# Senior AI Builder

**Company:** [Replit](https://hotfix.jobs/companies/replit)
**Location:** Foster City, CA
**Role:** Fullstack Engineering
**Salary:** $200k – $275k/yr
**Experience:** 5+ years
**Skills:** Python, TypeScript, JavaScript, LLMs, Prompt Engineering, RAG, Agentic Workflows, SQL, Relational Databases, ai model orchestration, third-party api integrations, Evaluation Frameworks
**Posted:** 2026-07-17

> Build and ship custom AI-powered internal platforms and agentic workflows that automate operations across all Replit departments (People Ops, Sales, Support, Finance, etc.). Requires strong business acumen, startup experience, LLM engineering expertise, and full-stack development in Python/TypeScript.

## Job Description

## Key Responsibilities
- Design, architect, and ship custom AI-powered internal platforms that serve operational needs across departments including People Operations, Customer Support, Sales, Recruiting, Marketing, Finance, and Executive Operations.
- Translate ambiguous business requirements into technical specifications, system architectures, and shipped software products.
- Own platform development end-to-end, including front-end interfaces, back-end services, data models, third-party integrations, and AI model orchestration.
- Architect multi-stage AI pipelines incorporating large language models, including prompt engineering, tool-call architecture, structured output generation, retrieval-augmented generation, and agentic workflows.
- Conduct model selection across frontier and open-source providers, evaluating on cost, latency, quality, reliability, and performance.
- Design and implement evaluation frameworks for AI features, including test datasets, scoring rubrics, and regression tests.
- Optimize AI systems for cost and performance using lighter models, batching, and caching.
- Partner with department leads to identify inefficiencies, scope solutions, and prioritize high-leverage work.
- Conduct stakeholder interviews, lead requirements-gathering, and translate feedback into iterative improvements.
- Present technical work and outcomes to executive leadership.
- Design and implement integrations with third-party platforms such as HR systems, support ticketing, CRM, ATS, project management tools, and identity providers.
- Maintain and operate platforms in production, including observability, incident response, and iteration based on feedback.
- Document architectural decisions, designs, and procedures; onboard team members.

## Requirements
- Bachelor’s or master’s degree in Technology Management, Computer Science, Software Engineering, Information Systems, or related field (or equivalent experience with strong shipped portfolio).
- Demonstrated portfolio of shipped AI-powered applications, with ability to discuss architecture and trade-offs.
- Experience running own business or working at a fast-scaling startup with end-to-end business exposure.
- Proficiency in modern software engineering practices (version control, code review, CI/CD, debugging).
- Hands-on experience with LLM providers, APIs, tool-calling, and structured outputs.
- Experience designing prompt/tool-call architectures, model selection, and optimizing for cost/latency.
- Programming proficiency in Python and TypeScript/JavaScript, with relevant AI frameworks.
- Experience with relational databases, SQL, and modern data tooling.
- Strong communication skills for technical and non-technical audiences.
- Ability to operate autonomously in ambiguous, fast-paced environments.

## Preferred Qualifications
- Prior experience as a founder, co-founder, or early team member at a venture-backed, AI-native startup.

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