Senior Backend Engineer_Billing & Accounting Systems

Senior Backend Engineer - Billing & Accounting Systems

Keylight is a global subscription technology vendor founded in 2015, with offices in Berlin, Zurich, Belgrade, New York, and Singapore. The keylight platform is the only user-centric, end-to-end solution on the market, streamlining recurring operations across commerce, sales, subscription management, billing automation, revenue and accounting automation, and advanced data analytics.

Due to the nature of this role, candidates must be based in Germany and hold valid authorization to work in the country.

Role Overview

We are looking for a highly experienced Senior Backend Engineer to strengthen our billing and accounting engine for our subscription management platform. In this role, you will work on backend services built with Node.js (TypeScript), implementing scalable and performant systems for invoicing, usage metering, and accounting workflows.

The role focuses on execution and technical ownership, where you will be implementing and optimizing technical concepts for critical financial processes. You will collaborate closely with the Product and DevOps teams to enhance our billing infrastructure, increasing its scalability and efficiency.

Responsibilities

• Enhance backend services for billing, usage metering, invoicing, and accounting in Node.js (TypeScript).
• Develop asynchronous, event-driven processes to process large volumes of financial transactions efficiently.
• Ensure data consistency and correctness across billing and accounting workflows using PostgreSQL.
• Build secure, auditable, and compliant systems that meet financial regulations.
• Collaborate with the Product team, Computational Billing Architects, and other technical stakeholders to translate complex billing logic into high-performance solutions.
• Optimize system performance for scalability, concurrency, and fault tolerance.

Qualifications

• 8+ years of backend engineering experience, with strong expertise in Node.js and TypeScript.
• Proven track record in fintech, SaaS billing, or accounting systems.
• Strong problem-solving skills and the ability to deliver clean, maintainable, and efficient code.
• Solid understanding of computational models, applied mathematics, and algorithms in financial or large-scale data processing contexts.
• Hands-on experience with PostgreSQL, including query optimization and transactional correctness.
• Experience with event-driven and asynchronous processing architectures, such as Kafka, RabbitMQ, or AWS SQS.
• Proficiency in AWS cloud services, including serverless, messaging, compute, and storage.
• Excellent collaboration and communication skills for cross-functional teamwork.
• Familiarity with financial compliance standards, such as IFRS, GAAP, and SOX, is a strong plus.
• Prior experience with high-throughput, mission-critical transaction systems is a strong plus.

We offer a competitive compensation and benefits package, as well as the opportunity to shape and scale the critical infrastructure that powers a fast-growing SaaS platform trusted by leading enterprises.

Keylight is an equal opportunities employer and welcomes applications from all qualified candidates.