Integration Engineer

About Light: Light is a premier, internationally recognized financial technology pioneer, enterprise SaaS innovator, and digital workplace accelerator on an absolute mission to replace factory-era, rigid ERP systems with software that feels alive. Our state-of-the-art Smart Financial Platform equips modern, global enterprises with financial superpowers—including fully automated multi-currency accounting, real-time reporting dashboards, and frictionless capital flows that move at the exact speed of business operations. In a short time, Light has evolved from a conceptual milestone into the mission-critical operating core for leading companies like Lovable, Legora, and Keyshot. Backed by world-class global venture capital firms and advised by industry-leading fintech titans, our team unites engineers who love debits and credits, designers who obsess over reconciliation states, and operators who treat corporate finance as a high-fidelity product. Light provides high-agency backend developers with an uncompromised remote canvas to leverage modern cloud microservices, manipulate corporate banking APIs, and deploy category-defining financial products safely worldwide.

Position Overview

We are seeking a highly analytical, systems-minded Integration Engineer to join our core centralized Tech collective in a full-time remote or hybrid capacity based out of Copenhagen, Denmark. At Light, our platform is only as powerful as the external ecosystems it securely interfaces with; money flows because we seamlessly speak the exact digital language of clearing networks, banking mainframes, and regulatory reporting ledgers. In this high-leverage and backend-heavy individual contributor (IC) role, you will step up to claim individual strategic operational accountability for the design, implementation, and execution of our core integration surface. Moving completely past passive script writing, routine API wrapping, or minor web updates, you will act as a principal pipeline architect—translating complex, incompatible external partner data formats into one coherent internal model. This position requires an engineering veteran with 4+ years of professional full-stack history who programs server-side banking microservices fluidly natively using Backend primitives (specifically Kotlin on AWS), verifies client-facing parity smoothly natively using React, and enforces strict, zero-fault data reconciliation layers confidently.

Key Responsibilities

• Corporate Banking API Connectivity Architecture: Design, develop, and operate high-performance backend pipelines that interface directly with global corporate banking and treasury APIs—managing payment initiation, automated FX loops, and status logging cleanly natively utilizing Backend frameworks (Kotlin on AWS stacks).
• Advanced Authentication and Format Triage: Handle and secure complex bank integration protocols, configuring certificate-based authentication infrastructure, mutual TLS (mTLS) pipelines, advanced OAuth flows, and message mappings across ISO 20022 formats (pain/pacs/camt data blocks) and legacy MT systems.
• Multi-Tenancy Isolation Engineering: Architect high-fidelity multi-tenant integration layers where credentials, database schemas, and data structures are rigidly isolated per entity, ensuring that onboarding new multinational business subsidiaries is an automated workflow rather than a manual code adjustment.
• Global E-Invoicing Clearance Management: Connect Light to prominent global e-invoicing networks and country-specific tax mandates (including Peppol systems and emerging national clearance frameworks), mapping data schemas to keep transactional histories fully auditable.
• Resilient System Fault Defense: Engineer robust error-handling, idempotency tokens, programmatic retries, webhook strategies, and dead-letter queue (DLQ) processing frameworks to safeguard Light against partner APIs that fail silently or incorrectly return 200 OK statuses containing error payloads.
• End-to-End Financial Reconciliation Governance: Enforce rigid data integrity rules so that virtual ledger expectations and real-world physical bank statements remain perfectly synced, ensuring zero dropped messages or silent mismatches.
• AI-Powered Workflow Upscaling: Maintain an AI-forward development mindset, efficiently leveraging advanced generative coding tools inside your everyday IDE workflows to accelerate software delivery while remaining fully responsible for code audits and structural safety.
• Agile Cross-Functional Micro-Shipping: Collaborate closely with distributed product managers, designers, and operators within an Agile framework, prioritizing small-batch production deployments, fast testing, and continuous system iteration.

Required Skills & Qualifications

• A minimum of 4 years of verified professional history running advanced backend software engineering, distributed systems development, core financial API architecture design, database optimization, or technology product consulting.
• Demonstrated history shipping real, robust software products into live production settings for actual user cohorts (prototypes or basic boot-camp exercises will not be considered).
• Deep, authoritative technical command of object-oriented server languages, multi-tenant database partitioning, data-plane security patterns, network concurrency, and system tracing methods.
• Expert-tier capability writing clean, high-throughput backend services, mapping data schemas, and building RESTful or web-service connections natively utilizing Backend toolsets (specifically requiring strong Kotlin, Java, or similar JVM-based programming mastery).
• Practical operational familiarity configuring distributed web components, tracking state parameters, and integrating user views natively using frontend systems (specifically utilizing React methodologies).
• Mandatory Field Sourcing Experience: Proven, hands-on history integrating software architectures against corporate banking platforms, treasury applications, open banking arrays, SWIFT hubs, or payments networks (specifically valuing direct experience with platforms like J.P. Morgan Payments or HSBC developer consoles).
• Outstanding written and verbal communication traits in fluent English, enabling uncompromised clarity and seamless collaboration when detailing technical approaches before international distributed teams.
• Location Context: Position open exclusively to qualified integration developers based permanently and resident within **Copenhagen, Denmark** to operate under a remote or flexible hybrid-office model.

Preferred Strategic Indicators (Nice to Have)

• Prior commercial backend software engineering history operating explicitly within a hyper-growth venture-backed fintech startup, automated accounting SaaS, or global invoice factoring network.
• Direct hands-on experience managing infrastructure as code maps within Terraform or scaling serverless microservices inside Amazon Web Services (AWS).
• Strong conceptual familiarity with foundational accounting terms, including tracking debits, credits, multi-tiered ledger journals, and automated reconciliation states.
• An outcome-driven personal philosophy rooted in an intense passion for data craftsmanship, an aversion to brittle or fragile integration flows, and a relentless drive to ship code early and often.

What We Offer

• Market-Competitive Danish Salaried Blueprint: An attractive full-time base compensation package calibrated precisely to evaluate your backend integration authority, Kotlin craftsmanship, and financial data validation velocity, supplemented by corporate stock option opportunities.
• The exceptional professional canvas to join an early-stage category-defining startup with the complete creative freedom to ship ambitiously and own high-stakes global financial outcomes.
• Profound work-from-home remote parameters offering an elite virtual or hybrid layout out of Copenhagen, complete scheduling trust, and zero rigid corporate red tape.
• Access to elite lifestyle calibration benefits, providing 25 days of annual leave allowance plus localized public holidays based on your residence, regular corporate team socials, and global company off-site weeks.