Job Type : Freelance (with the possibility of full-time employment based on performance and project needs)

Responsibilities :

- Analyze distributed system APIs to validate correctness, consistency, and failure handling across services involved in account creation, data persistence, and related record-linking.

- Execute pre-approved request variations and boundary-validation scenarios using sanitized tracer payloads against designated staging endpoints.

- Investigate system behavior under malformed, malicious, or unexpected inputs and document findings clearly.

- Capture complete request/response evidence, including HTTP status codes, latency, headers, and payload bodies, subject to approved data-handling requirements.

- Validate behavior of near-real-time inline checks (evaluated within milliseconds at the gateway) as distinct from longer-running background verification/risk pipelines (evaluated over minutes to hours), confirming each layer of defense behaves as expected.

- Verify data persistence, referential integrity, and correct linkage of related records/relationships written by backend services during processing.

- Execute controlled replay suites and compare expected versus observed API behavior.

- Correlate replay results with the API schemas and network evidence produced by the Middleware SDET.

- Document observable account/CID lifecycle behavior and downstream state changes for handoff.

- Capture and archive test logs and evidence in a structured, retrievable format to support audits and post-incident reviews.

- Collaborate with backend engineering teams to reproduce, isolate, and validate fixes for distributed-system defects.

- Contribute to test strategy for backend/middleware reliability, including failure-mode and chaos-style testing.

- Maintain traceability between test evidence, defects, and system requirements.

- Reconcile backend observations with the frontend FSM and middleware/API evidence produced by earlier workstreams.

Required Qualifications :

- Strong experience of 5 - 8+ years in testing distributed systems and analyzing inter-service API behavior.

- Hands-on experience with request payload tampering, fuzzing, or adversarial API testing techniques.

- Understanding of layered defense architectures, including the distinction between synchronous/inline validation and asynchronous/background verification processes.

- Familiarity with testing data persistence and relational/hierarchical integrity in backend data stores.

- Demonstrated discipline in test log archival, evidence capture, and structured documentation practices.

- Solid understanding of backend/middleware architecture, failure modes, and system boundaries.

- Familiarity with API testing tools and scripting for building custom fuzzing/tampering test cases.

- Strong analytical and investigative skills for root-causing complex, systemic defects.

- Experience executing controlled API replay or staging validation is strongly preferred.

- Experience correlating API responses with observable application/account lifecycle states is preferred.

- Experience supporting audit, compliance, or evidence-based reporting requirements is a plus.