Why Senior C# .NET Developers are like apples.

Mongoose Gray; Toronto; Hybrid; CAD 95,000 - 130,000; Full time

Job summary

Mongoose Gray in Toronto is seeking a Senior C# .NET Developer to design and scale AI-enabled backend services within a fast-paced SaaS scaleup. You will own the full lifecycle of AI features, from retrieval-augmented generation to agentic workflows, leveraging Claude Code and AWS to ship robust systems.

You will collaborate with Product, Data and Platform teams to shape how AI powers our core product while ensuring observability, reliability and cost discipline as we scale.

Qualifications

• Senior C# .NET Developer with experience in fast-paced SaaS scaleups.
• Proficient in building scalable C# .NET services on AWS.
• Experience with retrieval-augmented generation and vector search.

Responsibilities

• Own end-to-end AI feature lifecycle from concept to production.
• Design scalable backend services powering AI-driven features.
• Work with Product, Data, and Platform teams to deliver value.
• Architect RAG pipelines and multi-step agentic workflows.
• Deploy and monitor AI infrastructure on AWS.

Skills

C# .NET

AWS

AI/ML

RAG pipelines

Vector search

LLM integration

Backend architecture

Observability

Claude Code

Tools

AWS Lambda

ECS/EKS

S3

Bedrock

RDS

Job description

Apples float because they're about 25% air. You'll be floating on air too once you see what we're building.

There are 2 versions of this ad. Below is the anodyne version. Bonus points if you can find the more analeptic version. And provide proof of your quest. Good luck!

• The Senior C# .NET Developer will work for a fast-paced SaaS scaleup.
• The Senior C# .NET Developer will enjoy hybrid working (3+2).
• The Senior C# .NET Developer will have prior experience at a high-growth SaaS startup or scaleup.
• The Senior C# .NET Developer will own the full lifecycle of AI features as we scale.
• The Senior C# .NET Developer will work on everything from retrieval-augmented generation to agentic workflows.
• The Senior C# .NET Developer will leverage Claude Code and other AI-assisted development tools to ship faster.
• The Senior C# .NET Developer will be comfortable designing scalable C# .NET services on AWS.
• The Senior C# .NET Developer will architect RAG pipelines and orchestrate multi-step agentic workflows.
• The Senior C# .NET Developer will deploy, monitor and optimise AI infrastructure on AWS e.g. Lambda, ECS/EKS, S3, Bedrock, RDS.
• The Senior C# .NET Developer will work closely with our Product, Data and Platform teams.
• The Senior C# .NET Developer will turn gnarly business problems into clean, scalable AI-powered solutions.
• The Senior C# .NET Developer will design, build, and scale backend services that will power hundreds of AI-driven features.
• The Senior C# .NET Developer will work on data ingestion and chunking strategies to vector search and retrieval optimisation.
• The Senior C# .NET Developer will showcase their systems design skills.
• The Senior C# .NET Developer will help shape how AI gets woven into our core product from the ground up.
• The Senior C# .NET Developer will mentor other engineers on AI engineering patterns and backend architecture.
• The Senior C# .NET Developer will turn cutting-edge LLM capabilities into robust, production-grade systems.
• The Senior C# .NET Developer will build robust, scalable, low-latency, fault-tolerant and highly performant systems.
• The Senior C# .NET Developer will establish best practices for LLM observability, prompt/version management, cost control and reliability at scale.