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Startup Backend Engineer Jobs in California (NOW HIRING)

We are hiring on behalf of a venture-backed AI startup building intelligent software that automates ... The company is hiring a Backend Engineer to build the reliable systems behind its AI products.

Launched in 2012, Koding, a fast-growing startup (with over a million users), is seeking a Backend Engineer. In this role, you will be implementing available, resilient and highly performant services ...

Maxana is seeking an experienced Backend Engineer for a confidential client -- a well-funded AI ... Prior startup or high-growth company experience required * Must be able to work hybrid 2 days/week ...

Maxana is seeking an experienced Backend Engineer for a confidential client - a well-funded AI ... Prior startup or high-growth company experience required * Must be able to work hybrid 2 days/week ...

Senior Backend Engineer

San Francisco, CA · On-site

$110K - $200K/yr

About the Role A fast-growing, Y Combinator-backed AI startup in the supply chain space is looking for a Senior Backend Engineer to join their small, high-velocity engineering team in San Francisco.

About Clerkie Clerkie is a fintech startup on a mission to democratize financial wellness using the ... About the role We're looking for a Backend Engineer who wants to build and own critical systems in ...

The Backend Engineer will lead a team in developing scalable backend systems and APIs, implementing ... a startup) and is enthusiastic about driving innovation and growth. Company : Luminary Travel ...

About Clerkie Clerkie is a fintech startup on a mission to democratize financial wellness using the ... About the role We're looking for a Backend Engineer who wants to build and own critical systems in ...

Senior Backend Engineer

San Francisco, CA · On-site

$110K - $200K/yr

About the Role A fast-growing, Y Combinator-backed AI startup in the supply chain space is looking for a Senior Backend Engineer to join their small, high-velocity engineering team in San Francisco.

... startup environment. You'll work as an equal member of our 3-4 person software team. You'll be ... backend engineering, with a focus on cloud infrastructure and data-intensive applications

They are seeking a founding Senior Backend Engineer to design, develop, and ship robust backend ... stage startup • You embrace the challenges and growth that come with joining an early-stage ...

... Startup: Work closely with other engineers, product management, marketing, and customers ... backend engineer, preferably in security-related domains. • Proficiency in backend cloud ...

Staff Backend Engineer

Los Angeles, CA · On-site +1

$200K - $230K/yr

About the Role Join our fast-growing startup as a Staff Backend Engineer and help scale the backbone of our platform and expand into new product categories. We are a dynamic, high-growth company ...

Staff Backend Engineer

Los Angeles, CA · On-site

$200K - $230K/yr

About the Role Join our fast-growing startup as a Staff Backend Engineer and help scale the backbone of our platform and expand into new product categories. We are a dynamic, high-growth company ...

Role Step is looking for a Backend Software Engineer. As part of the team you'll be at the ... Stock in an early-stage startup * Flexible WFH and vacation policy * Employee referral program

About the Role Join our fast-growing startup as a Staff Backend Engineer and help scale the backbone of our platform and expand into new product categories. We are a dynamic, high-growth company ...

Backend Engineer

San Francisco, CA · On-site

$170K - $220K/yr

Position Summary As a Backend Engineer at HeyGen, you'll be at the forefront of building the core ... Prior experience in a startup or fast-paced tech environment. What HeyGen Offers * Competitive ...

Backend Engineer

San Francisco, CA · On-site

$130K - $160K/yr

Backend Engineer San Francisco, CA Being a Backend Engineer at a company smaller than 10 people is ... It would be great if they've been at an early stage startup before and understand the type of ...

Experience working in a small startup environment (Seed or Series A). * Understanding of data lake ... Engineering, or a related technical field. * Excitement about the mission and working at an early ...

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Startup Backend Engineer information

What are some common challenges faced by backend engineers in a startup environment?

Backend engineers in startups often face the challenge of balancing rapid feature development with maintaining system stability and scalability. Due to limited resources and fast-changing priorities, you may need to wear multiple hats, such as managing infrastructure, addressing technical debt, and ensuring security. Collaboration is typically close-knit, requiring frequent communication with frontend developers, product managers, and sometimes even customers. Adapting quickly to new technologies and evolving project requirements is key to thriving in this dynamic setting.

