Castle is the finance app that saves homeowners time and money.

Homeowners use Castle to pay for and track all of their home expenses in one place. Castle then monitors those transactions for opportunities to save. The average Castle customer saves more than $10,000 on their home.
Housing affordability is a major problem in the U.S. At Castle, we believe that homeowners deserve better data when it comes to managing their biggest asset. We’re building payments infrastructure for the largest consumer category in the U.S. — to help people automate, consolidate, and reduce their spend.

In this role you’ll be a foundational and versatile member of our engineering team, focused on building a simpler, smarter, and more intuitive experiences for homeowners. You’ll collaborate closely with our Head of Engineering, Head of Design, and fellow engineers to bring to life a user-friendly app that clarifies complex home expense management and builds long-term trust with our customers.

This role is perfect for someone who is passionate about solving complex problems and excited to learn new technologies. You’ll have an opportunity to shape a powerful product at an early-stage, high-growth company.

Core Responsibilities Include:

Building and maintaining:
- A robust, scalable, and secure financial platform;
- Web and mobile applications that help homeowners track, understand, and pay for their home expenses;
- AI-powered data pipelines that transform customer data into insights, including finding savings opportunities.

What You’ll Need:

Strong computer science fundamentals and problem-solving skills.
Ability to write clean, maintainable, and well-tested code.
Curiosity to learn new technologies and tackle ambiguous challenges.

Qualifications:

Bachelor’s degree in Computer Science or a related field (or equivalent practical experience).
Experience with modern programming languages and web technologies (e.g., JavaScript/TypeScript, React, Node.js, Python, etc.).
Bonus: experience in fintech, billing systems, or working with financial data.

www.getcastle.com

About the company

Castle is a financial technology platform that helps homeowners manage their home-related finances through a mobile app. Users can track all home expenses in one place, pay bills, and identify potential savings from tax credits and rebates. The app consolidates financial data about property costs to give a comprehensive view of homeownership expenses, enabling more informed decisions. It operates on a subscription model with a two-week free trial and various plans targeted at United States homeowners. Compared to general personal finance apps, Castle focuses specifically on home finances, including renovation planning and eligibility for tax credits and rebates, to help users reduce overall homeownership costs while simplifying bill payments and expense tracking.

Company Size

11-50

Company Stage

Early VC

Total Funding

$2.6M

Headquarters

New York City, New York

Founded

2019

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Simplify's Take

What believers are saying

Castle’s September 2026 site refresh doubled down on homeowner payments and savings.
Castle’s tax-credit and rebate tooling sells concrete savings tied to renovations and energy upgrades.
Castle’s closing-payment tools expand revenue into attorneys and title companies.

What critics are saying

Castle lacks visible scale; 2026 materials still read like an early-stage niche startup.
Castle depends on pricey annual subscriptions while competing with banks, fintechs, and closing platforms.
If bill-pay errors or fraud losses spike, Castle’s trust proposition dies quickly.

What makes Castle unique

Castle bundles homeowner bills, payments, and savings discovery into one workflow.
Castle’s 2026 homeowner pages emphasize wire fraud protection and late-fee guarantees.
Castle also targets title and closing payments, extending beyond consumer budgeting.

Castle

Software Engineer

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