Senior Backend Engineer

👶 About Junior

We're building cutting-edge LLM-powered tools that supercharge investment research for the world's most demanding deal teams. Our clients include several of the top 10 global private equity firms, Big 4 professional services firms, and leading consulting practices: organisations responsible for deploying billions of dollars annually.

We're a profitable, bootstrapped company with a growing team of ~43 people based in London and New York. We 10x'd our revenue in 2025 and are on track to grow 2-3x again this year. Junior saves clients an average of 10 hours per week, and we're expanding fast into new verticals including investment banking, hedge funds, and research firms.

You can read more about the company mission & values here.

💡 Role Description

As a Backend Engineer, you’ll help build and scale the systems that power our AI-driven research platform. This is a systems-level role - ideal for engineers who love thinking about data flows, orchestration, and performance across complex distributed systems.

You'll have the unique opportunity to:

• Ship quickly

• Architect and scale backend systems that support high-throughput LLM interactions, vector search, and multi-agent orchestration.

• Stitch together AI infrastructure across model providers, data stores, and internal APIs to create cohesive, performant systems.

• Own reliability and observability, helping us evolve our database (Postgres / ClickHouse) and job orchestration systems.

• Prototype new backend capabilities (retrieval pipelines, caching layers, async task queues) that let us build faster and smarter.

• Shape our engineering culture

🔥 About You

We're looking for product-minded backend engineers who:

• Are based in NYC and excited to work 5 days a week in person

• Are excited by the intersection of AI infrastructure, financial systems, and backend engineering

• Have experience owning backend projects end-to-end — from architecture through to production

• Are strong in Python and TypeScript

• Have worked with PostgreSQL and care about data modelling, reliability, and system design

• Are comfortable building APIs, internal tools, workflows, and infrastructure that support real customers

• Are eager to contribute to product decisions, not just execute tickets

• Feel like you are never building fast enough

Bonus points for experience working on:

• Billing, payments, usage-based pricing, or financial workflows

• Internal infrastructure / dev tools at startups

• Data pipelines, workflow orchestration, or event-driven systems

• Retrieval, embeddings, or prompt orchestration

🌵 Benefits

All the usual benefits (competitive pay and equity, private healthcare etc). Unusual benefits:

• Gym membership

• In-office cook

• Summers working in Greece by the beach

📩 How to Apply

If you're excited about the opportunity to drive innovation at Junior, we'd love to hear from you! Email us at [email protected] with your resume and a brief introduction. We can't wait to meet you! 🙌