Senior Back End Developer

Senior Backend Engineer
About the Role

We are looking for a Senior Backend Engineer to architect the "ales Operating System  that powers our platform. You will build the closed-loop infrastructure that connects real-world performance with AI-driven simulation.

Your code will ingest data from live sales calls, analyze them to find skill gaps, and autonomously trigger personalized AI roleplay sessions to fix those gaps. You are building the engine that turns "What happened on the call" into "What to practice next."

🌕 About Yolk

 Yolk is a VC-backed startup (Investors of Anthropic, Groq, Tentsornet)  on a bold mission: To build the best sales departments in the world with elite AI coaching available to every team. Our AI sales coach helps revenue teams catch deal-killing mistakes before they hit your forecast—sharpening discovery, objection handling, negotiation, and more. We’re not just replacing traditional corporate training; we’re lifting win rates, shortening ramp, and unlocking millions in new revenue.  Being the #1 AI coach is big. That’s where you come in.

Core Simulation Architecture Design the backend systems that power our interactive training loops. You will move us beyond simple request/response cycles into stateful, persistent WebSocket connections that can handle interruptions, context switching, and dynamic feedback in real-time.

The Async Evaluation Engine You will architect the analysis pipeline that processes both Real Calls and Simulated Roleplays. This system must scale to handle long-form audio processing, utilizing LLMs to extract structured rubric data (e.g., "Did they ask for budget?") and feeding it into our analytics layer.

Observability & Resilience Enhance our "blind spots" in production. You will implement distributed tracing to visualize the full lifecycle of an AI conversation—from packet arrival to LLM inference to audio generation—ensuring we can debug race conditions and latency spikes effectively.

The "Gap-to-Game" Orchestrator This is the heart of the product logic. You will write the algorithms that: Ingest performance data from real calls. Identify specific skill gaps . and assign the correct AI Roleplay scenario to the user. Update the Manager Dashboard with progress.

Idempotency & Data Integrity: Ensuring that  if something  fails, we never corrupt the user's performance metrics.

• Core: Python 3.12+ | FastAPI | SQLAlchemy 2.0 (async) | PostgreSQL
• Async & Messaging: RabbitMQ + FastStream | WebSockets | Redis (Optional) 
• AI & Data: OpenAI/Anthropic APIs | Vector Stores | Real-time Audio Protocols (WebRTC/RTMP, Pipecat)
• Tooling: uv | ruff | basedpyright (strict) | OpenTelemetry

• State Management in Stateless Environments: Maintain the precise context of a 20-minute AI conversation when services scale up/down or when connections drop?
• Complex LLM Orchestration: Work along our AI research on "Chain-of-thought" pipelines that can branch dynamically based on user input without adding perceptible delay.
• Strict Latency Budgets: Optimizing our Python async loop to handle audio stream chunks and vendor API calls within strict millisecond windows.
• Concurrency at Scale: Designing the system to handle hundreds of concurrent audio streams and LLM contexts without blocking the event loop.

Must-Have:

• 5+ years backend engineering experience, with deep expertise in Python 3.10+.
• Mastery of AsyncIO: You understand the Python event loop inside out. You know how to write non-blocking code that handles concurrent WebSocket connections efficiently.
• API Design Excellence: You build clean, RESTful (or GraphQL/RPC) interfaces that frontend teams love to use. You use Pydantic and strict typing to enforce contracts.
• Database Design: You are comfortable writing complex SQL queries and designing normalized schemas in PostgreSQL/SQLAlchemy.
• Architectural Pattern Knowledge: You understand State Machines, Event-Driven Architecture, and how to decouple services cleanly.

Nice-to-Have (But DevOps handles the heavy lifting):

• Familiarity with containerization (Docker) — you know how to build your app for production, even if you don't manage the cluster.
• Experience with FastStream or RabbitMQ. 
• Understanding of WebSocket scaling patterns (Redis Pub/Sub) 

🌟 Why You’ll Love Working at Yolk

- Ground-floor ownership: Shape the core AI systems at a fast-moving, venture-backed startup.

- High visibility & impact: Work directly with the CEO and leadership team.

- Upside: Competitive salary, stock options, build something that matters. 

- Culture: A dynamic, collaborative, and supportive team that moves fast and wins together.

- Perks:  Bi-annual retreats abroad, performance based comp,  advance through the ranks fast.

🚫 Who This Role Isn’t For

- Engineers who want to manage people and avoid hands-on building.

- Corporate-minded architects who expect massive infrastructure and rigid processes.

- Those seeking the order and stability of big-company environments—priorities here shift fast.

Apply on Linkedin or write us to hello@yolk.coach