8 Best API Security Testing Tools in 2026

That gap is what API security testing tools fill. They point at a running API, work out which endpoints exist, and send the requests a normal client never would. Malformed payloads, tampered tokens, another user’s object IDs, a thousand requests where one was expected.

APIs make that harder than web apps do. There is no UI to crawl, so a scanner needs a spec, live traffic, or introspection to know what exists. It also needs working credentials to reach anything worth testing. Those two constraints drive most of the differences between the tools below.

This guide covers eight of them: what each does, where it fits, what it costs, and which popular names belong to a different category.

What Are API Security Testing Tools?

API security testing tools find vulnerabilities by exercising a running API the way an attacker would. They send requests, tamper with parameters and tokens, and check whether an endpoint returns data or performs actions it should not. The failures they hunt are API-specific, and OWASP ranks Broken Object Level Authorization as API1:2023, the top risk in the 2023 edition, which is still the current one.

BOLA tops that list because it is both common and awkward to catch. The authorization decision depends on the object, the caller, and the action, so it only fully resolves at runtime. Testing it means confirming that a user cannot read, modify, or delete an object belonging to another user. Where an object is exposed to an unauthenticated caller, one identity is enough to prove it.

The three categories people keep confusing

OWASP’s community page on API tooling splits the market into three groups. These are primary jobs, not walls; several products in this guide do more than one.

Category	Primary job	What it does not answer by itself
API security testing	Exercises a running API to find exploitable behavior	Whether production is under attack right now
API security posture	Inventories APIs, definitions, exposure, and policy gaps	Whether a specific deployed behavior is exploitable
API runtime security	Observes or blocks production traffic	Whether the same defect could have been caught before release

That page is a community-maintained directory and can be useful for classifying products, but not necessarily for validating them.

This guide covers the first group. For functional rather than security testing, our roundup of API testing tools covers that adjacent category, and our guide to how API security testing works covers the methodology behind it.

API Security Testing Tools Compared

In the table below, we’ve put together some of the most popular tools out there in the API security testing category. Here we have them side by side so you can easily see how each compares. Below, we have a more detailed breakdown of the tools, one by one.

Tool	Class	Open source	CI/CD fit	API types	Pricing (Aug 2026)
StackHawk	DAST scanner	No	Native, 13 CI/CD integrations	REST, GraphQL, gRPC, SOAP, JSON-RPC, MCP	$10/user/mo; 14-day trial
OWASP ZAP	Scanner + proxy	Yes (Apache 2.0)	Automation framework	REST, SOAP, GraphQL	Free
Burp Suite	Proxy + scanner	No	Burp Suite DAST	OpenAPI, WSDL, Postman upload; GraphQL by introspection	Community free; Pro $499; DAST by quote
Akto	Discovery + testing	MIT-licensed core	Yes	REST, GraphQL, SOAP/XML, gRPC	MIT core free; platform by quote
Wallarm	Agentic DAST	No	Docker container in pipeline	OpenAPI or Postman input	From $3,000/yr; demo only
APIsec	Exploit validation	No	Full CI/CD on Pro tier	Not specified by vendor	$0 for public APIs; $690/mo Standard
Metlo	Discovery + testing	MIT	Yes, documented	HTTP APIs (not specified further)	Free; some features enterprise-licensed
42Crunch	Audit + scan + firewall	No	Enterprise tier only	OpenAPI; GraphQL in Scan v2	14-day trial only; from $9/mo; Enterprise custom

The 8 Best API Security Testing Tools in 2026

Building on the table above, we will now go into detail on each of these tools so you can learn more about their capabilities and how/when to use them.

1. StackHawk

StackHawk runs DAST scans from CI/CD workflows against a reachable application. It covers REST, GraphQL, gRPC, SOAP, JSON-RPC, and MCP servers. Each target type uses its own discovery input: an OpenAPI spec for REST, introspection or a schema file for GraphQL, a service path for gRPC, a WSDL or XSD for SOAP, a method list for JSON-RPC, and an automatic tools/list handshake for MCP servers.

Business Logic Testing is the part aimed at authorization. Cross-profile BOLA testing takes resources one profile discovered and tries to read them with another profile’s credentials. Cross-profile BFLA testing attempts to mutate operations across profile boundaries to see whether an unprivileged user can perform privileged operations. There are also BOPLA and related authorization plugins, as well as custom scripts for application-specific multi-step workflows. Each is configured separately from multi-profile scanning.

