Job Specifications
Job Description
Most engineering job descriptions read like a checklist. This one is different. At pmtbox (“Payment Box”), we’re building a fintech platform that helps businesses manage their payments-related risk, fraud, card declines, chargebacks, and related processes intelligently. We’re a VC-backed fintech with a small team, over 1,000 active clients, and big ambitions, and we’re looking for engineers who want to build things, not just complete tickets. If you’ve spent your career in a dev shop where product managers feed you Jira tickets all day … this role might feel very different. We’re looking for engineers who:
Build things on their own
Are comfortable working within systems and workflows and thinking of ways to improve processes
Use AI as a force multiplier in your development workflow
Enjoy solving complex problems that span the layered architecture of web applications
What You Might Work On
You’ll be building real products alongside founders, including a technical co-founder with deep industry experience and expertise, and a small, high-performing engineering team. Expect to:
Design and build product features within a structured Rails codebase using a tests-first approach in a CI/CD environment
Improve internal tooling, automation and data workflows
Build integrations with mid-market and enterprise clients
Use and refine AI-assisted development workflows and tools
Contribute to architectural decisions as our platform's data model and intelligence layer grows
How Our Engineering Team Works
This is not a role where everything is already defined but it’s also not greenfield. You’ll be building within established patterns and codebases. Our engineering team is small and deliberately so. We currently support over 1,000 active clients across a Rails/Postgres stack with AI-assisted development workflows integrated into daily work.
We maintain a TDD-first codebase with CI pipelines, and structured project context that keeps both humans and AI tools oriented. This isn't a “move fast and break things” environment; it's a “move fast because the guardrails are good” kind of environment. You'll have real autonomy within well-defined boundaries: a tested codebase, clear architectural patterns, and context documentation that means you can ship independently without waiting for someone to unblock you.
What We’re Looking For
We care less about years of experience and more about how you think and what you’ve built. You might be a great fit if you:
Have experience with PHP, Python, or Ruby
Can show things you’ve built yourself: GitHub projects, side tools, automation scripts, or personal software projects are great to share with us
Think beyond coding and into systems and workflows
Are curious about how AI changes how software gets built
We use AI-assisted development workflows daily as part of our core infrastructure. We’re looking for engineers who’ve already started building their own workflows and can demonstrate: :
A project where AI assistance measurably changed your development speed or approach
How you support AI workflows with other scripts or tools when it doesn’t work to one-shot it
Knowledge of how to feed data into the AI so that it can deliver quality results
A workflow you built to validate the output from an AI workflow
A workflow where you learned that AI confidently lied to you and what you did to build around that
We want engineers who understand where AI helps the workflows and where it breaks down, not just the latest tools and methods
The Kind Of Engineer Who Thrives Here
You’ll probably enjoy this role if you:
Like solving ambiguous problems
Prefer building over attending meetings
Have shipped things without being told exactly what to do
Enjoy improving systems and processes
Want real ownership of what you build
Our Stack (and What We’re Exploring)
Our team works across modern backend technologies and is constantly experimenting with better tools and workflows. Current and emerging technologies include:
Ruby / Rails
Postgres
AI-assisted development workflows
Modern cloud infrastructure
We’re far more interested in how you solve problems than whether you’ve used a specific framework.
Why Join pmtbox
Early-stage fintech with real momentum and VC-backing by Tandem Ventures (Founders of fintech unicorns Divvy, Finicity, etc.)
Small team, high ownership
Work on meaningful ecommerce infrastructure
Build alongside founders and experienced operators in a five-days-a-week in-office culture
Competitive compensation and benefits package including enterprise-level medical, dental, vision, 401k, and generous time off
About the Company
At pmtbox, we believe payments should fuel growth, not hold it back. That’s why we focus on what matters most: lowering the cost of getting paid, simplifying the payments landscape, and unlocking new sources of revenue.
We help businesses keep more of what they earn by reducing fees and friction in every transaction. Our platform cuts through complexity by unifying payment processes and replacing outdated systems with seamless, transparent solutions. And beyond cost savings, we open new revenue opportunities by enabling bus...
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