Best API Security Testing Companies in 2026: Who Actually Tests APIs by Hand

APIs fail in ways scanners do not see. Broken object-level authorization, the top item in the OWASP API Security Top 10, is a request that is perfectly valid except that the record ID belongs to someone else. A scanner sees a 200 response. A tester sees another customer’s invoice. That is why API security testing is a manual discipline, and why the useful question for any vendor on this list is how much of the work a person does.

This list is written by a penetration testing company, so Invadel is first and this is our site. Descriptions of other firms are limited to what they publicly say about themselves. No prices for other firms appear here, because none publish any; ours are on the API penetration testing pricing page.

What an API security test has to cover

The OWASP API Security Top 10 is the baseline, and the first five items are all authorization and business logic: broken object-level authorization, broken authentication, broken object property-level authorization, unrestricted resource consumption, broken function-level authorization. Every one of them requires a tester to understand what the API is for. A good engagement also covers:

• Every role and tenant, testing horizontal and vertical access from each.
• Authentication flows: OAuth and OIDC, token handling, refresh, revocation.
• Rate limiting and resource consumption, tested without taking the service down.
• Undocumented and deprecated endpoints (the “zombie” surface).
• GraphQL specifics: introspection, batching, nested query abuse.
• The gateway and the services behind it, not only the gateway.

IBM found that 27% of breaches targeting AI models or applications came through compromised APIs, applications or plug-ins. (IBM Cost of a Data Breach Report 2026) The API is also how most AI features are wired in. Our API penetration testing guide covers the method step by step.

The best API security testing companies in 2026

1. Invadel

Best for: manual API penetration testing at a fixed price, every role and tenant included.

Our API engagement is manual-first against the OWASP API Security Top 10, with authorization tested from every role and tenant, authentication flows walked end to end, and GraphQL and REST treated as different problems. Findings come with reproduction steps, CVSS scores, and remediation in priority order, and the report maps to SOC 2, PCI DSS or whichever framework drives the test. Prices are published and the retest is free. The honest limitation: we are a boutique, and we do not sell an API security monitoring product; if you want runtime protection, that is a different purchase.

2. Bishop Fox

Best for: enterprise application and API security programs.

A large independent offensive security firm with a strong application security research history, engaged by enterprises that want API testing inside a broader product security program.

3. NetSPI

Best for: high-volume API testing programs at large enterprises.

An enterprise penetration testing company with a large tester bench and a delivery platform, common in banking and other regulated industries with hundreds of APIs to test on a schedule.

4. Praetorian

Best for: API and product security for technology companies.

An offensive security firm with a research culture that pairs API testing with product and cloud security work.

5. Cobalt

Best for: PTaaS API testing with fast scheduling.

A penetration-testing-as-a-service platform with a tester network, integrated with developer ticketing. Quick to start; depth depends on the tester assigned. See our Invadel vs Cobalt comparison.

6. Synack

Best for: crowdsourced API testing with a managed platform.

A managed crowdsourced testing platform that routes engagements to a vetted researcher community. Broad coverage; the tester changes from engagement to engagement. See our Invadel vs Synack comparison.

7. HackerOne

Best for: bug bounty and community-driven API testing.

Best known for bug bounty programs, with pentest offerings drawn from the same community. Well suited to organizations that want continuous crowd coverage alongside scheduled testing. See our Invadel vs HackerOne comparison.

8. Software Secured

Best for: developer-focused API and application testing for SaaS companies.

A boutique focused on application security for software companies, with an emphasis on working alongside development teams. See our Invadel vs Software Secured comparison.

9. Packetlabs

Best for: manual-first application and API testing from a Canadian boutique.

A manual-first firm whose application testing services include APIs. See our Invadel vs Packetlabs comparison.

10. BreachLock

Best for: platform-driven API testing with continuous retesting.

A PTaaS provider combining automated scanning with human validation and a retest portal. See our Invadel vs BreachLock comparison.

The questions that separate a test from a scan

• How do you test authorization? The right answer describes testing every endpoint from every role and swapping object identifiers between tenants. The wrong answer names a tool.
• Do you need documentation? A good tester wants the OpenAPI spec or Postman collection and will still look for what is not in it.
• How do you handle rate limiting and resource consumption without a denial of service? The answer should include an agreed test window and thresholds.
• Will the same person test the retest? It should be.
• Can I see a sample report? Ours is on the sample report page.
• What is the price before the call? See how much a penetration test costs for what a fixed API test should cost.

Frequently asked questions

Is an API security test different from a web application test? The overlap is large, but APIs have no browser to protect them, so authorization and rate limiting carry the whole load, and mobile or partner clients often use endpoints the web front end never touches. Testing them together, as in our web application penetration testing plus API scope, catches the gaps between them.

Can a DAST tool replace the test? It finds a subset: injection, missing headers, some authentication issues. It does not find broken object-level authorization or business logic flaws. See DAST vs penetration testing.

How long does an API test take? Five to ten testing days for most APIs, plus a retest, depending on the number of endpoints, roles and flows.

Does it satisfy SOC 2 and PCI DSS? The report maps to both; PCI DSS Requirement 11.4 requires application-layer penetration testing of anything in the cardholder data environment, and APIs that touch payment flows are in scope.

The short version

Hire people who test authorization by hand, from every role, and who will show you a sample report and a price before the call. If that is what you want, scope an API test.