Base64 Decode & Encode
Convert between Base64 and readable text or JSON.
Opens the editor with a Base64 string on the left and its decoded value on the right. Runs entirely in your browser.
Base64 encodes arbitrary bytes as a safe subset of ASCII, which is why it shows up everywhere JSON travels: inside JWT tokens, in data: URLs, in API fields that carry binary content, and in HTTP Basic auth headers. Decoding turns that opaque string back into readable text or JSON; encoding does the reverse.
Where you meet Base64
- JWTs. The header and payload of a JSON Web Token are Base64url-encoded JSON — decode them to read the claims.
- API payloads. Files, images and signatures are often shipped as Base64 strings inside JSON.
- Auth headers. HTTP Basic auth encodes
user:passwordas Base64.
Decode, then read as JSON
A lot of Base64 you run into decodes straight into JSON. The sample above decodes to a small JSON object — once decoded, format it or open it in the tree viewer to explore it like any other document. Because the decode and the JSON tooling live in the same editor, you go from opaque string to structured data in two clicks.
Encode the other way
Need to produce Base64 instead? Paste your text or JSON and run Base64 encode to get a string you can drop into a field or header. The tool handles full Unicode correctly, so non-ASCII characters survive the round trip.
Private and local
Decoding a token can expose sensitive claims, so it matters that this runs in your browser only. Nothing is uploaded, logged or stored — decode production tokens safely.
Frequently asked questions
How do I decode a Base64 string?
Paste the Base64 into the editor and run Base64 decode. The decoded text — often JSON — appears in the other panel, ready to format or explore.
Is it safe to decode a JWT or token here?
Yes. Decoding runs entirely in your browser and nothing is uploaded, so the claims inside a token never leave your device. For full JWT inspection, use the JWT decoder.
Does it handle Unicode and emoji?
Yes. Encoding and decoding round-trip full UTF-8, so non-ASCII characters are preserved correctly.
Related tools
Prefer to start from scratch? Open the JSON editor and paste your own data — everything runs locally in your browser.