JWTDecode

A command-line devtools toolkit for working with JWT tokens. Check, validate, generate, format, lint, explain, convert, diff, preview, fix, and report on JWT data — all from your terminal with persistent logging and activity tracking.

Why JWTDecode?

• Works entirely offline — tokens and data never leave your machine
• No external dependencies or accounts needed
• Every action is timestamped and logged for full auditability
• Export your history to JSON, CSV, or plain text anytime
• Pure bash implementation — lightweight and portable

Commands

Each data command (check, validate, generate, etc.) works in two modes:

• With arguments — logs the input with a timestamp and saves to its dedicated log file
• Without arguments — displays the 20 most recent entries from that command's log

Data Storage

All data is stored locally in ~/.local/share/jwtdecode/. The directory structure:

• check.log, validate.log, generate.log, etc. — per-command log files
• history.log — unified activity log across all commands
• export.json, export.csv, export.txt — generated export files

Set the JWTDECODE_DIR environment variable or modify DATA_DIR in the script to change the storage location.

Requirements

• Bash 4.0+ (uses set -euo pipefail)
• Standard Unix tools: date, wc, du, tail, grep, sed, cat
• Works on Linux and macOS
• No external packages or network access required

When to Use

1. Debugging authentication flows — use jwtdecode check and jwtdecode explain to inspect token contents when troubleshooting login or API auth issues
2. Validating token structure — run jwtdecode validate to verify that tokens conform to expected JWT format before deploying auth changes
3. Comparing tokens across environments — use jwtdecode diff to spot claim differences between staging and production tokens
4. Auditing token usage — use jwtdecode stats, jwtdecode recent, and jwtdecode export to review your JWT analysis history over time
5. Formatting tokens for documentation — run jwtdecode format to produce clean, readable token breakdowns for technical docs or code reviews

Examples

# Check a JWT token for issues
jwtdecode check "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."

# Validate a token's structure
jwtdecode validate "eyJhbGciOiJSUzI1NiJ9..."

# Explain what a JWT token contains
jwtdecode explain "eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxMjM0NTY3ODkwIn0..."

# View all recent checks (no args = show history)
jwtdecode check

# Export all history as JSON
jwtdecode export json

# Search for a specific claim in logs
jwtdecode search "admin"

# View summary statistics
jwtdecode stats

# Health check
jwtdecode status

Output

All commands output structured text to stdout. You can redirect output to a file:

jwtdecode report mytoken > analysis.txt
jwtdecode export csv

Configuration

The data directory defaults to ~/.local/share/jwtdecode/. Modify the DATA_DIR variable at the top of script.sh to customize the storage path.

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