Senior Software Engineer – Tech Lead, AI

Threecolts

. Design, develop and launch AI features using LLMs for listing optimisation, product descriptions, pricing insights, translation and image enhancement .

Posted 11/12/2026contractRemote • United KingdomSenior💰 $5,500 per monthWebsite

Core Competencies

Role fit

Core Competencies

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Demonstrates expertise in designing and developing AI features using LLMs, with a strong focus on building reliable APIs and integrations for e-commerce platforms. Proven ability to optimize performance and scalability while collaborating effectively within a remote team environment.

Highest-signal resume keywords

AI Feature DevelopmentLLM IntegrationBackend EngineeringAPI DesignSaaS Application Experience

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills

C#SQL ServerMongoDBREST APIsGraphQL APIsOpenAIAnthropicPrompt EngineeringFunction CallingData Synchronisation

Soft Skills

Strong Communication SkillsCollaborative ApproachPragmatic Problem Solving

Tools & Technologies

MCP ServerAI Agent FrameworksOAuthWebhooksRate Limiting

Industry Keywords

E-Commerce PlatformsMarketplace APIsSeller ToolsSaaS Team Experience

Tech Stack

Tools & technologies

GraphQLMongoDBSQL.NET

About the role

Key responsibilities & impact

Design, develop and launch AI features using LLMs for listing optimisation, product descriptions, pricing insights, translation and image enhancement
Build reliable AI workflows focused on output quality, performance, latency and cost
Evaluate and improve AI features using real customer usage and measurable results
Design, build and maintain the MCP server and public API
Develop secure, scalable integrations enabling AI agents to act on behalf of sellers
Ensure APIs are reliable, well-documented and scalable
Work across .NET, C#, SQL Server, MongoDB, REST and GraphQL APIs
Build and maintain integrations with e-commerce platforms and marketplaces
Improve platform performance, reliability and scalability
Own features from design through development, testing and production
Break complex projects into manageable stages and deliver regular improvements
Collaborate with developers, product and the GM on technical solutions
Contribute to code reviews, technical discussions and knowledge sharing
Communicate progress, identify risks and keep delivery on track

Requirements

What you’ll need

5+ years of software engineering experience, ideally building and maintaining production SaaS applications
Hands-on experience developing and shipping AI-powered features using LLM APIs such as OpenAI, Anthropic or similar; real production experience required
Strong understanding of LLM integration, including prompt engineering, function calling, structured outputs, evaluation and cost optimisation
Experience building an MCP server or similar AI agent/tool integration architecture
Strong backend engineering skills, with the ability to design scalable, reliable applications and APIs
Experience with third-party APIs, including OAuth, webhooks, rate limiting and data synchronisation
Comfortable taking technical ownership while remaining hands-on with development
Collaborative, pragmatic approach to engineering, with strong communication skills and willingness to share knowledge
Good working English, comfortable collaborating with an international remote team
.NET/C#, SQL Server or MongoDB experience is advantageous, but other backend stacks are accepted
Experience with AI agent frameworks, RAG or AI evaluation tools is nice to have
Experience with e-commerce platforms, marketplace APIs or seller tools is nice to have
Mobile development experience is nice to have
Browser extension experience is nice to have
Experience working in a small, fast-moving SaaS team is nice to have

Benefits

Comp & perks

Fully remote working