Crypto Trading Desk - Add Multi-tenancy

We need an experienced TypeScript engineer or small senior team to add multi-customer support to 4ON Trade, a live institutional trading application. This is not a greenfield project. V1 is deployed in production, fully tested, and used by one customer. The existing application, infrastructure, test suite, and business workflows provide a strong base for fast delivery. Objective Extend the current application to: Add customer organizations and user memberships. Allow a user to belong to one or more organizations, with one role per membership. Maintain one active organization per session and allow organization switching. Give 4ON Operators controlled access to all customer organizations. Scope buy flows, orders, history, exports, oversight, pricing reports, configurations, and real-time events by customer. Preserve immutable customer ownership from quote through execution. Migrate existing production data to the first organization. Onboard the second customer. The detailed functional, technical, security, testing, and acceptance requirements are included in the attached RFP. Current technology The current application uses: React Router 7, React 19, TypeScript, Vite and Node.js. Express, Zod, SSE/WebSocket and Drizzle. PostgreSQL 16. Google Cloud Run, Cloud SQL, Load Balancer, VPC, NAT, Secret Manager, Artifact Registry and Cloud Scheduler. Terraform and GitHub Actions. Vitest, fast-check, ESLint and automated CI checks. The selected vendor must be comfortable working directly in this stack. Replatforming or major technology upgrades are out of scope. Required delivery dates Day 7: V2 deployed to production and ready for production UAT. Day 10: Second customer onboarded successfully. Days are counted from the agreed project start. These dates are mandatory. Required technical proposals Provide two alternative approaches: Extend the existing TypeScript and PostgreSQL user-management implementation. Integrate an IAM service such as Logto, Ory, or a comparable solution. Recommend one approach and explain the main trade-offs. Price each alternative separately. Only one approach will be selected. The selected approach, including the AI development harness, must fit within the total USD 1,000 budget. Main deliverables Approved solution architecture, data model, migration design and minimal UI/UX changes. Production-ready implementation and database migrations. Customer isolation across all required application surfaces. Infrastructure-as-code updates. Automated tests and required manual testing. Migration of current production data. Production UAT evidence. Second-customer onboarding. Technical documentation and handover. AI development harness supporting both Claude and Codex. AI development harness USD 200 of the total budget is reserved for a separately quoted AI development harness. The harness must include project instructions for Claude and Codex, deterministic quality checks, architecture and financial-data safeguards, verification workflows, and team documentation. All AI-generated code must be reviewed by a human before merging. The vendor must disclose all AI providers, services, plans and models. Services must not use our code for training and must provide appropriate intellectual-property rights. What is not included This project does not include: New trading venues, countries, currencies or assets. Sell, withdrawal, payout or wallet functionality. Self-service customer registration or KYC. Customer-facing APIs. New user roles beyond the existing roles. Separate databases or schemas for each customer. Major redesign, replatforming or broad refactoring. Increased availability, certification or scale targets. Milestones Milestone 1 — Design approval: USD 100 Accepted solution architecture, data model, migration design, minimal UI/UX design and Day 0–10 delivery plan. Milestone 2 — Production UAT: USD 350 The exact V2 release is deployed to production by Day 7, with automated test results and UAT evidence. Milestone 3 — Customer onboarding: USD 350 Existing data is migrated, the second customer is onboarded by Day 10, regression testing is complete, and documentation is handed over. Milestone 4 — AI development harness: USD 200 Claude and Codex harness implemented, documented, demonstrated and integrated into the development and CI workflow. Total fixed price: USD 1,000 Preferred qualifications Strong production experience with TypeScript, React, Node.js and PostgreSQL. Experience implementing secure multi-tenant applications. Experience with financial or transaction-processing systems. Strong understanding of tenant isolation, authorization, idempotency and exact decimal handling. Experience with production database migrations. Experience with Google Cloud Run, Cloud SQL and Terraform. Strong automated-testing and CI/CD practices. Ability to work independently and provide a daily written update. Availability for quick decisions during UTC-3 business hours. Fluent written English. A 90% or higher Upwork Job Success Score is preferred, but strong relevant evidence may be accepted.