Freelance Back-end JavaScript Developer

Project overview

Our client in the Banking and Finance sector is looking for a freelance Back-end JavaScript Developer H/F

Mission Description:

A growing fintech startup, operating in the wealth management sector, is developing a digital solution for wealth management advisory firms to centralize and automate their clients' asset management. The tech team is working on banking connectors for real-time financial data aggregation, a strategic focus for the platform.

As part of strengthening the integration team, the mission involves developing and maintaining the banking connectors that feed the platform. The consultant will join an agile team in a startup environment, where autonomy, responsiveness, and the ability to manage production are as important as developing new features.

Main Missions

Profile Sought

Technical Environment

Expected Deliverables

Essential Skills / Qualities:

JavaScript / TypeScript back-end, Nest.js, PostgreSQL, API and data flow integration, Production run / incident management, Agile and product/front collaboration

• Develop and maintain banking integration connectors, including APIs and data flows
• Ensure the stability and performance of production services, with a strong production run component
• Participate in Agile rituals: sprint planning, daily stand-ups, and retrospectives
• Collaborate with product and front-end teams on new features
• Document developments in Notion
• Contribute to the continuous improvement of the technical architecture
• Solid experience in back-end JavaScript / TypeScript development
• Proficiency in Nest.js and PostgreSQL
• Experience with integration projects: third-party APIs, connectors, data flows
• Strong aptitude for production run: incident management, maintenance of production services, and rapid fixes
• Startup culture: autonomy, pragmatism, and adaptability to a rapidly evolving environment
• Good communication and teamwork skills
• Nest.js: main back-end framework
• React.js: interfaces, with understanding of front-end expected
• PostgreSQL: relational database
• Notion: documentation and collaboration
• Back-end developments on banking connectors
• Corrective and evolutionary maintenance of production services
• Documentation of developments
• Contributions to the evolution of the technical architecture

Nice to have

Ability to integrate into a startup

Project details

2 days per week

Profile Sought

• JavaScript / TypeScript back-end
• Nest.js
• PostgreSQL
• API and data flow integration
• Production run / incident management
• Agile and product/front collaboration
• Start: 06/12/2026
• Duration: 6 mois
• Remote: hybrid
• Location: Bordeaux, Nouvelle-Aquitaine, FR
• Rate: 49-49 EUR/h
• Languages: French