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jwt-token-validator skill

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/skills/03-security-fundamentals/jwt-token-validator

This skill helps you validate jwt tokens and implement secure token patterns with production-ready guidance and code.

npx playbooks add skill jeremylongshore/claude-code-plugins-plus-skills --skill jwt-token-validator

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SKILL.md

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---
name: "jwt-token-validator"
description: |
  Validate jwt token validator operations. Auto-activating skill for Security Fundamentals.
  Triggers on: jwt token validator, jwt token validator
  Part of the Security Fundamentals skill category. Use when working with jwt token validator functionality. Trigger with phrases like "jwt token validator", "jwt validator", "jwt".
allowed-tools: "Read, Write, Grep, Bash(npm:*)"
version: 1.0.0
license: MIT
author: "Jeremy Longshore <[email protected]>"
---

# Jwt Token Validator

## Overview

This skill provides automated assistance for jwt token validator tasks within the Security Fundamentals domain.

## When to Use

This skill activates automatically when you:
- Mention "jwt token validator" in your request
- Ask about jwt token validator patterns or best practices
- Need help with essential security skills covering authentication, input validation, secure coding practices, and basic vulnerability detection.

## Instructions

1. Provides step-by-step guidance for jwt token validator
2. Follows industry best practices and patterns
3. Generates production-ready code and configurations
4. Validates outputs against common standards

## Examples

**Example: Basic Usage**
Request: "Help me with jwt token validator"
Result: Provides step-by-step guidance and generates appropriate configurations


## Prerequisites

- Relevant development environment configured
- Access to necessary tools and services
- Basic understanding of security fundamentals concepts


## Output

- Generated configurations and code
- Best practice recommendations
- Validation results


## Error Handling

| Error | Cause | Solution |
|-------|-------|----------|
| Configuration invalid | Missing required fields | Check documentation for required parameters |
| Tool not found | Dependency not installed | Install required tools per prerequisites |
| Permission denied | Insufficient access | Verify credentials and permissions |


## Resources

- Official documentation for related tools
- Best practices guides
- Community examples and tutorials

## Related Skills

Part of the **Security Fundamentals** skill category.
Tags: security, authentication, validation, owasp, secure-coding

Overview

This skill automates validation and guidance for JWT token validator tasks within the Security Fundamentals domain. It helps developers implement, test, and verify JWT validation logic following industry best practices. Use it to generate production-ready code snippets, configurations, and clear validation reports.

How this skill works

The skill inspects JWT structure, signature algorithms, claims, expiration, and audience/issuer checks. It generates step-by-step validation flows, sample code for common stacks, and configuration examples (e.g., middleware, libs) and verifies outputs against common security standards. It also detects common misconfigurations and offers remediation suggestions.

When to use it

When implementing or reviewing JWT validation logic in an application
When you need production-ready code or config for JWT middleware or libraries
When auditing tokens for signature, claims, expiry, audience, and issuer issues
When you want to standardize JWT handling to follow secure coding practices
When you need concise remediation steps for common JWT misconfigurations

Best practices

Always verify signature and use strong, appropriate algorithms (avoid none and weak algorithms)
Validate exp, nbf, iss, aud and nonce where applicable; fail closed on missing claims
Rotate and protect signing keys; prefer asymmetric keys (RS256/ES256) for public clients
Limit token lifetime, use refresh tokens, and check token revocation where possible
Use vetted libraries and framework middleware rather than custom parsing code

Example use cases

Generate middleware code for validating JWTs in Python (FastAPI/Flask) or Node.js (Express)
Audit a deployed service to find tokens missing issuer or audience validation
Create a CI validation step that checks JWT configuration and test tokens
Produce remediation steps after detecting tokens signed with deprecated algorithms
Provide sample unit tests and sample tokens to validate validator behavior

FAQ

Which claims must I always validate?

Always validate signature, exp (expiration), aud (audience) and iss (issuer); validate nbf and iat when relevant and apply application-specific checks like scopes or roles.

Should I use symmetric or asymmetric signing?

Prefer asymmetric keys (RS256/ES256) for distributed systems and public clients; symmetric (HS256) can be acceptable for simple trusted server-to-server scenarios with strict key management.