Founding Backend Engineer

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

Job summary

Arrows in London is seeking an experienced Backend Engineer to own the core platform as throughput scales 100x over the next year. You’ll work directly with the CTO on architecture and alongside ML and content engineers, with clear scope to grow into technical leadership.

This is an ownership role: you’ll shape service boundaries, drive migrations from Railway to Cloudflare, manage deployments, CI/CD, observability and incident response, and own the Postgres data platform.

Qualifications

• 4+ years building and operating backend systems in production.
• Strong Python and TypeScript experience.
• Deep PostgreSQL experience, incl. migrations on live data.
• Track record building infrastructure from scratch and leading platform migrations.
• End-to-end ownership of containers, CI/CD, networking, observability and incidents.

Responsibilities

• Own service architecture: boundaries, API and data contracts, and inter-service communication.
• Lead a full migration from Railway to Cloudflare with zero production disruption.
• Oversee deployments and production health: CI/CD, environments, rollbacks, secrets, observability, feature flags.
• Manage the scheduler, queues and sandboxes for long-running, multi-step workloads.
• Develop internal APIs and the Postgres data platform, including schema design and migrations.

Skills

Python

TypeScript

Postgres

System design

Lead teams

Tools

Docker

GitHub Actions

Sentry

Cloudflare Workers

SQLAlchemy

Alembic

Job description

My client is an AI company with a small, highly technical team of ten that has just raised a £4M pre seed round to fund its next phase of growth. They’re hiring a Backend Engineer to own the core platform as throughput scales 100x over the next year.

This is a genuine ownership role. You’ll work directly with the CTO on architecture and alongside ML and content engineers, with clear scope to grow into technical leadership.

What you’ll own

• Service architecture: boundaries, API and data contracts, and how services communicate
• A full platform migration from Railway to Cloudflare, from target architecture through cutover, with zero disruption to production
• Deployments and production health: CI/CD, environments, rollbacks, secrets, observability and feature flags
• The scheduler, queues and sandboxes behind long running, multistep workloads
• Internal APIs and the Postgres data platform, including schema design, migrations and performance at scale
• The backend engineering standard: code quality, documentation and the guardrails that let the team ship fast

What my client is looking for

• 4+ years building and operating backend systems in production, with strong Python and TypeScript
• Production experience with job and workflow systems, and sound judgement on idempotency, retries, backoff and concurrency
• Deep Postgres experience, including migrations on live data and query performance
• A track record of building infrastructure from scratch, scaling it through rapid growth, and leading at least one significant platform migration
• End to end infrastructure ownership: containers, CI/CD, networking, observability and incidents
• Experience leading technical work through setting direction, reviewing designs and mentoring

Nice to have

• Cloudflare in production (Workers, Queues, Workflows, Durable Objects, R2)
• Event driven systems, outbox patterns and webhooks
• Founding or early engineer experience, or equivalent ownership in a larger company
• Stack: Python (FastAPI, SQLAlchemy, Alembic), TypeScript, Postgres, Docker, GitHub Actions, Sentry, LLM APIs.