Senior Software Engineer - Data & AI

Lightspark is creating the Money Grid, modern, open financial infrastructure that makes payments accessible, affordable, and instant for businesses and users worldwide. We're challenging the status quo, updating the current system, and empowering our partners to build better solutions. Together, we're building the most advanced financial infrastructure, open, instant, and global, inspiring a future where anyone, anywhere can access the full potential of digital money.

We are looking for engineers who enjoy building and shipping quickly, learning how other teams work, and seeing their work change how an entire company operates. As a Senior Software Engineer on the Data & AI team, you'll expand Lighthouse, our internal data and AI platform, into the layer that lets every function at Lightspark run on trusted data and AI agents.

Most of the value in applied AI comes from the connective work: wiring models to a company's data, its tools, and the way people actually work, then getting the result adopted. We've built that layer for analytics, where Lighthouse now handles most of what our team used to do by hand and is used across the company. This role extends it to Sales, Finance, Ops, Legal, Compliance, and Partnerships: the agent harness, tool integrations, governed source-of-truth data, and the execution layer those teams run their workflows on. General-purpose assistants get partway there and miss things; you'll build the structure underneath so the answers are right, repeatable, and owned by the teams that need them.

You'll work on a small, senior team with a lot of ownership. Problems come from talking with the teams you support rather than from a spec; you'll scope them, ship the solution, and make sure it sticks.

WHAT YOU'LL BE DOING

• Building and owning our internal AI platform: the agent harness, MCP servers and tool integrations, context and access services, sandboxed execution, and cost and usage tracking

• Embedding with Finance, Sales Ops, Compliance, and onboarding to understand how their work actually happens, then shipping the systems that replace the manual version and handing them off to those teams

• Extending our data infrastructure alongside our Staff Data Engineer: DBT models, BigQuery, orchestration, and the production pipelines

• Sharing ownership of monitoring, alerting, and data reliability for the systems that unblock product launches

• Partnering with Engineering to optimize their own dev systems and tooling

WHAT WE'RE LOOKING FOR

• 4+ years experience shipping and maintaining production systems; data engineering, ML engineering, and backend/full-stack backgrounds all fit

• You've built an internal platform or workflow system that other teams adopted, not just features on top of one

• You've built with LLM APIs, agent frameworks, and MCP in production, beyond prompting, and you know what belongs in code versus a model

• Strong fundamentals in TypeScript/Node or Python and the willingness to work in both, plus fluency with a cloud data warehouse such as BigQuery, Snowflake, or Databricks

• You can sit with a non-technical team, understand how their work actually happens, and come back with a system

• Comfortable working with ambiguity in a startup environment

• Experience in payments, crypto, or blockchain is a plus, but not required

• Based in LA or Openness to relocate to Los Angeles, California

This is not an ML infrastructure, model-training, or prompt-engineering role. You might currently be an AI engineer, ML engineer, data engineer, or full-stack engineer who has spent the last year or two building agents and internal tooling. If you don't match every line above but have built systems like these, we'd like to hear from you.

Lightspark is on a mission to build the future of open, instant, and global financial infrastructure making payments accessible and affordable for everyone, everywhere. We're committed to creating a more inclusive and diverse workplace to reflect the customers we serve. We welcome interest from individuals of all backgrounds and levels of experience who share our mission. We do not discriminate based on race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, disability status, or other applicable legally protected characteristics.

For US Applicants:

We will consider for employment qualified applicants with criminal histories in a manner consistent with the requirements of the State of California Fair Chance Initiative for Hiring.

For EU Applicants:

In accordance with applicable EU and local regulations, including the Estonian Employment Contracts Act, Equal Treatment Act, and Gender Equality Act, Lightspark ensures equal treatment throughout the hiring process.