Base64 to JSON
Decode a Base64-encoded string back into readable, formatted JSON — supporting both standard and URL-safe Base64 alphabets. Toggle pretty-print to beautify the output, or paste an encoded file directly to extract its JSON payload. Everything runs in your browser with no data sent to any server.
Base64
Decoding
Output
JSON
What is Base64 to JSON Converter?
JWT tokens, Kubernetes secrets, Docker config files, and many webhook payloads embed JSON as Base64-encoded strings. Reading them requires decoding the Base64 first — something that interrupts any debugging or inspection workflow. This tool decodes a Base64 string and parses the underlying JSON in one step. It accepts both standard Base64 (using + and /) and Base64URL encoding (using - and _, as used in JWT header and payload segments) with or without padding. For JWTs, the middle segment (between the first and second dot) is the payload — paste just that segment to inspect claims like sub, exp, iat, roles, and any custom claims. For Kubernetes secrets, paste the value from the data field to decode credentials, certificates, or dockerconfigjson content. The decoded value is displayed as formatted, syntax-highlighted JSON alongside the raw decoded text.
How to Use
- 1
Paste the Base64 String
Paste your Base64-encoded string into the input panel. Standard Base64 and Base64URL (used in JWTs, with - and _ instead of + and /) are both accepted. Padding (=) is optional.
- 2
Set Decode Options
Choose whether to auto-detect Base64URL encoding, and select the output indentation level for the parsed JSON. Enable "Extract JWT Payload" mode to automatically decode the middle segment of a JWT token.
- 3
Decode and Parse
Click "Decode to JSON". The Base64 string is decoded to a UTF-8 string, then parsed as JSON. If the decoded value is not valid JSON, the raw decoded text is shown for inspection.
- 4
Inspect the JSON
Review the formatted JSON output — check JWT claims like exp (expiry), iat (issued at), sub (subject), and role fields, or inspect the decoded credentials and config objects.
Common Use Cases
JWT Payload Inspection
JWT tokens contain a Base64-encoded JSON payload as their second segment. Decode it to inspect claims like user ID, roles, expiry time, and issuer without a dedicated JWT debugger.
API Response Decoding
Some APIs return Base64-encoded JSON bodies to avoid encoding issues in HTTP headers or to pack binary-safe payloads. Decode them to access the structured JSON data.
Webhook Payload Debugging
Webhooks from services like GitHub, Stripe, or Twilio sometimes Base64-encode their event payloads. Decode them here to inspect the full JSON event structure during integration development.
Embedded Config Decoding
Kubernetes secrets, Docker config files, and cloud provider credentials are stored as Base64-encoded JSON. Decode them to inspect or edit the underlying configuration safely.
Conversion Examples
Base64 String → JSON Object
A Base64-encoded string is decoded and parsed into formatted JSON.
Input JSON
eyJpZCI6MSwidXNlcm5hbWUiOiJhbGljZSIsInJvbGUiOiJhZG1pbiJ9
Output CSV
{
"id": 1,
"username": "alice",
"role": "admin"
}JWT Payload Segment → Decoded Claims
The middle segment of a JWT token decoded to reveal its JSON claims.
Input JSON
eyJzdWIiOiJ1c2VyXzEyMyIsIm5hbWUiOiJBbGljZSIsImlhdCI6MTcwMDAwMDAwMCwiZXhwIjoxNzAwMDg2NDAwfQ
Output CSV
{
"sub": "user_123",
"name": "Alice",
"iat": 1700000000,
"exp": 1700086400
}