Senior Fullstack Engineer — AI & LLM Platform

blackbird.xyz; New York (NY); Hybrid; USD 180,000 - 220,000; Full time

Job summary

Blackbird Labs is seeking a product-minded fullstack engineer to own our AI-powered dining assistant. You will ship end-to-end features across frontend React/TypeScript and backend Python/Kotlin, including tool calls and retrieval improvements.

This hands-on IC role emphasizes product judgment, fast iteration, and collaboration with design and data teams. NYC-based, you’ll impact how diners discover and experience restaurants through our loyalty and payments platform.

Qualifications

• 5+ years shipping production software, owning features end to end.
• Able to debug across the stack: streaming client, application code, SQL, and services boundaries.
• Deep experience with LLM app development: tool calling, context management, retrieval, streaming.
• Strong React and TypeScript, fluent Python; Kotlin/Spring on platform side as needed.
• Solid Postgres and data modeling instincts; good retrieval sense.
• Judgment about trustworthy, fast agent experiences.

Responsibilities

• Build the chat experience diners talk to every day.
• Own the agent runtime end to end.
• Ship new tools the model can call and tests to pin behavior.
• Make answer quality measurable: evals, tracing, user feedback.
• Improve retrieval to ensure correct dining recommendations.
• Take the product from answering questions to completing tasks.
• Keep turns fast, cheap, and reliable on mobile networks.
• Collaborate with product and design to ship rapidly.

Skills

React

TypeScript

Python

Kotlin/Spring

PostgreSQL

LLM application development

Tool calling

Retrieval

Tools

Langfuse

LangSmith

Braintrust

PostGIS

pgvector

Job description

Blackbird Labs is seeking a product-minded fullstack engineer to own our AI-powered dining assistant. You will ship end-to-end features across frontend React/TypeScript and backend Python/Kotlin, including tool calls and retrieval improvements.

This hands-on IC role emphasizes product judgment, fast iteration, and collaboration with design and data teams. NYC-based, you’ll impact how diners discover and experience restaurants through our loyalty and payments platform.