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API Security Testing

Free

Comprehensive testing for REST and GraphQL API security.

by sickn3344.7k stars on sickn33/agentic-awesome-skills
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Updated Aug 10, 2026
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Free · Opens the source repo

What API Security Testing does

The API Security Testing workflow is designed for developers and security professionals who need to ensure the robustness of their REST and GraphQL APIs. This skill provides a structured approach to identify potential vulnerabilities across various security aspects, including authentication, authorization, input validation, and rate limiting. By following the defined phases, users can systematically assess the security posture of their APIs and implement necessary improvements.

This workflow begins with API discovery, where users can enumerate endpoints, document methods, and identify parameters. Following this, the authentication phase tests various authentication mechanisms like API keys and JWT tokens. The authorization phase then ensures that access controls are correctly implemented, preventing unauthorized access to sensitive data and functions. Input validation is crucial for defending against injection attacks, and this workflow includes specific tests for SQL, NoSQL, and command injections.

In addition to these core areas, the skill addresses rate limiting to mitigate brute force attacks and resource exhaustion, as well as GraphQL-specific vulnerabilities such as query depth and complexity. The final phase focuses on error handling, ensuring that error messages do not disclose sensitive information. The included API security checklist and quality gates help users track their progress and ensure that all critical security elements are addressed before deployment.

When to use it

Use this workflow when performing security assessments on REST APIs or GraphQL endpoints, especially during development or before deployment.

When not to use it

This skill is not suitable for general-purpose testing or when environment-specific validations are required; expert review is recommended for comprehensive security assessments.

What you can build with it

Testing a New API

When developing a new API, use this workflow to ensure that all security aspects are thoroughly tested before launch.

Conducting a Security Audit

Utilize this skill during a security audit to assess existing APIs for compliance with security best practices.

Preparing for a Bug Bounty Program

Before launching a bug bounty program, run this workflow to identify and fix potential vulnerabilities.

How to install API Security Testing

View source

1. Install with the skills CLI

npx skills add sickn33/agentic-awesome-skills/api-security-testing --agent claude-code

2. Or install it manually

Download the skill folder and drop it into ~/.claude/skills/ for all projects, or .claude/skills/ to scope it to one repo. Restart Claude Code so it picks up the new skill.

Anthropic's agentic coding CLI, and the reference implementation of Agent Skills. Drop a skill folder into ~/.claude/skills and Claude Code loads it automatically whenever a task matches the skill's description. Claude Code docs

Inside SKILL.md

Written by sickn33

API Security Testing Workflow

Overview

Specialized workflow for testing REST and GraphQL API security including authentication, authorization, rate limiting, input validation, and API-specific vulnerabilities.

When to Use This Workflow

Use this workflow when:

  • Testing REST API security
  • Assessing GraphQL endpoints
  • Validating API authentication
  • Testing API rate limiting
  • Bug bounty API testing

Workflow Phases

Phase 1: API Discovery

Skills to Invoke

  • api-fuzzing-bug-bounty - API fuzzing
  • scanning-tools - API scanning

Actions

  1. Enumerate endpoints
  2. Document API methods
  3. Identify parameters
  4. Map data flows
  5. Review documentation

Copy-Paste Prompts

Use @api-fuzzing-bug-bounty to discover API endpoints

Phase 2: Authentication Testing

Skills to Invoke

  • broken-authentication - Auth testing
  • api-security-best-practices - API auth

Actions

  1. Test API key validation
  2. Test JWT tokens
  3. Test OAuth2 flows
  4. Test token expiration
  5. Test refresh tokens

Copy-Paste Prompts

Use @broken-authentication to test API authentication

Phase 3: Authorization Testing

Skills to Invoke

  • idor-testing - IDOR testing

Actions

  1. Test object-level authorization
  2. Test function-level authorization
  3. Test role-based access
  4. Test privilege escalation
  5. Test multi-tenant isolation

Copy-Paste Prompts

Use @idor-testing to test API authorization

Phase 4: Input Validation

Skills to Invoke

  • api-fuzzing-bug-bounty - API fuzzing
  • sql-injection-testing - Injection testing

Actions

  1. Test parameter validation
  2. Test SQL injection
  3. Test NoSQL injection
  4. Test command injection
  5. Test XXE injection

Copy-Paste Prompts

Use @api-fuzzing-bug-bounty to fuzz API parameters

Phase 5: Rate Limiting

Skills to Invoke

  • api-security-best-practices - Rate limiting

Actions

  1. Test rate limit headers
  2. Test brute force protection
  3. Test resource exhaustion
  4. Test bypass techniques
  5. Document limitations

Copy-Paste Prompts

Use @api-security-best-practices to test rate limiting

Phase 6: GraphQL Testing

Skills to Invoke

  • api-fuzzing-bug-bounty - GraphQL fuzzing

Actions

  1. Test introspection
  2. Test query depth
  3. Test query complexity
  4. Test batch queries
  5. Test field suggestions

Copy-Paste Prompts

Use @api-fuzzing-bug-bounty to test GraphQL security

Phase 7: Error Handling

Skills to Invoke

  • api-security-best-practices - Error handling

Actions

  1. Test error messages
  2. Check information disclosure
  3. Test stack traces
  4. Verify logging
  5. Document findings

Copy-Paste Prompts

Use @api-security-best-practices to audit API error handling

API Security Checklist

  • Authentication working
  • Authorization enforced
  • Input validated
  • Rate limiting active
  • Errors sanitized
  • Logging enabled
  • CORS configured
  • HTTPS enforced

Quality Gates

  • All endpoints tested
  • Vulnerabilities documented
  • Remediation provided
  • Report generated

Related Workflow Bundles

  • security-audit - Security auditing
  • web-security-testing - Web security
  • api-development - API development

Limitations

  • Use this skill only when the task clearly matches the scope described above.
  • Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
  • Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.

Frequently asked questions about API Security Testing

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