QA & Release Assurance

API Security

Find the weaknesses in your REST and GraphQL APIs before they're exploited. We test authentication, authorization and data exposure with your permission, report verified findings and retest your fixes.

Discuss your project Discuss API security

Whose APIs we test

Your apps only call the API the way their screens allow, but anyone can send it a modified request directly. You need to know what such a request can read, change or exhaust.

SaaS products where many tenants share one API and database
Mobile app teams whose back-end API anyone can call once they inspect traffic
Teams whose API grew fast with AI coding tools and was never security-tested

How each API risk gets tested

Illustrative plan for a REST API with several user roles; your mix follows the agreed scope.

	Automated scanning	Manual testing	Retest after fix	Regression check
Authentication and tokens	Used selectively	Core technique for this area	Core technique for this area	Used selectively
Object-level authorization	Of little use here	Core technique for this area	Core technique for this area	Core technique for this area
Input handling and injection	Core technique for this area	Used selectively	Core technique for this area	Core technique for this area
Rate limiting and brute force	Used selectively	Core technique for this area	Used selectively	Of little use here
Excess data in responses	Used selectively	Core technique for this area	Core technique for this area	Used selectively
Business-logic abuse	Of little use here	Core technique for this area	Core technique for this area	Used selectively

Core technique for this area
Used selectively
Of little use here

Your API is the front door to your data

Most serious API flaws aren't exotic. A user changes an ID and reads someone else's records, an endpoint returns more fields than the screen shows, or a missing rate limit invites brute force and scraping. Whether your API serves your own apps, partners or customers, we test it within a scope you authorize in writing, following OWASP guidance. You get reproducible findings with fix guidance, and we retest once your fixes are in.

AI-assisted coverage, manually confirmed findings

How AI assists

Maps endpoints, parameters and roles from your API specs, code and traffic to plan what to test.
Builds authorization test matrices of which role can call what, on whose data, for testers to work through.
Drafts fuzzing inputs and abuse cases for each endpoint from its schema and business rules.
Searches code and logs for the same flaw elsewhere once an issue is confirmed.

What our experts own

Security engineers agree scope and rules of engagement with you; testing stays within what you authorize.
Each finding is reproduced manually before it's reported. Raw scanner output isn't passed on as findings.
Business-logic abuse, such as skipping a payment step, is tested by people who learn your workflows first.
Severity is rated by the real impact on your data and users, and fix advice fits your framework.

What you receive

Authorized API testing with verified findings

API attack surface map
Endpoints, methods, roles, data flows and third-party connections documented, including undocumented endpoints found during testing.
Authorization testing
Object- and function-level access checks across roles and tenants, to find where one user can reach another user's data or actions.
Authentication and token review
Login, password reset, session expiry, multi-factor flows and token handling for JWT, OAuth and API keys, checked for weaknesses.
Input, exposure and abuse checks
Injection, mass assignment, excessive data in responses, rate limiting, and GraphQL query depth, batching and introspection controls.
Findings report with fixes
Each issue mapped to the OWASP API Security Top 10, with reproduction steps, impact, severity and fix guidance for your framework.
Retesting and regression checks
Fixes retested to confirm they work, and key security checks added to your automated tests so the same flaw is caught if it returns.

How an API security assessment runs

01
Scope and authorization
Agree endpoints, environments, test accounts and rules of engagement in writing. Nothing is tested without your authorization.
02
Map and plan
Map endpoints, roles and data flows from specs, code and traffic, then plan tests around the data and actions most at risk.
03
Test and confirm
Combine automated scans with manual testing of authorization, authentication, input handling and abuse cases. Confirm every finding.
04
Report, fix, retest
Deliver reproducible findings with fix guidance, help with fixes if you want, then retest and add regression checks.

Two ways to work with AI tools

AI helps draft tests and investigate defects. Choose where it may process your code and test data.

Private / Local AI Engineering
Privately hosted models inside infrastructure you control or an agreed isolated environment.
Discuss with this package
Claude Code / OpenAI Codex Engineering
Claude Code and/or OpenAI Codex with cloud settings your organization approves.
Discuss with this package

Not sure? We'll recommend one during scoping. Compare AI delivery options

Typical API security requests

Typical scenarios we scope, not client case studies.

Tenant checks after adding team workspaces
A SaaS product added team workspaces, so every query now needs a tenant check. We test with accounts in separate tenants across every role to see whether one tenant can read or change another's data, and retest once fixes ship.
API keys for outside developers
A company plans to issue API keys to external developers. We check how keys are scoped, rotated and revoked, test what a key can reach beyond its intended scope, and confirm rate limits apply per key.
A checkout API that trusts the app
A store's checkout API accepts totals and discount codes as the app sends them. We test whether a modified request can change prices, reuse a code or skip the payment step, and confirm each finding by hand.

What API testing doesn't cover

Web front ends, cloud settings and attacks that chain across systems are covered by Penetration Testing; here the API is the target.
Redesigning endpoints or rebuilding the API isn't included; structural fixes can be scoped under API Development.
Services you call but don't own stay out of scope unless their owner agrees; we test how your API copes with their errors instead.
A full read of the API's source code is Code Audit & Review; here code is used to locate and confirm findings.

How API security connects to design, QA and operations

Design: safe, clear error states
Designers and engineers agree error and permission-denied messages that help users without revealing internal details to attackers.
QA: security in every release
Authorization and input checks join the regression suite, so new endpoints and AI-generated changes are tested the same way.
Operations: monitoring and secrets
Findings feed API logging, alerts on suspicious use, secret rotation and gateway rate limits, set up with your DevOps team.
Ongoing: retest as the API grows
New endpoints and major releases are reviewed and retested on a schedule agreed with you, so coverage keeps pace with the API.

FAQ

Frequently asked questions

Do you test GraphQL as well as REST APIs?

Yes. GraphQL needs extra attention: introspection exposure, query depth and complexity limits, batching abuse and field-level authorization. We test both within the scope you authorize.

Will an API security assessment make us compliant?

Not on its own; no test can. We support your compliance work: testing follows OWASP guidance, reports are written so auditors and your customers' security teams can review them, and retest results help you prepare evidence that issues were fixed.

Can you fix the vulnerabilities too?

Yes. Our engineers can implement fixes, work alongside your developers or review your fix pull requests. Either way, we retest each fix and add regression checks, so you have evidence that it works.

Do AI tools see our API specs and findings?

Only within the boundary you choose, because security findings are sensitive. With Private / Local AI Engineering, models run on infrastructure you control or in an isolated environment we agree. With Claude Code / OpenAI Codex Engineering, commercial providers process data under agreed account and retention terms. We use test accounts and synthetic data wherever possible.