Senior Backend Engineer

About the role

Fonzi is an AI recruiting platform where 250+ pre‑vetted startups in NYC and San Francisco compete to interview you. Companies review curated engineer profiles each week and submit salary bids upfront. The service is free for engineers and includes an iMessage agent plus human support for scheduling and coordination.

How it works

• 5‑minute application — we learn what you’re building 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

Requirements

• 2–8 years of experience building and scaling backend systems in production (APIs, services, databases, queues)
• Strong proficiency in Python, Go, TypeScript, Java, or Rust
• Deep experience with Postgres or similar relational databases
• 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 with ambiguous problems and small teams
• Ideally have experience at at least one high‑growth company

What you’ll build

• 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

Pay

$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.

Interview process

• Screening conversation assessing 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