Base64 Decoder — Decode Base64 Online, Free

Q: How do I decode a Base64 string online?

Paste your Base64 string into SmartDevBox at smartdevbox.com. It automatically detects Base64 encoding and decodes it instantly — no configuration needed.

Q: How do I decode a JWT token without a secret?

Paste your JWT token into SmartDevBox. The JWT Inspector tool decodes the header and payload and displays them as readable JSON. Note: this decodes but does not verify the signature — you don't need the secret to read the claims.

Q: How do I format or pretty-print JSON?

Paste your minified or unformatted JSON into SmartDevBox. The JSON Formatter tool detects it automatically and pretty-prints it with configurable indentation.

Q: How do I convert a Unix timestamp to a human-readable date?

Paste a Unix timestamp (e.g. 1700000000) into SmartDevBox. The Unix Timestamp converter detects it and shows the equivalent date and time in UTC and your local timezone.

Q: How do I convert JSON to CSV?

Paste a JSON array of objects into SmartDevBox and select the JSON → CSV tool. It converts your data to comma-separated format with headers derived from the JSON keys.

Q: How do I compute a SHA-256 hash online?

Use the Hash Generator tool on SmartDevBox. Paste any text and it computes MD5, SHA-1, SHA-256, and SHA-512 hashes simultaneously in the browser.

Q: How do I parse and understand a cron expression?

Paste your cron expression (e.g. "0 9 * * 1-5") into SmartDevBox. The Cron Job Parser explains it in plain English and shows the next scheduled run times.

Q: How do I decode an X.509 certificate online?

Paste a PEM-encoded certificate (beginning with -----BEGIN CERTIFICATE-----) into SmartDevBox. The Certificate Decoder extracts and displays the subject, issuer, validity dates, public key, and extensions.

Q: Is SmartDevBox free to use?

Yes. SmartDevBox is completely free with no account or sign-up required. All tools run in the browser. An optional AI mode (for ambiguous input detection) can be enabled with your own OpenAI API key.

Q: Does SmartDevBox send my data to a server?

No. All tools run entirely in the browser using client-side JavaScript. Your data never leaves your machine unless you opt into the AI mode, which sends input to OpenAI for format detection.

Question 1

What is Base64 encoding?

Answer

Base64 is a binary-to-text encoding scheme that represents binary data using 64 printable ASCII characters (A–Z, a–z, 0–9, +, /). It is widely used to transmit binary data over text-based protocols like HTTP, email (MIME), and JSON.

Question 2

How do I decode a Base64 string online?

Answer

Paste your Base64 string into SmartDevBox. The tool automatically detects Base64 encoding and decodes it to plain text — no manual tool selection needed.

Question 3

What is the difference between standard Base64 and URL-safe Base64?

Answer

Standard Base64 uses + and / as the 62nd and 63rd characters. URL-safe Base64 replaces them with - and _ so the encoded string can be used safely in URLs and file names without percent-encoding.

Question 4

Can I decode a Base64 image data URI?

Answer

Yes. Paste a Base64 data URI (e.g. data:image/png;base64,...) and use the Base64 Image Decode tool to see the MIME type and byte size. To decode generic Base64, use this Base64 Decoder.

Base64 Decoder — Decode Base64 Online, Free

Common Use Cases

Frequently Asked Questions

What is Base64 encoding?

How do I decode a Base64 string online?

What is the difference between standard Base64 and URL-safe Base64?

Can I decode a Base64 image data URI?

Privacy & Security

Base64 Decoder — Decode Base64 Online, Free

Common Use Cases

Frequently Asked Questions

What is Base64 encoding?

How do I decode a Base64 string online?

What is the difference between standard Base64 and URL-safe Base64?

Can I decode a Base64 image data URI?

Privacy & Security

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