Senior SDET — Flexible, Distributed API Testing Expert

Welo Data; United States; Remote; USD 120,000 - 170,000; Full time

Job summary

Welo Data is seeking a seasoned software tester to validate the resilience of distributed backend systems powering account provisioning. You will execute tracer/replay scenarios against staging endpoints and document lifecycle behaviors for downstream state.

Ideal candidates bring 5+ years testing distributed systems and APIs, familiarity with payload tampering, fuzzing and adversarial testing, and strong evidence capture & documentation discipline to support high-quality AI data platforms.

Qualifications

• 5-8+ years testing distributed systems and API behavior.
• Experience with payload tampering, fuzzing, and adversarial testing.
• Strong documentation and evidence capture discipline.

Responsibilities

• Test resilience and correctness of distributed backend systems for account provisioning.
• Execute approved tracer/replay scenarios against staging endpoints.
• Document observable lifecycle and downstream state behavior.
• Validate API correctness, consistency, and failure handling across services.
• Investigate system behavior under malformed inputs and capture evidence.
• Compare expected versus observed API behavior in controlled replay suites.

Skills

Distributed systems testing

API behavior testing

Payload tampering

Fuzzing

Adversarial testing

Documentation discipline

Job description

Welo Data is seeking a seasoned software tester to validate the resilience of distributed backend systems powering account provisioning. You will execute tracer/replay scenarios against staging endpoints and document lifecycle behaviors for downstream state.

Ideal candidates bring 5+ years testing distributed systems and APIs, familiarity with payload tampering, fuzzing and adversarial testing, and strong evidence capture & documentation discipline to support high-quality AI data platforms.