Senior Full-Stack Engineer

Plan:it; Greater London; Hybrid; GBP 117,000 - 143,000; Full time

Benefits offered by this job

Equity

30 days holiday

London hybrid

Job summary

Plan:it is seeking a senior full-stack engineer to join as engineer #4 in a London-based startup with hybrid work (3–4 days in the office). You will own features end-to-end, work across the stack, and raise the quality bar with autonomy in a fast-paced environment built on AI-native product foundations.

You will touch UI, API, and database layers, use AI tooling daily, and contribute to agentic systems with real ownership and impact. Equity is included alongside a strong base salary.

Qualifications

• Senior full-stack engineer with ownership and autonomy.
• 6+ years of professional software engineering experience.
• Comfort across UI, API, and database layers.
• Experience with AI tooling, agents, or similar.
• Hands-on experience with agentic systems or LLM-powered features is a plus.

Responsibilities

• Build features end-to-end across the stack.
• Spot and fix rough edges before users notice.
• Build directly on top of agentic systems.
• Use AI tooling daily to plan, write, review, and ship code faster.

Skills

Full-stack engineering

TypeScript

React

AWS

GCP

AI tooling daily

Agentic systems

Tools

AI tooling

Job description

London / hybrid, 3–4 days per week in the office

This is a rare opportunity. Chance to join an early-stage startup as engineer #4. Autonomy, responsibility and working with cutting edge AI.

Company

A well-funded, early-stage startup building a genuinely AI-native product. AI at the core, with agentic systems already running in production. Small team, high standards, and an awesome team culture.

The Role

This is a senior full-stack engineering role for someone who thinks in systems, not just tickets. You'll build features end-to-end, maintain what you ship, and raise the quality bar across the codebase. The team is small, so you'll touch most parts of the stack most weeks - and you'll be expected to operate with minimal oversight.

Key responsibilities

• Build features end-to-end
• Spot and fix rough edges before users do
• Build directly on top of agentic systems
• Use AI tooling daily to plan, write, review, and ship code faster

Stack

TypeScript, React, AWS, GCP. Agentic systems and LLM-powered features already in production.

You'll be a good fit if you…

• Early-stage or startup experience is a must!
• Have 6+ years of professional software engineering experience - ideally with real ownership
• Are genuinely comfortable across the full stack - UI, API, and database
• Already use AI tooling daily - coding assistants, agents, or similar. This is a must
• Have hands-on experience with agentic systems or LLM-powered features in production (nice to have)
• Are high agency you find work that needs doing and do it

The Package

• Up to £130k base (DoE) + equity
• 30 days holiday
• London - hybrid, 3–4 days per week in the office

Interview Process

• On-site final and meet the team