Sr Founding Backend Engineer

Syndesus, Inc.; San Francisco (CA); Hybrid; USD 200,000 - 280,000; Full time

Benefits offered by this job

Medical, dental, vision

Unlimited meals and snacks

Gym and commute reimbursement

Visa sponsorship available

Job summary

Syndesus, Inc. is hiring a Founding Senior Backend Engineer in the San Francisco area to build core systems powering millions of AI-driven conversations. You will own backend architecture, real-time services, and telephony integrations.

Join a YC-backed startup moving fast, working closely with the founding team to shape APIs, tooling, and delivery from architecture to production. 2+ years of backend experience and a CS/CE/EE degree are required.

Qualifications

• 2+ years of backend development experience.
• Degree in CS/CE/EE or equivalent practical experience.
• Ownership mindset with a drive for impactful software.
• Ability to work in fast-paced, ambiguous environments.
• Strong communication and cross-functional collaboration.
• Startup experience and cloud/DevOps knowledge is a plus.

Responsibilities

• Build foundational architecture including orchestration, testing, observability, and telephony integrations.
• Design scalable backend systems and DevOps workflows for millions of calls.
• Lead complex projects from architecture to production, owning delivery.
• Collaborate with product and design to create intuitive APIs for onboarding.
• Support onboarding, troubleshoot issues, and translate feedback into product improvements.

Skills

Backend development

Ownership mindset

Cross-functional collaboration

Communication

Problem solving

Cloud/DevOps knowledge

Education

CS/CE/EE degree or equivalent

Job description

Senior Backend Engineer | Voice AI Startup

About the Company

Our client is a fast-growing Y Combinator-backed Voice AI startup transforming sales, support, and customer engagement. With $5M in seed funding and approaching $30M ARR already, achieved with just 20 people, they're building the standard for voice automation at scale.

The Role

As a Founding Senior Backend Engineer, you'll build the core systems powering millions of AI-driven conversations. You'll work on real-time audio, global telephony, and developer tooling, collaborating directly with the founding team to define a category-leading product.

Key Responsibilities

• Build foundational architecture including prompt orchestration, testing frameworks, observability dashboards, and telephony integrations
• Design scalable backend systems and DevOps workflows for reliable performance across millions of calls
• Lead complex projects from architecture to production, owning delivery and monitoring
• Collaborate with product and design teams to create intuitive APIs for rapid customer onboarding
• Support customer onboarding, troubleshoot issues, and translate feedback into product improvements

Requirements

• 2+ years backend development experience
• CS, CE, or EE degree or equivalent practical experience
• Ownership mindset with passion for impactful software
• Thrives in fast-paced, ambiguous environments with strong problem-solving skills
• Clear communication and cross-functional collaboration abilities
• Bonus: Startup experience and cloud infrastructure/DevOps knowledge

Compensation & Benefits

• Salary: $200K - $280K
• Equity: 0.25% - 0.45%
• Schedule: Full-time, 70 hrs/week (50 onsite + 20 remote, flexible hours)
• Location: Redwood City, CA
• 100% medical, dental, vision coverage
• Unlimited meals and snacks
• Gym and commute reimbursement
• Visa sponsorship available (H1B, TN, L-1, E-3, F-1, O-1)

Interview Process

1. Online coding assessment (25-30 min)
2. Technical phone interviews (2 rounds focusing on data structures and algorithms)
3. Onsite/virtual interviews: practical coding, system design, and automation