Senior Full-Stack Engineer (Backend-Leaning) | Fully Remote (UK hours) | Full-time

The Sales Centre co

2d • Remote

About The Position

The Senior Full-Stack Engineer will be the company’s first engineer and technical lead, owning how its new platform is built, including architecture, data modeling, security, payments, background jobs, integrations, and production readiness. The company is rebuilding its UK B2B SaaS product for property-investment businesses from a white-labelled GoHighLevel setup into its own platform. Planned capabilities include property search, deal management, portfolio tracking, financial calculators, Claude-powered AI features, and Stripe billing.

A key initial milestone is launching the new platform and migrating around 60 paying customers from GoHighLevel without losing data, including a two-week parallel run. The engineer will work with the product founder, who builds with Claude Code, guiding briefs, identifying risks, and coordinating work so contributions do not conflict. A part-time QA analyst tests each release.

The first 90 days include learning the code and build plan and shipping a small fix in weeks 1–2; becoming the reviewer for all releases and taking ownership of security and data protection during month 1; and leading the launch and customer migration during months 2–3. The role also includes documenting the platform and helping hire and lead the next engineer.

Requirements

• At least 5 years of professional software engineering experience, including at least 2 years building and running a multi-tenant SaaS product in production.
• Strong experience with strict TypeScript, React 19, and the Next.js App Router, including Server Components, Server Actions, streaming, and caching in Next.js 15/16.
• Strong Postgres skills beyond the ORM, including schema design, migrations, indexing, query performance, and row-level security.
• Production experience with Stripe, including subscriptions, webhooks, idempotency, and usage- or credit-based billing.
• Experience with background jobs and queues such as Inngest, Trigger.dev, BullMQ, or similar.
• Experience with automated testing as a release gate, CI, and Vercel preview deployments.
• Production ownership experience with Sentry or a similar tool.
• Daily, disciplined use of agentic AI coding tools, preferably Claude Code; Cursor or Codex are also acceptable. The workflow should include small pull requests, tests before merging, and reviewing diffs.
• Experience reviewing others’ code as a gate to production and mentoring less experienced builders.
• Able to work independently as the only engineer, take initiative, explain technical risks in plain English with options and a recommendation, speak up when something goes wrong, and ship small changes often.

Nice To Haves

• Supabase experience.
• Experience building features using LLM APIs such as Anthropic or OpenAI.
• Experience migrating customers and data between platforms.
• Experience working with large external datasets and third-party data APIs.
• Knowledge of multi-tenant security fundamentals, OWASP Top 10, secrets management, audit logging, and UK GDPR.
• Experience with GoHighLevel, Resend, MapLibre, SEO, and Core Web Vitals.

Responsibilities

• Own technical direction, including architecture, data model, security, testing, and code review.
• Review and approve everything that ships; the product founder signs off on visual changes.
• Set up the test framework using Vitest, Playwright, and GitHub Actions as a merge gate.
• Build platform foundations including Postgres with row-level security, authentication, Stripe billing, background jobs, transactional email, and third-party integrations.
• Lead the platform launch and customer migration, including a two-week parallel run.
• Own production operations, including error tracking, logging, alerts, incident response, performance, and cost control.
• Guide the product founder’s development work, shape briefs, identify risks early, and coordinate work to avoid conflicts.
• Document the platform and help hire and lead the next engineer.

What This Job Offers

• Job Type: Full-time
• Career Level: Senior
• Education Level: No Education Listed