Senior Backend Engineer

Ersilia; Greater London; Ibrido; GBP 110.000 - 150.000; Tempo pieno

Vantaggi offerti da questo lavoro

Equity participation (ESOP)

Descrizione del lavoro

Ersilia is seeking a Senior Backend Engineer to build production-grade Python services (FastAPI) powering AI features used by professional investors. You will own critical APIs, design scalable data flows, and contribute to the real-time data platform in a small, technically ambitious team.

You will work with PostgreSQL and ClickHouse, mentor teammates, and influence architecture. Based in Europe, stay hands-on, ship features sprint to sprint, and help shape what gets built next with the

Competenze

• 5 to 15 years of backend engineering experience in production environments.
• Proven ownership of APIs or services used by real customers.
• Startup/scaleup experience in smaller teams (~30–100 people).
• Hands-on experience shipping AI/LLM features to production (agentic workflows, RAG, tooling).
• Strong SQL with PostgreSQL or equivalent.
• Hands-on coding preference over management.
• Based in Europe; London-based candidates should be able to work from the office five days a week.

Mansioni

• Build and ship production backend services and APIs in Python (FastAPI).
• Design and own the orchestration layer for agentic AI capabilities.
• Work with PostgreSQL and ClickHouse for fast, reliable data retrieval.

Conoscenze

Python

APIs

PostgreSQL

SQL

LLM features

Startup experience

Data platform

DevOps

Mentoring

Europe-based

Strumenti

ClickHouse

Redshift

Descrizione del lavoro

Senior Backend Engineer - London or England remote
London, UK · Permanent · Hybrid

Join a team small enough that what you build is what exists, and take agentic AI features from a founder's idea to something hundreds of investment firms rely on to make real capital decisions.

What you'd actually work on

• Building and shipping production backend services and APIs in Python (FastAPI) that power the platform's AI features, used daily by professional investors

• Designing and owning the orchestration layer for agentic AI capabilities: how the system plans, calls tools, and retrieves the right data at the right time

• Working directly with PostgreSQL and ClickHouse to enable fast, reliable data retrieval for AI-driven analysis at real scale

• Taking a feature from a founder's rough idea to something live in production within the same sprint, without layers of process in between

• Mentoring teammates and helping set engineering standards as the team grows from around seven engineers today to over thirty

• Making real calls on architecture and tooling rather than inheriting decisions frozen in place years ago

• Working closely enough with the founders that your technical judgment shapes what gets built next, not just how it gets built

Where it gets technically interesting

• Agentic workflows and tool use sit on top of a data platform that has to stay fast and correct under real investor usage, not a demo

• Two different database workloads in the same system: PostgreSQL for transactional data, ClickHouse for the columnar, analytics-heavy queries behind the AI insights

• AI coding tools (Cursor, Claude) are part of the actual day-to-day workflow, not a side experiment

• A genuinely small engineering team means no one else is quietly maintaining the parts you don't touch

• Retrieval and embeddings work that has to hold up against messy, high-stakes private market data rather than clean public datasets

What we're looking for

• 5 to 15 years of backend engineering experience, most of it in Python, in production environments

• A track record of building and personally owning APIs or services used by real customers, not just maintaining systems someone else designed

• Time spent at a startup or scaleup (roughly 30 to 100 people), not exclusively large corporate environments

• Hands-on experience shipping AI or LLM features to production: agentic workflows, RAG, or tool use

• Strong SQL and solid experience with PostgreSQL or an equivalent relational database

• A genuine preference for staying hands-on and coding day to day rather than moving toward management

• Based in Europe (outside France and the Nordics); if based in London, comfortable working from the office five days a week

• Bonus: experience with columnar databases (ClickHouse, Redshift, Snowflake) or general DevOps/infrastructure skills

The company

An alternative data and private market intelligence platform, giving investors real-time data and AI-driven analysis to make faster, better-informed decisions. Used by hundreds of leading VC and PE firms across Europe and beyond. Small fast-moving engineering team of around thirty people, still shaped day to day by its founders. Equity participation (ESOP) after six to nine months.

Languages: English (fluent, working language of the team)

A search run by The French Sourcer, recruitment built for technical teams.