Best CLI API security scanner

A command line API security scanner automates the discovery of runtime risks by sending read-only requests against an endpoint and analyzing responses. It probes authentication mechanisms, authorization boundaries, input validation, rate limiting, data exposure, encryption posture, SSRF surfaces, and in some implementations, LLM-specific adversarial prompts. The output is typically a prioritized list of findings with a summary risk rating and links to contextual remediation guidance. Because it operates without code access or agents, it fits into fast feedback loops without requiring builds or deployments.

When comparing tools, verify that the CLI exposes consistent, scriptable output and safe default behavior. Look for support for common authentication methods such as Bearer tokens, API keys, Basic auth, and cookies, with a domain verification gate that requires ownership proof before credentials are used. The scanner should limit forwarded headers to an allowlist and never send destructive payloads. Key capabilities include:

• Black-box probing of authentication bypass and JWT misconfigurations
• BOLA and BFLA checks with adjacent ID probing and privilege escalation indicators
• Input validation tests for CORS misconfigurations and dangerous HTTP methods
• Detection of data exposure patterns such as emails, card-like numbers, and API key formats
• Identification of SSRF surfaces where URL inputs are accepted
• LLM security probes focused on prompt extraction and jailbreak techniques
• OpenAPI spec parsing with cross-reference to runtime behavior

A well designed CLI integrates cleanly into local development and CI/CD workflows. It should accept a target URL, optional authentication headers, and a choice of output formats such as JSON for downstream parsing or text for human review. Support for recursive $ref resolution in OpenAPI specifications ensures that security schemes and parameters defined across files are correctly mapped. Examples:

middlebrick scan https://api.example.com --auth-type bearer --auth-token <token> --format json

curl -s https://api.example.com/openapi.json | middlebrick scan - --format text

Reliable tools also provide sensible timeouts, concurrency limits, and a clear indication when scans cannot proceed due to connectivity or authentication issues. The ability to output structured results enables automated gating in pipelines.

Evaluate how the scanner connects with your existing toolchain. Many products offer a GitHub Action that fails a build when the risk score drops below a chosen threshold, or an MCP server that allows AI coding assistants to trigger scans on demand. A programmatic API client should support HMAC-SHA256 signed webhooks for alert delivery and include mechanisms to disable alerts after repeated failures. For compliance evidence, confirm that the tool can generate reports aligned with security frameworks such as PCI-DSS 4.0, SOC 2 Type II, and OWASP API Top 10 (2023). These capabilities help you prepare for audits and surface findings relevant to security controls without claiming certification or guarantees.

Any CLI scanner is constrained by its scope and safety model. It does not perform active exploitation such as SQL injection or command injection, which require intrusive payloads outside the intended use case. It does not detect business logic flaws that depend on deep domain knowledge, nor does it perform blind SSRF testing that requires out-of-band infrastructure. Because it does not patch or block issues, remediation still requires human review and engineering effort. The tool should clearly document its exclusions, and data retention policies should allow deletion on demand with a defined purge window. Understanding these limits helps you position the scanner as one component of a broader security program rather than a standalone solution.