What are the key skills and qualifications needed to thrive as a startup backend engineer?

To thrive as a Startup Backend Engineer, you need strong programming skills (commonly in Python, Node.js, or Java), a solid grasp of databases, and experience with scalable system design—often backed by a degree in computer science or equivalent experience. Familiarity with cloud platforms (like AWS or GCP), containerization tools (Docker, Kubernetes), and CI/CD pipelines is typically required. Adaptability, problem-solving, and effective communication are crucial soft skills for navigating the fast-paced, dynamic startup environment. These abilities are vital for rapidly building robust, scalable solutions that can evolve with the company's growth.

What does a startup backend engineer do?

A Startup Backend Engineer is responsible for building and maintaining the server-side logic, databases, and APIs that power a startup's applications. They work closely with frontend developers and product teams to ensure the application is scalable, secure, and performs well. In a startup environment, backend engineers often handle a wide range of tasks, including designing system architecture, optimizing application performance, and quickly deploying new features. Their versatile skill set enables them to adapt as the company grows and technology needs change.
What cities in California are hiring for Startup Backend Engineer jobs? Cities in California with the most Startup Backend Engineer job openings:
Infographic showing various Startup Backend Engineer job openings in California as of August 2026, with employment types broken down into 81% Full Time, 13% Part Time, 2% Temporary, and 4% Contract. Highlights an 87% Physical, 4% Hybrid, and 9% Remote job distribution.

Backend Engineer

ProNexus

San Francisco, CA • On-site

Full-time

Re-posted 17 days ago


Job description

We are hiring on behalf of a venture-backed AI startup building intelligent software that automates complex business workflows.

The platform uses large language models, proprietary data, and human-in-the-loop systems to complete work that previously required significant manual effort. Its backend systems power AI agents, customer integrations, data processing, evaluation infrastructure, and production workflows.

The company is hiring a Backend Engineer to build the reliable systems behind its AI products.

About the role

As a Backend Engineer, you will design and build the services, APIs, data models, and infrastructure that power the company’s product.

You will work primarily in Python and PostgreSQL while collaborating closely with product engineers, AI engineers, customers, and company leadership.

This is not a narrow API-development role. You will work on production architecture, data systems, model integrations, security, reliability, and product capabilities.

What you’ll do
  • Design, build, and maintain production backend services using Python
  • Develop APIs that support customer-facing applications and AI workflows
  • Design scalable relational data models using PostgreSQL
  • Build integrations with model providers, customer systems, and third-party platforms
  • Develop systems for asynchronous jobs, event processing, and long-running AI workflows
  • Deploy and operate services using AWS
  • Debug production issues across application, data, model, and infrastructure layers
  • Help shape backend architecture and engineering practices as the company grows
What we’re looking for
  • Approximately 2–9 years of professional software engineering experience
  • Strong professional experience with Python
  • Experience designing and operating production APIs or backend services
  • Strong understanding of relational databases, SQL, and data modeling
  • Experience with PostgreSQL or a comparable production database
  • Familiarity with AWS, GCP, or another major cloud platform
  • Understanding of application security, authentication, and authorization
  • Experience debugging and operating systems in production
  • Ability to independently own technical projects from design through deployment
  • Comfort making pragmatic engineering decisions in an early-stage environment
  • Strong communication and cross-functional collaboration skills
Nice to have (not required)
  • Experience building AI, LLM, agent, or machine-learning infrastructure
  • Experience integrating OpenAI, Anthropic, or other model providers
  • Familiarity with LLM evaluation, retrieval, embeddings, or vector databases
  • Experience with Docker, Kubernetes, Terraform, or CI/CD systems
  • Experience with Redis, Kafka, queues, or event-driven architectures
  • Experience building multi-tenant SaaS products
  • Previous experience at an early-stage startup
  • Experience with data-intensive or distributed systems