API Security Vulnerability Playground | BOLA, BFLA & BOPLA
Explore common API vulnerabilities, edit real-looking payloads, and compare vulnerable versus hardened responses without leaving the browser.
This API security playground helps developers and security engineers test BOLA (Broken Object Level Authorization), BFLA (Broken Function Level Authorization), and BOPLA (Broken Object Property Level Authorization) vulnerabilities in a live request editor with zero setup. Choose a vulnerability class, switch between Vulnerable and Hardened modes, edit realistic payloads, and compare how the API leaks or blocks sensitive data. Every scenario maps directly to the OWASP API Security Top 10 categories so you can see exactly what you are testing and why it matters.
The playground shows how authorization vulnerabilities behave in a controlled environment. To find BOLA, BFLA, and BOPLA across your actual API endpoints without writing test scripts or hiring a pen tester, run an automated scan with ApyGuard. Your first API penetration test report is ready in minutes, with prioritized findings and specific remediation steps per endpoint.
Review API security best practices for a full framework to harden your APIs beyond authorization testing.
Broken Object Level Authorization
BOLA occurs when an API fails to verify whether a user has permission to access a specific resource. In practice, a user can access resources they do not own by modifying identifiers such as IDs, paths, or parameters.
Mode
Presets
A user requests their own account record.
Target endpoint
GET /v1/accounts/details
Use a JSON object.
Roles and identity usually appear here.
Try adding or removing fields.
Response
Cross-tenant probe
Request preview
What to look for
Attack surface
This shows what happens when an API lets someone read another user's data just by changing an ID.
Impact
A single predictable identifier can expose invoices, API keys, balances, or profile data from another customer.
Defensive cues
- Change `accountId` without changing `viewerAccountId`.
- Switch to hardened mode to see the expected 403 behavior.
- Look at how the response body changes when authorization is enforced server-side.
Coverage in this playground
Authorization failures
BOLA and BFLA flows show what happens when route access is based on user input instead of backend policy.
Unsafe object binding
Mass assignment highlights why allowlisted fields are safer than binding full request bodies directly into models.
Backend fetch abuse
SSRF simulation demonstrates how internal metadata and private services become reachable through server-side integrations.