About Piaxis

Piaxis builds AI agents for the architecture, engineering, and construction (AEC) industry. We're solving a $150B problem in US construction documentation that remains largely untouched by software. Our Detail Library product is already live with paying customers, and our AI Detailing Agent is on track to launch - replacing weeks of manual drafting work with minutes.Founding team: an ex-McKinsey operator, a US-licensed architect (ex-Perkins Eastman), and ex-technical cofounder of Belong.co - domain depth plus technical depth to build this right.The RoleWe're hiring a Senior Backend Engineer (5+ years) to own core services in our agent platform - the pipelines that orchestrate LLM reasoning, retrieve the right reference details, place elements accurately, and prove it with evals. You'll work close to the metal of an LLM-driven system: retrieval quality, pipeline architecture, data contracts, and the evaluation harness that tells us whether the agent is actually getting better.This is a high-ownership IC role. You'll ship production services, shape architecture decisions (we write ADRs before code lands), and partner directly with our founders and domain experts to translate messy construction knowledge into robust backend systems.What You'll Do

- Build and own backend services in Python - a FastAPI service backed by LangGraph pipelines that orchestrate multi-step agent reasoning with Postgres-backed checkpointing.
- Design and strengthen the agent pipeline - using vector search over a corpus of extracted detail views (Weaviate), embeddings, etc.
- Invest in evaluation - extend our eval framework so every change is measured, not guessed. Evals are a first-class deliverable here.
- Integrate LLMs pragmatically - work across multiple providers (Anthropic, OpenAI, Bedrock, Google, Groq, Ollama) via LangGraph, tuning prompts, structured outputs, and cost/latency tradeoffs.
- Shape architecture - write and review ADRs, weigh coupling and extension cost,



and keep the system easy to extend without rewrites.

Our Stack

- Language: Python
- Services: FastAPI
- Agent orchestration: LangGraph, LangChain (core + multi-provider integrations)
- Data: PostgreSQL (psycopg), Supabase, Weaviate (vector DB)
- LLMs: Anthropic, OpenAI, AWS Bedrock, Google Vertex/GenAI, Groq, Ollama
- Infra: Docker / Compose, AWS (S3, ECR), GitHub Actions CI/CD
- Integration: a Revit plugin (in C#) that executes the placement commands our service generates

What We're Looking For

- 5+ years building and operating production backend systems, with solid Python depth.
- Experience designing API services and asynchronous/multi-step pipelines (FastAPI, or equivalent frameworks).
- Solid grasp of data modeling and databases relational (PostgreSQL) and ideally vector/search systems.
- A track record of owning systems end to end: design, ship, measure, iterate.
- Comfort working in an evaluation-driven culture - you reach for metrics and test harnesses, not vibes, to know if something improved.
- Strong engineering judgment: you weigh tradeoffs, write clearly about decisions, and keep systems simple and extensible.
- Clear written communication and the ability to collaborate closely with founders and domain experts.

Bonus Points

- Hands-on experience with LLM applications RAG/retrieval, embeddings, prompt engineering, structured outputs, agent frameworks (LangGraph/LangChain).
- Experience with retrieval/search quality work: ranking, recall/precision tuning, kNN, hybrid search.
- Cloud & infra fluency: AWS (S3, ECR), Docker, CI/CD.
- Background in AEC, CAD/BIM, computational geometry, or Revit or genuine excitement to learn a rich physical domain.
- Experience building or maintaining evaluation frameworks for ML/LLM systems.

CompensationAbove-market salary + meaningful ESOP.

Why Join

- Work on a genuinely hard, non-commodity problem - turning building-science expertise into a reliable AI system, not another chatbot wrapper.
- High ownership and direct impact; small team, fast iteration, real architectural influence.

Share your resume to [email protected]

📌 Senior Backend Engineer (Tamil Nadu)
🏢 PKC Management Consulting
📍 Tamil Nadu