Senior Software Engineer - APIs & Integrations

As a Senior Software Engineer at Performativ, you’ll lead the design and implementation of robust, high-throughput APIs and backend systems. Everything we build is grounded in open web standards - JSON, webhooks, OpenAPI - and built for scale, reliability, and clear interoperability. You’ll work on the core systems that power mission-critical financial infrastructure for institutions across Europe.

What you’ll do 📈

• Design and implement modern, standards-based APIs using REST and OpenAPI specifications
• Build scalable backend systems that handle millions of transactions daily with low latency
• Develop and maintain secure, event-driven integrations via webhooks and callback mechanisms
• Lead the backend design of new products and services, ensuring interoperability and long-term maintainability
• Optimize for resilience, observability, and fault-tolerant behavior across distributed cloud systems
• Deploy infrastructure using AWS CDK and build with modern tools like Golang, TypeScript, Python, and PHP
• Ensure clean interface contracts and clear documentation for client developers
• Collaborate across engineering, product, and security to deliver business-critical functionality
• Mentor engineers and help define backend engineering standards across the team
• Continuously improve performance, security, and scalability of the core API platform

What we’re looking for 🎯

• 10+ years of backend engineering experience, with a strong focus on API development and integration
• Deep understanding of open web standards including JSON, webhooks, and OpenAPI
• Track record of building reliable, low-latency systems at scale handling millions of daily API calls
• Experience with backend languages like Go, TypeScript (Node.js), Python, or PHP in production environments
• Exposure to Infrastructure and Cloud using AWS and tools like AWS CDK or Terraform
• Familiarity with distributed system architecture, asynchronous processing, and data consistency models
• Excellent communication skills and the ability to explain trade-offs to technical and non-technical stakeholders
• Strong security mindset with knowledge of authentication patterns (e.g. OAuth2, JWT)
• Comfort operating in a hybrid work environment with 3 days per week onsite in central London
• Experience mentoring developers and contributing to team-wide technical strategy

What we can offer you 🌱

• Trust and responsibility to shape the future of Performativ’s success in the European market from day 1.
• Join a fast-growing fintech scaleup supported by top-tier VCs.
• Work with intelligent, passionate, and driven professionals with experience from leading institutions (such as Goldman Sachs, McKinsey, BCG, Amazon etc).
• Accelerate your career with opportunities for professional development, leadership and plenty to build and learn.
• Competitive compensation package of salary + equity.

Join a Team of Fintech heroes! 🚀

Performativ is making waves in the wealth management ecosystem and is changing the way investment advisors and financial institutions do business around the world. Working at Performativ means working at a fast-paced tech scaleup with intelligent people who are passionate about their work. We are on a scaling journey beyond all metrics and expectations and can't wait to have you join us in making a real impact.

We are funded by some of the leading VC funds in the world and expectations are set to be established as a European market leader in a record amount of time.

You can read more about our product at performativ.com

We value passion 🔥

At Performativ, we are builders first. We are passionate with ambitious goals and value the time and effort people put into their work. You will be part of the family from day one, and responsible for making your mark and driving forward your vision. Autonomous work is embedded in our culture, and we are committed to ensure you have all the tools and support you need while acknowledging the importance of flexibility.