Is Base64 encryption? Is it secure?

No. Base64 is encoding, not encryption. Anyone can decode it. Do not use Base64 to protect secrets or sensitive data.

What is Base64 used for?

Base64 is used to represent data as plain text so it can be transported in text-only systems like JSON, HTTP headers, URLs (with Base64URL), email, logs, and config files.

What is Base64URL and why is it used in JWT?

Base64URL is a URL-safe variant that replaces '+' and '/' with '-' and '_' and often omits '=' padding. JWT uses Base64URL for its header and payload segments.

Why does Base64 output sometimes end with '=' or '=='?

That’s padding. It makes the output length a multiple of 4. Some decoders require padding; many Base64URL/JWT contexts omit it. This tool lets you keep or remove it.

Why does Base64 increase size by about 33%?

Base64 encodes 3 bytes of data into 4 characters. The overhead is the cost of making binary/text safe to transport in ASCII-friendly systems.

What’s the difference between UTF-8 and Binary (Latin1) mode?

UTF-8 supports full Unicode (recommended). Binary/Latin1 matches older `atob`/`btoa` behavior and may be needed for legacy inputs that aren’t true UTF-8 text.

Why does decoded output look corrupted or show � characters?

Usually the encoder/decoder disagrees on character encoding. Try UTF-8 for normal text. Use Binary/Latin1 only for legacy or non-text bytes.

How do I know if a string is valid Base64?

Valid Base64 uses only A–Z, a–z, 0–9, +, / and optional '=' padding. Base64URL uses - and _. This tool helps detect invalid characters and structure quickly.

Can I Base64-encode a file here?

This tool is focused on text. For files (images, PDFs), use a dedicated File → Base64 converter to avoid memory/size issues and get correct binary handling.

When should I avoid Base64?

Avoid Base64 for large files (it increases size) and never rely on it for security. If you need confidentiality, encrypt first and Base64-encode the ciphertext only for transport if needed.

Base64 Encoder / Decoder

Encode to Base64 or decode Base64 to text — supports Base64URL (JWT), UTF-8/Latin1, padding toggle, and auto-detect.

Text (Plain)

Auto-detect: paste text or Base64

Input

Mode

Encoding

Base64 (Encoded)

Spacer

Output

What is Base64 Encoder / Decoder?

Base64 Encoder / Decoder is a developer tool for converting between plain text and Base64, plus Base64URL (the URL-safe variant used by JWT). Base64 represents binary data as ASCII text so it can safely pass through text-only channels like JSON, HTTP headers, query strings, environment variables, and configuration files. This tool supports UTF-8 (recommended for Unicode like Hebrew/emoji) and Binary (Latin1) for legacy `atob`/`btoa` compatibility. You can also control padding (`=`) because some ecosystems require it, while JWT/Base64URL often omits it. Use it to debug encoded API fields, inspect JWT segments, validate whether a string is Base64, and generate safe encoded values for apps and scripts—entirely in your browser.

How to Use

Paste plain text to encode or a Base64/Base64URL string to decode

Auto-detect chooses Encoding vs Decoding (you can override by swapping if needed)

Select UTF-8 for modern text (recommended) or Binary (Latin1) for legacy compatibility

Enable Base64URL (JWT) when working with URL-safe tokens (uses - and _ instead of + and /)

Toggle “Without padding” if your target system expects no '=' padding (common for Base64URL/JWT segments)

Copy the output and use it in headers, payloads, configs, tests, or scripts

Common Use Cases

Decode Base64 fields from API responses, logs, and database records

Encode JSON or config blobs for environment variables (single-line transport)

Decode JWT header/payload segments (Base64URL) for debugging auth issues

Generate URL-safe identifiers for query params or filenames (Base64URL mode)

Create HTTP Basic Auth values (Base64 of username:password)

Validate whether an input is valid Base64/Base64URL before parsing in code

Troubleshoot broken Unicode output by switching UTF-8 vs Binary mode

Prepare Base64 test fixtures for unit/integration tests

Key Features

All-in-one Base64 encode + decode

One tool for both directions

Base64URL (JWT) mode

URL-safe alphabet (- and _) for tokens and URLs

Padding control

Keep '=' for strict decoders or remove it for JWT/Base64URL use

UTF-8 support

Correct handling for Unicode text (Hebrew, emoji, accents)

Binary (Latin1) mode

Matches legacy `atob`/`btoa` expectations when needed

Auto-detect workflow

Paste anything and the tool chooses the likely direction

Fast local processing

Runs in-browser (no uploads), great for sensitive data

Copy-friendly output + examples

Designed for day-to-day dev debugging

Learn more about this tool with our in-depth guides

Jan 6, 2025•8 min read

Base64 Encoding and Decoding: Complete Developer Guide

Master Base64 encoding and decoding with practical examples. Learn when to use it, common pitfalls, and best practices for handling binary data.

#base64 #encoding #data-conversion+2

Quick Examples

Try these to get started

Encode simple text → Base64

Convert plain text into Base64 for safe transport.

Hello, World!

Decode Base64 → text

Decode a standard Base64 string back into readable text.

