Software Engineer (Infrastructure (Early Career))

• If you want to be part of the AI wave and are drawn to the systems challenges of a product used by both people and agents, this role is for you
• Lightfield’s infrastructure supports human-interactive requests, agent-driven queries and actions, scheduled agents, and continuous ingestion of email, calendar, and meeting data
• Based in our Cambridge office, you’ll work on the databases, scheduling, permissions, and distributed systems that keep these workloads fast, isolated, and reliable as they share the same underlying customer data
• The work is not research, but many of the same habits matter: forming hypotheses, reading unfamiliar systems deeply, designing careful experiments, and explaining what the evidence shows
• You’ll use those habits on problems like these:
• Querying a schema-flexible data model. Customers define their own object types, fields, and relationships at runtime, while the underlying data is stored in Postgres. We work on query planning, indexing, and data-access patterns that keep those records fast to filter and aggregate as datasets grow
• Record-level permissions across relationships. Access can come from ownership, direct grants, group membership, or inheritance from another record. We need a permissions model that evaluates those paths efficiently and produces the same answer across the application, API, search, dashboards, and agents
• Balancing real-time and batch workloads. Search indexing competes with historical imports and backfills for shared database and queue capacity. We use concurrency controls, prioritization, and backpressure to keep real-time updates moving while still processing large batches
• You’ll design and review systems, debug production behavior, and gradually take full ownership of one or more subsystems. You’ll ship production work early with close design and code review, then take on increasingly open-ended projects as you demonstrate readiness
• You’d join a small, systems-focused engineering group in our new Kendall Square office early enough to help establish how it works, alongside a site lead who is one of our most senior infrastructure engineers
• Ship production work early with close design and code review, then grow into end-to-end ownership of a system
• Investigate systems methodically: reproduce behavior, add instrumentation, form a hypothesis, and test it against production evidence
• Work on query performance, data modeling, permissions, scheduling, and keeping customer-facing data fresh
• Debug real production issues across application code, databases, queues, and infrastructure
• Learn how production systems are designed and operated through code review, incident response, and owning what you ship
• Most new grad roles put you several layers away from the systems that matter. This one doesn’t. You’ll see how decisions about data models, query plans, permissions, and scheduling affect real customers, while working closely with experienced infrastructure engineers. If you want to turn academic depth into production judgment and do serious systems work without leaving Cambridge, this is that job

Benefits

• Meaningful early equity
• 3 weeks of PTO
• Health insurance (medical, dental, vision)
• 11 paid company holidays + we enjoy a winter holiday break
• Regular team dinners, events, offsites, and retreats
• Wednesdays work from home
• 3 months of paid family leave
• 401k plan
• Other perks include: commuter and lunch stipend- Clear communication about technical decisions and tradeoffs
• Curiosity about how things actually work. You’d rather understand the query planner than work around it
• Strong computer science fundamentals and a degree in CS or a related field
• Ownership: you finish things, and you care that they keep working after you ship them
• Depth somewhere systems-shaped: research experience, coursework you went deep on (operating systems, databases, distributed systems, security), a systems-flavored internship, or a project you can talk about for an hour