Senior Full-Stack Engineer — Build a QuickBooks Alternative

We are a deep tech firm with serious develoeprs who are looking for an exceptional Senior Engineer who can use AI coding tools to build extraordinarily quickly while still understanding architecture, security, testing, accounting logic, and the weaknesses of AI-generated code. The ultimate goal is to build a modern, AI-native QuickBooks alternative. Core Product Requirements: Double-entry accounting engine General ledger, journal entries & chart of accounts Trial balance and account reconciliation Bank feeds (Plaid or equivalent) Automated transaction categorization and matching Customers, vendors, invoices, bills & expenses Accounts receivable / accounts payable P&L, Balance Sheet & Cash Flow Statement Fixed assets & depreciation Inventory & COGS Multi-company / multi-user support Role-based permissions Receipt/document upload + OCR Audit trails and period locking Recurring transactions Payroll / contractor integrations Sales tax & 1099 tracking Tax-ready GL/TB exports Multi-currency Reporting and dashboards AI categorization, reconciliation and anomaly detection AI accounting assistant Human review, confidence scores and overrides The accounting engine must remain deterministic and auditable. AI should assist the accountant—not replace the underlying accounting rules. Paid One-Week Engineering Test Our hiring test is unusual: Build a QuickBooks alternative from scratch in one week. You may use any modern AI coding tools, but cannot start with prior accounting software/code you've already built. We recognize that a complete production-grade QuickBooks replacement cannot realistically be built in seven days. We want to see how much a truly exceptional engineer can correctly build and architect within that constraint. We will evaluate: Engineering velocity Accounting correctness Architecture and database design AI-tool proficiency Code quality and testing Security UI/UX Ability to identify and correct AI-generated mistakes Production scalability Compensation The one-week test will be a paid test and the person will receive $800 for completing the test. Afterward, we will hire the strongest engineer regardless of their requested hourly rate. We care about demonstrated ability more than credentials. When applying, please send examples of technically sophisticated products you've built, your AI development workflow, and what you believe you could realistically accomplish in the one-week challenge. Please do not apply if you are a team. Only single freelancers.