Principal Backend Engineer

Heron processes millions of sensitive financial documents for some of the fastest-growing MCA Funders, Brokers, Insurers, and Fintechs in the US and UK. We’re at a point where the volume, velocity, and complexity of the data flowing through our systems are outgrowing the way they were originally built. We need someone who’s done this before: taken a platform that works and made it scale.

The Challenge

We’ve built a document automation and workflow orchestration platform that lenders, funders and fintechs rely on to make real decisions. It’s working, customers love it, and we’re onboarding new ones faster than ever. Our backend was built for speed‑to‑market, and now we need to make it built for scale.

• Abstractions that let us move fast: backend systems and patterns that let a 15‑person engineering team ship product confidently without breaking things for existing customers.
• Multi‑tenancy at scale: dozens of enterprise customers sharing the same cloud infrastructure, each with different data‑sensitivity requirements, SLAs, and integration patterns.
• Data volume and velocity: high‑throughput processing of financial documents (bank statements, tax returns, pay stubs) with ML pipelines that need to be fast, accurate, and reliable.
• Security and compliance: sensitive financial data handled to exacting standards.

What You’ll Own

This is a hands‑on, high‑autonomy IC role. You’ll work directly with our CTO and Head of Engineering, and you’ll have real ownership over the systems that matter most.

• Assess our current backend architecture and identify the highest‑leverage areas for improvement around reliability, scalability, and security.
• Partner with the platform and infrastructure team to design and implement core abstractions (data model, data pipeline reliability, deployment patterns) that will support our next phase of growth.
• Set the technical direction for scaling our infrastructure from handling hundreds of customers to thousands, and from millions of documents to tens of millions.
• Raise the bar on backend engineering practices across the team: building systems that make the right thing the easy thing.

Who Thrives Here

The best person for this role has likely spent 8+ years building and scaling backend systems, with at least a couple of meaningful "at‑bats" taking a system from early stage to serious scale. You’ve probably worked in B2B SaaS and have opinions (earned the hard way) about how to build systems that are both reliable and fast to develop on.

• Strong CS foundation and deeply technical. Write code, review architectures, and debug production issues.
• Experience scaling backend systems at Series A to Series C+ companies (approximately £5M to £100M+ ARR).
• Know what breaks and when.
• Recent production experience with Python and cloud infrastructure.
• Dealt with sensitive data at volume: financial, health, or similarly regulated domains.
• IC at heart: set direction and mentor others, but want to build, not manage.
• Pragmatic: care about getting things right but also about shipping.

What You Can Expect As a Heron

• Competitive compensation, including equity.
• Based full‑time in London or NYC, where most of the team is in‑person multiple days per week.
• Your choice of top‑of‑the‑line equipment to fit out your desk in the office.
• Occasional travel for retreats and to work with the team.
• Competitive benefits: health insurance; pension/401k; uncapped annual leave; parental leave.
• Free mental health support via Spill – on‑demand access to therapy.
• Weekly company lunches (always inclusive and vegan‑friendly). If you like Korean or Vietnamese food we’ll serve it.
• Applicants from any background and gender are welcome and we have a zero‑tolerance policy on discrimination.

Compensation Range: £190K – £270K