100% In-Browser JWT Parsing • Zero Cloud Telemetry

JWT Decoder Online

Decode JSON Web Tokens (JWT) safely. Inspect headers, payload claims, and expiration timestamps locally without exposing Bearer tokens to external servers.

Encoded Token InputActive (expires in 2h)

Issued At (iat) Oct 25, 2026, 11:08:26 PM

Expiration Time (exp) Oct 26, 2026, 1:13:26 AM

Not Before (nbf) Immediate

Header (Algorithm & Token Type)

{
  "alg": "HS256",
  "typ": "JWT"
}

Payload (Data Claims)

{
  "sub": "user_94821804",
  "name": "Alex Morgan",
  "email": "alex.morgan@example.com",
  "role": "admin",
  "iat": 1792949906,
  "exp": 1792957406,
  "iss": "https://auth.fileveda.com"
}

Signature Digest

w29d8k192msdkw9283k1sm923k10293js92ks10

How to Decode and Inspect JSON Web Tokens

Paste Your JWT

Paste your raw encoded authentication or ID token into the top editor.

Local Base64URL Parsing

The browser decodes UTF-8 payloads and highlights key claims without sending tokens across the web.

Verify Expiration & Claims

Inspect formatted UTC/local timestamps for token issuance (`iat`) and expiration (`exp`) times.

Why Paste JWTs Only In FileVeda?

Many online JWT debuggers send tokens to cloud servers or include third-party tracking scripts that capture full Authorization header values. Pasting production tokens into insecure tools creates major security vulnerabilities. FileVeda never makes a network request—the code runs 100% locally in your browser memory.

FileVeda vs Third-Party Online JWT Debuggers

Evaluating token privacy, security hygiene, and debugging capabilities.

Evaluation Metric	FileVeda Decoder	Public Web Debuggers	Local Terminal CLI
Token Privacy	100% Client-Side In-Memory Only	Logged or tracked by analytics	Saved in bash history unless masked
Secret Key Safety	Never Prompts For Private Keys	Encourages pasting private keys	Stored on disk or env vars
Timestamp Expiration	Auto-calculated Expiry & Human Dates	Raw UNIX epoch numbers only	Manual date conversion needed
Tracking & Telemetry	Zero Analytics on Tokens	Google Ads, Meta Pixel trackers	None
Offline Usability	Runs completely offline in tab	Fails without internet access	Fully offline

Technical Guide: RFC 7519 JSON Web Token Architecture

The Three Components of a JWT

RFC 7519 standardizes compact, URL-safe representations of claims transferred between two parties. Tokens follow the pattern header.payload.signature:

Header: Specifies signing algorithm (alg: HS256, RS256, ES256) and token type (typ: "JWT").
Payload: Encodes claims categorized as Registered, Public, or Private claims.
Signature: Cryptographic hash calculated over Base64URL-encoded header and payload to prevent tampering.

Standard Registered Claim Semantics

IANA and RFC 7519 define standard claim keys used by OAuth 2.0 and OpenID Connect (OIDC):

iss: Issuer that created and signed the security token.
sub: Subject identifier (typically the user ID or client identifier).
aud: Audience (target recipient service allowed to accept this token).
exp / nbf / iat: Expiration, Not Before, and Issued At epoch timestamps.

Frequently Asked Questions

Is it safe to paste production JWT tokens into FileVeda?

Yes, FileVeda is 100% client-side. The token string is decoded strictly in your browser using local Base64URL parsing. No network requests are made, preventing credential leakage.

What are the three parts of an RFC 7519 JSON Web Token?

A JWT consists of Header (identifies the signing algorithm like RS256 or HS256), Payload (contains claims such as sub, iss, and exp), and Signature (verifies integrity), separated by periods.

Why is pasting JWT tokens into third-party online debuggers dangerous?

Many public debuggers transmit tokens to remote logging servers or run ad-tracking scripts that harvest Bearer auth tokens, giving bad actors live access to your production APIs.

What do the standard JWT claims 'exp', 'iat', and 'nbf' mean?

'exp' is Expiration Time (UNIX epoch seconds after which the token is invalid), 'iat' is Issued At timestamp, and 'nbf' is Not Before (token is not valid before this timestamp).

Can an expired JWT token still be parsed and inspected?

Yes. Base64URL encoding is an encoding scheme, not encryption. Expired tokens can still be decoded to inspect historic user IDs, scopes, and expiration timestamps for debugging.

Does FileVeda require or store my private signing key?

Never. FileVeda never asks for your HMAC secret or RSA/ECDSA private key. It safely inspects structure and claims without risking your server's cryptographic keys.