Senior Backend Engineer - London

Department: Engineering

Location: London

Compensation: £100K – £120K • Offers Equity

Employment Type: FullTime

👶 About Junior

We’re building cutting-edge LLM-powered workflow tools to supercharge investment research for private market investors. Our clients include most of the global top 10 private equity and consulting firms - Junior already powers hundreds of billions of dollars invested annually. We’re a profitable, bootstrapped company with a growing team of 30+ based in London, NYC and Sydney. We 10x’d our revenue in 2025.

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

💡 Role Description

You’ll design and build the systems that support our you’ll help build and scale the systems that power our AI-driven research platform along with our commercial, product, and operations teams — automating workflows, improving decision-making, and enabling the company to move significantly faster.

This is a high-ownership backend engineering role (~4+ years experience) where you’ll work across data pipelines, integrations, automation, and internal infrastructure.

You’ll have the opportunity to:

• 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 the architecture of internal data systems and pipelines

• Build automation and integrations across product, CRM, and financial systems

• Help shape engineering culture and internal infrastructure decisions

🔧 Example Projects You’ll Work On:

Customer Health Intelligence System

• Design data pipelines that consolidate product usage, CRM data, and user feedback into a unified system of record.

• Build automated signals and alerts that detect churn risk, usage drops, or emerging product issues - enabling the team to act quickly.

User Feedback → Product Development Pipeline

• Build internal tooling that processes feedback calls with users.

• Use LLMs to extract themes, cluster feature requests, and surface the most important insights to the product team.

Billing & Revenue Infrastructure

• Design systems to support complex B2B pricing models — combining usage-based, seat-based, and platform fees.

• Automate invoicing, reconciliation, and financial reporting.

Internal Data Platform

• Build and own our internal data platform, integrating product telemetry, CRM data, and financial systems.

• Create reliable pipelines and APIs that power reporting, automation, and decision-making across the company.

🔥 About You

We’re looking for a Backend Engineer who enjoys building systems that make a company run better.

You might be a good fit if you:

• Are based in London and excited to work from our Farringdon office (5 days/week)
• Have experience owning technical projects end-to-end, from architecture through production
• Enjoy translating business problems into clean technical systems and automation
• Like building high-leverage internal platforms that make teams dramatically more efficient
• Have strong experience with PostgreSQL and modern data platforms (Snowflake, BigQuery, Databricks, Firebolt, etc.)
• Write production code in Python, or TypeScript
• Thrive in fast-moving startup environments and enjoy shipping quickly while maintaining strong engineering standards

Bonus

Experience building AI-enabled workflows, automation systems, or internal developer platforms.

🌵 Benefits

• Private health insurance
• Gym membership (Third Space)
• Dinner when working late
• Frequent team offsites (Crete 🇬🇷, Upstate NY 🇺🇸, Cancun 🇲🇽)