Software Engineer, Platform

We are looking for engineers who want to own problems end to end, and who care about making investment portfolio management scalable, correct and reliable. You have a high degree of personal responsibility and enjoy working across the entire application all the way from requirements through implementation and deployment.

About Us

Smartleaf is a Boston-based investment portfolio rebalancing service handling over $90 billion in assets. Our next milestone is doubling our capacity to handle 1 million accounts. In order to get to this next level of scale, we need to evolve our architecture and you can have a big impact on how we do that.

We value software engineering as a discipline. We’ll use AI where it reduces toil but not where it reduces understanding. We still expect every teammate to deeply understand what they ship. Generating lines of code has never been our bottleneck; figuring out the right problem to solve and the right thing to build is far more important.

We need a teammate who will ramp up within 1-3 months and help us get things done. We have more things to do than people to do them; if you are proactive, competent and reliable you can earn responsibility very quickly and help shape the way the department functions.

If you can bring skill, attention to detail and focus on getting working code into the world, while being a genuinely nice person to work with, we want to talk to you.

What You’ll Be Doing

As a member of our platform team, you’ll be at the intersection of domain knowledge, a complex data model and a stream of real-world events. Every day, every portfolio is acted on simultaneously by market movements, corporate actions, user actions and system processes. Your job is to make sure the right things happen in the right order, and that edge cases are handled correctly so that financial advisors can trust what they’re seeing.

You’ll spend a lot of your time figuring out what correctness even means when multiple actions hit a portfolio at once. The UI work is real but mostly straightforward CRUD; the depth in this role is in the domain logic. You’ll need to reason carefully about state, event ordering and how the system behaves when it scales.

You’ll need to distill this complexity into a clear experience that allows financial advisors to understand the impact of their choices and present the best possible information to their clients. You’ll work closely with our product management team and our users to gather requirements and design solutions that help our users get things done and hold up under real world conditions. You’ll also participate in our support rotation and see firsthand how our users are interacting with the system.

To do this well, you’ll need to explain issues, potential solutions and tradeoffs in ways that make sense to a variety of stakeholders. Whenever you need to build internal tools or pick up new skills to achieve our goals, you’re able to roll up your sleeves and bootstrap quickly.

Requirements

• 2-6+ years of experience building production web applications

• Demonstrated ability to reason about systems with complex domain logic and concurrent, order-sensitive state

• Strong understanding of computing fundamentals, particularly multiprocessing and multithreading considerations

• Proficiency in Ruby on Rails or similar MVC frameworks

• Strong SQL skills: comfortable writing complex multi-table queries, understanding query plans, and reasoning about data integrity

• 1+ years of daily experience working in a Linux environment: strong familiarity with common command-line utilities and Unix process management; comfortable with bash scripting

You’ll Be a Great Fit If You

• Are able to dive into unfamiliar codebases and quickly build up working knowledge of how multiple components interact

• Enjoy taking a cloud of complex problems and making them clear and straightforward

We hire carefully because this domain is complex and correctness matters. The engineers who thrive here care deeply about understanding problems. They are comfortable talking things through with others, even when they know their understanding might be incomplete. They can make meaningful progress even before they fully understand the system. They strike a practical balance that keeps work moving: they can ship a fix, stabilize a production fire, or get an MVP out the door and keep thinking critically about the problem afterward, turning it over until they reach a root cause or a clearer understanding.

Location

We prefer candidates who are willing to work in a hybrid environment. Candidates in the Boston area should expect to work in-office 2 days/week for the first 6 months. Candidates outside the Boston area should expect to travel to Boston for 1 week at a time several times in the first six months and 3x per year thereafter.

Tech Stack

• Ruby on Rails, Stimulus, React, PostgreSQL, Debian Linux

• Open source coding agents + local LLMs

Salary Range

$140,000 - $160,000/year depending on relevant experience