API testing that validates contracts, integrations, and security
QAble tests REST, GraphQL, and gRPC APIs across functional correctness, schema compliance, error handling, authentication, and performance, ensuring your APIs behave reliably for every consumer and under every condition.
Testing coverage for:
Engineering teams that rely on QAble
What API testing actually covers
A definition for engineering and product leaders who know their APIs are business-critical but have not yet invested in structured API testing.
More than endpoint reachability
API testing validates the contract: correct schemas, correct error codes, correct data types, and correct behaviour for every input. Endpoint reachability is a starting point, not a coverage target.
Security is part of every engagement
Authentication, authorisation, and input validation are tested as part of every API engagement, not deferred to a standalone security audit scheduled months after the API has already shipped.
Integration correctness at the boundary
APIs do not exist in isolation. QAble tests how APIs interact with downstream services, databases, and third-party providers, validating data flow at every system boundary.
API testing is the right investment when:
What happens without structured API testing
Without API testing coverage
APIs ship without contract validation, so consumer applications break silently when schemas change between releases
ContractAuthentication and authorisation logic tested only through the UI, leaving direct API access vulnerabilities undetected
SecurityError responses leaking internal paths, stack traces, and database names to any client that sends a bad request
ExposureIntegration failures between services discovered only in staging or production, never caught in the test cycle
IntegrationNo performance baseline for API endpoints, so degradation under load surfaces in production rather than in testing
PerformanceThe QAble Solution
Structured API testing validates contracts, catches security flaws, and confirms integration correctness before any of these risks reach production.
Contract validated
Every endpoint tested against its documented schema before release
Security checked
OWASP API Security Top 10 covered on every testing engagement
Integration confirmed
Service-to-service data flows verified before the release goes out
Performance baselined
Response time and throughput benchmarks documented from the first run
What QAble tests in every API engagement
QAble tests every dimension of API quality, from functional correctness to integration reliability and security posture.
Contract and schema validation
Validates that API responses match documented schemas, catching breaking changes before they reach any consumer application or downstream service.
Functional API testing
Validates every endpoint for correct behaviour, covering CRUD operations, query parameters, filters, pagination, and business logic correctness.
Integration testing
Tests how APIs interact with databases, downstream services, and third-party providers, validating data flow across every system boundary.
Error handling and edge cases
Validates API behaviour under invalid inputs, missing fields, malformed payloads, and unexpected conditions that production traffic will eventually send.
Authentication and authorisation
Tests that security controls work correctly, validating token handling, role-based access, and protection of sensitive endpoints against direct access.
Performance and load testing
Evaluates API response times, throughput, and behaviour under concurrent load, identifying bottlenecks before they affect production traffic.
How QAble approaches an API testing engagement
A five-step methodology that maps every endpoint, designs coverage across all disciplines, executes testing, and closes every engagement with validated fixes.
Discovery and spec review
Mapping every endpoint from API specs, architecture diagrams, and documentation to establish what needs to be tested before any test design begins.
Test case design
Designing functional, contract, security, integration, and performance test cases for every endpoint and data flow, mapped to documented behaviour.
Functional and contract testing
Executing endpoint tests, schema validation, error handling scenarios, and business logic verification against every documented API interface.
Security and integration
Testing authentication flows, authorisation boundaries, input validation, and service integration correctness, including OWASP API Security Top 10 scenarios.
Reporting and remediation
Delivering structured findings with severity ratings, remediation guidance, and retest validation to confirm every fix is resolved before the engagement closes.
Tools QAble brings to an API testing engagement
QAble selects tools based on your API type, stack, and coverage needs, from contract testing frameworks to security scanners and load testing platforms.
Postman / Newman
API collection testing and CI-integrated automation runs
REST Assured
Java-based REST API testing framework for automated suites
Pact
Consumer-driven contract testing for microservices architectures
k6 / JMeter
API performance and load testing under real traffic patterns
OWASP ZAP / Burp Suite
API security scanning and OWASP Top 10 validation
GraphQL Inspector
GraphQL schema change detection and compliance validation
What every API testing engagement produces
Structured documentation across contracts, security, integrations, and performance, so quality status and ownership are always traceable.
API test report
Endpoint coverage summary, functional test results, schema compliance findings, and error handling assessment across every tested interface.
Security findings
Authentication and authorisation test results, sensitive data exposure risks, input validation gaps, and prioritised remediation recommendations.
Integration report
Service dependency mapping, contract validation results, data flow correctness across boundaries, and third-party integration findings.
Performance baseline
Response time benchmarks, throughput measurements, rate limit validation, and a load behaviour summary to track against future releases.
API vulnerabilities QAble consistently uncovers
The API defects and security issues that appear most frequently across QAble testing engagements.
Broken authentication
API endpoints accessible without valid tokens, or token validation logic that can be bypassed with malformed or expired credentials.
Excessive data exposure
APIs returning more fields than the consumer needs, exposing sensitive data that should be filtered server-side before any response is sent.
Missing input validation
APIs accepting malformed or unexpected inputs without validation, allowing data corruption, server errors, or injection attacks through the interface.
Contract drift
API response structures deviating from documentation, causing silent failures in consumer applications on every release without a visible error.
Information leakage in errors
Error messages exposing stack traces, database names, or internal paths to any client that sends a malformed request or triggers a server error.
Rate limiting gaps
Missing or misconfigured rate limits that allow API abuse, credential stuffing, or unintended resource consumption at scale.
Ways to work with QAble
Three engagement models covering a rapid audit, a comprehensive testing project, and continuous sprint-aligned API QA.
1-2 weeks
API audit
A rapid structured review of your API endpoints covering contracts, error handling, and security posture with a prioritised remediation list.
Deliverables
Best for
3-6 weeks
Full API testing project
Comprehensive API testing covering functionality, contracts, integrations, security, and performance with structured findings across all disciplines.
Deliverables
Best for
Ongoing
Continuous API QA
Sprint-aligned API testing that validates every new endpoint and contract change as they are deployed, keeping security and contract coverage current.
Deliverables
Best for
Why choose QAble
Why organisations choose QAble to test their APIs and validate interface quality before every release.
QAble API Testing Expertise
Questions buyers actually ask.
Direct answers to the questions we get on the first advisor call.
Do you test GraphQL as well as REST APIs?
Yes. QAble tests REST, GraphQL, and gRPC APIs. For GraphQL, we validate schema compliance, query and mutation correctness, resolver behaviour, and introspection security. Testing approaches differ by protocol, but the coverage principles apply to all three: functional correctness, contract compliance, security validation, and performance under load.
Can you test APIs that require authentication?
Yes. QAble handles OAuth 2.0, JWT, API key, and session-based authentication as part of the test setup. We also specifically test the authentication and authorisation mechanisms themselves, not just work around them to reach endpoints.
Do you do consumer-driven contract testing?
Yes. For microservices architectures where multiple consumers depend on a shared API, QAble can implement consumer-driven contract testing using Pact. This ensures that API changes do not silently break downstream consumers before they reach production.
What security issues do you test for in APIs?
QAble tests for the OWASP API Security Top 10, including broken authentication, excessive data exposure, injection vulnerabilities, insufficient rate limiting, and improper access control. These are the most common and impactful API security risks across modern web applications.
Structured API testing from contract to security
QAble validates your APIs across functional correctness, schema compliance, integration reliability, and security posture, so every interface behaves as documented and as expected.
APIs that consumers can depend on
QAble validates your APIs across functional correctness, schema compliance, integration reliability, and security posture, so every interface behaves as documented and as expected.
Talk to QA Advisor
Direct access to QAble's API testing specialists.
Response within 24 hours