Senior SDET – (India)

About this job

Welocalize is hiring a freelance Senior SDET in India to test the resilience and correctness of distributed backend systems supporting account provisioning and onboarding workflows. The team at Welocalize and Welo Data focuses on AI data services, localization, and building ethical data to train advanced AI systems. A normal day for the Senior SDET involves executing pre-approved tracer and replay scenarios against staging endpoints, analyzing request and response behavior, testing near-real-time inline checks versus background verification pipelines, verifying data persistence, and documenting observable account lifecycle and downstream state behavior while capturing detailed technical evidence.

Responsibilities

• Analyze distributed system APIs to validate correctness, consistency, and failure handling across account creation and data persistence services.
• 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 and response evidence including HTTP status codes, latency, headers, and payload bodies.
• Validate the behavior of near-real-time inline checks and longer-running background verification pipelines.
• Verify data persistence, referential integrity, and correct linkage of related records written by backend services.
• Execute controlled replay suites and compare expected versus observed API behavior.
• Document observable account lifecycle behavior and downstream state changes and collaborate with backend engineering to isolate defects.

Requirements

• 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, synchronous validation, and asynchronous verification processes.
• Familiarity with testing data persistence and relational or hierarchical integrity in backend data stores.
• Demonstrated discipline in test log archival, evidence capture, and structured documentation practices.
• Solid understanding of backend and middleware architecture, failure modes, and system boundaries.
• Familiarity with API testing tools and scripting for building custom fuzzing or tampering test cases.
• Strong analytical and investigative skills for root-causing complex and systemic defects.

Good to have

• Experience executing controlled API replay or staging validation.
• Experience correlating API responses with observable application or account lifecycle states.
• Experience supporting audit, compliance, or evidence-based reporting requirements.

Who should apply

This role suits experienced testing professionals with a strong background in distributed systems, API testing, and backend reliability. Candidates should have 5 to 8+ years of relevant experience, a disciplined approach to evidence capture, and familiarity with payload tampering or fuzzing techniques. Freshers are not suited for this senior position. If you have solid expertise in analyzing inter-service behavior and staging validation, you are encouraged to apply.

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