Base64 to JSON — Decode & Pretty-Print JSON from Base64

Paste a Base64-encoded JSON string and instantly get beautifully formatted, syntax-highlighted JSON. Perfect for decoding API payloads, JWT claims, and configuration data.

Decode Base64 JSON payloads instantly

APIs, webhooks, and configuration files often transmit JSON data as Base64-encoded strings. This tool decodes the Base64 encoding and formats the resulting JSON with proper indentation and syntax highlighting.

The formatter validates the JSON structure and catches common issues like trailing commas, missing quotes, or unescaped characters. Choose between 2-space, 4-space, or tab indentation.

Common use cases

  • Decode Base64-encoded API response bodies
  • Inspect JWT payload claims after Base64 decoding
  • Debug webhook payloads and event data

Features

  • Syntax-highlighted JSON output
  • Configurable indentation (2/4 spaces or tabs)
  • JSON validation with error messages

FAQs

What if the decoded content is not JSON?

The tool will show you the decoded text and indicate that it's not valid JSON. You can still see the raw decoded output. Try the Base64 to Text tool for non-JSON content.

Can I decode nested Base64 JSON (Base64 inside JSON inside Base64)?

This tool decodes one level of Base64 encoding. If your JSON contains Base64-encoded values, decode the outer layer first, then decode individual values separately.

Does this tool validate the JSON structure?

Yes. After decoding, the tool parses the JSON and reports any syntax errors including the position of the error. Valid JSON is displayed with proper formatting.

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