Founding Engineer | Tech Lead

Fluxo is a startup focused on digitizing the used vehicle market. We are building a platform that transforms the process of buying and selling used cars into a reliable and integrated experience, from start to finish — including the escrow of transaction funds until vehicle delivery.

We are looking for Fluxo's Tech Lead / Founding Engineer — the company's first technical leader. A person who will write much of the code and, at the same time, define how the product and architecture will be built from the ground up. This position comes with equity, recognizing the fundamental role this person will play in building the company.

This is a technical reference position for the business: you will participate in strategic decisions alongside the Founder, with an active voice on where technology should go, and will be the person accountable for the product's architecture, quality, and technical direction.

What you will do

• In the first months, be the main product engineer: program most of the system, put it into production, and be responsible for it (monitoring, incidents, and runbooks).
• Build the product's financial engine — double-entry ledger, reconciliation, integrations with custody and banks, idempotent webhooks, queues, and deadlines. This is the core that supports Fluxo's security promise.
• Design the architecture and data modeling from the start, with a verifiable audit trail, data integrity, and maintainability.
• Ensure security and compliance in handling sensitive data (LGPD, KYC).
• Work alongside the Senior AI Engineer, being responsible for the overall architecture on which AI automations operate.
• Act as the company's technical reference, participating in product and business decisions alongside the Founder.
• Prepare the ground for the engineering team's growth — best practices, quality standards, and processes that will serve as the foundation for future hires.
• Define, together with company leadership, the stack and tools that make sense for the product — the list below is a starting reference, not a limitation.

What we are looking for

Experience and profile:

• Senior professional with a consistent track record of strong backend work and responsibility for architecture decisions.
• Experience building financial systems: ledger, reconciliation, idempotency, integrations with banks, payment methods, or custody, and audit trails.
• Real experience building products from scratch — you have been in the position of making structural decisions without a predefined path.
• Hands-on profile: you code day to day and enjoy it, not just lead.
• Fluent use of AI tools in development (code assistants, agents) as part of your day-to-day.
• Technical leadership posture: ability to influence decisions, communicate trade-offs clearly, and, in the future, build and mentor an engineering team.
• Advanced English.

Stack and technical knowledge:

• TypeScript (advanced) as the project's base language, from backend to frontend.
• Node.js on the backend (we use Fastify), with queues, jobs, and asynchronous processing.
• PostgreSQL — robust data modeling, migrations, transactions, and SQL proficiency.
• Next.js and React for the web.
• Architectural patterns for separation of concerns and event-driven design (e.g., CQRS, event sourcing, or equivalents).

The stack above is a directional reference, not a constraint. We equally value experience with equivalent or related technologies — what we seek is technical maturity and architectural judgment, not attachment to a specific tool.

Nice-to-haves (non-eliminating):

• React Native + Expo / EAS Build (the mobile app is built in parallel with the web)
• Supabase (Postgres and Auth)
• Monorepo (Turborepo, pnpm workspaces, Nx, or similar)
• Automated testing — Vitest, Playwright (or Jest, Cypress)
• Zod (or equivalent schema validation libraries)
• Observability — Sentry (or equivalent)
• Deployment and infrastructure — Vercel, Fly.io, AWS
• Experience with LGPD and handling sensitive data
• Anti-money laundering (AML/CFT), transaction monitoring, or BACEN regulation
• Integrations with Pix, Open Finance, or APIs for financial partners (banks and finance companies)
• Digital signature and key management (ICP-Brasil, KMS, or similar)
• Permission modeling and multiple companies on the same platform (RBAC, multi-tenant)
• Two-sided marketplaces: matching, ranking, and demand routing
• Credit and risk: credit analysis, credit bureaus, receivables anticipation, or collections
• Public APIs for partners and data platforms (data warehouse, event pipelines)

Work model: Hybrid in São Paulo

B2B contract: Compensation + Equity