JWTDeveloper & Data

Read JWT contents and timing without confusing decoding with verification.

JWT Inspector decodes header and payload JSON locally, surfaces issued-at, not-before, and expiry claims as readable dates, and labels the current expiry state. It also keeps the signature trust boundary explicit: decoded claims remain untrusted until a server verifies the token.

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What it does

Decode a JWT into readable JSON and timing diagnostics while preserving the signature warning.

Decode Base64URL header and payload segments locally.

Read structured claims instead of raw token text.

Convert iat, nbf, and exp into readable dates.

See whether the expiry is valid or expired.

Keep the unverified-signature warning beside the token.

Decode without false trust

Read the claims, timing, and signature boundary together.

The token stays beside structured header and payload JSON, readable dates, expiry state, and the warning that decoding is not verification.

Inspect the token without trusting it

Decode a realistic Northstar JWT locally while Foldout keeps the crucial boundary visible: contents are readable, but only the server can verify the signature.

Foldout JWT Inspector decoding a fictional Northstar token with header, payload, timing claims, and signature warning close-up showing inspect the token without trusting it

Separate header and payload into readable JSON

See the signing algorithm, subject, name, role, and numeric claims as structured JSON instead of manually decoding Base64URL segments.

Foldout JWT Inspector decoding a fictional Northstar token with header, payload, timing claims, and signature warning close-up showing separate header and payload into readable JSON

Read issued, not-before, and expiry timing at a glance

Convert iat, nbf, and exp into readable local dates and see whether the expiry is currently valid or already expired.

Foldout JWT Inspector decoding a fictional Northstar token with header, payload, timing claims, and signature warning close-up showing read issued, not-before, and expiry timing at a glance

Why it belongs

Why JWT earns a place in the toolbox.

The practical details that make this job faster, clearer, or safer than doing it by hand.

The trust boundary stays visible

Foldout explains that decoding reveals contents but does not prove authenticity.

Claims become readable

Header and payload are formatted as JSON, with timing fields promoted into a dedicated summary.

Useful during debugging

Inspect role, subject, dates, and expiry without sending a bearer token to a website.

How to use it

From opening the tool to saving the result.

01
Paste the complete JWT.
02
Decode the header and payload.
03
Review claims and readable timing.
04
Treat the contents as untrusted until server verification.

Questions

Before you try JWT

Does it verify signatures?

This tool focuses on decoding and inspecting token contents.

Related tools

Read JWT contents and timing without confusing decoding with verification.

Decode a JWT into readable JSON and timing diagnostics while preserving the signature warning.