Base64 Encode & Decode online with instant conversion.
Encode and decode text, UTF-8 strings, and JSON payloads into standard Base64 or URL-safe Base64URL format. 100% private in-browser with zero server uploads.
JSONGlow's Base64 Encode & Decode tool is a 100% private in-browser utility that converts text, JSON payloads, and binary strings into standard Base64 or URL-safe Base64URL with zero server latency.
Overview
Why Base64 encoding remains fundamental in web protocols
Base64 (RFC 4648) encoding is widely utilized across web development to represent binary assets, HTTP Basic Authentication authorization headers, JWT segments, inline data URIs, and webhook signatures as ASCII character strings.
Standard Base64 contains '+' and '/' characters with '=' padding, which frequently cause parsing corruption when passed inside URL query parameters or REST path variables. A flexible encoder supports both standard RFC 4648 Base64 and URL-safe Base64URL without losing unicode characters. If you are working with tokens, check out our dedicated JWT Decoder or pretty-print decoded JSON with the JSON Formatter.
Unlike cloud conversion websites that send your sensitive authentication tokens, authorization credentials, and proprietary payloads across remote web servers, JSONGlow processes all data 100% locally in your browser memory sandbox. Your tokens never leave your computer.
You can toggle between Base64 and Base64URL formatting, swap input and output directions with a single click, copy results immediately, or download decoded files directly. For embedding JSON into code string variables, explore our JSON Escape Tool or auto-repair syntax errors with JSON Repair.
Workflow Guide
How to encode and decode Base64 in 3 steps
Input your text or string
Paste raw text, JSON, or an encoded Base64 string into the left editor panel.
Choose Encode or Decode
Toggle 'Encode Base64' or 'Decode Base64', and enable URL-safe encoding if needed for query parameters.
Instant clipboard export
Click 'Copy' to copy the converted output to your clipboard or download as a text file.
Practical Demonstration
Base64 Encoding & Decoding Example
See how JSON payloads and UTF-8 text translate to and from standard Base64 representation.
{
"user_id": 98214,
"role": "admin",
"verified": true
}ewogICJ1c2VyX2lkIjogOTgyMTQsCiAgInJvbGUiOiAiYWRtaW4iLAogICJ2ZXJpZmllZCI6IHRydWUKfQ==Troubleshooting & Edge Cases
Common Base64 encoding pitfalls & solutions
Invalid Base64 characters in decode input
Why it happens: Base64 strings can only contain characters A-Z, a-z, 0-9, '+', '/', and '=' padding. Whitespace or foreign symbols trigger decode errors.
UTF-8 multi-byte encoding corruption
Why it happens: Standard browser btoa/atob functions fail on non-ASCII characters (e.g. emojis or accented letters) without UTF-8 byte array conversion.
URL query parameter corruption (+ replaced with space)
Why it happens: Web servers often interpret the '+' character in standard Base64 as a space in URLs.
Core Capabilities
Engineered for data fidelity & speed
Full UTF-8 Compatibility
Accurately encodes and decodes multi-byte unicode strings, symbols, and emojis without truncation.
100% Client-Side Privacy
Zero server uploads. Sensitive passwords, API keys, and authorization headers remain completely private.
URL-Safe Base64URL Mode
Toggle RFC 7515 Base64URL format for seamless integration with JWTs, URLs, and REST APIs.
One-Click Direction Swap
Instantly swap between encoding and decoding with synchronized editor content.
Real-Time Byte Size Display
Monitor payload expansion and compression ratios in real-time.
Instant File Download
Save encoded or decoded results directly to your local file system.
Frequently Asked Questions
Common questions answered.
Need more help? Our tools execute entirely in your browser without transmitting any payload to remote servers.
What is the difference between Base64 and Base64URL?+
Standard Base64 uses '+' and '/' as characters 62 and 63, and '=' for padding. Base64URL replaces '+' with '-' and '/' with '_', and omits padding, making it safe to use directly in URLs and JWT tokens without escaping.
Does this Base64 tool upload my data to any server?+
Never. All encoding and decoding operations run 100% in your local browser sandbox using client-side Web APIs. No network requests are made.
Can this tool handle emojis and international characters?+
Yes. JSONGlow utilizes modern TextEncoder and TextDecoder APIs to ensure full UTF-8 compatibility without Latin1 encoding errors.
How can I decode a JSON Web Token (JWT)?+
For complete JWT token inspection, signature verification, and expiration auditing, visit our dedicated JWT Decoder tool.
Why is the Base64 output larger than my original input?+
Base64 encodes 3 bytes of binary data into 4 ASCII characters, resulting in an approximately 33% increase in data size.
Is there any payload size restriction?+
No. The tool processes large payloads smoothly in your local browser memory without artificial limits.
Explore More Tools & Guides
The JSONGlow developer kit.
JWT Decoder
Decode Base64URL header & payload, check expiration countdown, and verify HMAC/RSA signatures offline.
JSON Escape
Escape double quotes, newlines, and backslashes for embedding JSON safely in programming code variables.
JSON Formatter
Format, beautify, indent, sort keys alphabetically, and inspect nested JSON structures.