SGVsbG8sIFdvcmxkIQ==

Encode Unicode text (UTF-8)

UTF-8 preserves Unicode characters correctly (Hebrew/emoji/accents).

שלום 👋 — café

Encode JSON for APIs/configs

Encode a JSON string for env vars, config fields, or text-only systems.

{"env":"prod","flags":{"newUI":true},"region":"eu-west-1"}

HTTP Basic Auth credential (username:password)

Encode `username:password` for the Authorization header (prefix with `Basic `).

username:password

Decode a JWT header segment (Base64URL)

Decode a JWT header segment. Enable Base64URL mode if needed (JWT uses Base64URL).

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9

Decode a JWT payload segment (Base64URL)

Inspect JWT claims quickly by decoding the payload segment (Base64URL).

eyJzdWIiOiJ1c2VyXzEyMyIsInNjb3BlIjoicmVhZDp1c2VycyJ9

URL-safe token (Base64URL + optional no padding)

Enable Base64URL (and optionally remove padding) for URL-safe tokens.

user:12345|role:admin|ts:1700000000

Multiline value (store as single line)

Base64 is useful for storing multiline values as a single-line string in env vars.

-----BEGIN KEY-----
line1
line2
-----END KEY-----

Detect invalid Base64 quickly (bad characters)

Validation should fail when illegal Base64 characters appear (like '$').

SGVsbG8$IFdvcmxkIQ==

Common Questions

Find answers quickly

Popular conversions

You might also need

Base64 Encode

Encode text to Base64 instantly (UTF-8). Create Base64 strings for APIs, configs, Basic Auth, and safe text transport — locally in your browser.

Base64 Decode

Decode Base64 strings to readable text instantly with UTF-8 support

Base64URL Encode

Encode text to URL-safe Base64URL format for JWTs and URLs

Base64URL Decode

Decode Base64URL strings from JWTs and URLs to readable text

Text to Base64

Convert plain text to Base64 encoding instantly

Base64 to Text

Convert Base64 encoding back to readable plain text

URL Encoder & Decoder

Encode or decode URL strings and query parameters using percent-encoding (UTF-8)

HTML Escape & Unescape

Escape HTML characters into entities or unescape entities back to text (safe for XSS-sensitive output)

JWT Decoder

Decode JWT tokens locally to inspect header + payload claims (exp/nbf/iat, iss/aud, scopes/roles) and debug OAuth2/OIDC authentication issues.

JSON Formatter & Validator

Format, validate, beautify, and minify JSON — instantly detect errors and debug API payloads safely in your browser.

What is Base64 Encoder / Decoder?

Base64 Encoder / Decoder

What is Base64 Encoder / Decoder?

How to Use

Common Use Cases

Key Features

All-in-one Base64 encode + decode

Base64URL (JWT) mode

Padding control

UTF-8 support

Binary (Latin1) mode

Auto-detect workflow

Fast local processing

Copy-friendly output + examples

Related Articles

Base64 Encoding and Decoding: Complete Developer Guide

Quick Examples

Encode simple text → Base64

Decode Base64 → text

Encode Unicode text (UTF-8)

Encode JSON for APIs/configs

HTTP Basic Auth credential (username:password)

Decode a JWT header segment (Base64URL)

Decode a JWT payload segment (Base64URL)

URL-safe token (Base64URL + optional no padding)

Multiline value (store as single line)

Detect invalid Base64 quickly (bad characters)

Common Questions

Is Base64 encryption? Is it secure?

Is Base64 encryption? Is it secure?

What is Base64 used for?

What is Base64 used for?

What is Base64URL and why is it used in JWT?

What is Base64URL and why is it used in JWT?

Why does Base64 output sometimes end with '=' or '=='?

Why does Base64 output sometimes end with '=' or '=='?

Why does Base64 increase size by about 33%?

Why does Base64 increase size by about 33%?

What’s the difference between UTF-8 and Binary (Latin1) mode?

What’s the difference between UTF-8 and Binary (Latin1) mode?

Why does decoded output look corrupted or show � characters?

Why does decoded output look corrupted or show � characters?

How do I know if a string is valid Base64?

How do I know if a string is valid Base64?

Can I Base64-encode a file here?

Can I Base64-encode a file here?

When should I avoid Base64?

When should I avoid Base64?

Popular conversions

Base64 Encode

Base64 Decode

Base64URL Encode

Base64URL Decode

Text to Base64

Base64 to Text

URL Encoder & Decoder

HTML Escape & Unescape

JWT Decoder

JSON Formatter & Validator

Base64 Encoder / Decoder

What is Base64 Encoder / Decoder?

How to Use

Common Use Cases

Key Features

All-in-one Base64 encode + decode

Base64URL (JWT) mode

Padding control

UTF-8 support

Binary (Latin1) mode

Auto-detect workflow

Fast local processing

Copy-friendly output + examples

Related Articles

Base64 Encoding and Decoding: Complete Developer Guide

Quick Examples

Encode simple text → Base64

Decode Base64 → text

Encode Unicode text (UTF-8)

Encode JSON for APIs/configs

HTTP Basic Auth credential (username:password)

Decode a JWT header segment (Base64URL)