We're creating the shift to voice as humanity's default interface. Why voice? Because voice captures the nuance, the emotion, and the humanity of interactions in ways text alone can't: voice makes technology human again.
MissionWe're building the platform for the future of voice technology. Our market edge is extensible, reliable infrastructure designed for the full complexity of voice interactions. 18 months, 150k developers, adding 1000 every day. Give it a try here
The RoleThe Senior Backend Engineer will own features end-to-end from customer requests to their deployment, building on a modular API-first architecture, working within real-time low-latency constraints. You’ll also be a foundational part of how we build the culture at Vapi.
OutcomesOwn and deliver entire features + projects
Ship a pre-scoped feature within the first 7 days
Ship a feature independently within the first 30 days
Ship optimizations and refactors
Ship a pre-scoped optimization or refactor within the first 14 days
Ex. improve the latency of a component of the speech-to-speech pipeline
Ship an optimization independently within the first 30 days
Ex. refactor a tool-calling mechanism to make it more deterministic
Talk to customers
Receive a request from Support team and ship the fix within the first 14 days
Pick up customer threads unprompted, investigate and solve within the first 14 days
Build things that delight customers
Unprompted, delight a customer within the first 30 days (ex. call analytics endpoint)
Experience with Typescript + Node or similar backend framework
Communication: You can clearly articulate what you’re thinking and feeling
Cracked-ness: You’re more cracked than the most cracked person on the team
Startup Ready: You have a reason to be here and can make sacrifices for something uncertain
Founder Juice: New ideas come from you, you build it yourself or annoy everyone until it’s done ;)
Previous Founding/Senior/Staff/Principal Engineer
1+ years of experience at company <100 ppl
5+ years experience in Full-Stack / Backend Software Engineering
Top Skills
What We Do
Vapi lets enterprises deploy human-like voice agents in minutes. Whether you’re building a voice product or trying to handle millions of calls, Vapi’s reliable infrastructure and flexible APIs make it easy.
Everyone from YC startups to Fortune 500 companies rely on Vapi because it is:
Flexible: Plug in your APIs, your customer data, your models
Scalable: Handle millions of calls with <500ms latency
Secure: LLM guardrails, HIPAA, SOC-2
Helping enterprises over this challenge, Vapi, has raised $20 million in Series A funding, led by Bessemer Venture Partners with participation from Abstract Ventures, AI Grant, Y Combinator, Saga Ventures, and Michael Ovitz.
