Senior Software Engineer (Full Stack)

The opportunity

We're solving a multi-billion dollar problem: AML/KYC compliance is slow, expensive, and drowning in false positives. Castellum.AI is an all-in-one AI agents and screening platform that cuts false-positive alerts by up to 94% compared to legacy providers, and we're growing fast as new customers come on board.

You'll join a growing engineering team and own meaningful projects end to end: data pipelines, our Go API layer, AI agents, and the platform our customers rely on every day. This is a high-agency role for someone who wants to take an ambiguous problem, decide how to solve it, and ship it.

What your week actually looks like

~1 hour/day in meetings. Standup, sprint planning, retro. We keep it light.

The rest of the day is building. Feature work and bug fixes, going from architecture decision to shipped code. You'll use AI/LLMs as a force multiplier but you own the tradeoffs and QA your own changes.

Real ownership. You take a project and run with it. You help decide what's in scope, what's out, and where it's okay to cut a corner.

On-call. A one-week rotation shared across the team, mostly during ET business hours.

We run a modern stack (Docker, Kubernetes, and similar tooling), and you have a dedicated DevOps engineer handling the heavy infrastructure lifting so you can stay focused on building.

Our stack

API layer: Go, gRPC, protobufs

Agents & ETL / data pipelines: Python

Frontend: TypeScript + React

Data: PostgreSQL, Elasticsearch

Who thrives here

Our strongest engineers share a few traits

High agency and urgency. They move quickly, take ownership, and understand that getting things done matters. They've worked on small teams that had to ship to survive.

Architecture to code. They can write an architecture doc, break the work into manageable chunks, and then build it.

Good judgment, including with AI. They use AI tools well without leaning on them blindly. They catch when the model makes the wrong tradeoff and they ship code they understand and stand behind.

Clear communicators. They communicate well within engineering (and ideally with customers), understand customer requirements, and will push back on a decision but can disagree and commit.

What we're looking for

Required

Strong professional experience building web applications, APIs, and back-end systems (5+ years) Python or Go experience Plus strong experience in TypeScript. You don't need all three on day one; we expect you to ramp on the one you know least Experience with PostgreSQL or similar relational databases technology Clear written and verbal communication Experience getting real value out of AI developer tools Prior startup or small, fast-moving team experience Nice to have Experience with Elasticsearch, gRPC/protobufs Experience building AI agents Experience with containerization and distributed systems

How we work

Fully remote, US-based, working Eastern hours.

We work hard but we don't burn out. Expect ~45–50 hour weeks. Life happens, and there's real flexibility when it does.

We like each other. We have as much fun as we can while we work, and it's genuinely exciting to watch the business take off.

A straightforward hiring process

We move fast and we don't believe in endless interview loops. Most candidates can move at their own pace, as quickly as four days. Every stage is designed to be a real conversation.

Intro Call: Meet with our CTO to talk through the role.

Architecture Interview: We'll take a larger problem and break it down together on a virtual whiteboard. We're looking at how you structure a solution and reason about the pieces, not whether you memorized anything.

Coding Interview: Solve a problem and walk us through your thinking. We care more about how you approach it than about a perfect answer.

Final Round: Meet people outside of engineering, get a feel for the wider team, and ask us anything about the business.

Compensation

$160,000–$200,000 base, plus equity. This is a rare chance to earn meaningful equity while working on a mission with real-world impact.

Perks and Benefits (Full-time Employees)

Remote-first workplace

Unlimited PTO

Paid parental leave

Medical, dental, and vision (100% coverage for employees)

401(k) through Vestwell

Stipends

One-time: $350 stipend for home office setup

Monthly

$350 coworking,

$100 phone,

$100 home internet

Childcare or petcare when attending work events Annual: up to $5,000 professional development Castellum.AI is building a healthy, respectful, and intellectually rigorous environment. If this sounds like you, we'd love to talk.