Senior AI Builder

Job Overview

EarnIn is seeking a Senior AI Builder to join their Engineering team in Mountain View. As a pioneer in earned wage access, EarnIn's mission is to deliver real-time financial flexibility for those living paycheck to paycheck. The successful candidate will work at the intersection of platform engineering, developer experience, and applied AI, focusing on building AI-native capabilities.

Responsibilities

• Design and build agents that take real actions, including prompts, reasoning chains, tool calls, and architecture
• Develop production infrastructure, including MCP servers, agent scaffolding, context harnesses, and a Skills Marketplace
• Challenge and improve the product development lifecycle by replacing manual friction with agentic workflows
• Build evaluation infrastructure, including pipelines, benchmarks, and quality gates to ensure AI reliability and trustworthiness
• Create reusable libraries, templates, and reference implementations for AI integration

Requirements

• 4+ years of full-time software engineering experience, with 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, prompt engineering, RAG pipelines, tool/function calling, and agent architectures
• Proficiency working across the stack when needed
• Experience with MCP, LangChain, or comparable orchestration frameworks
• Experience with open-source LLM models

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, bias evaluation, audit logging, model cards
• Exposure to multi-step reasoning pipelines or human-in-the-loop system design

What Success Looks Like

• Teams across engineering can ship AI-assisted features faster, with fewer rework loops
• Harnesses built are actively used and well-documented
• AI pilot quality and safety metrics are visible, trustworthy, and improving

Benefits

The Mountain View base salary range for this full-time position is $228,000 - $279,000, plus equity and benefits. This is a hybrid position requiring in-office work 2 days a week.