Senior Software Engineer, Applied AI

Onsite — San Francisco

$180,000 USD + Equity & Benefits

About TestBox

TestBox was founded with a bold mission: to fundamentally transform how software is bought and sold. We’re building an innovative platform that empowers buyers with transparent, interactive software experiences, while equipping sellers with powerful tools to deliver exceptional buying and onboarding journeys. Our core technologies - synthetic data, intelligent orchestration, and our unique product graph - help teams achieve faster implementations, clearer insights, and increase trust with their customers.

At TestBox, we're not just improving demos; we're building the next generation infrastructure for software transactions, creating seamless experiences from initial interest to successful onboarding and beyond.

We're a fast-growing startup built by a team that values experimentation, velocity, and customer impact. We’re backed by world-class investors and are building a platform that’s disrupting the traditional B2B sales motion.

Role Overview

We are hiring a Senior Software Engineer to build the intelligent services that will define the future of our platform. This role is at the heart of our mission to create a smarter, more automated way for software to be bought and sold. You will be responsible for designing and implementing the AI-driven features that will supercharge both our internal development velocity and our external user experience.

You will be a key member of our Platform team, working at the intersection of data and platform engineering to bring our most ambitious ideas to life. You will focus on two key areas: building services that dramatically accelerate our internal development, and creating intelligent, user-facing features that simplify complex tasks. You won't just be applying existing models; you will be building the robust, scalable systems that productionize AI within our core product.

If you are a hands‑on engineer who is passionate about leveraging the power of AI to solve real-world problems and want to build intelligent systems from the ground up, this role is for you.

What You’ll Do

• Build LLM‑powered services that automate internal development workflows and accelerate complex integration tasks.
• Create user‑facing features that translate natural language commands into complex platform actions, making our product more accessible and powerful.
• Design and implement intelligent services that allow users to interact with, clean, and enrich their datasets using conversational interfaces.
• Collaborate closely with data and platform engineers to ensure our core infrastructure is optimized for AI and ML workloads.
• Own the end‑to‑end lifecycle of our AI services, from prototyping and model selection to building scalable, production‑ready systems.
• Stay at the forefront of the rapidly evolving AI/LLM landscape, continuously identifying new opportunities to apply cutting‑edge technology to our product.

Who You Are

• You are a pragmatic and product‑minded engineer who is driven to apply AI to solve concrete business and user problems.
• You are a strong software engineer first and foremost, with a passion for building robust, well‑tested, and scalable systems.
• You are a "full‑stack" AI practitioner, comfortable working with everything from data processing and prompt engineering to model integration and API design.
• You are highly collaborative and thrive on working with data engineers, backend engineers, and product designers to build cohesive features.
• You take initiative and see projects through to completion and are excited by the challenge of building a new category of intelligent developer and user tools.

Preferred Experience

• 5–7+ years of experience in software engineering, with a demonstrable focus on building AI or ML‑powered features.
• Hands‑on experience building with Large Language Models (LLMs) and their ecosystems (e.g., OpenAI, Anthropic, open‑source models).
• Experience with modern AI development frameworks and tools).
• Proficiency in a modern backend language, preferably Python.
• Experience building and deploying services on cloud infrastructure (e.g., AWS, GCP).
• Bonus: Experience with Retrieval‑Augmented Generation (RAG) and other advanced LLM patterns.
• Bonus: Experience building developer tools or services that involve code generation.
• Bonus: A strong background in data engineering or working with complex data pipelines.

Why Join TestBox

• Be a foundational member of the team building our core AI and intelligence layer.
• Work on a wide range of fascinating AI problems, from developer acceleration to end‑user "magic."
• Define how a modern SaaS company productionizes the power of LLMs.
• Join a company obsessed with customer experience, speed, and scale.

Benefits

• Generous equity package for meaningful ownership.
• Prioritization of your professional growth, with dedicated career development support.
• Flexible, unlimited PTO with a minimum expectation for recharge.
• Mental Health benefits.
• Fitness allowances.
• Learning allowances.
• Remote and office set‑up allowances to ensure productive and comfortable working environments.