Senior Backend Developer Python Jobs in California

Senior Backend Engineer — AI Healthcare

The Opportunity

Our client is building an AI-powered healthcare platform with an ambitious mission: make high-quality healthcare more accessible to everyone.

The platform is already processing millions of healthcare interactions, and the next challenge is scale. They're looking for a Senior Backend Engineer to build the infrastructure that can eventually support hundreds of millions — and potentially billions — of AI-driven consultations while maintaining the reliability, security, and clinical safeguards required in healthcare.

This is a high-ownership engineering role for someone who enjoys building distributed backend systems, solving difficult infrastructure problems, and working in an environment where engineers are expected to own problems from idea through production.

What You'll Own

• Build and scale backend services in Python and FastAPI supporting millions of healthcare requests

• Design APIs and distributed systems that connect the core platform, AI models, healthcare data, and external partners

• Build integrations with EHRs, QHINs, telehealth platforms, healthcare networks, and third-party APIs

• Architect secure systems for processing sensitive healthcare data in HIPAA-compliant environments

• Optimize PostgreSQL, Redis, caching, and data infrastructure for rapidly increasing traffic

• Build reliable systems with strong error handling, failover, monitoring, and disaster recovery

• Develop backend infrastructure supporting AI inference, preprocessing, validation, and clinical workflows

• Build deterministic safeguards and escalation systems that operate alongside AI agents

• Improve deployment infrastructure, observability, CI/CD, and multi-region reliability

The Engineering Environment

This is not a heavily layered engineering organization.

There are no project managers handing engineers perfectly defined tickets. Engineers are expected to understand the problem, make good technical decisions, and ship.

You'll work in an environment with:

• A flat engineering organization

• Direct access to company leadership

• High individual ownership and autonomy

• Minimal specifications and significant freedom around implementation

• Modern AI-assisted development tools

• Fast iteration and a bias toward shipping

• Senior engineers who own systems end-to-end

The expectation isn't simply to write good code.

It's to identify what needs to be built, make the right tradeoffs, and get it into production.

What We're Looking For

Backend Engineering

• 6+ years of software engineering experience with significant backend ownership

• Strong Python experience

• Experience with FastAPI, Flask, Django, or similar frameworks

• Deep understanding of REST APIs and API architecture

• Experience designing systems handling significant production traffic

• Strong relational database experience with PostgreSQL or MySQL

• Experience with Redis, caching strategies, and distributed systems

• Cloud infrastructure experience, ideally in AWS

Systems & Infrastructure

You should be comfortable working with:

• Microservices and distributed architectures

• Third-party APIs and webhook integrations

• Docker and containerized infrastructure

• CI/CD and deployment automation

• Monitoring, logging, and observability

• Production reliability and failure recovery

• Security best practices for sensitive data

Particularly Relevant Backgrounds

We're especially interested in engineers who have worked on difficult technical problems in environments where reliability and data security matter.

Relevant experience could include:

• Healthcare technology

• Fintech or other regulated industries

• High-scale SaaS platforms

• AI/ML infrastructure

• Real-time or event-driven systems

• Developer infrastructure or API platforms

Experience with FHIR, HL7, EHR integrations, QHINs, HIPAA compliance, message queues, model serving, or AI agent infrastructure is valuable but not required.

Startup experience is highly relevant. Founders, founding engineers, and engineers who have built systems during Seed through Series B growth tend to align well with the level of ownership expected here.

Who Tends to Thrive Here

This environment is best suited for someone who:

• Wants significant ownership rather than narrowly scoped tickets

• Can take an ambiguous problem and turn it into a production system

• Thinks deeply about reliability without allowing perfectionism to slow shipping

• Enjoys solving backend and infrastructure problems at scale

• Is comfortable making technical decisions independently

• Moves quickly and exercises good judgment

• Wants their work to directly influence the trajectory of a company

Funding & Momentum

The company has attracted significant backing from leading technology investors:

• Seed: Union Square Ventures — February 2025

• Series A: Lightspeed Venture Partners — August 2025

• Series B: Abstract — January 2026

Each subsequent round was raised within months of the prior financing, giving the team significant resources to continue scaling the platform and engineering organization.

Why This Role

This is an opportunity to build foundational infrastructure at the intersection of AI, distributed systems, and healthcare.

You'll have the chance to solve technically challenging problems around scale, reliability, healthcare interoperability, AI safety, and sensitive data — while working on a product designed to materially expand access to healthcare.

Compensation: Competitive salary ($200,000 - $240,000) + meaningful equity
Reporting: Direct access to company leadership
Benefits: Benefits reimbursement