Base64 Encode / Decode
Local Base64 / Base16 / Base32 tools with JWT payload decode, hex preview, and batch file ZIP export. Nothing is uploaded.
All processing on this page runs locally in your browser unless noted otherwise.
Input: 0 chars · 0 bytes
How to use
- Pick an encoding (Base64 / Base64URL / Base16 / Base32). Live convert updates Output after ~300ms.
- Choose file to load bytes into Input using the current encoding (Data URI only for Base64 family).
- Decode JWT payload reads the middle segment as Base64URL JSON — it does not verify signatures.
- Optional local history is off by default; enable it in Options to keep recent Inputs on this device only.
- Sample / Swap / Download TXT / Download file behave as in v1; MIME wrap applies only to Base64 family.
- Enable hex preview for binary payloads; multi-select files to batch-encode and download a ZIP (local only).
Sample
Plain text:
Hello, Base64 Workbox!
你好，Base64。
JWT / Basic Auth / Data URI often use Base64 or Base64URL.
UTF-8 Standard Base64:
SGVsbG8sIEJhc2U2NCBXb3JrYm94IQ==FAQ
Is my text uploaded?
No. All conversion runs in your browser. Option preferences may be saved locally. History is off unless you enable it.
When should I use Base64URL?
Use Base64URL for JWT segments, URL query values, and anywhere + / or = would break parsing.
UTF-8 vs GBK?
Use UTF-8 for modern APIs. Choose GBK when interoperating with legacy Chinese Windows systems.
What is the file limit?
10 MB per file. Batch mode: up to 20 files and 50 MB total; oversized items are skipped.
Is Base64 secure storage?
No. Encoded data is trivial to decode. Treat it like plaintext for secrecy purposes.
Does Decode JWT payload verify the signature?
No. It only Base64URL-decodes the payload (and optionally the header). Anyone can forge an unverified JWT.
Where is history stored?
Only in this browser’s localStorage when you enable “Save history locally”. Clearing history or turning the switch off removes those snapshots.
When should I use hex preview?
When decoded data is binary or hard to read as text. Preview shows at most the first 64 KB; download the file for the full bytes.
Can I install this as an app (PWA)?
Yes, if your browser offers install. The shell can work offline from cache, but encode/decode still runs only on your device — nothing is uploaded.