Software Engineer - Full Stack San Francisco

FriendliAI Inc.

San Francisco (CA)

On-site

USD 180,000 - 230,000

Full time

14 days+

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Benefits offered by this job

Flexible hours

Lunch/dinner provided

Unlimited snacks

Collaborative environment

Health check-up support

Startup equity

Top-tier equipment

Job summary

FriendliAI Inc. in San Francisco is recruiting a Full-Stack Software Engineer to design, build, and scale our web platform that deploys multimodal models, monitors workloads, and supports agent workflows.

You will own onboarding, authentication, org access, and billing visibility across the product. You will work with product, infra, and design teams to ship high-performance, developer-friendly tools, from UI to backend services.

Qualifications

4+ years of backend or full-stack experience.
Degree in CS/CE or equivalent required.
Experience with production auth: SSO/OAuth2/OIDC, RBAC, API keys, multi-tenant.
Experience building billing or usage-based systems.
Fluent in Python and TypeScript; React/Next.js.
Strong backend with FastAPI or similar.
SQL/PostgreSQL; familiarity with OLAP like ClickHouse.
API design across gRPC/REST/GraphQL in production.
Cloud-native development background.
Familiarity with OpenTelemetry tracing and logging.

Responsibilities

Design, build, and maintain web apps for AI model deployment, monitoring, and performance optimization
Own authentication, organization management, and billing end-to-end.
Develop clean, scalable APIs powering AI agents, workflows, and UIs.
Collaborate with infra to integrate backend with deployment pipelines.
Drive code quality through automated testing, CI/CD, and code reviews.
Contribute to architecture and design decisions shaping platform direction.
Identify and resolve technical debt; improve production reliability.

Skills

Backend engineering

Full-stack

CS degree

SSO/OAuth2

Billing systems

Python

TypeScript

React/Next.js

FastAPI

PostgreSQL

SQL

API design

Cloud-native

OpenTelemetry

Education

Bachelor's or Master's in CS/CE

Tools

Stripe

Auth0/WorkOS

Kubernetes

ClickHouse

Job description

About FriendliAI

FriendliAI is the fastest inference cloud for agents, built to run frontier open-weight models at scale in production. It delivers up to 7x faster output token speed, up to 90% lower inference costs, and 99.99% uptime across the most demanding agent workloads — long-context inference, real-time streaming, and accurate tool calling.

We are a small, fast-moving team doing work that matters at one of the most exciting moments in the history of technology. With our world-class inference stack, we are building the platform teams can actually rely on.

About the Role

We're seeking a Full-Stack Software Engineer to design, build, and scale our web platform, which serves as the core interface for deploying multimodal models, observing workloads, and building agent workflows. You'll own how customers experience the platform end-to-end- signing up, authenticating, managing access across an organization, and understanding what they're being billed for - from the services and data models through to the interface. In this role, you'll work closely with product, infrastructure, and design teams to create high-performance, developer-friendly, and enterprise-ready tools.

We are looking for a hands-on engineer who is eager to work across the surfaces of our application — authentication and access control, billing and usage, and the model deployment and inference features customers use every day. The ideal candidate has built backend systems where correctness matters, is comfortable carrying a feature all the way to the UI, cares deeply about developer workflows, and is excited to help define the future of AI adoption.

Key Responsibilities

Design, build, and maintain web applications and tools for AI model deployment, monitoring, and performance optimization
Own authentication, organization management, and billing end-to-end.
Develop clean, scalable, and robust APIs powering AI agents, workflows, and user-facing systems
Collaborate with infrastructure engineers to integrate backend systems with deployment and orchestration pipelines
Drive code quality through automated testing, CI/CD, and code reviews
Contribute to architecture and design decisions that shape our platform's long-term direction
Identify and resolve technical debt and improve system reliability in production systems

Qualifications

4+ years of industry experience in backend or full-stack engineering, with meaningful time spent on backend systems
Bachelor's or Master's degree in Computer Science, Computer Engineering, or equivalent
Production experience with authentication and authorization — SSO/OAuth2/OIDC, RBAC, API keys, and multi-tenant isolation
Experience building billing or usage-metering systems: usage-based or subscription pricing, entitlements, quotas, or payment integration
Fluent in Python and TypeScript; proficient with React/Next.js
Strong backend experience with FastAPI or similar Python frameworks
Proficiency in designing data models, writing SQL, and working with PostgreSQL; familiarity with OLAP systems such as ClickHouse
Strong API design experience across gRPC/REST/GraphQL in production systems
Solid foundation in cloud-native development
Familiarity with OpenTelemetry tracing, metrics, and structured logging

Preferred Experience

Experience with payment processors (e.g., Stripe) and usage-based or subscription SaaS billing
Familiarity with enterprise identity requirements — SAML, SCIM provisioning, or providers like Auth0/WorkOS
Familiarity with LLM-based workflows, tool invocation, or agentic systems
Familiarity with Kubernetes for container orchestration, including deploying, scaling, and managing containerized applications in production environments
Have worked in a startup or fast-paced environment with ownership
Built developer-facing SDKs/CLIs
Passion for developer experience and enabling AI adoption

Benefits