Backend Software Engineer Senior/Staff

DualEntry; Remote; PLN 399,000 - 636,000; Full time

Job summary

A fast-growing AI startup is seeking a Senior Backend Software Engineer to design and build core backend systems using Python. You'll join a remote-first team that values speed and impact. The role offers significant equity ownership and a competitive salary ranging from $110K to $175K, along with benefits like 15 PTO days and visa sponsorship for relocation within 2 years. This is an opportunity to shape the future with cutting-edge AI technology.

Benefits

15 PTO days

12 public holidays

Remote-first culture

Visa sponsorship for relocation

Equity ownership

Qualifications

• 5+ years of experience in backend engineering.
• Embedded complexity in business logic products.
• Understanding of software lifecycle, CI/CD, and production readiness.

Responsibilities

• Design and build core backend systems using Python.
• Build APIs handling complex accounting logic.
• Launch production-ready features from scratch.
• Manage complexity in a business-logic-heavy product.
• Integrate third-party tools and external systems.

Skills

Backend engineering experience

Python proficiency

Experience with complex business logic products

Strong database skills

API development

Fluent in English (C1+)

Tools

PostgreSQL

AWS

FastAPI

Flask

Django

Job description

Backend Software Engineer (Senior/Staff) @ DualEntry
Polska

Remote-first team - the fastest team you will have ever worked with

• 15 PTO days + 12 public holidays
• Visa sponsorship option for relocation to NYC within 2 years
• Freedom, autonomy, and impact from day one

If you’re excited to build systems that power AI and build the first true accounting AI product with your own hands, we’d love to hear from you.

About DualEntry

Founded in 2024, DualEntry is one of NYC’s fastest-growing AI startups.

DualEntry is changing the future of finance. Our AI-native ERP lets teams achieve more in less time. $5M-ARR businesses and NYSE-listed companies trust DualEntry to automate away busywork and fuel their growth with powerful reporting and insights. We’re making the one-person finance team a reality and putting the pain of legacy ERPs from the 1990s in the past.

We operate with urgency and ownership. We move fast.

Why This Role Matters Now

Since launching 18 months ago, we’ve raised $100M with backing from Lightspeed, Khosla, and Google Ventures. We got there by moving incredibly fast and hiring the best and brightest talent. To accelerate that momentum, we’re growing our team. Come and join us at one of NYC’s fastest-growing startups and have an impact on our product from day one.

This is an intense, hands-on role with full ownership.

You’ll be joining at an early and defining moment. Your work will directly shape our product, customers, and trajectory.

You’ll architect features and systems end-to-end at an incredible pace.

This is an opportunity to own critical infrastructure at the early stage of a category-defining AI company. Build the first, true AI accounting product with your own hands - alongside our elite team.

Where You’ll Create Impact

• Design and build core backend systems using Python
• Build APIs, services, and infrastructure that handle real-time, business-critical, and complex accounting logic
• Launch production-ready features from scratch, including CI/CD pipelines and deployment
• Work with product to turn complex finance workflows into performant, secure systems
• Manage complexity in a business-logic-heavy product, including data migrations and scale challenges
• Integrate third-party tools and external systems — proactively managing edge cases and risk
• Own your work from architecture to testing, monitoring, and post-release care

What Sets You Up for Success

• 5+ years of experience in backend engineering
• Deep experience with complex business logic products
• Proficient in Python and a modern web framework (FastAPI, Flask, or Django)
• Experience deploying on AWS (or similar cloud infrastructure)
• Strong database skills: PostgreSQL, SQL, ORMs, migrations, schema design
• Experience building and testing robust APIs
• Solid understanding of software lifecycle, CI/CD, and production-readiness
• Ability to manage complex systems with evolving requirements
• Fluent in English (C1+) with strong written and verbal communication

How You Operate

• Pragmatic: You like to move forward and make decisions based on reality (not theory). We don't debate if Cassandra has the most theoretical scalability -- we use Postgres until it breaks
• Hard working: "You can work long, hard, or smart, but [here] you can't choose two out of three" - Jeff Bezos. We wrote this job post during the weekend
• Curious: You love to learn, are highly curious about new frameworks and solutions to engineering problems
• Fast-moving – You deploy daily, iterate quickly, and never wait for permission

Why You’ll Thrive Here

• Significant equity ownership in one of the top AI companies in the world
• You’re joining early and will grow with DualEntry
• Your feedback shapes the product directly
• High-speed culture
• High-trust environment with high expectations
• Ambitious mission

Compensation & Benefits

• Base salary: $110K–$175K USD
• Equity: ~$50K+ USD
• B2B contract (regular employment contract available)
• Remote-first team - the fastest team you will have ever worked with
• 15 PTO days + 12 public holidays
• Visa sponsorship option for relocation to NYC within 2 years
• Freedom, autonomy, and impact from day one

If you’re excited to build systems that power AI and build the first true accounting AI product with your own hands, we’d love to hear from you.