Senior Rails Engineer -- Fintech Platform (Thoughtful …, Miami

Compensation:
Competitive, commensurate with experience
About Topkey
Topkey is a rapidly-growing fintech platform for short-term rental managers.
We offer deposit accounts, credit cards, full bill-pay, external cards, and expense management—all in one Rails monolith on the latest Ruby/Rails.
With $1M+ ARR, zero churn (at the time of posting this), and a small, tight-knit engineering team, you'll have a huge impact on our roadmap, our stack, and our customers' success.
We're backed by top-tier investors like Felicis Ventures, Andreessen Horowitz (a16z), and Y Combinator.
Topkey is recognized as one of the top emerging vertical startups, and our trajectory is steep.
We're looking for driven individuals to join our team and help shape the future of financial infrastructure in the $110 billion hospitality market.
We've been featured in numerous media outlets, including
Axios
,
Wall Street Journal
,
Fortune
,
Phocuswire
,
Short Term Rentalz
, and
Fintech Global
.
What You'll Do
Own features end-to-end in our Rails monolith (Rails 8+, Ruby 3.x)
Build rich, reactive UIs with Hotwire/Turbo, Stimulus, and Tailwind CSS
Integrate with external APIs (Plaid, Stripe, Unit, etc.) securely and robustly
Use large context LLMs (Claude, Gemini, ChatGPT, etc.) to accelerate coding, QA, and spec writing
Participate in architecture discussions -- help us evolve our beautiful monolith
Work closely with product and founders to take specs from prototype to prod
Ship daily/weekly, review critically, and treat AI as a multiplier—not a replacement for good judgment
Optimize performance, reliability, and scalability of our core platform
Act as your own pair programmer—debugging, prompting, reviewing AI-generated code for quality (the eng team will also review, but the initial onus is on the contributor)
You Have
5+ years building production-grade Rails applications
Deep expertise in Ruby, Rails conventions, background jobs, and service objects in a growing monolith
Confidence reviewing, prompting, and editing AI-generated code from tools like Claude, Devin, Gemini, Cursor, etc.
A reflexive approach to using AI in specs, code, QA, testing, and documentation
Strong front-end chops: Stimulus/turbo/hotwire, components, etc.
Experience designing and consuming REST APIs
Solid SQL skills (PostgreSQL) and an eye for data modeling
Track record writing maintainable test suites (RSpec) and CI pipelines
Comfort working autonomously and asynchronously in a high-trust, high-output team
Nice-to-Haves
Previous fintech or payments or accounting experience
Familiarity with Plaid, Stripe, or similar
Experience with observability tooling (NewRelic, Honeybadger, etc.)
Open-source contributions or personal projects you're proud of
Contributions to open-source or side projects involving AI/LLMs
Using Repomix or similar tooling for large-scale code summarization and reasoning
Perks & Benefits
Remote-friendly
Generous PTO and paid holidays
Equity in a high-growth startup
Generous professional development stipend
Home-office setup budget
Health, dental, and vision insurance (U.S.) + 401(k) match
—
*Topkey is a financial technology company and is not a bank.
Banking services provided by Thread Bank; Member FDIC.
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