Back End Developer

Maxwell Bond; Greater London; On-site; GBP 85,000 - 105,000; Full time

Job summary

Descrial is hiring Back-End Engineers in London to build the services that power our AI-enabled workflows. You will work on multi-tenant data and integration layers between our Java/Spring core and Python AI services, reporting to the Head of Engineering.

You should have 5+ years in backend SaaS, strong Python with FastAPI, PostgreSQL, and AWS experience. The team collaborates across London and Bengaluru, with a focus on CI/CD, observability, and safe failure handling in high-stakes environments.

Qualifications

• 5+ years in backend engineering for production SaaS or platform systems.
• Strong Python with FastAPI or comparable frameworks.
• Solid SQL/PostgreSQL and ability to work at Java/Spring boundaries.
• Production AWS experience and comfort with Git, CI/CD and Linux.
• Experience in multi-tenant architectures with isolation and auditability.

Responsibilities

• Design REST and asynchronous services in Python 3.11+ and FastAPI, working at Java/Spring boundaries with PostgreSQL and async SQLAlchemy.
• Implement tenant isolation, context, role-based access and configuration.
• Maintain unit and integration tests, observability and safe failure behaviour for outputs that may be well-formed yet wrong.

Skills

Python

FastAPI

PostgreSQL

Java/Spring

AWS

CI/CD

Git

Linux

AI coding tools

Multi-tenant

Education

Engineering/CS degree

Tools

Kubernetes

Jenkins

OpenTelemetry

SQLAlchemy

EKS/ECS

CI/CD pipelines

Job description

Back End Developer

London – Kings Cross

£85,000 - £105,000

We're hiring Back-End Engineers to build the services Descrial runs on. Investment professionals need APIs and workflows that respect permissions, keep an audit trail and fail safely when an AI result can't be trusted.

You’ll build multi-tenant data and workflow services, plus the integration layer between our Java/Spring core and our Python AI services. This role is part of a nine-person engineering cohort being hired across front-end and back-end.

About Descrial

Descrial is a startup inside a twenty-year-old company

TresVista has run the analytical work behind private capital since 2006. 2,000 people, 400+ clients including some of the biggest names in the industry, no outside capital and no outside board. That was the first chapter. And we enjoyed getting here!

The next chapter is harder and more interesting

We are moving from services to software, from one firm's workflows to an industry's, and from executing investment decisions to shaping how they get made. Thirty of us in King's Cross, small and senior, with day one founder intensity. At its fullest expression, Descrial changes how every serious investment firm decides.

The role

You report to the Head of Engineering and join the UK core team, shipping through disciplined CI/CD alongside the Bengaluru delivery organisation. The work combines service design with the production constraints of demanding enterprise users.

Your remit

The services and contracts

You design REST and asynchronous services in Python 3.11+ and FastAPI, working at Java/Spring boundaries with PostgreSQL and async SQLAlchemy persistence. You implement tenant isolation, context, role-based access and configuration. You version and evolve contracts between core and AI services without breaking consumers.

The production quality

You maintain comprehensive unit and integration tests with pytest and pytest-asyncio and uphold code review standards. OpenTelemetry traces, structured logs, metrics and actionable alerts expose model-call latency, failure rates and token cost. You build validation, schema enforcement and safe failure behaviour for outputs that may be well-formed yet wrong. Authentication, authorisation, secrets, input validation, OWASP awareness and audit trails are part of everyday engineering.

The delivery and cost

You deploy and operate on AWS using EKS/ECS patterns, RDS and S3 through Jenkins quality gates. You improve queries, caching, asynchronous throughput and right-sizing. For model-calling services, you build queueing, rate limits and orchestration that account for cost.

Your experience

• You have real multi-tenant or enterprise-system experience with isolation, permissions and auditability.
• You have 5+ years in backend engineering for production SaaS or platform systems.
• You have strong Python, using FastAPI or comparable frameworks, solid SQL/PostgreSQL and the ability to work at
• Java/Spring service boundaries.
• You have production AWS experience and are comfortable with Git, CI/CD and Linux.
• You use AI coding tools daily, such as Cursor or Claude Code, and have a considered view of where they help.
• You have a degree in engineering, computer science or a related field, or equivalent experience.

Useful to have, none required

• Java/Spring depth alongside Python
• Event-driven architecture, queues and workflow engines
• Financial services or regulated-industry systems
• LLM service integration patterns

The reality

This will be difficult.

It demands pace and accuracy. We are building autonomous systems inside high-stakes live businesses, where decisions carry real consequences and impact and waiting for everyone to agree is not always an option.

The systems will sometimes get things wrong. In this phase the London team needs to create the evaluations, visibilities and safeguards that catch mistakes early, reducing them over time and stopping the same failures happening again.

If you want to build the foundations of an enterprise grade technology platform to service a multi-billion $ serviceable market opportunity, and share in that growth, this is your chance to join us.

In our conversations

Come ready to discuss three pieces of work:

• A service or API contract you evolved without breaking its consumers.
• A tenant or permission boundary you implemented and tested.
• A production quality, reliability or cost problem you diagnosed and improved.

Compensation

• The all-inclusive package is typically £85,000–£105,000 a year, depending on experience.
• Practical details
• King's Cross, London. In office (3 to 5 days a week), with colleagues in London and Bengaluru.
• Visa sponsorship is not available for this role.
• We aim to finish the process within three weeks. Tell us if you need an adjustment to the interviews.
• Descrial is an equal opportunity employer.