Private Offline JWT Inspector — Decode JSON Web Tokens safely without leaking secrets to public sites
Inspect JWT header, payload claims, expiration timestamps, and signature status completely offline without transmitting tokens over the wire.
Step-by-Step Client-Side Workflow
- 1. Local Base64Url Parsing: Your token is split into Header, Payload, and Signature segments and decoded strictly in browser memory using native UTF-8 byte decoders.
- 2. Claim & Timestamp Inspection: Standard RFC 7519 claims (exp, iat, nbf, sub, iss) are automatically evaluated and converted into human-readable local timestamps.
- 3. Zero-Telemetry Verification: Unlike cloud debuggers that log analytics or accidentally cache URL parameters, your bearer tokens never leave your machine.
Why Use VaultTools Zero-Upload Architecture
- Zero Production Token Leaks: Safely inspect live bearer tokens, OAuth ID tokens, and session cookies without violating SOC2 or ISO 27001 security policies.
- Instant Expiration Diagnostics: Immediately see whether a token is active or expired with live countdowns and formatted claim breakdowns.
- Works in Air-Gapped Environments: Debug authentication flows on locked-down corporate VPNs or offline development machines.
Frequently Asked Questions
Is it safe to paste a live production JWT into VaultTools?
Yes. VaultTools runs 100% client-side in your browser RAM with zero network requests. You can even disconnect from the internet before pasting your JWT to verify that no data leaves your device.
Can anyone read the payload of a JWT without the secret key?
Yes! Standard JWTs (JWS) are Base64Url-encoded, not encrypted. Anyone who intercepts a JWT can read its header and payload claims—the secret key is only used to verify that the signature was not tampered with.
What do the exp, iat, and sub claims mean in a JWT?
"exp" (Expiration Time) defines when the token becomes invalid, "iat" (Issued At) records when the token was minted, and "sub" (Subject) identifies the user or principal the token belongs to.