Full-Stack Product Engineer (AI)

Mbnsolutions; Greater London; On-site; GBP 90,000 - 130,000; Full time

Job summary

MBN is partnering with an early-stage, founder-led company to hire a full-stack product engineer who has shipped AI-powered features to real customers.

This is a true ownership role where you’ll own product areas end to end, from understanding the customer problem to releasing features and iterating after deployment.

Qualifications

• 5+ years of professional software engineering or evidence of independently building and owning substantial production products.
• Experience shipping AI features to customers, including prompt design and multi-step orchestration.
• Ability to work directly with founders and customers with ownership over product areas.

Responsibilities

• Own product development from discovery through design, build and release across frontend, backend and data integrations.
• Design AI-native workflows, deciding model/data/software/human review fit and when simpler deterministic approaches suffice.
• Make outputs traceable to sources and clearly communicate limitations of model-generated estimates.
• Define success criteria, build evaluations against realistic cases, and ship maintainable software with tests and monitoring.
• Break work into milestones, provide estimates, flag blockers early and iterate on customer feedback.

Skills

TypeScript

React

Python

Node.js

SQL

PostgreSQL

LLM features

Critical thinking

Tools

Git

CI/CD

Docker

Cloud deployment

Job description

MBN is partnering with an early-stage, founder-led company looking for a full-stack product engineer who has shipped AI-powered features to real customers.

This is a true ownership role. You’ll take product areas end to end: understand the customer problem, define the approach, build across the stack, evaluate the results and keep improving after release. You’ll work directly with the founders and customers, with real influence over what gets built and how.

What you’ll be doing:

• Owning product development from discovery through design, build and release, covering frontend, backend and data integrations
• Designing AI-native workflows: deciding where models, data, conventional software and human review fit, and when a simpler deterministic approach is the better answer
• Making outputs traceable to their sources, separating observed data from model-generated estimates and communicating limitations clearly
• Defining what good looks like, building evaluations against realistic cases, and shipping maintainable software with solid testing, monitoring and failure handling
• Breaking work into milestones, giving realistic estimates, flagging blockers early and iterating based on customer feedback

What we’re looking for:

• 5+ years of professional software engineering, or clear evidence of independently building and owning substantial production products
• Strong TypeScript and React
• Python or Node.js backend experience: APIs, business logic, external integrations, background jobs
• Strong SQL and PostgreSQL: schema design, data transformation, tracing data-quality issues
• Hands-on experience shipping LLM features to customers, including prompt design, structured outputs, tool calling and multi-step orchestration
• Experience with AI evaluation: building test datasets, handling inconsistent outputs, and implementing validation, retries and fallbacks with a good grasp of quality/latency/cost trade-offs
• Production engineering: Git, automated testing, CI/CD, Docker, cloud deployment, logging, monitoring and access controls
• Strong critical thinking. You use AI confidently but question its output and take responsibility for what you ship

Nice to have:

• Founder, founding engineer or early-stage startup experience
• Analytics products, data visualisation or recommendation systems
• Experimentation and statistical reasoning, including correlation vs causation
• Subscription businesses: pricing, conversion or retention
• RAG, embeddings or agent orchestration used to solve real product problems

Please note: we’re looking for people who have delivered and maintained AI features in production.