---
title: 'Back-End Engineer at fifthdoor.com'
canonical: 'https://feeny.ai/job/back-end-engineer-fifthdoor-com-san-francisco-b2a1dxn2pp9q'
type: 'job'
last_seen: '2026-09-05'
---

# Back-End Engineer at fifthdoor.com

- **Company:** fifthdoor.com
- **Location:** San Francisco, CA
- **Employment:** full-time
- **Work type:** remote
- **Posted:** 2025-05-13
- **Last confirmed live:** 2026-09-05
- **Apply:** https://jobs.gem.com/fifthdoor-com/am9icG9zdDrX-wP7g20pP_T9nM6Dt4YT

## Job description

## About Us

Fifth Door unlocks the power of imagination by making it easy for anyone to create, share, and play turn-based games anywhere, with anyone. We exist to inspire connection, creativity, and community through the limitless joy of games.

Create. Play. Anywhere.

## About the Role

We are seeking a Back-End Engineer who is passionate about delivering outstanding user experiences that delight our users. This is an opportunity to join a fast-moving, ambitious team where your work will have real impact from day one.

## Responsibilities

- Help architect, develop, and maintain the backend for our AI-powered game engine and web applications.
- Collaborate with cross-functional teams to design scalable and secure systems.
- Optimize applications for maximum speed, performance, and scalability.
- Write clean, maintainable, and well-tested code.
- Identify and troubleshoot back-end performance issues.
- Stay current with trends and emerging technologies, bringing ideas back to the team.

## Qualifications

Must-Have:

- 3+ years of experience as a backend or full stack engineer or similar role.
- Expert proficiency in a programming language used on the backend, such as Ruby, Typescript, Python, or Golang
- Strong understanding of backend development concepts (e.g. API development, structuring applications, databases, workflows)
- Experience working with databases, both SQL and NoSQL
- Familiarity with modern build pipelines and tools
- Strong interest in AI technologies or experience integrating AI into a product
- Experience working in an agile development environment
- Proficiency using AI tools in development workflows

Nice-to-Have:

- Some familiarity with front-end technologies and working with Typescript and React is a plus.
- Passion for gaming, creative tools, or AI applications.
- Experience with AI prompt engineering.

## Benefits

- Competitive salary and meaningful equity.
- Health, dental, and vision coverage.
- Flexible work hours and unlimited vacation policy.
- A collaborative, supportive team environment.
- Opportunity to shape product direction and culture early.

## About fifthdoor.com

## Company Overview
- **One-liner**: Fifth Door is a generative game engine that enables anyone to create, share, and play turn-based browser games using AI, with no coding required.
- **Entity Type**: Private (Startup, Y Combinator Fall 2025 batch)
- **Headquarters**: San Francisco, California, USA
- **Founded**: 2025
- **Founders**: Daniel Kan (CEO) and Amir Ghazvinian (CTO)

## Core Business
- Primary industry: AI-powered game creation platform / Generative gaming
- Target customers: B2C creators and players; community-driven platform for all skill levels
- Mission statement: "Unlock the power of imagination by making it easy for anyone to create, share, and play turn-based games anywhere, with anyone."

## Products & Services
- **[Fifth Door Platform]**: A browser-based, no-code generative game engine that uses AI to let users create, remix, customize, and publish turn-based games instantly. Features include AI-assisted creation, remixing of existing games, community sharing, and one-click publishing.

## Market Standing
- **Valuation/Market Cap**: Not publicly available (early-stage startup)
- **Key Metric**: Total team size of 3–4 employees (as of Fall 2025); currently in private beta
- **Notable Investors/Partners**: Y Combinator (Fall 2025 batch)
- **Growth Signals**: Recently graduated from Y Combinator; actively hiring founding engineers (Back-End and Front-End); building a community via Discord; private beta waitlist active

## Competitive Advantages
- **No-code AI game creation**: Differentiates from traditional game development tools by removing all coding barriers.
- **Remix culture**: Allows users to instantly transform any existing game into a unique creation, lowering the barrier to entry.
- **Instant playability**: Browser-based with no downloads; games are playable immediately as they are built.
- **Strong founding team**: Daniel Kan (CEO) and Amir Ghazvinian (CTO) are Y Combinator alumni with relevant experience.

## Strategic Focus
- Building out the core AI-powered game engine and community platform
- Scaling the engineering team with founding-level hires (Back-End and Front-End Engineers)
- Growing the private beta user base and expanding the library of user-generated games
- Establishing a community-driven ecosystem for creation and sharing

## Why Work Here
- **Early-stage impact**: As one of the first engineering hires, you will shape the product and technical architecture from the ground up.
- **Hybrid/Remote flexibility**: San Francisco-based with a hybrid workspace; roles are open to remote US applicants as well.
- **Competitive compensation**: Salary range of $150k–$250k plus 0.10%–0.50% equity (per Y Combinator job postings).
- **Founding team culture**: Small, tight-knit team (currently 3–4 people) with a focus on creativity, connection, and fun.
- **Y Combinator backing**: Access to YC's network and resources provides strong startup acceleration support.

## Sources
1. [fifthdoor.com](https://fifthdoor.com/)
2. [Y Combinator - Fifth Door](https://www.ycombinator.com/companies/fifth-door)
3. [Built In - Fifth Door](https://builtin.com/company/fifth-door)
4. [LinkedIn - Fifth Door](https://www.linkedin.com/company/fifth-door)
5. [Gem - Fifth Door Careers](https://jobs.gem.com/fifthdoor-com)

## Other roles at fifthdoor.com

- [Front End Engineer](https://feeny.ai/job/front-end-engineer-fifthdoor-com-san-francisco-jg6b2skcp8x4) — San Francisco, CA
- [Back-End Engineer](https://feeny.ai/job/back-end-engineer-transfergo-vilnius-4h9f5pvscvr4) — Vilnius, Lithuania
- [Back-End Engineer](https://feeny.ai/job/back-end-engineer-kpler-athens-wn8634agzjzb) — Athens, Greece
- [Back-End Engineer](https://feeny.ai/job/back-end-engineer-alinia-ai-barcelona-zwknn7qk6tbd) — Barcelona, Spain