodeBase58,
encodeBase64,
encodeAscii85,
decodeHex,
decodeBase32,
decodeBase58,
decodeBase64,
decodeAscii85,
} from "@std/encoding";
import { assertEquals } from "@std/assert";
// Many different encodings for different character sets
assertEquals(encodeHex("Hello world!"), "48656c6c6f20776f726c6421");
assertEquals(encodeBase32("Hello world!"), "JBSWY3DPEB3W64TMMQQQ====");
assertEquals(encodeBase58("Hello world!"), "2NEpo7TZRhna7vSvL");
assertEquals(encodeBase64("Hello world!"), "SGVsbG8gd29ybGQh");
assertEquals(encodeAscii85("Hello world!"), "87cURD]j7BEbo80");
// Decoding
assertEquals(new TextDecoder().decode(decodeHex("48656c6c6f20776f726c6421")), "Hello world!");
assertEquals(new TextDecoder().decode(decodeBase32("JBSWY3DPEB3W64TMMQQQ====")), "Hello world!");
assertEquals(new TextDecoder().decode(decodeBase58("2NEpo7TZRhna7vSvL")), "Hello world!");
assertEquals(new TextDecoder().decode(decodeBase64("SGVsbG8gd29ybGQh")), "Hello world!");
assertEquals(new TextDecoder().decode(decodeAscii85("87cURD]j7BEbo80")), "Hello world!");
```
URL-Safe Base64
```js
import { encodeBase64, encodeBase64Url } from "@std/encoding";
import { assertEquals } from "@std/assert";
assertEquals(encodeBase64("ice creams"), "aWNlIGNyZWFtcw=="); // Not url-safe because of `=`
assertEquals(encodeBase64Url("ice creams"), "aWNlIGNyZWFtcw"); // URL-safe!
// Base64Url replaces + with - and / with _
assertEquals(encodeBase64("subjects?"), "c3ViamVjdHM/"); // slash is not URL-safe
assertEquals(encodeBase64Url("subjects?"), "c3ViamVjdHM_"); // _ is URL-safe
```
Binary Data Encoding
```js
import { encodeHex, encodeBase64 } from "@std/encoding";
import { assertEquals } from "@std/assert";
// Working with binary data
const binaryData = new Uint8Array([0xDE, 0xAD, 0xBE, 0xEF]);
assertEquals(encodeHex(binaryData), "deadbeef");
assertEquals(encodeBase64(binaryData), "3q2+7w==");
```
```js
import { encodeVarint, decodeVarint } from "@std/encoding";
import { assertEquals } from "@std/assert";
// Varint encoding support
assertEquals(encodeVarint(9601n), [new Uint8Array([129, 75]), 2]);
// Decode a varint
const bytes = new Uint8Array([129, 75]);
assertEquals(decodeVarint(bytes), [9601n, 2]);
```
### Add to your project
```sh
deno add jsr:@std/encoding
```
See all symbols in @std/encoding on