Founding Engineer (Full Stack / Backend)

At Affinity Labs, we’re building the future of company creation, a full-stack AI venture studio that partners with content creators to co-found authentic, scalable software businesses. By combining AI-native development with creator-led distribution, we are pioneering a new model of monetisation to rapidly build, launch, and scale digital ventures aligned with creators and their audiences. We aim to launch ventures 10x faster and cheaper than traditional methods using our internal "AI factory": a multi-agent architecture, reusable component libraries, and a growing knowledge graph that learns from every product we ship.

Why Affinity Labs: Ship at rapid pace with AI-accelerated workflows, see your work distributed to thousands of users at launch, and compound impact across multiple products, not just one.

Role Description: You’ll lead end-to-end backend development across our products: scoping services, designing data models and APIs, building, testing, shipping, and iterating in tight cycles. This is an early-stage, hands-on role with significant autonomy and responsibility to drive backend product development, collaborating closely with founders, creators, and product/design to turn lean specs into reliable, scalable services.

Responsibilities:

• Implement features end-to-end on the backend (APIs → data models → integrations) and maintain quality while moving fast.
• Run tight build, test, iterate, ship loops; provide realistic estimates and surface blockers early.
• Manage tech debt pragmatically; record key decisions as lightweight ADRs/notes in the tooling.
• Participate in daily standups and weekly planning, contribute to technical strategy & execute from Linear tickets.
• Contribute to architecture and product discussions; be heard in debate, align to unified decisions.
• Own operability: set up and maintain CI/CD, monitoring/alerting, performance & error budgets, and safe rollback paths.
• Build and integrate AI features (LLM/agent workflows, RAG/vector DB integration, eval hooks, cost/safety guardrails).

Essential Requirements:

• 3-6+ years building production backends/services, with shipped work and clear ownership.
• Strong Python (FastAPI) and database skills (PostgreSQL/MongoDB); solid API design fundamentals.
• Familiarity with AWS serverless patterns and Docker for bespoke services; basic CI/CD concepts.
• Comfortable with Redis (caching/sessions) and common queue/messaging patterns.
• Startup mindset: high ownership, pace, ambiguity; willing to burn the midnight oil when needed.
• Growth mindset & flexibility: open to feedback; not rigid about stack/tools.
• Clear communicator & collaborator; lean on your experience to guide product decisions.
• Evidence of shipping quickly in small teams (links to repos, case studies, or live services).

Desired:

• Node.js alongside Python for services or integrations.
• Experience with vector databases (e.g., Chroma) and embedding pipelines.
• LangChain or CrewAI for orchestration; MCP servers for integrations.
• Security hygiene (secrets, permissions, least-privilege) and practical data-privacy basics.
• Planning & execution in Linear (or similar).

Tools & Stack:

• Backend/Runtime: Python (FastAPI), Node.js.
• Datastores: PostgreSQL, MongoDB (as appropriate), Redis (caching/sessions).
• Vectors/Embeddings: Chroma (or similar).
• AI Models & APIs: Claude (Anthropic), Gemini (Google); Amazon Nova Canvas (vision), Deepgram (audio).
• AI Dev Tools: LangChain or CrewAI (orchestration), MCP servers (integration), GitHub Copilot / Claude Code.
• Infrastructure: AWS (serverless functions), Docker (primarily for custom MCPs).
• Frontend (when needed): React/Next.js (for dashboards/admins, used selectively).

Competencies & Behaviours:

• Communicates clearly with technical and non-technical teammates.
• Takes ownership from concept to deploy and through maintenance.
• Balances technical excellence with pragmatic delivery to meet business needs.
• Adapts quickly to changing requirements and emerging tech; applies AI learnings.
• Sets clear goals, tracks progress, and hits commitments; collaborates across disciplines.

Why this role is a career launchpad:

• Own the code & the company. You step in as a Founding Engineer with a meaningful equity stake from day one.
• Ship faster with AI at your side. Our workflow bakes in AI so you spend your time solving real problems—not boilerplate.
• Ride a rocket. Our wider vision is big and the bar is high; we need driven people who can help us achieve an ambitious roadmap.
• Grow like crazy. You’ll architect, build, and launch multiple products each year. The shipping reps you’ll get in 12 months here would take 3–4 years in a typical startup.
• There’s a lot of work, it’s high intensity, and the expectation is to ship extremely quickly.
• Learn from builders, not bosses. Work shoulder-to-shoulder with a team that has scaled VC-backed startups, closed multi-million-pound term sheets, and collaborated with 1,000+ creators across formats and categories.