Turn one unreliable API mutation into a bounded, observable workflow. Includes: - Reproduction of one concrete duplicate, timeout, or transient 4xx/5xx failure - Idempotency-key or deduplication design where the API supports it - Bounded retry policy with explicit timeout and backoff rules - Result validation, failure evidence, and a short rollback or handoff note Best for webhook delivery, checkout/order mutations, background workers, and browser-to-API flows that occasionally repeat or disappear. Delivery: 2 business days after access and acceptance criteria. Fixed price: US$299. Work starts only through Contra's funded/protected checkout. I never bypass CAPTCHA, MFA, authentication, or access controls.