Senior Backend Engineer - London

junior· Engineering
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📍 LondonFullTime💰 GBP 100K–120K/yr

About this role

👶 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 🇲🇽)

Frequently Asked Questions

What is the salary for the Senior Backend Engineer - London role at junior?
The listed salary for this Senior Backend Engineer - London position at junior is GBP 100K–120K/yr. This is an FullTime role.
Where is the Senior Backend Engineer - London position at junior located?
This Senior Backend Engineer - London role at junior is based in London. The position is listed as on-site or hybrid. Check the full job description or apply directly to confirm the work arrangement.
Is the Senior Backend Engineer - London role at junior full-time or part-time?
This is listed as a FullTime position. It is posted as a Senior Backend Engineer - London role in the Engineering department at junior.
Which team or department does the Senior Backend Engineer - London at junior belong to?
This Senior Backend Engineer - London position is part of the Engineering department at junior. See the full job description for more information about the team structure and responsibilities.
How do I apply for the Senior Backend Engineer - London position at junior?
Click the "Apply Now" button on this page. You will be redirected to junior's official application portal hosted on ashby where you can submit your application directly.
When was the Senior Backend Engineer - London job at junior posted?
This Senior Backend Engineer - London position at junior was posted on Jan 21, 2026. Apply as soon as possible — early applications are often reviewed first.
Senior Backend Engineer - London
junior · 💰 GBP 100K–120K/yr
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