Senior Backend Architect — Scalable, Real-Time Systems

Praxis, Inc.; San Francisco (CA); On-site; USD 150,000 - 190,000; Full time

Job summary

Praxis, Inc. is building Known’s backend infrastructure from the ground up in San Francisco. You will architect scalable services, streaming workloads, and real-time chat/voice pipelines while ensuring reliability and developer velocity.

As an infrastructure architect, you’ll own key decisions for data pipelines, payments integration, and scalable architecture, partnering with AI/ML teams to enable rapid product iteration and growth from thousands to millions of users.

Qualifications

• 4–6 years building production backend systems, ideally in consumer products, high-traffic apps, or startups.
• Strong proficiency in TypeScript and Node.js with async patterns, performance optimization, and error handling.
• Expert-level knowledge of Postgres — complex queries, transactions, indexing, pooling, and tuning.
• Experience designing and scaling RESTful APIs with rate limiting, auth, caching, and versioning.
• Hands-on experience with cloud platforms (AWS, GCP) including compute, storage, databases, and networking.
• Familiarity with containerization and orchestration (Docker, Kubernetes) and infrastructure-as-code tools.
• Experience with WebSockets and WebRTC for real-time systems.
• Strong understanding of observability — logging, metrics, tracing, alerting.
• Security, data privacy, and compliance as first-class concerns.

Responsibilities

• Design and build scalable backend services in Node.js/TypeScript, including RESTful APIs, background jobs, and data pipelines for real-time and batch workloads.
• Architect and optimize Postgres databases, including schema design, queries, indexing, and ensuring data integrity at scale.
• Implement real-time infrastructure using WebSockets for chat and WebRTC for audio/video with low latency.
• Integrate and manage third-party services (e.g., OpenAI/Anthropic LLMs, payment providers, SMS/push, CDNs) with robust error handling.
• Collaborate with AI/ML engineers to build APIs and data pipelines for model predictions and training data collection.
• Own infrastructure, deployment, monitoring, CI/CD, and cost optimization for reliability at scale.
• Design for performance and scale with caching strategies to support 10x growth and fast API responses.

Skills

TypeScript

Node.js

Postgres

RESTful APIs

Cloud platforms

Docker

Kubernetes

WebSockets

WebRTC

Observability

Security & compliance

Tools

Redis

AWS

GCP

Job description

Praxis, Inc. is building Known’s backend infrastructure from the ground up in San Francisco. You will architect scalable services, streaming workloads, and real-time chat/voice pipelines while ensuring reliability and developer velocity.

As an infrastructure architect, you’ll own key decisions for data pipelines, payments integration, and scalable architecture, partnering with AI/ML teams to enable rapid product iteration and growth from thousands to millions of users.