About the Base64 Decoder
Base64 encoding is everywhere in web development — in JWT tokens, image data URIs, email attachments, and API responses. When you receive Base64-encoded data and need to see what it contains, our free Base64 Decoder converts it back to readable text or binary data instantly.
What Is the Base64 Decoder?
Base64 Decoding is the reverse of Base64 encoding — it takes a Base64-encoded string (using characters A-Z, a-z, 0-9, +, /) and converts it back to the original binary or text data. For example, the Base64 string "SGVsbG8gV29ybGQ=" decodes to "Hello World". Our tool handles standard Base64 and URL-safe Base64 automatically.
Key Features
- Instant Decoding — Paste a Base64 string and see the decoded text immediately.
- Auto-Format Detection — Automatically handles both standard (+/) and URL-safe (-_) Base64 variants.
- Error Handling — Clear error messages when the input isn't valid Base64.
- One-Click Copy — Copy the decoded output instantly.
How to Use the Base64 Decoder — Step by Step
- Paste Base64 String — Paste your Base64-encoded string into the INPUT box.
- View Decoded Text — The decoded plain text appears in the OUTPUT box immediately.
- Copy Result — Click Copy Output to use the decoded content.
Benefits
- Inspect Encoded Data: See what's hidden inside Base64-encoded API payloads, tokens, and data URIs.
- JWT Inspection: JWT headers and payloads are Base64Url-encoded. Decode them to see the claims.
- Debug Encoding Issues: Quickly verify that your encoder produces correct output by decoding and comparing.
- Email Analysis: MIME email bodies are Base64-encoded — decode to see the original content.
Use Cases
- JWT Token Inspection: Decode the header and payload sections of JSON Web Tokens to inspect claims.
- Email MIME Parts: Email clients encode message bodies and attachments in Base64 — decode MIME parts for analysis.
- Data URI Inspection: Extract the original binary from Base64-encoded image data URIs.
- API Response Debugging: Decode Base64-encoded API response fields for debugging.
Why Choose Toolimi's Base64 Decoder?
Toolimi's Base64 Decoder is completely client-side, ensuring your encoded data (which may contain sensitive tokens or credentials) never leaves your browser. Paired with our Base64 Encoder, it's the complete encoding toolkit.
Tips for Best Results
- JWT tokens have three parts separated by dots (.). You can decode the first two (header and payload) with this tool.
- Base64 strings always end in 0, 1, or 2 "=" padding characters.
- URL-safe Base64 uses "-" and "_" instead of "+" and "/" — our decoder handles both.
- If decoding produces garbled output, the source data may be binary (not text) — use a hex viewer instead.
Frequently Asked Questions
Ready to Get Started?
The Base64 Decoder on Toolimi is completely free, takes seconds to use, and requires no registration.
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