Strengths: Scans run locally before a pull request or in CI on pushes and merges, so testing is continuous instead of quarterly. Protocol coverage is unusually wide for a DAST tool, including gRPC and MCP. Cross-role authorization testing targets the OWASP API Top 10 directly, and there are documented integrations for GitHub Actions, GitLab CI/CD, Jenkins, and ten other CI/CD systems. StackHawk also ships Agent Skills for Claude Code, Cursor, Codex, Antigravity, and GitHub Copilot, which need Hawk CLI 6 or later plus a locally running app.

Limits: It requires a running application, so it is not something you can run with your first line of code. Multi-profile testing is complicated and, by its nature, requires configuration, which means StackHawk needs an API definition, working credentials, and at least two test identities. BOLA compares peers at the same role. Only BFLA needs a privilege gap, so isPrivileged: true should mark only the profiles meant to represent elevated access.

Our scanner, HawkScan, is an aggressive scanner that will create, update, and delete data. Multi-profile scans, in particular, belong in staging, not against production systems that hold real customer data. Setup effort scales with authentication complexity and the quality of your API definitions.

Best for: Teams that want high-severity API vulnerabilities continuously caught within the development workflow. For more info, see our API security testing page.

2. OWASP ZAP

ZAP is a free, Apache 2.0-licensed scanner, now branded ZAP by Checkmarx, while still describing itself as an independent open-source project. It works as an automated scanner and as what its own docs call a “manipulator-in-the-middle proxy,” so you can run unattended scans or drive requests by hand from one tool. For API work, it imports an OpenAPI, SOAP, or GraphQL definition and scans from that.

Strengths: No license cost, active development, and an automation framework that makes CI runs repeatable. It handles both scripted scanning and exploratory manual work, which few tools on this list do well.

Limits: You own the authentication setup: users, session handling, and verification all need to be configured and validated. Some flows support autodetection, browser, form, JSON, or header-based auth, while others require a custom script. Cross-role coverage is available through the Access Control Testing add-on, but it requires explicit user and rule configuration and is still marked as alpha. Results need tuning before a team trusts them.

Best for: Teams with the engineering time to configure and maintain their own scanning setup.

3. Burp Suite

Burp Suite from PortSwigger pairs an intercepting proxy with a vulnerability scanner. There is a free Community edition and a paid Professional edition at $499, with Burp Suite DAST above them for automated scanning at scale, priced on a quote basis. Burp AT, PortSwigger’s agentic pentesting capability, is not a separate edition: it runs in public beta inside Burp Suite Professional and consumes AI credits.

The API inputs differ by format. You can upload an OpenAPI definition, a SOAP WSDL, or a Postman Collection. GraphQL works differently, since the Burp Scanner points to a reachable GraphQL URL and relies on introspection rather than a definition upload.

Strengths: The strongest tool here for hands-on testing and manual authorization probing, and Professional is close to standard issue among penetration testers. Burp Suite DAST adds scheduled, unattended scanning without leaving the toolchain.

Limits: The Community has no automated scanner and no project save, so sustained work requires paying. Deep use is manual and skill-intensive, and the proxy-driven workflow assumes a tester at the keyboard as much as a pipeline.

Best for: Security teams doing manual API pentesting and validating findings by hand.

4. Akto

Akto’s MIT-licensed core maintains a continuous API inventory, runs business logic tests in CI/CD pipelines, and monitors for runtime issues. Akto says its test coverage spans the OWASP API Top 10 and HackerOne Top 10, including BOLA, authentication flaws, SSRF, and XSS. Documented protocol support covers REST, GraphQL, SOAP/XML, and gRPC.

The company’s public identity has moved. As of August 2026, the homepage headline reads “Secure AI Agents, MCPs, LLMs, Skills with Akto,” and API security no longer appears in the main product navigation. The API Security Testing product still seems to exist, and the repository is busy: five releases shipped in mid-August 2026 alone, the most recent being v2.20.4.

Strengths: An MIT-licensed entry point that pairs discovery with testing, which is uncommon in free tooling, backed by a repository under active development.

Limits: The pricing page now prices only the AI security products, so the commercial boundary around the API testing product is unclear from public pages. Confirm the package scope and support terms with the Akto team before planning to include it in your stack.

Best for: Teams that want an open-source starting point pairing inventory with testing, and who will confirm commercial terms directly.

5. Wallarm

Wallarm is best known for runtime API protection, but it now ships API Security Testing as a distinct product. It is an agentic DAST scanner that runs as a public Docker container inside a CI/CD pipeline. You supply an OpenAPI spec or a Postman collection, and it tests for BOLA, BFLA, broken authentication, and other multi-step business-logic attacks, attaching a reproducible proof of exploit to each finding. Wallarm quotes a 50-endpoint scan at roughly 30 minutes.

