Backend Developer

About Robyn

We're building the
world's first emotionally intelligent AI that powers connection. We're building a deeply human company that will make billions of people come alive.

You'll be building the backend infrastructure that powers all of it:

• Conversations, memory, and real-time personalization
• Scalable infra for emotional intelligence
• Secure and fast APIs for our iOS app

You'll be the
technical backbone of Robyn
— designing and shipping fast, scalable, emotionally aware systems while collaborating closely with iOS, product, and AI teams.

Responsibilities

1. Backend & Infra Ownership

• You'll work and add to our
  C# / .NET /
  ASP.NET
  backend api layer (have experience in this or something similar like Java/Spring and can learn quickly) and progressively add many
  Python microservices (FastAPI or AWS Lambda)
  with modular, AI-native architecture in mind to build our intelligence layer. Deploy models and setup some ml training pipelines.
• Understand dependency injection, Strategy Pattern, inversion of control, and other best practices for code maintainability
• Own the full backend surface area — auth, APIs, infra, orchestration — and design all of your features for scale and velocity.
• Build and maintain REST and GraphQL APIs consumed by our iOS client; low-latency, resilient, and well-instrumented.
• Architect a microservice-style ML model serving backend deployed via
  Docker containers or AWS Lambda (SnapStart)
  , backed by async eventing and pub/sub where needed.
• Own CI/CD, rollback strategies, logging, error handling — the backend is your domain, end-to-end.

2. AI & ML Systems Integration

• Architect and manage existing
  vector DB
  (PgVector) and potentially add more to power retrieval-augmented generation, evolving memory, and personalization.
• Build tools and add to our custom memory pipelines tied to user context, embeddings, and interaction history.
• Integrate and scale inference with OpenAI, Claude, Llama, or other models. Build wrappers, manage caching, fallbacks, and prompt routing logic.
• Own emotion and sentiment tagging workflows; plug in APIs or run lightweight classifiers in-line.
• Maintain API orchestration layer with 3rd party model providers (OpenAI, ElevenLabs, etc.).

3. Cloud Infra, DevOps, and Data Stack

• Manage our AWS infrastructure and add to our current stack with new innovate technologies:
  Lambda, ECS, S3, RDS (Postgres), CloudFront, IAM, Route53
  — you'll be the one making the call on architecture and trade-offs.
• Be able to use search databases like OpenSearch
• Infra-as-code with
  Terraform
  . Pipelines through
  GitHub Actions
  .
• Full observability: metrics, structured logging, tracing, alerting — Open Telemetry, Sentry, Grafana, Cloudwatch, etc.
• Optimize latency across API surface, tune Postgres indexes, add Redis caching layers to many of your services and pub/sub or streaming for near-instantaneous data sync.
• Set up and secure infra for SOC-2 readiness: access controls, data lifecycle policies, encrypted storage.

4. Personalization & Emotional Intelligence Layer

• Design and ship emotion-aware backend systems that update in real time based on user behavior.
• Implement custom memory engines — user embeddings, experience graphs, emotional scores — and build APIs that adapt over time.
• Work with product and AI to tune behavior of Robyn based on user feedback, emotion logs, memory history, and interaction loops.
• All personalization logic

4. Frontend Support

• You can spin up a React webapp and maintain the webapp

You'll Own This Stack

Core Backend

• Languages:
  C# / .NET / ASP.NET (CRUD database and application layer), Python (ML Intelligence Microservices)
• Protocols:
  REST, WebSockets, SignalR, SSE, GraphQL
• Datastores:
  PostgreSQL, Redis/ValKey (cache + pub/sub), Graph Databases Neo4j/Neptune (Graph Rag), S3 Datalake
• CDC
  : Debezium and Kinesis streaming
• Product Analytics
  : Posthog

Infra + DevOps

• Auth
  : AWS Cognito
• Cloud:
  AWS (RDS Aurora, ECS, Lambda, S3, Route 53, CloudFront, IAM, SQS, SNS, SES, etc)
• IaC:
  Terraform
• Containers:
  Docker, Kubernetes (EKS)
• CI/CD:
  GitHub Actions
• Monitoring:
  Sentry for APM, Grafana/Datadog/NewRelic/CloudWatch

AI/ML Layer

• LLMs:
  OpenAI, Claude, Llama, Gemini, etc.
• Libraries:
  HuggingFace, PyTorch/TensorFlow/Keras/H2O (for lightweight classifiers/fine-tuning)
• RAG / Memory:
  PgVector, Redis Vector, FAISS, Pinecone
• Voice Stack:
  AWS Transcribe (STT), ElevenLabs (TTS)
• Emotion/Personality Engine:
  custom classifiers, prompt chains, and embedding-based user profiles

You're NOT the right if if you:

• Want a 9 -5
• Used to others owning pieces of the backend
• Copy-paste vibe code

The ONLY right fit:

• You have a track record of owning the backend end-to-end and taking the codebase personally.
• You ship with rigor and velocity
• You are proud to put your name on the codebase

Why Join Robyn

• Build the
  most emotionally intelligent AI product on Earth
  — at a moment of hypergrowth.
• Work directly with a visionary founder (Harvard-trained surgeon turned CEO).
• Backed by elite investors (Google Maps co-founder, x.ai founder, and more).
• Early team = massive ownership, creative control, and impact.
• Remote-first, async-friendly culture with deep focus and emotional clarity.

***TO APPLY***

Complete the typeform application -- applicants MUST complete the typeform to be considered.