Founding Fullstack Engineer

Caddie is hiring for a Founding Engineer Role
on behalf of
BlueJay
. The job description below is provided directly by the Bluejay team.

About Bluejay

Bluejay is the end-to-end testing platform for conversational AI, with a strong focus on voice. We serve customers ranging from very large enterprises to the hottest startups and are backed by Y Combinator and other prominent investors and angels. Faraz and Rohan, former AI engineers at Microsoft and AWS founded the company. During Y Combinator, we grew to over $100K in ARR in under a month, and we now have deals with multiple Fortune 500 companies.

At Bluejay, we believe that trust is not a feature — it's the foundation. In the future, the AI agent companies that win will be those we can trust: safe, reliable, and aligned with human intent. Our mission is to engineer trust into every AI interaction—whether it's a voice agent answering a call or a multi-modal system handling sensitive data.

We're setting the gold standard for trustworthy AI agent testing through three guiding principles:

Simulation is the New Standard. If your AI agent hasn't been tested in a simulated environment, it hasn't really been tested. We rigorously pressure-test every scenario, failure condition, and edge case before your agent reaches the real world.

Safety Isn't Optional. Security, compliance, adversarial testing, and red teaming aren't just boxes to check—they're pillars of responsible AI development. We make it easy to proactively evaluate agents for failure modes before they cause harm.

Trust Demands Accountability. In a world where AI agents make decisions for us, we need impartial systems to evaluate their behavior. That's why Bluejay exists as an independent, third-party arbiter—a standard of truth that companies, regulators, and end users can rely on. We aim to be the scoreboard, not the player.

Stop vibe testing. Quality is engineered. Bluejay is here to build the future of trustworthy AI.

About the role

Skills: Python, React, PostgreSQL, Amazon Web Services (AWS)

Bluejay is building the simulation, evaluation, and observability layer for voice + text AI agents.

We work with Fortune 500s, multi-national corporations, and startups to make sure their AI agents perform as intended. We raised a 4m seed backed by Floodgate, PeakXV, and YC in June, and have been doubling our growth every 3 months since inception.

We are looking for cracked, FULL STACK, founding engineers with 1-2 years of experience who would like to join the Bluejay rocketship. We want fresh, scrappy engineers who get really excited building cool shit. We hold a high technical bar and expect proficiency across the stack.

At Bluejay, you'll be working with some of the largest companies in the world to QA their voice and text AI agents. You'll be working with tech across the stack, and taking full ownership for your work. We are a super small team punching well above our weight, and expect you to do so as well

Frontend:

• React, Tailwind
• TypeScript
• NextJS

Backend:

• Python, FastAPI
• Supabase, Redis
• AWS (a lot of it)
• Voice AI: LiveKit, Deepgram, Cartesia, Elevenlabs, Gemini, etc
• Text AI: Pydantic AI, OpenAI, agentic frameworks
• Websockets
• CI/CD chops

Desirable Quirks:

• super opinionated about random design decisions
• enjoys keeping a clean room (codebase cleanliness)
• physically cringes when seeing inefficient code or poorly designed systems
• has good intuition when designing new systems
• aesthetic, inspired, artsy, in touch

Desirable Experiences (any of these will pique our interest):

• Has worked at a YC company as a founding engineer for over 6 months
• Has worked in the voice AI space
• Has built beautiful frontend websites
• Is a technical, ex-VC-backed founder

What You'll Do:

• Architect and develop systems that simulate, analyze, and evaluate conversational AI agents, including voice and multimodal systems.
• Design resilient, scalable infrastructure using AWS (Lambda, EC2, Websockets, SIP) to handle thousands of real-time conversations.
• Develop algorithms and pipelines that surface insights, detect failure modes, and ensure agents are safe, reliable, and aligned with human intent.
• Work on-site with customers. This early on, you'll be building, selling, and deploying the product to real customers.