Strengths: Built for the pipeline from the start, with a container you can drop into any CI system and trigger per release or on a schedule. Proof-of-exploit on every finding is aimed squarely at the triage problem that sinks most scanners.

Limits: There is no self-serve trial, and the only route in is a demo. Pricing starts at $3,000 per year and scales with scan volume. The testing product is documented on the marketing site more thoroughly than in the technical docs.

Best for: Teams that want business logic testing in CI/CD and are comfortable with a sales-led purchase.

6. APIsec

APIsec builds a model of your application, generates the attacks it expects a real attacker to use, and executes them against the running target. They refer to themselves as “a security agent, not a scanner with AI bolted on.” The category label on their own pages is now “application exploit validation,” not “API security” specifically.

Strengths: Model-generated, application-specific tests can surface logic and authorization flaws that generic scans miss. Remediation verification appears easy: re-running the same exploit against the patch and reporting it as verified closed or still open, with evidence either way.

Limits: The $0 tier is limited to public and test APIs. Testing your own private APIs starts at $690 per month per 100 endpoints, and full CI/CD and ticketing integrations sit in the Pro tier at $2,750 per month per 100 endpoints. Their platform page does not publish a list of protocols, so confirm coverage for your stack before trialing. The modeling workflow also has its own onboarding curve.

Best for: Teams that want app-aware exploit generation plus proof that a fix actually closed the hole.

7. Metlo

Metlo is MIT-licensed and pairs traffic-based endpoint discovery with security testing. It scans network traffic to inventory endpoints, automatically generates tests for OWASP Top 10 issues such as BOLA and broken authentication, and integrates with CI/CD to catch problems in development and staging. Its README advertises setup in under 15 minutes.

The maintenance picture needs to be stated plainly. The latest published release is v0.1.1 from April 14, 2023. The most recent commit to the default branch is a README change from late July 2025, and the last visible substantive code commit is from August 2023. The repository is not archived.

Strengths: Self-hostable under a permissive license, with discovery and testing in a single project.

Limits: Limited recent maintenance shifts compatibility, dependency, and security validation onto the adopting team. User management, roles, and attack protection also require an enterprise license, even with the MIT core. Metlo is not testing-only either: its own summary covers detecting bad actors and blocking malicious traffic in real time, so it spans two of the three categories above.

Best for: Teams that want a self-hosted open-source option and will evaluate project health themselves.

8. 42Crunch

42Crunch is an OpenAPI-centric lifecycle platform with three named components. API Security Audit checks the definition at design time, API Scan tests the deployed API, and API Protection defends it at runtime through what 42Crunch calls an API-native micro firewall.

API Scan is dynamic. The docs say it “runs checks on your live API implementation” and “generates real traffic to the selected API endpoint.” Two scan types are documented. A conformance scan, which 42Crunch labels design-time even though it runs against a live endpoint, tests whether the implementation matches the contract by omitting, adding, and fuzzing fields. It supports OpenAPI definitions and, in the Scan v2 engine, GraphQL as well. A drift scan is a lighter pass that, by default, tests only GET requests and covers only OpenAPI.

Strengths: Strong for OpenAPI governance and for pushing security into API design. The Scan v2 engine documents identity tests for BOLA/IDOR and BFLA, in which you define a credential that should not grant access to a resource and the correct credential that replaces it. Audit, dynamic scan, and runtime protection under one roof also remove a couple of integration seams.

Limits: Everything is anchored to your OpenAPI definition, so accurate specs are a prerequisite. Identity tests are Scan v2-only and not automatic: each one requires a source credential, a target credential, and explicit attachment to the authorization tests for a per-operation scan scenario. There is no permanent free tier, only a 14-day trial. Individual plans start at $9 per month; team plans are priced per seat and endpoint count; and CI/CD integration is available in the Enterprise plan.

Best for: Teams standardizing on OpenAPI who want spec audit, dynamic scanning, and runtime protection in one place.

What Is Not on This List (and Why)

These products are excluded because their primary job is not sending test traffic to a pre-release API. Several can still participate in testing workflows.

Product	Primary job	Why it is not in the list
Salt Security	Discovery, posture governance, runtime threat protection	Its shift-left workflow assesses governance and feeds generated API specs into separate SAST, DAST, or IAST tools, so it is not a standalone DAST scanner
Imperva API Security	Discovery, risk assessment, detection, mitigation	Its own product page stresses stopping threats “in real time,” which is runtime work
Postman	API development and functional testing	See below
SoapUI	Functional API testing	See below

Postman is primarily an API development and functional-testing platform. Its Governance rules lint OpenAPI specifications and can fail a CI/CD run on violations, which is static spec checking. Collections and scripts can also send hostile inputs and assert against authentication or authorization behavior on a running API, enabling dynamic testing. What Postman does not provide by default is the automated discovery and attack generation of a dedicated scanner.

