Senior AI Builder

The role

You will build production infrastructure for AI agents, including prompts, reasoning chains, and tool calls. You will redesign the product development lifecycle using agentic workflows and own the evaluation infrastructure for AI quality.

What you will do

• Design agent thinking including prompts, reasoning chains, and tool calls
• Build production infrastructure including MCP servers, agent scaffolding, and context harnesses
• Replace manual friction in the product development lifecycle with agentic workflows
• Build evaluation pipelines, benchmarks, and quality gates
• Design eval harnesses for AI-assisted workflows
• Build reusable libraries, templates, and reference implementations for AI integration

Required qualifications

• 4+ years of full-time software engineering experience
• At least 2 years building tooling, platforms, or internal developer products
• Bachelor’s, Master’s, or PhD in Computer Science, Computer Engineering, or a related technical discipline, or equivalent industry experience
• Hands-on experience with LLM integration patterns including prompt engineering, RAG pipelines, tool/function calling, and agent architectures
• Proficiency and comfort working across the stack when needed
• Experience with MCP, LangChain, or comparable orchestration frameworks
• Experience with open source LLM models
• Strong opinions about developer experience and a track record of building things other engineers actually use

Nice to have

• Hands-on experience with reinforcement learning especially RLHF, RLAIF, or reward modeling in applied product contexts
• Experience in fintech or regulated/security-sensitive environments
• Hands-on work with AI governance including bias evaluation, audit logging, model cards
• Exposure to multi-step reasoning pipelines or human-in-the-loop system design

Benefits

• equity
• benefits

Before you apply

• You are encouraged to use AI tools throughout much of the interview process
• Some interview rounds focused on career history and past experiences will not allow the use of AI

About the company

EarnIn is an AI-native company building products that deliver real-time financial flexibility for people living paycheck to paycheck. They embed AI agents into how they build, analyze, and operate across every function.