Functional API Testing
Every endpoint checked for correct data, status codes and headers, across valid requests, edge cases and input nobody expected to send.
API Testing
Test Every Endpoint Before Your Users Do
We test REST, GraphQL and SOAP APIs for authentication, access control, error handling, schema issues and performance, helping catch vulnerabilities before they reach production.
- REST, GraphQL & SOAP
- Automated Test Suites
- Auth & Data Validation
- CI/CD Integration
0+ Years testing production systems
0+ API test suites shipped
0% Defects caught before release
0/7 Pipeline monitoring & support
Common API Risks
Your API works. Until it doesn't.
APIs fail quietly. A broken endpoint rarely throws an obvious error; it returns the wrong field, the wrong status code, or the wrong person's data, and the damage shows up several layers downstream.
40% of API vulnerabilities trace back to broken object-level
authorization
- 01
Access control nobody checked
Broken object-level authorization tops the OWASP API Security Top 10 for a reason: it lets one user reach another user's data just by editing an ID in the request, and the endpoint still returns a clean 200 OK.
- 02
Authentication built on assumptions
A 2025 review of disclosed API breaches by Wallarm found broken authentication behind more than half of them. A token that isn't revalidated, a scope that isn't enforced, and the door is open with no error thrown.
- 03
Responses that only work on the happy path
An endpoint that returns clean data for one request type can send back malformed or incomplete payloads for edge cases, optional parameters or unusual input combinations that manual spot-checks rarely reach.
- 04
Versions that break without warning
A renamed field, an altered response shape or a parameter quietly made required breaks every client consuming that endpoint, usually discovered only once an integration partner reports it back to you.
- 05
Endpoints that buckle under real traffic
An endpoint that answers instantly to a single test call can time out or throttle unpredictably once dozens of clients hit it at once, a failure mode invisible until production load actually arrives.
- 06
Shadow APIs nobody is watching
Endpoints shipped for a feature, a test, or a deprecated app version often stay live and undocumented long after anyone remembers them, and unmonitored surface is exactly where attackers look first.
Our API Testing Stack
Tools Matched to How Your API Actually Talks
Tools are picked to fit your API's architecture and protocol, whether REST, GraphQL, SOAP or event-driven, so coverage matches how your services actually communicate.
Po Postman
So SoapUI
RA REST Assured
Sw Swagger / OpenAPI
In Insomnia
Ka Karate DSL
Ne Newman
JM JMeter
k6 k6
GQ GraphQL Playground
Pa Pact
Hc Apache HttpClient
Cy Cypress
cU cURL
Wm WireMock
Mo Mockoon
Ap Apigee
AW AWS API Gateway
Ch Charles Proxy
JS JSON Schema Validator
What We Test
API Testing Services We Offer
Every engagement is scoped around your actual API surface, including how your services and clients depend on it, not a generic endpoint checklist run once and filed away.
Authentication & Authorization Testing
Tokens, API keys, OAuth flows and role-based permissions tested against the exact BOLA and broken-auth patterns behind most real-world API breaches.
Schema & Contract Validation
Request and response payloads checked against your defined schema, so front-end and back-end teams stop drifting apart as the API evolves.
Regression & Version Compatibility Testing
Breaking changes between API versions caught in your pipeline, before they reach a client application or an integration partner.
Load & Performance Testing
Response times and throughput measured under concurrent load, so degradation shows up in a report instead of a user complaint.
Test Automation & CI/CD Integration
Automated suites wired into your build pipeline, flagging a regression the moment it lands rather than weeks later.
Negative & Edge Case Testing
Malformed input, missing parameters, boundary values and out-of-order requests, the scenarios manual testing skips almost every time.
Third-Party & Integration Testing
Your API tested against the real behavior of the third-party services it depends on, and confirmed to degrade gracefully when they fail.
GraphQL Query & Mutation Testing
Queries, mutations and subscriptions tested for correct resolution, authorization and performance under deeply nested, real-world queries.
Mock & Stub Service Testing
Realistic mock services built so client teams can build and test against expected API behavior before the real backend exists.
API Documentation Validation
Your OpenAPI or Swagger spec checked line by line against actual endpoint behavior, so consumers integrate against what the API really does.
Ongoing API Monitoring
Continuous testing built into your release cycle, catching endpoint regressions before they ever reach production traffic.
Who We Work With
API Testing Across Integration-Heavy Sectors
API reliability requirements differ sharply depending on who consumes your endpoints and what is at stake when they fail.
SaaS Platforms
Financial Services
eCommerce & Retail
Healthcare
Travel & Hospitality
Logistics & Supply Chain
Online Marketplaces
Hotels & Booking Platforms
Startups & Scale-Ups
Professional Services
Why Teams Choose Us
API Testing That Catches What Manual Checks Miss
Running a few requests through Postman tells you an endpoint works on the happy path. We test what happens everywhere else: bad input, missing auth, concurrent load, so your contracts hold under real conditions, not just a demo.
Book a Free API Test Review-
Full protocol coverage
REST, GraphQL and SOAP tested with the same rigor, each adapted to its own specific failure modes instead of one generic checklist.
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Edge cases, deliberately
Malformed input, missing fields and out-of-order sequences get tested on purpose, not just the requests your own team expects to send.
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Access control checked everywhere
Every endpoint is checked for proper authorization, not just the ones that look security-sensitive from the outside.
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Automation built to last
Suites are built for maintainability, so they keep catching real regressions instead of breaking with every release like brittle scripts do.
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Contract-first validation
Tests run against your actual API schema, catching drift between documentation and real behavior before it confuses an integration partner.
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CI/CD native
Suites run inside your existing pipeline, giving your team feedback on every pull request and deployment, not a report weeks later.
