Senior Full Stack Engineer (Backend-Heavy)

Who we are

We build and run cold-email sending infrastructure as a product — Microsoft 365 and Google Workspace tenants, domains, DNS, mailboxes, and deliverability.

A customer orders 100 tenants and 10,000 mailboxes and expects them to appear, working.

We are a small, fully remote team with live customers and real revenue. You would be our senior engineering hire, working directly with the founder.

What we're looking for

• A senior engineer who has run a production SaaS system, not only built features inside one

• Someone who has been the only backend engineer somewhere — the person called when it broke at night

• Strength in catching silent failures: an order marked complete before the work actually
happened, while the dashboard looks healthy for two days. Queues, transactions, migrations.

• Comfortable owning the backend and shipping the Next.js admin and customer interfaces on top of it — roughly 70/30 backend to frontend

• Works fluently with AI tooling and reviews its output critically

Requirements

• 4–6 years of backend experience, with genuine ownership of a production system

• TypeScript and Node.js in depth — not JavaScript with type annotations

• PostgreSQL at depth — transactions, row locking, indexing, and migrating a schema under live traffic. Managed-database experience alone is not enough.

• Redis and BullMQ, or equivalent job queues — retries, idempotency, dead-letter handling, and what happens when the same job runs twice.

Long-running workers rather than serverless; if your recent experience is primarily Lambda and API Gateway, it will not map cleanly to this stack.

• Production browser automation — Puppeteer, Playwright or Selenium against real third-party portals. Not scraping: authenticated, multi-step flows including MFA, which have to be idempotent and safe to re-run.

This is core infrastructure for us, not a side concern — when it breaks, provisioning stops.

• Express (or NestJS — the concepts transfer)

• Next.js and React — able to build and ship a working admin screen end to end, unassisted

• Prisma, or any ORM you know well enough to reason about the SQL it generates

• REST API design — authentication, idempotency keys, rate limiting, versioning

• Docker, and comfort working in Linux and the command line

Our stack runs on Railway and Vercel.

Nice to have

• Microsoft Graph, Google Workspace Admin SDK, or similar vendor API integration at scale

• Email infrastructure — SPF, DKIM, DMARC, and deliverability

• Stripe or subscription billing

• Experience migrating a live system between codebases with users on it

Likely not a fit: consultancy or service-company backgrounds built on a series of short client projects, or engineers who have only worked inside a framework someone else set up.

Hiring process

We keep this short and respect your time. Nothing unpaid takes more than 30 minutes.

1. Apply — CV
2. Short Loom video — if we're interested, we'll send three questions that you can answer in a quick loom video
3. Introductory call — 20 to 30 minutes with the founder
4. Technical interview — with a senior engineer
5. Paid trial — real work, paid at your rate, on our development environment