Senior Full-Stack Engineer – Fintech Platform

Roundtable; Paris; Hybrid; EUR 60,000 - 90,000; Full time

Benefits offered by this job

Employee stock options plan

25 days of holidays + RTT days

Health insurance covered at 50%

Restaurant card

Transportation allowance

Job summary

Roundtable in Paris is seeking a Senior Full-Stack Developer to join their tech team. You will collaborate on product strategy, develop new features, and maintain existing systems. Ideal candidates have 5+ years of experience in TypeScript, a strong understanding of financial systems, and have a mindset geared towards quality and correctness. The role offers competitive compensation, including stock options and benefits like a restaurant card and health insurance.

Qualifications

• 5+ years building full-stack TypeScript applications.
• Comfortable with PostgreSQL and ORMs (Prisma preferred).
• Understanding of financial calculations and decimal precision.
• Experience with fintech or regulatory compliance is a plus.

Responsibilities

• Collaborate on product strategy and make key technical decisions.
• Develop, deploy, and maintain new features.
• Conduct code reviews and share knowledge within the team.

Skills

Building full-stack TypeScript applications

PostgreSQL and ORMs (Prisma preferred)

Financial calculations and decimal precision

Comfortable with domain complexity

Clear communication with non-technical stakeholders

Tools

TypeScript

PostgreSQL

Google Cloud Platform

Job description

About the role

We are looking for a highly skilled Senior Full-Stack Developer to join our tech team.

As collaborative building is at the core of how we operate - not just within the engineering team but across all departments. We are developing a platform that offers an incredible opportunity to co-invest in the Private Equity sector. To achieve our vision, we need to establish both a premium brand and platform.

As our tech team continues to scale, you’ll wear many hats. Your responsibilities will include:

• Collaborating closely with the team on product strategy, assessing the effort required for various features, and making key technical decisions

• Supporting the overall decision-making process and the company’s sustained growth

• Developing, deploying, and maintaining new features

• Conducting code reviews and facilitating knowledge sharing within the team

What you’ll work on

• Cap table engine: Build systems that track ownership across thousands of investors with cent-level precision

• Multi-country compliance: Implement investor qualification rules and regulatory workflows across jurisdictions

• Multi-asset platform: Extend the platform to support diverse asset classes and investment structures

• Financial operations: Design robust workflows for complex financial transactions and fund operations

• Real-time dashboards: Create high-performance investor platform with live portfolio valuations

• Document automation: Generate legal documents (subscription agreements, shareholder reports) from dynamic templates

• Security: Protect sensitive financial data with robust authentication, authorization, and encryption

Technical challenges

We handle sensitive financial data, which presents us with unique challenges:

Precision at scale: Our engines compute fractional ownership across thousands of investors. Rounding errors must cascade correctly - we can’t lose or create cents.

Complex financial state machines: Financial operations involve coordinated updates across multiple entities and ledger entries. State transitions must be atomic and auditable.

Multi-jurisdiction compliance: Different countries have different regulatory requirements. The system must enforce these rules programmatically while remaining flexible.

Historical reconstruction: Auditors need to see data at any point in time. Our architecture supports point-in-time queries tied to specific operations.

Domain complexity: We model sophisticated financial instruments and multi-currency valuations all with type safety.

Overall tech stack

Type Safety: 100% TypeScript across the entire stack (frontend, backend, shared libraries)

Quality Assurance:

• Vitest for unit/integration testing

• Playwright for E2E testing

• Biome for linting and formatting

• Zod for runtime validation at all system boundaries

Architecture:

• pnpm workspace monorepo with Turborepo for build orchestration

• Domain-Driven Design with 20+ shared domain libraries

Application Layer:

• Frontend: Next.js (App Router), Tailwind, Shadcn

• Backend: TRPC + Nexus (type-safe schema generation)

• Database: PostgreSQL & Redis

• Job Queue: BullMQ with Redis

• Design System: Figma & Storybook

API Layer:

• REST (admin-facing) with Zod schemas via lib/api-schemas

Cloud Infrastructure:

• Google Cloud Platform (Cloud Run, GCS)

• Container-based deployments

Observability:

• OpenTelemetry for distributed tracing

• Datadog for monitoring (browser + server)

• Sentry for error tracking

AI Integration: OpenAnthropic-powered document analysis and data extraction pipelines

Engineering culture

• Domain-Driven Design: coherent domains with clear boundaries

• Strict TypeScript: No any types, Zod validation at all boundaries

• Observability-first: Datadog + OpenTelemetry + Sentry from day one

• Code review culture: Every PR gets thoughtful review

• AI-assisted development: We leverage AI tools (IDE assistants, PR review) to augment engineers while keeping humans in the loop for all decisions

You’re a great match ifTechnical skills:5+ years building full-stack TypeScript applicationsComfortable with PostgreSQL and ORMs (Prisma preferred)Understanding of financial calculations and decimal precisionBonus: Experience with fintech, regulatory compliance, or cap table managementMindset:You care about correctness-bugs in financial systems have real consequencesYou enjoy domain complexity and learning new business conceptsYou prefer clean architecture over quick hacksYou communicate clearly with non-technical stakeholdersInterest: You have a genuine interest in angel investment and the venture capital worldEntrepreneurial mindset: You thrive in fast-paced environments where you have broad responsibilitiesOwnership mentality: You are a doer and have a bias for action, no task is below youOrganization skills: You know how to prioritize and split your tasks efficientlyTeam player: You enjoy sharing and learning from each otherInitiative and innovation: You propose improvements and challenge assumptions constructivelyProduct lover: You fully understand what we want to bring to our users, and you are eager to deliver the best possible UX to themSystems thinking: You are able to step back and rethink our model globallyStrong attention to details: Code quality is important for you and you set a high barWhat we offerA front-row seat in a fast-growing startup shaping the future of investment operations - ranked 14th in the Sifted 250, which highlights Europe’s 250 startups with the highest percentage revenue growth over the past three yearsA quality-driven environmentAwesome colleagues with high ambitionsA culture of ownership, collaboration, learning and growthBeautiful offices in central Paris, Toulouse and Luxembourg + flexible remote options for people in other countriesCompetitive compensation (including an employee stock options plan)Other perks / terms and conditions :Time off: 25 days of holidays + RTT daysHealth insurance: Mutuelle Alan (50% covered by the company)Meals: A restaurant card with our partner Swile (10€ per workday)Tools: A MacBook is our standard working toolTransportation: Forfait Mobilité Douce (600€ /year)