Senior Full-stack Engineer (React/Next.js + Python): bilingual EN/HE client portal, 5-month contract

We are a US tax firm based in Israel building our own client platform for the 2027 filing season. You will build the client portal and the staff console on top of a FastAPI backend built by our lead engineer: a forms-heavy, bilingual (English and Hebrew, right-to-left) web application where clients accept an engagement letter, pay, answer a conditional questionnaire, upload documents, confirm values extracted from them, attest, sign and download their return, and where staff run a job board with review and release gates. YOU WILL - Build the portal and console in React/Next.js with TypeScript, from the written design and API specification, with a component library and a small design system. - Implement schema-driven forms: the questionnaire is generated from a JSON schema with conditional fields, repeating groups, validation and evidence requirements, in two languages with RTL layout. - Implement auth flows (magic link, OTP, MFA, step-up), document upload with pre-signed URLs and progress, extraction confirmation screens, Stripe Checkout/Elements, e-signature handoff, status pages and notifications. - Own accessibility, responsiveness (phone first for clients), and front-end security (CSP, no sensitive data in client storage, masked identifiers). - Write Python when needed for API endpoints that serve the UI, and end-to-end tests (Playwright). MUST HAVE - 4+ years with React in production, 2+ with Next.js and TypeScript - Forms-heavy applications with complex validation - One shipped bilingual or RTL product (Hebrew or Arabic) - Auth and payment flows implemented end to end - Comfortable reading and writing Python - At least four hours of daily overlap with UTC+2 (Israel) NICE TO HAVE Python/FastAPI; fintech or document-heavy UX; Playwright; design sense; Hebrew. TERMS - 5-month contract, December 1, 2026 to April 30, 2027, 30-40 hours/week, then a maintenance retainer (5-15 hours/week) from May 2027. - US$25-40/hour, or a fixed US$3,000-5,000/month for full-time availability. - NDA and IP assignment required. Development and staging only, synthetic data; no production data access. - Not available to contractors located in Russia. PROCESS 1. Written application with links to two shipped products you built the front end of, and a short answer to the screening question below. 2. 30-minute call with the owner. 3. Paid trial task: 10-15 hours over one week, US$500 paid regardless of outcome (a schema-driven form slice with RTL and validation against a provided API stub). 4. References, contract, onboarding. Start December 1, 2026. SCREENING QUESTION (please answer in your proposal) How would you render a 60-question conditional questionnaire from a JSON schema in two languages, one of them right-to-left, so that a non-technical person can change the questions without a deploy?