Backend Engineer

Backend Engineers: Let 250+ Companies Compete For You

Fonzi is an AI recruiting company.

No job boards. No recruiter spam. Companies request to interview you and submit salary bids upfront.

Every week, hiring managers at 250+ pre-vetted startups in NYC and San Francisco review a curated group of engineers. They're reading profiles optimized by our team to surface what matters: what you've built, how you think about systems, and whether you're the kind of engineer who ships.

Companies on Fonzi are Applied AI startups, Frontier labs, Hypergrowth startups, PE firms starting lean AI teams and more. They're backed by investors like A16z, Sequoia Capital, General Catalyst, Y Combinator and more.

How It Works

• 5-minute application
• We reach out, learn what you're building and what excites you, and optimize your profile
• Hiring managers review the cohort and request interviews with candidates they want
• Companies submit competing salary bids directly to you
• You only interview where you're genuinely interested
• Completely free. We have an iMessage agent + humans in the loop you can text anytime w/ questions or requests to help handle scheduling and coordination

Who We're Looking For

The backend engineers who do best on Fonzi:

• Have built and scaled backend systems in production: APIs, services, databases and queues
• Are strong in Python, Go, TypeScript, Java or Rust, and deep in Postgres or similar
• Think in data models, distributed systems and failure modes
• Have built backends for LLM-powered products (orchestration, tool calling, retrieval, async jobs) or want to
• Thrive in startup environments where the problem is ambiguous and the team is small
• Have 2-8 years of experience, ideally with experience at at least one high-growth company

What You'll Build

The companies on Fonzi are working on:

• Backends powering agentic workflows across healthcare, fintech, legal and logistics
• High-throughput APIs and integrations with complex enterprise systems
• Payments, trading and real-time financial infrastructure
• Event-driven architectures and data pipelines that scale with the business
• LLM orchestration layers: tool calling, retrieval, job queues and eval hooks

Compensation

• $175,000 to $290,000+ base salary depending on experience and role. Many positions include meaningful equity at pre-seed through Series B stage companies.

The Interview Process (Typical)

• Screening conversation looking for communication skills, cultural fit and genuine curiosity about AI
• Technical deep-dive on system design: APIs, data models and scaling
• Coding or pairing session on a realistic backend problem

If you care about building systems that don't break when the product takes off, we want to hear from you.