Senior Backend Engineer

HelioAI (helioai.tech) is building a reliable AI concierge for Shopify brands, helping shoppers get accurate answers, discover products faster, and complete purchases with confidence, while reducing support workload for brands.

We're looking for a senior backend engineer to own our backend architecture end to end. You'll design the systems that power AI conversations across hundreds of Shopify storefronts, build the agent infrastructure that runs catalog, order, and policy tools at scale, and set the engineering bar for the rest of the team. You'll work directly with the founders on architecture decisions and roadmap. Real production systems, real load, real customers (Soulflower, Nysh, Ashpveda, SarinSkin, Bake, and growing).

What you'll do

Own backend architecture for Node.js + TypeScript services across AI, Shopify, and platform layers

Design and scale the agent runtime: tool registry, brand config scoping, conversation state, structured RAG, prompt caching

Build reliable Shopify infrastructure: Admin API integrations, webhook pipelines, store sync, rate limit handling, idempotency

Lead data architecture decisions across MongoDB, Postgres, Redis, and queues; own scaling, indexing, and cost

Drive observability and reliability: logging, tracing, alerting, SLOs, incident response

Build conversation to order attribution, billing, and usage metering across monthly and variable plans

Set the bar on code quality, PR review, testing, and deploy hygiene

Mentor backend interns and engineers, run design reviews, write the docs that scale the team

What you'll work on (examples)

Agent runtime powering live conversations across hundreds of Shopify storefronts

Shopify onboarding, store sync, and high throughput webhook pipelines

Tool layer for catalog fetch, order status, policies, FAQs, recommendations, escalations

Billing and usage tracking across monthly and variable plans

Conversation to order attribution infrastructure

MongoDB Atlas scaling, Redis caching strategy, BullMQ job pipelines

What we expect

5+ years building production backend systems, ideally 3+ on Node.js + TypeScript

Shipped and operated systems at meaningful scale, not just CRUD behind an LLM call

Strong on at least one of MongoDB or Postgres at a level beyond "I write queries", schema design, indexes, query plans, scaling tradeoffs

Real experience with Redis, queues (BullMQ or similar), and async workflows with retries, idempotency, and backpressure

Comfortable owning incidents, observability, and cost

Care about API design, contracts, and clean boundaries between services

Async, written communication first, low ego, ships small and often

Nice to have

Built Shopify apps or worked deeply with Shopify Admin APIs and webhooks at scale

Production experience with LLM systems: agent loops, tool calling, RAG, prompt caching, eval pipelines

GraphQL at scale (server side, not just consuming)

Multi tenant SaaS architecture (brand config scoping, isolation, per tenant rate limits)

Open source or a side project we can actually run

Why this role

Own backend architecture for a fast growing AI infra product, not maintain someone else's

Real production systems, real customers, real load

Direct work with founders on architecture and roadmap

Build at the intersection of AI agents, ecommerce, and Shopify, one of the most interesting backend problem spaces right now

To apply

Send your Resume + GitHub + 2 projects you've shipped + a 3 line note on the hardest backend problem you've solved, to [hidden]