Senior Python Backend Engineer - Commerce Core

Why Fulfil
Fulfil is a technical founder-led, bootstrapped company in our 11th year of operations. We're a small team of exceptional engineers powering millions of orders for brands like HexClad, Ridge Wallet, and Caraway. No red tape. No product managers. No layers of approval. You'll own critical systems, make architectural decisions, and work directly with merchants — sometimes in their warehouses. You'll ship to production in your first two weeks.

You'll work directly with our Product Support team, who talk to merchants daily. They bring you real problems, you propose solutions, you ship. No PRDs. No one translating customer pain through three layers of abstraction.

At a large company, senior engineers write docs and attend meetings. Here, you'll design systems that process millions of transactions monthly and ship them yourself.

The Team
Commerce Core owns order management, inventory, fulfillment, purchasing, and warehouse management. Our mission: orders flow without human intervention.

A Typical Week

• Monday: Lead design review for re-architecting order allocation. Current system handles 100K orders/day — design one that handles 10x.
• Tuesday: Build a prototype. Benchmark against production data from a merchant doing 2M orders/month.
• Wednesday: Call with a merchant's warehouse manager. They're expanding to a second warehouse. Help design the multi-location setup.
• Thursday: Code review for two SDE-IIs on wave picking. Guide them on edge cases.
• Friday: Ship the first phase of the new allocation engine. Monitor it during a beta merchant's weekend sale.

What You'll Own

• Order processing architecture: allocation, routing, splitting
• Inventory system reliability at scale
• WMS scalability for high-SKU warehouses
• Technical direction (with Product Lead)
• Mentoring engineers

What We're Looking For

• 4-6 years building backend systems
• Systems that process millions of transactions
• Expert Python, large codebases
• Deep PostgreSQL: partitioning, query planning, performance
• Strong debugging across services
• Clear communication with technical and non-technical people

Tech Stack
Python, PostgreSQL, Redis, Celery, RabbitMQ, SQLAlchemy, Kubernetes, pytest, Claude Code

Hiring Process

• Initial interview — What you've built and owned
• Live coding — Real-time problem solving
• Interview loop — Architecture, system design, bar raiser
• Bootcamp — Even senior engineers start in Product Support to learn how merchants use Fulfil