Online Base64 Encoder Decoder
Encode text to Base64 or decode Base64 back to plain text. 100% client‑side, no uploads, no signup — works entirely in your browser.
Your data never leaves your browser. All encoding and decoding happens locally using JavaScript. No tracking, no signup, no uploads.
Online Base64 Encoder Decoder — Fast, Secure, and 100% Free
Our online Base64 encoder decoder helps you convert text to Base64 and decode Base64 strings back to readable text instantly. Whether you're working with API tokens, inspecting JWT headers, debugging HTTP Basic Authentication strings, or generating data URIs for images, this Base64 converter handles it all — directly in your browser with zero server uploads.
Switch between encoding (text to Base64) and decoding (Base64 to text) with a single click.
Easily copy results to clipboard, paste from clipboard, or download as a .txt file.
Works offline — just click "Convert" and see results immediately.
Properly handles emojis, international characters, and non-ASCII text — no "InvalidCharacterError".
Your data stays on your device. No uploads, no servers, no tracking. Complete privacy.
Use the online Base64 encoder decoder immediately — no registration, no email, no payment.
How to Encode and Decode Base64 Online
1. Enter your plain text or Base64 string into the input box.
2. Select mode: "Encode (Text → Base64)" or "Decode (Base64 → Text)".
3. Click "Convert" or use the Swap button to quickly switch between modes.
4. Copy the result to your clipboard, download it as a .txt file, or use it directly in your project.
5. Use the Sample button to test the tool with example data.
Why Use a Base64 Encoder Decoder Online?
- API Development — Encode API keys, authentication tokens, and binary data for JSON payloads.
- JWT Debugging — Decode JWT header and payload segments without external tools.
- Data URIs — Generate Base64 data URIs for images, fonts, and other assets.
- Email MIME — Encode attachments and email bodies for SMTP transmission.
- Cross‑platform Testing — Verify Base64 strings across different systems quickly.
What is Base64? How Does Base64 Encoding Work?
Base64 is a binary-to-text encoding scheme that represents binary data using a 64-character ASCII alphabet (A–Z, a–z, 0–9, +, /). It converts every 3 bytes (24 bits) into 4 characters of Base64. When the input is not a multiple of 3 bytes, the encoder adds padding with "=" characters. Base64 is widely used in email attachments (MIME), JSON web tokens (JWT), HTTP Basic Authentication, and data URIs in HTML/CSS. Remember: Base64 encoding is not encryption — it's just a way to safely transmit binary data over text-only protocols.
Why Choose Our Online Base64 Encoder Decoder?
- Completely free Base64 tool — no watermarks, no hidden fees, no limits
- No sign-up required — start encoding/decoding Base64 immediately
- Privacy-first design — all processing happens locally in your browser
- Unicode-safe — proper UTF-8 handling for emojis and special characters
- Fast and lightweight — uses native browser APIs for maximum performance
- Works offline — once loaded, the tool works without an internet connection
Frequently Asked Questions
Learn how to use this tool correctly by reading our step-by-step tutorial.
