Utilities
Base64, encoded and decoded on your device
Encode text to Base64 or decode it back instantly, computed locally, so tokens and secrets never leave your device.
For the best results: Encoding and decoding happen on your device, which is the point: tokens, keys, and config values never travel anywhere. Use URL-safe mode for values going into a query string.
Runs entirely in your browser, what you paste is never uploaded, logged, or stored.
What is Base64 Encode & Decode?
Base64 Encode & Decode is a free online utility that encodes text to Base64 or decodes it back, computed locally so tokens and secrets never leave your device. The conversion runs as plain JavaScript in this tab, so whatever you paste, including anything sensitive, never leaves your device. There is no server call involved at all, no account to make, and no cap on how often you use it.
- ✦Runs entirely in your browser. Nothing you enter is ever uploaded
- ✦No account, no sign-up, and no data leaves your device
- ✦Works offline once the page has loaded
See it in action
A webhook secret needs Base64 encoding, and a mystery blob from a config file needs decoding.
What you type
"café العربية 🧪" encoded, then the result decoded back
What you get
The decode returns the exact original text, accents, Arabic and emoji intact, because the tool goes through proper UTF-8 bytes rather than assuming ASCII. Junk input gets "Not valid Base64" instead of garbage.
Tip: URL-safe mode swaps + and / for - and _ and drops padding, which is what JWTs and URL parameters expect. Decoding accepts both alphabets, so paste either form.
Use cases
What people use it for
Decode the payload of a JWT on your own device so the token never reaches another server.
Encode a username and password pair for a Basic Authorization header while testing an API.
Read a Base64 value copied from a Kubernetes secret, email source or configuration file.
Who uses Base64 Encode & Decode?
Backend developers
inspect token payloads and encode test credentials without exposing secrets to a third-party service
DevOps engineers
decode secrets from Kubernetes manifests and CI variables safely on their own machine
API testers
craft and check Authorization headers while probing endpoints, keeping keys off the network entirely
How it works
- 1Vary step 1 by tool shape using the existing FORM_TOOL_IDS set in app/(public)/[category]/[tool]/page.tsx. Form tools get "Set the options for what you need." and text tools get "Paste your text into the box." Where a tool's config makes it easy, name its own inputs instead. Steps 2 and 3 stay shared as they are.
- 2Your browser computes the result instantly. Nothing is uploaded anywhere.
- 3Copy the output; the tool keeps working even offline.
Tips for the best results
- Never treat Base64 as secrecy; anyone can reverse it in a second.
- If decoding fails, check for the URL-safe variant that uses hyphens and underscores.
- A JWT is three Base64 sections joined by dots; decode each part separately.
- Watch for stray whitespace and missing padding when copying encoded strings from logs.
- Prefer local tools for anything involving credentials; a secret pasted into a server-side tool is a secret shared.
FAQ
Frequently asked questions
What is Base64, in plain terms?
Base64 is a way of writing any data using only 64 safe characters: letters, digits, plus and slash, with equals signs as padding. Every three bytes of input become four characters of output, which is why encoded text is about a third longer. It exists so binary data can travel through systems built for plain text.
Is Base64 a form of encryption?
No, and this trips people up constantly. Base64 is an encoding, a reversible representation with no key and no secrecy; anyone can decode it instantly. It hides nothing. If you find a password or token stored in Base64 and described as encrypted, treat that as a security problem rather than a protection.
Why does it matter that encoding happens locally?
Because the strings people run through Base64 tools are often credentials: API keys, JWTs, connection strings, auth headers. Pasting those into a tool that posts them to a server means your secret now exists in someone else's logs. Here the conversion runs inside your browser, so the value never crosses the network at all.
Why does my decoded output look like garbage?
Three usual causes. The data may be genuinely binary, such as an image or compressed blob, which has no sensible text form. The string may use the URL-safe variant, which swaps plus and slash for hyphen and underscore. Or characters were lost in copying, since Base64 needs its exact length and padding to decode cleanly.
Where is Base64 used in the real world?
Everywhere text-only channels need to carry binary or structured data: email attachments through MIME, images embedded in CSS and HTML as data URIs, the three segments of a JWT, Basic Authorization headers, and values in Kubernetes secrets and countless configuration files. Recognizing it on sight is a genuinely useful developer skill.
How can I tell if a string is Base64?
Look for the tell-tale alphabet: only letters, digits, plus and slash, often ending in one or two equals signs, with a length divisible by four. It is a strong hint rather than proof, since short ordinary words can match the pattern by coincidence. Decoding it is the definitive test.
Why do Base64 strings end with equals signs?
The equals signs are padding. Base64 converts input in blocks of three bytes, and when the data does not divide evenly into threes, the final block is filled out and the leftover space marked with one or two equals signs so decoders know exactly how many real bytes to restore.
Does Base64 compress data?
The opposite: encoding makes data roughly 33 percent larger, because every three bytes are spread across four characters. Base64 is purely about surviving transport through text-only systems. If you need smaller payloads, compress first with something like gzip, then encode the result if a text channel requires it.
Are there any usage limits?
None. Everything is generated locally in your browser, so there is no server cost, no metering, and no daily cap, use it as many times as you like, completely free.
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