Senior Full-Stack Engineer

- About BaseOne
BaseOne is a data and AI-driven solutions company based in London, United Kingdom. We build design-led, data-driven products — from enterprise analytics platforms and AI automation tools to consumer-facing health and fitness apps.

Our product portfolio includes:
AI-powered consumer platforms — subscription apps combining personalised AI experiences with commerce

B2B SaaS products — coaching and client management tools for professionals

Enterprise data & analytics — dashboards, data integration, and predictive analytics for large organisations

AI & automation — conversational AI, agentic workflows, and intelligent process automation

Primer Accelerator — our pre-built data platform for PMO and project controls

We're a small, high-output team that blends strategy, design, and engineering in-house. We ship real products, not decks.

- The Role
We're looking for a senior full-stack engineer to work across multiple products and codebases. You'll ship features end-to-end — web, mobile, API, database, AI integrations — and move between projects as priorities shift.

You'll work directly with our founder, own meaningful chunks of each product, and have real influence over technical decisions.

AI-assisted development (Claude Code, agentic workflows) is a core part of how we build.

This is a hands-on, high-autonomy role. You'll need to context-switch, pick things up fast, and deliver without hand-holding.

- What You'll Work On
Consumer app features — AI-powered personalisation, content generation, tracking, social/gamification

SaaS platform — dashboards, client management, plan assignment, messaging, check-ins

AI integrations — LLM-powered features, prompt engineering, streaming, function calling (OpenAI + Anthropic)

Commerce & affiliate systems — product catalogues, recommendations, click tracking

Data & analytics products — dashboards, data visualisation, real-time reporting

Mobile apps — React Native / Expo with web feature parity

Platform quality — accessibility, security, compliance, performance

The mix will shift depending on what's shipping. Flexibility matters more than specialism.

- Tech Stack
Frontend: Next.js, React, React Native (Expo), TailwindCSS

Backend: Node.js, PostgreSQL, Supabase, REST APIs

AI: OpenAI + Anthropic (Claude)

Payments: Stripe, RevenueCat

Infrastructure: Turborepo monorepos, Railway, EAS Build

Language: TypeScript throughout

Testing: Vitest, Playwright

Analytics: PostHog, custom dashboards

- What We're Looking For
Must Have;
5+ years building production web apps with React and TypeScript

Strong Next.js experience (App Router, API routes, SSR)

Comfortable with PostgreSQL — migrations, schema design, query optimisation

Experience integrating AI/LLM APIs (OpenAI, Anthropic, or similar)

Solid API design skills — auth, validation, error handling, rate limiting

Testing discipline — unit, integration, E2E

Comfortable context-switching across multiple products

Can work autonomously with clear scope and minimal oversight

- Nice to Have
React Native / Expo experience

Supabase or similar BaaS

AI-assisted development workflows (Claude Code, Cursor, Copilot)

Data visualisation / dashboard experience (D3, Recharts, Power BI embeds)

SaaS subscription patterns (tiering, feature gating, billing)

Wearable / IoT integrations

WCAG 2.1 AA accessibility

UK GDPR / data compliance awareness

- How We Work
Small team, high trust, fast shipping

AI-augmented development — agentic tooling built into the workflow

Architecture-first — we agree on contracts before coding

Monorepo patterns with shared types and design tokens

Quality gates on every piece of work — build, lint, type-check, tests

Phase-based delivery with clear scope docs

- What You'll Get
Direct collaboration with the founder — short feedback loops, real influence

Variety — multiple products, not the same CRUD app forever

AI tooling that genuinely accelerates your output

Well-documented, well-architected codebases

Ownership of meaningful features across the portfolio

- Working Arrangement
Fully remote

Part-time to start

Opportunity to move to full-time

- To Apply
Send us:
Your CV or portfolio

A brief note on why this interests you

Links to relevant shipped products

Your availability and rate/salary expectations

Contact: ----------

We look forward to hearing from you