
Retell is the #1 voice AI agent platform, enabling you to build, test, deploy, and monitor voice AI agents. Industries such as healthcare, insurance, financial services, and logistics use Retell to automate and enhance call operations.

Retell is the #1 voice AI agent platform, enabling you to build, test, deploy, and monitor voice AI agents. Industries such as healthcare, insurance, financial services, and logistics use Retell to automate and enhance call operations.
What they do: Voice-first conversational AI platform to build, deploy, and monitor AI voice agents that automate inbound and outbound phone calls.
Stage & funding: Seed-stage; $4.6M seed round (lead: Alt Capital).
Founding & HQ: Founded 2023; co-founder & CEO Bin Wu; based in San Francisco, CA.
Enterprise features: Telephony integrations (SIP trunking), low-latency LLM + speech models, and enterprise compliance claims (HIPAA, SOC 2 Type II, GDPR).
| Company |
|---|
Call center and phone-based customer workflows (inbound/outbound calls, customer service, appointment scheduling, call operations automation).
2023
Technology, Information and Internet
$4.6M
Round included participation from Y Combinator, Carya Venture Partners, and 20+ founders/executives/operators; named participants include Jack Altman, Aaron Levie, Siqi Chen, Michael Seibel, and Peer Richelsen.
โSeed round led by Alt Capital with participation from Y Combinator, Carya Venture Partners, and multiple founders/executives (including named angels and operators).โ
About Retell Ai Retell AI is using the first principles to reimagine the call center with cutting edge voice AI.
Since launching 18 months ago, thousands of companies now utilize Retellโs AI voice agents to handle sales, support, and logistics calls that once required large teams of human agents. Backed by Y Combinator, Alt Capital, and other leading investors, we have scaled to $36M ARR with a team of 20 people, up from $5M at the start of 2025.
In 2026, We are expanding our vision to build a CX platform of the AI era where the entire contact center is reimagined as a team of AI employees. We are moving beyond mechanical automation that relies on human finetuning to instead transform core functions into intelligent, opinionated AI roles. Frontline agents, QA analysts, and managers now operate as distinct digital workers that serve as the new interface for customer experience. They execute, monitor, and improve continuously to create a system where software behaves like an organization.
Weโre scaling fast, and weโre looking for bold, ambitious people to help us build the gold standard for voice automation. If you want to work on deeply technical challenges, move fast, and make an outsized impact at one of the fastest-growing Voice AI startups in the world, youโll love it here.
Letโs build the future together.
THE ROLE
Weโre looking for a Principal/Staff Engineer to help own the technical direction of our core platform. This is a staff-level IC role for someone who thrives in ambiguity, moves fast, and raises the bar for everyone around them.
Youโll work across systems, infrastructure, and product surfaces โ partnering closely with engineering, product, and leadership to scale whatโs already working and build whatโs next.
This is not a โticket takerโ role. Youโll define problems, design solutions, and ship.
Key Responsibilities
YOU MIGHT THRIVE IF
Bonus points if youโve worked with: distributed systems, Voice AI, real-time systems, APIs at scale, infra/platform work, or developer-facing products.
WHY THIS ROLE
If you want a role where your decisions visibly shape the company, this is it.
JOB DETAILS
Other Benefits
Compensation Philosophy
INTERVIEW PROCESS
Recruiter Screen (15min): Speak with a member of the talent team to learn more about us and which team you would be a good fit for.
Technical Interview (45 min): Practical coding session focused on code fluency and system design (For frontend roles, we will focus on React-specific questions. For backend roles, we take a technology-agnostic approach.)
Technical Interview (45 min): This is a systems design-focused interview. There will be no coding; we want to assess your skills in systems design.
Onsite/Virtual Interviews (2โ3 hrs): Hosted in our office if located in the Bay Area or virtual, with three rounds:
Practical Coding: Tackle real-world coding tasks with debugging.
System Design: Architect a production-ready system.
Tools & Automation: Build automations or improve workflows in any basic environment setup like python, java, node.js, etc.