Principal Software Engineer (10+ years of experience)

Captions is the leading video AI company, building the future of video creation. Over 10 million creators and businesses have used Captions to create videos for social media, marketing, sales, and more. We're on a mission to serve the next billion.

We are a rapidly growing team of ambitious, experienced, and devoted engineers, researchers, designers, marketers, and operators based in NYC. You'll join an early team and have an outsized impact on the product and the company's culture.

We’re very fortunate to have some the best investors and entrepreneurs backing us, including Index Ventures (Series C lead), Kleiner Perkins (Series B lead), Sequoia Capital (Series A and Seed co-lead), Andreessen Horowitz (Series A and Seed co-lead), Uncommon Projects, Kevin Systrom, Mike Krieger, Lenny Rachitsky, Antoine Martin, Julie Zhuo, Ben Rubin, Jaren Glover, SVAngel, 20VC, Ludlow Ventures, Chapter One, and more.

Check out our latest financing milestone and some other coverage:

The Information: 50 Most Promising Startups

Fast Company: Next Big Things in Tech

The New York Times: When A.I. Bridged a Language Gap, They Fell in Love

Business Insider: 34 most promising AI startups

Time: The Best Inventions of 2024

** Please note that all of our roles will require you to be in-person at our NYC HQ (located in Union Square)

We do not work with third-party recruiting agencies, please do not contact us**

About the role:

Note: we don’t promote hierarchical titles or levels internally, “Principal Engineer” is for external clarity—we’re looking for a highly experienced engineer who can solve some of our hardest technical challenges, shape architectural direction, and provide technical leadership. 

As a technical lead, you will architect and drive platform-wide initiatives that push the boundaries of distributed systems, and you will solve complex technical challenges at massive scale. Your work will ensure our software engineering organization can innovate quickly and reliably, ultimately helping creators around the world tell their stories through video.

Key Responsibilities:

• Solve Complex Technical Challenges: Design, implement, and optimize large-scale distributed systems capable of handling massive throughput and concurrency. Own critical backend services end-to-end, ensuring they meet high standards of performance, reliability, and cost-efficiency.

• Drive Product Infrastructure Forward: Collaborate with product teams to build systems and services that are operationally sound while also enabling rapid feature development and deployment across iOS, Android, and Web platforms.

• Drive Platform Improvements: Continuously refine our existing systems, and identify new technologies or methodologies that can enhance our infrastructure,

• Influence Technical Direction: You’ll bring fresh ideas to the table, mentor other engineers, and balance short-term needs with longer-term architectural vision—ensuring we can scale effectively as our user base grows.

Requirements:

• 10+ years of industry experience designing, building, and operating highly scalable distributed systems.

• Deep understanding of computer science fundamentals (data structures, algorithms, concurrency) and strong proficiency in at least one modern programming language (Python, C++, Java, Rust, etc.).

• Hands-on experience with cloud infrastructures (GCP, AWS, Azure, or similar) and container orchestration (e.g., Kubernetes).

• Proven track record of delivering high-quality, scalable solutions to production, with an emphasis on performance and fault tolerance.

• Excellent problem-solving and communication skills, with the ability to mentor others, navigate ambiguity, and tackle open-en