Encode and decode Base64 instantly — no button clicks, no page reloads. Auto-detects encode vs decode mode as you type. Supports URL-safe encoding, per-line mode, and one-click copy.
Paste any text or Base64 string — the tool instantly detects which direction to process and shows live output as you type. No "Encode" button to click.
Every operation runs in your browser using the native Web Crypto API. Zero network requests, zero data logging, zero cookies. Works offline.
Click "Copy Output" or press C to copy the result instantly. The button confirms with a visual checkmark so you always know it worked.
Built for developers. Press D for dark mode,S to swap panes, X to clear — all without touching the mouse.
Toggle URL-safe encoding to produce strings safe for query parameters and file names — replaces + with - and/ with _.
Enable per-line processing to encode or decode each line of your input independently — perfect for processing CSV data, log files, or batches of values.
Open Standard
Understand what Base64 is, when to use it, and how it works under the hood — from binary encoding to real-world applications in APIs, emails, and images.
Read the guide →Guide
Everything you need to know about Base64 — from the basics to real-world use cases — so you can get the most out of this free tool.
Using our Base64 encoder decoder online could not be simpler. Open the tool, paste your plain text or your encoded string into the input panel, and the output appears instantly — no button clicks, no page reloads. The base64 encoder toolautomatically detects whether your input looks like raw text or an existing Base64 string, switching between encode and decode mode on the fly.
Need to go the other way? Our built-in Base64 decoder works the same way. Paste any Base64 string — perhaps one you received from an API response, an email attachment header, or a configuration file — and the decoded output appears in the right-hand panel immediately. There is nothing to install and nothing to configure.
Base64 is a binary-to-text encoding scheme that converts arbitrary binary data into a string of printable ASCII characters. It was designed to solve a fundamental problem: many text-based protocols — email (MIME), HTTP headers, JSON payloads, and XML documents — cannot safely carry raw binary data. By encoding the data with abase64 encoder, you guarantee safe, lossless transport across any text channel.
Common real-world scenarios include embedding images directly in CSS or HTML asdata: URIs, passing cryptographic keys inside JWTs, encoding file attachments in email, and serialising binary blobs into environment variables. Any time you have seen a long string of letters, numbers, +, and / characters, you were probably looking at Base64.
+and / which break in URLs. Toggle URL-safe mode to replace them with - and _, producing strings safe for query parameters and file names.Reach for a base64 decoder tool whenever you receive opaque-looking strings from an API, a configuration system, or a log file. Base64 is used extensively in JWT tokens (the header and payload sections are Base64url-encoded), SAML assertions, Basic Authentication headers, and MIME email parts. Paste the encoded segment into thisbase64 decoder online and you will immediately see the underlying JSON, XML, or plain-text content — making debugging dramatically faster.
Developers also use a base64 encoder decoder during local development to quickly inspect or craft HTTP headers, prepare image data URIs, and verify cryptographic payloads without writing a single line of code. Having a reliable, always-available base64 decoder tool in your browser bookmarks saves meaningful time every week.
Base64 is an encoding scheme, not an encryption scheme. Encoded data can be decoded by anyone with access to this or any otherbase64 decoder website — it provides no confidentiality. Also note that Base64 expands the data size by approximately 33 %, so it is not suitable as a compression strategy. For sensitive data, always encrypt first, then Base64-encode if the transport layer requires it.