Full Stack Engineer-SMS & RCS Agents

Location: Hybrid- NYC (3+ days in office required)

Type: Full-time W-2 employee, subject to a 90-day introductory period

Salary and equity commensurate with experience and performance

About AviaryAI

We build AI voice agents for banks, credit unions, and insurers.

Our agents are live and handling real customer calls today. We’re backed by Y Combinator and growing.

We started with voice. Our SMS and RCS agents began as clones of the voice product — and they’re growing fast. Messaging is becoming a major part of our platform, and it needs a dedicated owner

The Role

You’ll be the primary engineer building our messaging product. 

This means: 

• Writing the backend logic that manages conversation state and decision-making across asynchronous, multi-day text threads (Python) 

• Evolving SMS/RCS from a voice-agent clone into a messaging-native product — rich cards, suggested replies, media, session handling 

• Building internal dashboards and tools to configure and debug agents (TypeScript) 

• Integrating with messaging providers and carrier infrastructure — delivery, 10DLC, opt-in/opt-out 

• Debugging real production issues when things break 

You’ll own this vertical from prototype to high-volume production. 

This is not a ticket-driven role. You’ll have a lot of responsibility and a lot of autonomy. 

What We’re Looking For

• 1–3 years full stack experience (new grads welcome) 

• Strong in Python 

• Comfortable in TypeScript / modern frontend frameworks 

• Experience building systems with real state or multi-step workflows 

• Comfortable integrating third-party APIs 

• Able to work without detailed specs 

Bonus if you’ve worked in:

• Startups 

• Fintech / insurance 

• Messaging or telephony systems (Twilio, Telnyx, Bandwidth, SMS compliance) 

• LLM applications (prompting, agent frameworks, evals) 

What This Is Like

You won’t just be building CRUD endpoints. 

You’ll be building systems that: 

• Decide what to say next in a live conversation — hours or days after the last message 

• Enforce business rules and compliance requirements (TCPA, carrier filtering, quiet hours) 

• Handle messy, real-world edge cases 

• Run thousands of concurrent conversations reliably 

Your code will power real conversations with real customers — and unlike voice, every word is in writing. 

Interview Process

1. Introductory Call (20–25 minutes): Meet our CEO and get to know each other. (Virtual)
2. Hiring Manager Interview (30 minutes): Technical discussion (Virtual)
3. Practical Assessment Interview (90 minutes): You’ll submit a project in advance and walk us through your architecture and decisions. We care about clarity and systems thinking (Virtual or In-Person)
4. Final Interview (30-60 minutes per interview): Meet with the founding team. (In-person)
5. References + offer