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Web Application & API Security Testing
Test the controls behind every request.
Web application security testing examines whether a website, application or API protects its data and actions across users, roles and workflows. SabreShield AI tests authorised applications for UK businesses, combining technical checks with business-logic analysis.
Scope includes the agreed environments, API versions, accounts and workflows. Explicit written authorisation and rules of engagement define data handling, request limits and excluded activities.
BEYOND THE LOGIN SCREEN
A valid session should not mean unrestricted access.
Customer portals and APIs make decisions on every request: who is acting, which records they may access and whether the requested action is valid.
Testing considers OWASP concepts such as broken access control, injection and security misconfiguration, alongside the specific business rules your application is expected to enforce.
01
Broken access control
Users may be able to access another account’s objects, call privileged functions or cross tenant boundaries.
02
Authentication and sessions
Weak recovery flows, token handling or session invalidation may undermine otherwise sound login controls.
03
Input and output weaknesses
Untrusted input or unsafe handling of responses may expose injection, data disclosure or downstream processing risks.
04
Business-logic abuse
Valid requests used in an unintended sequence may bypass approvals, quotas or other important workflow rules.
Application and API coverage
- Websites and web applications
- Customer and partner portals
- API endpoints and versions
- Authentication and account recovery
- Object and role authorisation
- Sessions, tokens and logout
- Input validation and output handling
- Business rules and workflow steps
- Configuration and error exposure
- API inventory and data exposure
Final scope and permitted activities are agreed before testing begins.
How we test the application in context
Coverage is agreed around the actual routes, roles and workflows, with test accounts and representative data prepared before active checks.
01
Map
Document the application, APIs, user roles and sensitive workflows. Confirm scope, written permission and exclusions.
02
Model access
Establish expected permissions and account boundaries so tests can distinguish intended behaviour from a control failure.
03
Exercise controls
Test authentication, sessions, input handling and business rules using proportionate, authorised requests.
04
Validate findings
Reproduce material issues across the relevant roles or endpoints and capture evidence of the failed control.
05
Guide fixes
Provide actionable recommendations, then retest agreed fixes and relevant regression cases where included.
Test the business rule, not just the endpoint.
Scanners can spot familiar patterns, but they may not know that only an order owner can approve a change or that two accounts belong to different tenants.
Human-led testing uses the intended permissions and workflow to judge whether a response is a security failure. Findings describe the affected rule and the evidence behind that conclusion.
01
Role-aware testing
Compare expected and observed access for designated accounts and permission levels.
02
Workflow analysis
Examine state changes and sequencing around the business actions that matter.
03
Developer-ready evidence
Provide reproducible requests and responses with sensitive values minimised or redacted.
Findings developers can reproduce and fix
Your team receives a record of coverage and confirmed weaknesses, connected to endpoints, roles and application behaviour.
- Application and API scope summary
- Roles and workflows exercised
- Prioritised technical findings
- Affected routes and API versions
- Sanitised request/response evidence
- Business-rule and impact explanation
- Remediation recommendations
- Coverage limitations and exclusions
- Retest and regression results where agreed
Application testing vs infrastructure scanning
Infrastructure scanning can identify exposed services and some known software issues. It does not establish whether an application correctly enforces its own business rules.
Web and API testing works inside the application’s access model, examining requests, roles, sessions and workflows. This can reveal issues even when server software is current.
Where an application contains an AI assistant or agent, add AI-focused scenarios to examine instruction handling, retrieval and tool actions alongside ordinary application controls.
YOUR QUESTIONS, ANSWERED
Web Application & API Security Testing FAQs
Does API testing require a browser interface?
No. APIs can be tested directly where authorised. API documentation, example requests, authentication details and an inventory of intended endpoints help establish useful coverage.
Do you test authenticated areas and multiple roles?
Yes, where included in scope. Designated accounts for relevant roles help test access boundaries, including whether one user or tenant can reach another’s data.
Is an OWASP checklist enough?
OWASP provides useful risk categories and testing guidance, but it is not a substitute for understanding the application. Coverage should also reflect your workflows, data sensitivity and intended permissions.
Can you test business-logic flaws?
Yes. We agree important rules and workflows, then test whether permitted requests can be combined or sequenced to bypass them. Examples may include approval boundaries or restrictions on sensitive actions.
What should we prepare before testing?
Provide the agreed environment URLs, API documentation where available, designated accounts, role expectations and relevant exclusions. Representative test data and an escalation contact help contain operational risk.
Will fixes be checked for regressions?
Regression checks can be included in the agreed retest scope. A change to shared authorisation code may justify checking related endpoints as well as the originally affected request.
What permission is needed for live application testing?
Testing requires explicit written authorisation and agreed rules of engagement. Hosting, payment and third-party integration restrictions must be considered, and real customer actions are excluded unless specifically authorised.
Related security services
Combine application coverage with AI-focused testing where relevant, broader attack-path validation and a defined retest after development changes.
Explore the service that answers your next security question. View all services. Read what web application security testing checks before defining your scope.
AUTHORISED SECURITY TESTING
Check that your application enforces the rules you rely on.
Share the application, APIs and user roles you want assessed. We will agree a focused scope that fits your release and operational requirements.
Discuss your requirements through our existing assessment enquiry contact.