Backend Engineer (Mid / Senior)

About the Company

Flowmingo is a startup supported by Y Combinator, along with VinaCapital and other leading global investors. Its goal is to make hiring more accessible by rethinking how candidates are evaluated. The team believes the current hiring process leaves most applicants unseen because recruiters can only interview a small fraction of them.

The company is building an AI-first, high-scale interviewing platform designed to help recruiters evaluate large candidate volumes efficiently. To grow in Southeast Asia, LATAM, and Africa, the product is offered free to recruiters so the platform can capture markets that traditional paid tools often cannot serve.

The Engineering Challenge

This role focuses on building infrastructure that can support thousands of simultaneous video interviews across different devices and network conditions. The emphasis is not only on functionality, but on keeping performance strong, infrastructure lean, and costs low enough to serve millions of users at scale.

The company is seeking backend engineers at mid and senior levels who care about fast systems, efficient resource use, and thoughtful architecture.

What You Will Do

• Design and maintain low-latency, reliable APIs that power the core interview workflow, especially for users in emerging markets.
• Build asynchronous systems such as queues and workers to manage video upload, storage, and processing without disrupting the candidate experience.
• Improve code and infrastructure efficiency so the platform can scale while keeping compute and operational costs under control.
• Develop secure and scalable payment and monetization flows that support many small transactions across global payment providers.
• Organize, optimize, and extend SQL and NoSQL data layers to support millions of candidate interactions and reporting needs.

What the Role Requires

Responsibilities will vary depending on seniority. Senior engineers are expected to design complex systems independently and help guide others, while mid-level engineers should own features confidently and deliver clean, testable code.

The core stack includes Node.js, NestJS, and TypeScript. Python experience is also highly valued. Familiarity with asynchronous messaging and data storage tools such as RabbitMQ, Redis, and PostgreSQL is important for this role.

What Makes a Strong Fit

• You care deeply about performance and efficiency, and you do not consider a solution complete unless it is both functional and cost-effective.
• Experience with audio/video streams or large binary payloads is a strong advantage.
• You understand the constraints of fragmented devices and inconsistent connectivity in emerging markets, and you build for resilience.
• You are comfortable moving quickly in a startup environment, shipping frequently, and prioritizing practical progress without compromising security or core reliability.

Why This Opportunity Stands Out

• You will work on a product built for massive scale, serving millions of candidates in fast-growing economies.
• The technical problems are unusual and demanding, including bandwidth limitations, device latency, and high concurrency.
• You will collaborate with a team that includes people from top institutions and the YC ecosystem.
• The company is lean, so you can expect rapid shipping and minimal bureaucracy.
• As an early hire at a YC-backed startup, you gain exposure to a strong startup network.

Application Process

• CV review focused on builders and problem-solvers.
• A technical screening discussion centered on architecture and practical problem-solving, without whiteboard-style puzzles.
• A culture conversation with the founders.