Senior Business Analyst

About us:N-iX is a software development service company that helps businesses across the globe develop successful software products. Founded in 2002 in Lviv, N-iX has come a long way and increased its presence in eight countries Poland, Ukraine, Sweden, Bulgaria, Malta, the UK, the US, and Colombia. Today, we are a strong community of 2,000+ professionals and a reliable partner for global industry leaders and Fortune 500 companies. About the client:Our client, an award-winning global tax services and software provider, is the largest Firm in the world dedicated exclusively to business taxes. With global headquarters in Dallas, Texas, the Firm provides an integrated suite of federal, state, local, and international tax services on a multijurisdictional basis, including tax recovery, consulting, advocacy, compliance, and technology services.About Project: We are developing an API Engine for B2B SaaS platform that enables VAT compliance across multiple jurisdictions, ERP systems, and external tax authority APIs. The role focuses on transitioning complex system logic into a modern, integration-driven architecture while maintaining interoperability with existing core systems.Responsibilities: Collaborate with Product, Engineering, and Architecture to elicit functional and non-functional requirements for the API Engine, identify implicit assumptions, edge cases, and dependenciesTranslate high-level concepts into: epics, features, and well-structured user stories with clear acceptance criteria (functional + non-functional)Define requirements for public and partner-facing APIs, ERP system integrations (API-only, hybrid, file-based where relevant), external tax authority APIs with differing schemas, SLAs, and behaviorsCapture data contracts and payload expectations, error handling, retries, idempotency, versioning, authentication and authorization flowsWork closely with engineering to ensure requirements explicitly cover: security (API keys, secrets, access control, auditability), performance and scalability, observability (logging, traceability, error visibility), compliance and regulatory constraints, backward compatibility and migration from legacy systemsHelp define requirements that allow coexistence with a legacy platform until the latter's sunset and gradual migration paths for customers and integrationsAct as a bridge between product intent, engineering reality, external integration expectationsRequirementsMinimum 5 years of commercial experience as a Business Analyst.Proven track record working on API-first products and integration-heavy B2B SaaS platforms.Experience managing requirements for complex ecosystems, including ERP integrations and hybrid platform coexistence.Deep understanding of Agile delivery, with a focus on creating 'shippable' value and reducing ambiguity.Exceptional ability to translate technical complexity for stakeholders and collaborate effectively with architects and developers.Upper-Intermediate to Advanced English (written and verbal).Nice to HavePrior work in regulated domains (finance, tax, payments, compliance)Familiarity with ERP ecosystems (e.g. SAP, Oracle, NetSuite, Dynamics) and government or authority APIsExperience with event-driven or asynchronous integrations and multi-tenant SaaS platformsWe offer*:Flexible working format - remote, office-based or flexibleA competitive salary and good compensation packagePersonalized career growthProfessional development tools (mentorship program, tech talks and trainings, centers of excellence, and more)Active tech communities with regular knowledge sharingEducation reimbursementMemorable anniversary presentsCorporate events and team buildingsOther location-specific benefits*not applicable for freelancers