SoapUI deserves a more careful answer than most lists give it. Its open-source edition includes a Security Tests feature, shipped in version 4.0, covering scans such as XPath injection, XML bomb, and fuzzing. In the free version, you add each scan and its assertion by hand; auto-generation and the broader security, load, and virtualization tooling sit in the commercial ReadyAPI product.

One borderline call worth naming. Akamai API Security used to be a clean example of a runtime platform, and plenty of roundups still describe it that way. That is out of date. As of August 2026, Akamai advertises 200-plus API security tests that run in CI/CD and pre-production, with “test” sitting in its own lifecycle alongside discover, detect, and respond. The center of gravity is still runtime, and it is sold as an enterprise platform, but calling it a non-testing tool in 2026 would be wrong.

For the platform view of this market, we separately cover API security platforms that monitor and defend at runtime.

Open-Source vs Commercial API Security Testing

The open-source options carry no license fee, but self-hosting, maintenance, authentication setup, and CI ownership still require engineering time and infrastructure. The commercial options move some of that work to a vendor and create a different dependency. Neither is categorically cheaper.

Consideration	Open source	Commercial
License cost	No fee; infrastructure still costs money	Subscription or negotiated license
Setup	Authentication, tuning, and pipeline work stay with the team	More packaged workflows, but onboarding is still required
Control	Source and rule behavior can be inspected and modified	Behavior is largely vendor-controlled
Maintenance	You own upgrades, compatibility, and support	Vendor owns the product; you still own configuration
Data and deployment	Self-hosting can simplify data residency	Hosted, self-hosted, or hybrid, varying by vendor and plan
Support	Community, unless a commercial tier exists	Varies by package and service level

Compare total cost against your own numbers: scan frequency, authentication complexity, maintenance hours, support needs, deployment constraints, and the protocol and business logic coverage you actually require. License price alone does not settle it.

How to Choose an API Security Testing Tool

Match the tool to how your team works, not to a feature count. Seven questions that cut through it:

1. Does it test the API types you run? REST is table stakes. GraphQL and gRPC are not universally supported, and the way a tool ingests each protocol differs: some require a definition upload, while others require introspection or a service path. Confirm coverage before anything else.

2. Can it authenticate and test across identities? Authorization failures are among the highest-priority API risks, since they can expose another user’s objects, fields, or privileged functions. Look for multi-identity scanning and check which kind it is: proving BOLA requires two peer accounts, while proving BFLA requires an unprivileged account and a privileged one. Ask what the setup requires, because that is where the cost hides.

3. Does it fit your pipeline? Verify whether the product runs inside the pipeline or triggers a remote scan, how credentials are supplied, and whether findings can gate a build. Also check which plan includes CI/CD, since more than one vendor here gates it behind the top-tier plans they offer.

4. Does it discover your API surface? You can’t test endpoints you don’t know about, and shadow or deprecated APIs are a frequent source of findings. Discovery that reconciles your spec against real traffic beats a static endpoint list someone maintains by hand.

5. How much validation will findings need? Compare the evidence attached to each result, the suppression and deduplication controls, and whether confidence or severity thresholds are configurable. A tool your developers learn to ignore is worse than no tool.

6. How does it handle remediation? A finding is only useful if a developer can act on it. Look at whether results include a reproduction, whether the tool can re-verify a fix, and whether findings land where developers already work.

7. Who operates it, and where does the data go? Compare hosted against self-hosted deployment, network access requirements, data retention, maintenance ownership, and support. A tool that fits the test case but not the team’s operating constraints will not survive rollout.

Final Thoughts

Before you buy anything, ask the vendor to demonstrate a BOLA finding end-to-end against an app with two user accounts. Make them show the authentication setup, the evidence attached to the finding, the CI run, and a re-test after the fix. That exercise tells you more about setup effort and developer workflow than any feature checklist, and it is where these tools most sharply separate.

The other thing worth holding on to is category discipline. Testing tools find exploitable bugs before they ship; posture and runtime platforms watch what is already live. Protocol coverage, discovery inputs, authentication setup, and which plan includes CI/CD all differ materially across the eight tools above, so check those against your own stack rather than a summary.

StackHawk supports this workflow through multi-profile scanning. The current setup requirements are in the Business Logic Testing documentation. Need best-in-class API security testing support that’s agent-ready? Try out our agentic runtime testing platform with your favorite coding agents today.

Frequently Asked Questions