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Performance tested, not assumed
Real response times and throughput are measured under load, instead of assuming an endpoint that passes alone will hold up in production.
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Coverage that grows with you
Test coverage is extended as you add endpoints and versions, so the suite scales alongside your actual API surface, not last year's.
How We Work
Our API Testing Process
Every engagement follows a structured process built to validate functionality, security and performance across your full API surface, documented and repeatable, not tribal knowledge.
- 01
API Discovery & Scoping
We review your documentation, endpoints and consumer integrations, including any that were never officially documented, to set scope and priority.
- 02
Test Strategy & Schema Mapping
Request and response schemas get mapped against documentation to define expected behavior before a single test is written.
- 03
Test Case & Script Design
Functional, negative and edge case scenarios are designed around real usage patterns, not just the documented happy path.
- 04
Functional & Contract Testing
Endpoints are tested against defined schemas, status codes and business logic to confirm the contract holds under every scenario.
- 05
Security & Authorization Testing
Authentication flows and access controls are verified against known failure patterns, including the object-level authorization gaps attackers check first.
- 06
Performance & Load Testing
Endpoints are tested under concurrent load to measure response times and find throughput limits before production traffic does.
- 07
Automation & CI/CD Integration
Test suites are automated and wired into your deployment pipeline, so future regressions get caught automatically, not manually.
- 08
Reporting & Ongoing Maintenance
Findings are documented with clear fixes, and suites are maintained as your API grows with new endpoints and versions.
What Is Included
Ad-Hoc Checks Are Not the Same Asset
The difference between a one-off endpoint check and a professional test suite happens under the surface, not in the demo. Here is what comes standard with every engagement we deliver.
What you get Ad-hoc / Minimal Testing WebNX
Schema and contract validation
Negative and edge case coverage
BOLA and broken-auth pattern testing
Load testing under concurrent requests
Automated regression suite
CI/CD pipeline integration
GraphQL and SOAP protocol coverage
Basic happy-path request checks
Manual, one-off endpoint checks
Ongoing test suite maintenance
Client Words
Trusted by Teams That Depend on Their APIs
Our public API had forty-plus integration partners and no automated regression suite watching it. A version update broke a field type, and partners reported it before we did. The suite they built now catches that class of issue on every build, before it ships.
Every manual test on our GraphQL API looked fine until nested query testing surfaced a performance issue that only showed up under the deeply nested requests our larger clients were actually sending. Fixing it resolved a support complaint we had been chasing for months.
Authorization testing found an endpoint where changing an ID in the request pulled up another account's transaction history, exactly the kind of access-control gap that shows up in most API breach reports. It was closed within a day, well ahead of our next compliance review.
Questions, Answered
API Testing FAQs
How much does API testing cost?
The cost depends on endpoint count, protocols, automation and CI/CD requirements. A focused REST API test is simpler, while full coverage across REST, GraphQL and SOAP with automated regression requires more work. Every engagement is scoped and quoted individually.
How long does an API testing engagement take?
A focused suite covering a limited endpoint set typically takes 1 to 3 weeks. Full coverage with automation, security and performance testing usually runs 4 to 8 weeks, with working test cases delivered as we go, not all at once at the end.
Do you perform regression testing on our API?
Yes. We build automated regression suites that re-run on every release, so a change to one endpoint doesn't silently break behavior another endpoint or client application depends on.
Can API testing be automated?
Yes, and it should be. Manual checks alone can't keep pace with frequent releases or a large endpoint surface, so automated suites are central to how we work, not an add-on.
Can API tests run inside our CI/CD pipeline?
Yes. We wire automated suites directly into your deployment pipeline, so a failing test blocks a bad release instead of reaching production and your customers.
How do you report bugs found during API testing?
Every issue is logged with the exact request that triggered it, expected versus actual response, severity and reproduction steps, so your developers fix it without recreating the scenario themselves.
Does API testing cover security as well as functionality?
Yes. Authentication, authorization and input validation are tested against the OWASP API Security Top 10, including the broken object-level authorization and authentication patterns behind most disclosed API breaches. A dedicated penetration test goes further for high-risk applications.
Do you test compatibility across different API versions?
Yes. We test for breaking changes between versions and confirm backward compatibility where it's required, so an update doesn't silently break an existing client integration.
Can you test how our API performs at scale?
Yes. We test endpoints under concurrent load to measure throughput and response-time degradation, giving you real data on where performance limits sit before production traffic finds them for you.
Do you provide ongoing API testing, not just a one-time engagement?
Yes. Our maintenance plans extend test coverage as you add endpoints and versions, keeping the automated suite aligned with your actual API surface, including anything that goes live outside a formal release.
What does the final API testing report include?
You get a report covering every tested endpoint, defects found with severity and reproduction steps, schema validation results and performance metrics, plus a business-readable summary of overall API health.
What support is available after the engagement ends?
Ongoing suite maintenance, scheduled re-testing after major changes, and a support channel for questions as your API evolves. Most clients move to a recurring plan tied to their release cycle rather than a one-time engagement.
Keep Exploring
Related Services
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Real-world traffic simulated against your systems to find bottlenecks before they cost you customers.
ExploreSecurity Testing
Vulnerabilities and weak points identified across your stack before an attacker finds them first.
ExploreAutomated Testing
Automated suites that catch a regression on the build it was introduced in, not weeks into a manual QA cycle.
ExploreFind Out What Your API Actually Does Before an Attacker Does
Every API has a breaking point: an edge case nobody anticipated, an access check nobody wrote, a version change nobody flagged. Thorough testing gives you a documented, repeatable way to catch those failures before a client integration, or a breach report, does it for you.